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Posted by: trekkor Sep 14 2004, 06:12 PM

I'd like to start an open discussion on oil front mounted oil coolers and ducting.

I had a nice chit-chat with Brad today on the subject and I am convinced that I need to get one installed.

Planning to go BIG to be prepared for the SIX later in the year.

Any opinion on ducting from the fog/horn grilles and the round rubber front trunk body grommets?

Exit air into fender wells is what I think. You?
Andy and I tossed around the idea of getting the air out through the grill below the windshield. Might be tricky.

I'd like to use a piece of sheet metal to create an air space for the install and still have *some* trunk space available.

Pics would be nice.

KT

I did a search on this...I just want a fresh thread

Posted by: SirAndy Sep 14 2004, 06:44 PM

whatever gives you the least restriction. going through the fender wells means two 90 deg. angles on each side. air doesn't like that kind of thing.
it'll just pile up behind the oil-cooler, rendering it useless ....

only 2 (well, actually 3) options that will give you good results, IMHO ...

1. the factory GT shroud method. small angle, low resistance. good cooling. only drawback is adding more air under the car, which will give you more lift at very high speeds.

2. hang it under the bumper. the very early GT's had that, no cutting of the tub, just run a wide but slim cooler under the bumper, hot air will be directed under the car. very good air-flow. downside, you run the risk of ripping it off getting in/out the starbucks parking lot.

3. out the top. slightly more angle than 1. still very good airflow (add a lip in front of the hood cutout!). downside, highly visible and brad doesn't like the warm air coming over your windshield. (pussy!)


Andy

Posted by: brant Sep 14 2004, 06:59 PM

ohhh... I love this thread.
I've been there and tried a few things...

On my first race car, I ran 3 different set ups with the same cooler. I agree with Andy completely that its all about the exit. I finally went through the hood on my 3rd attempt and found another 20degrees each of the times I changed my exit.

since I don't have a camera or enough intelligence to post a picture, Andy can you post my front hood picture for me?

regarding fog light grills.... It is possible, but I don't know if you want to go there..... I have this set up right now on my race car, but since the car has still not had its maiden voyage I can't guarantee you that it works.

I first saw this set up from a friend of mine named tom hayes. He ran a pair of mocal coolers behind the fog lights with round PVC tubing behind the bumpers to force the air into the coolers.... Didn't work too well and he ended up ditching it for a race cooler in the spoiler (PCA-GT 5 car).

I realized that his exit was (IMHO) what was not working for him. In my new car I've run a pair of fluidyne double pass coolers in series. I talked with the engineers at fluidyne at length while planning my new set up. This car has no headlights so the air enters through the fog light grills and into an aluminum custom fit Square tunnel (approximately 6inches wide and 12inches tall.. Air goes through the coolers and still remains airtight inside of the tunnel on exit and then finally into the fender wells... The coolers are sealed inside of this tunnel, which I think is absolutely key. Its a straight shot with no bends... TONS of fabrication time into the tunnel... Double the fittings since I'm running 2 coolers in series, and pricey...

I wanted my fuel cell down lower than the stock location and was not allowed to go the hood route with the new car due to "Vintage Rules" in the new class I'm going into...

I strongly recommend you stick with what is tried and true. A good cooler set up will run a grand with lines and all.

brant

Posted by: spare time toys Sep 14 2004, 07:00 PM

Geeze I dont have a windshield wonder how that would make him feel

Posted by: trekkor Sep 14 2004, 07:16 PM

Here's what we're working with.
Use you favorite photo software to edit up your proposals.

Keep the comments about the dirty trunk to a minimum, thanks

KT


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Posted by: trekkor Sep 14 2004, 07:36 PM

I used a crayon to draw this

the ducting would be the same hieght as the spare tire arch with a rubber gasket on top so when the sheet metal is set over the top and into the space it is air tight.

Think rat running through maze. <_<

The flow of the air is large and unrestricted.
It " Y's " left or right straight out the wells.

storage on top.

KT


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Posted by: ArtechnikA Sep 14 2004, 07:36 PM

two coolers in series ? conventional wisdom says run them in parallel for a lot of good reasons. but if it works for you go for it...

back to Trekkor...

GT shroud, duct it out the bottom, be done with it. clean, safe, simple, works. the factory cars didn't lift at Le Mans, they didn't lift at the Nurburgring, and if you've got straights as long as Mulsanne i don't know where, now that the Riverside CanAm course is a shopping center ...

in front of the windscreen is a HIGH pressure area - might be good for a cooler INLET (have a look at have every NASCAR car uses cowl induction) but you'll never get air to exhaust there.

you might be able to duct it to the fender wells IF you add some exhaust vents to the bodywork. this isn't legal (unless stock) in even SCCA SOLO-II Prepared Class and will move you to Modified if your competitors have read the rulebook carefully.

GT shroud, duct it out the bottom, be done with it.

Posted by: SirAndy Sep 14 2004, 07:39 PM

how about the maestro himself? that'll keep things cool ...

Andy


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Posted by: trekkor Sep 14 2004, 07:48 PM

That's one of the funniest things I've ever seen...and it might work!

KT

Posted by: Randal Sep 14 2004, 08:23 PM

White wine and pumpkin pie; is that a Texas dinner?

Posted by: McMark Sep 14 2004, 08:36 PM

Trekkor, you need to stop by tomorrow or saturday. I know you like crazy ideas and I have a few.

Posted by: SpecialK Sep 14 2004, 09:22 PM

Granted, all of my experience with heat exchangers (or an oil cooler in this case) is military aircraft related, but they're all run in series (primary and secondary HE's). Just curious what the "conventional wisdom" and "good reasons" are for running them in parallel? Resistance/back pressure?

Posted by: ChrisReale Sep 14 2004, 09:26 PM

Word. Do it once this way and move on to other projects

Posted by: synthesisdv Sep 14 2004, 09:36 PM

I considered ducting air thru the fog light grille exiting the headlight cover. There is alot of plumbing involved with this arrangement. With a wet sump TIV, not sure it would be a good situation.

A six with dry sump and good scavenge arrangement could make this work, but the coolers are in a very vulnerable location.

Also, while you could make this work within production car rules, it would not fly in most vintage classes, at least down here.

dr


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Posted by: synthesisdv Sep 14 2004, 09:43 PM

So I'm going with dual coolers at the rear. I know of another 914 racecar that runs a similar arrangement with excellent results.

This is probably not good for a street car, won't cool unless the car is moving.

The coolers are actually mounted now, will post pictures later.

dr


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Posted by: SirAndy Sep 14 2004, 10:07 PM

actually, i think that was beer in a wine-glass. x-mas dinner party at my place lascht year ...

Posted by: Steve Sep 14 2004, 10:38 PM

I'm sorry but I always go factory whenever I can.
You can get the GT shroud and internal air baffle from Getty Design.
The GT option has kept my previous 2.7 motor very cool and my current 3.2 motor barely gets to 190degrees on the freeway.

Check out Jon Lowes GT page
http://fly.hiwaay.net/~jonlowe/MyGT.html
This page shows the cutouts.
http://fly.hiwaay.net/~jonlowe/MyGT0005.html

The GT won Lemans and many other races with this arrangement.

Posted by: J P Stein Sep 15 2004, 02:14 AM

I hab no thoughts....I gots a pic, tho.

You can see that I punched some holes in the bulkhead to vent the thing and was prepared to punch more if needed. They aren't. Maybe I found a low pressure area.

At any rate, the oil temps never go over 100 C....hot day, 2 driver AX. A mild temp track day....90C all day.

The feed line to the cooler is hot (no touchy hot) and the drain line is warm (grab aholt).....what more does one need?

Built a cover to go over the whole wurks...see next pic ....so's I can haul shittage in the front trunk....duh...piece of cake.


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Posted by: J P Stein Sep 15 2004, 02:17 AM

the quick brown fox........


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Posted by: thesey914 Sep 15 2004, 03:59 AM

VERY neat JP

Posted by: ArtechnikA Sep 15 2004, 05:03 AM

mostly, it has to do with the nonlinear efficiency of a heat exchanger and the temperature differentials.

if a heat exchanger can reduce the temperature of 250F oil to 200F, you've rejected 50F to the airstream. that same exchanger is not going to reduce the temperature of 200F oil to 150F. the greater the temperature differential between the oil and the heat sink (the freestream air) the more efficient it is going to be.

so for most efficiency, you want the oil entering the heat exchanger to be as hot as possible to avoid getting into diminishing returns.

as you've observed, there are places and applications where serial coolers make sense.

Posted by: trekkor Sep 15 2004, 07:41 AM

Nice cooler set-up JP.

Posted by: brant Sep 15 2004, 08:38 AM

Rich,

my ignorance shines through...
I should have clarified that my new set up is in parallel (sp)

and not in series...
(however I am using double pass coolers so actually the coolers are in series, but they have a built in parallel component also)

Andy, do you still have those pictures of my front hood and ducting on the black car?

brant

Posted by: synthesisdv Sep 15 2004, 08:47 AM

Can someone diagram or describe a parallel arrangement?

Do you need coolers with multiple ports like the ones fluidyne makes? If not, I imagine a couple T's in the lines.

dr

Posted by: Cloudbuster Sep 15 2004, 08:54 AM

JP,

I like that set-up. That kink in the tub where the steering rack is looks like a good low pressure area.

You do you leave the steering rack cover / skid plate off?

Posted by: maf914 Sep 15 2004, 09:00 AM

Series versus parallel?

Series is when all of the oil flows first through cooler #1 and then through cooler #2.

Parallel is when the oil flow is split with a part of it flowing through cooler #1 and the remainder flowing through cooler #2.

Posted by: ArtechnikA Sep 15 2004, 09:20 AM

yes, inline Tees.

less overall pressure loss too, even without considering the scenario where one cooler gets plugged with something.

since the flow is split, you might be able to take advantage of a reducing Tee and run smaller, cheaper, lighter lines to the separate coolers -- but i'd probably keep it all the same.

if you were determined to run two coolers in a /6, a second or replacement cooler in the pressure circuit can pay off -- the pressure-side oil has been de-aerated and pressure-side coolers are much more efficient. scavenge oil is more like foam, yet another reason the fittings must be on the top...

Posted by: J P Stein Sep 15 2004, 10:35 AM

The cover is on.

The holes are 3 inch diameter. That would seem to be an inadaquate amount of venting area, but it works.

Maybe the front valence helps build air pressure at the cooler.


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Posted by: p914 Sep 15 2004, 11:57 AM

JP,
How much did that cooler setup end up costing?

Posted by: J P Stein Sep 15 2004, 12:21 PM

IIRC

The cooler .....direct from Fulidyne... 300
Troutman thermo ....165....got a deal on that. They're around 200-210.
Fittings & hoses.....about 280 (IIRC)....ya need lots of bent fittings and them suckers aren't cheep...damnit....Summit Racin'.

I've got some -12 hose & straight fittings left over....or was that plan B? .....Anyhew, the stuff is F/S cheep.


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Posted by: SpecialK Sep 15 2004, 12:36 PM

As you stated, heat exchanger efficiency/transfer is non-linear. Let's assume that the maximum heat transfer one HE can achieve will drop the oil temp 50F. So using your example of a heat exchanger lowering the temp. of the oil from 250F to 200F, a parallel HE system would still have a total outlet temp of 200F (50F differential). So if there's an efficiency drop in the secondary HE of a series system (say 50% for the sake of argument) which only allows for a 25F differential over the inlet/outlet temp (200F to 175F), you would still have a total of a 75F differential from a series system VS a 50F differential from a parallel system. So wouldn't "diminished returns" on a series setup be better than "no returns" (in the form of added heat loss) on a parallel setup? NO disrespect intended with my question, just trying to get the facts straight prior to running all of my oil lines (dual cooler).

Kevin

Posted by: ArtechnikA Sep 15 2004, 12:55 PM

NOW i remember why i hate you

no matter what i do to the 911 this winter it's getting a front cooler, the big 911RS-sized FluiDyne one. naturally my '71E had no factory cooler and therefore no factory thermostat, so i'm gonna need to do -something- ... a quick search for Troutman thermostatsturned up nothing but people recommending them or bragging they were using them - no leads on suppliers. are these things even available any more ?

i'll use a factory thermostat console if i have to, the more i hear about the Mocal the less sure i am that's a viable alternative. (the factory thermostat console is expensive, but so's my engine ...)

Posted by: phantom914 Sep 15 2004, 01:00 PM

I think that in the parallel system, the temperature drop in each exchanger would be greater than it would be in the first exchanger of the series system since in the parallel system the fluid volume is split and would spend more time in each exchanger. But then again, this is all just theory (WAG).

How about you try it both ways and prove it one way or another with a real world experiment? Then we would know.


Andrew

Posted by: SpecialK Sep 15 2004, 02:27 PM

Good point Andrew....okay, same senerio but with equal flow/pressure through both types of systems.

Posted by: ArtechnikA Sep 15 2004, 02:38 PM

Carroll Smith (who had access to a lot of real-world data) covered this very succinctly in one of his books (the first, i believe, "Prepare To Win"). i don't recall all the details of the points, but give me a couple of hours and i'll be back home with access to all my reference materials. i'll post what Smith had to say on the subject, and then we can debate -that-

Posted by: SpecialK Sep 15 2004, 04:04 PM

Excellent! Should the data show a parallel system is more efficient at dissipating heat than the series system (which it obviously does or you wouldn't be posting) then I'll have to rethink my plumbing for my oil coolers and condenser coils. Now would be a good time find out if I'm F'n up by going with my original "series" setups!

Posted by: synthesisdv Sep 15 2004, 04:51 PM

I have all his books.

In "Tune to Win", Carroll says to plumb multiple coolers in parallel (pg 98)

Can someone diagram this parallel arrangement for me?? I am too dumb to figure it out.

dr

Posted by: TimT Sep 15 2004, 04:59 PM

Troutman still advertises the thermostat in Pano or Excellence

I believe this is http://germanpartsusa.com

I do have a factory thermostat though if your interested..

Posted by: ArtechnikA Sep 15 2004, 05:00 PM

hot oil from engine
cool oil to engine


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Posted by: ArtechnikA Sep 15 2004, 05:05 PM

that sure looks like Troutman's site - germanpartsusa.com - i'da never found that one by guessing !

interesting nomenclature on the thermostats tho, i suspect the website was built by someone who doesn't know Porsche oiling systems - lists 10mm, 12mm, and 30mm. that's gotta be AN-10, AN-12, and 30mm ...

Posted by: brant Sep 15 2004, 05:08 PM

Rich,

for the sake of it, since you obviously know how to use paint brush and I don't...

draw out the "series" diagram also please.
brant

Posted by: TimT Sep 15 2004, 05:19 PM

Perhaps... they have advertised the other (smaller sized) thermostats for years, perhaps for other applications..I think the print add reads 10an and 12 an

Posted by: ArtechnikA Sep 15 2004, 05:56 PM

hot from engine
connector line
cool oil to engine

sorry - there is no 'brown' textcolor...

note how ALL the oil goes through BOTH coolers.


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Posted by: brant Sep 15 2004, 06:11 PM

Ok...
not that it matters but I have to one final time correct myself....

I am running my coolers in series.


When I planned it out with the fluidyne engineer, they were very technical and were using not only PSI, but other info about my cooling needs....

They were very concerned about restrictions (for example you must use smooth 90's and not sharp 90's fittings)..

They wanted my total pumping lengths and factored in their cooler restrictions.

They were very concerned about the angle that I mounted the coolers and wanted them stood up straight with no lay back...

but they did not mention the series - parellel argument...

The reason I bring this up is do you fluid dynamics minded souls see a volume or pressure problem with the parallel design?

brant

Posted by: TimT Sep 15 2004, 06:40 PM

I do... You can plumb the coolers in parallel, and have only one cooler working.. Fluid will find the path of leat resistance...If one of the coolers has restrictions ( some gunk, a snot of teflon tape, trapped air) the fluid will flow to only one of the coolers.. You wont have and problems with pressure or flow, but you may only be using one of the two coolers you paid for.... a quick touch test will confirm this

Fluidyne coolers are the shizzle... the reason the want you to mount them straight up is again to not trap any air. if the cooler is layed over at an extreme angle, you may only get fluid flow through one or two of the passages..

Ill have to shoot some pics of the install on my 911... I have the cooler layed down at about a 45 deg angle, but it is don in such a fashion that there can be no trapped air..

Also ponder this... the front cooler in a 911 is plumbed in series ( stock from the factory)

Posted by: brant Sep 15 2004, 06:49 PM

Tim,

when I talked with the engineers they explained that they wanted the cooler stood up for maximum air flow reasons and not trapped air inside the cooler...

The guy had a percentage chart and told me that If I bought the larger cooler I was looking at and then laid it back at such and such angle, it would be less efficient than the smaller cooler I did buy and stood straight up.

Maybe its all bunk.. but they were insistent that there would be more restriction and less air flow if I laid it back.....

dunno, but I can say I was totally blown away from spending 45minutes on the phone with the guy and having him go over my whole oiling plans..

I may be way over cooled, but we choose to run 2 (a pair in series) of model # DB- 30617 coolers. They were also able to custom make them with the AN fittings on them instead of the NPT fittings (saves weight don't ya know, to not have an extra adapter in there)

brant

Posted by: ArtechnikA Sep 15 2004, 06:59 PM

that's true, but your engine won't die because a single-point failure shut off all the flow.

fundamentally, you want coolers normal (perpendicular) to the airstream, especially if there are fins involved. fins (vanes) are just like shutters, and if you can't see through the cooler, the air will have a hard time getting through. the entrained air issue is also significant.

you're gonna hafta s'plain your last point, unless you're talking about coolers on 3,4's and up. on all 911's with engine-mounted coolers, the engine cooler is plumbed into the pressure circuit, and the front cooler is plumbed into the scavenge circuit. they're actually completely separate, neither parallel nor serial - each cooler has its own separate pump ...

3,4's and newer that have no engine-mounted cooler - typically have only one cooler...

(and i agree with the FluiDyne... i'll be running one big RS-sized one behind my RS bumper...)

Posted by: trekkor Sep 15 2004, 07:01 PM

Here's a little something to get the juices flowing!

Discussed this with a club member today.
Bear with me on this one.

Put the cooler in the space between the fuel tank and the windshield , right under the fresh air intake grill.


Now, dig this...Use the existing air tubes to route the air out the back of the car where the hot air would normally come from the heat exchangers to the front of the car.

With careful planning, you can use this set-up as an alternate cabin heater by shifting the levers on the dash.

Another concept would involve using brass or copper pipe as oil lines to the front of the car in the rocker space.

Flexible hoses would thread onto each end. Using metal pipe would allow heat to escape freely the entire trip.

KT

Posted by: TimT Sep 15 2004, 07:02 PM

that all depends on how you get air to the cooler..you want the cooling air to enter the cooler dead on..if the cooler is at an angle to the airflow, it basically makes a high pressure area just before the cooler...ie less air passes through the cooler..

I will of course defer to the fluidyne techs.... they make a great product, and lots of big bucks race teams use fluidyne coolers...

also having the extra oil coolers gives the benefit of more oil capacity, which is a good thing

Posted by: SpecialK Sep 15 2004, 07:18 PM

Okay, now I'm getting confused

If the only reason for running parallel HEs VS series HE's is restriction/back pressure, then crunch some numbers to figure out what line sizes to use to achieve the desired outlet pressure/volume. I still haven't seen anything to show me (pressure, volume, and airflow/temp across the HEs being equal) how a parallel system could be more efficient than a series system.

Sorry, it's a "Missouri" thang.

Posted by: ArtechnikA Sep 15 2004, 07:20 PM

OK - if you guys -really- care about this stuff, go get "Tune To Win" and read Chapter 9. the edition i have is a bit dated and technology marches on - FluiDyne is now the Hot Setup for coolers. technology changes, but heat and air work pretty much the same way they did 30 years ago...

he actually doesn't elaborate much on the parallel setup, he just says do it - for efficiency.

since we're looking at total heat rejection, Delta-T is significant. assuming we're dealing with multiple coolers rather than one big one for packaging purposes, for a given Delta-T, two coolers in parallel will be smaller and lighter than if they're plumbed in series. put it another way - they'll reject more heat and "cool better".

that's my story and i'm sticking with it.

i wouldn't mind participating in a controlled test, but it has been done before...

now - that said, i will be plumbing the supplemental automatic transmission cooler in the Subaru (light-duty tow car) in series with the existing cooler. here's why: i will be adding a freestream air/oil heat exchanger upstream of the factory cooler that is actually part of the water radiator. by cooling the transmission oil when it is at its very hottest with air, i will be removing some of the heat rejection load from the engine's air/water heat exchanger ("radiator") under the conditions that it is also working at its hardest. in cold temperatures, if the trans fluid is cooled below its optimum by the airstream (which i will be able to block off), its trip through the engine radiator should actually warm it up a bit, since it is downstream.

Posted by: TimT Sep 15 2004, 07:21 PM

never said the engine would fail, just observed that by plumbing parallel you may not see the benefit of the plumbina second cooler this way....also trapped air can shut off some/part/much/all of an oil cooler benefit...



oops point taken...... I was considering them as a system the oil goes out iof the pump...to cooler #1 then to filter etc... to the front cooler....

Posted by: ArtechnikA Sep 15 2004, 07:27 PM

okay - imagine you have two identical, very efficient coolers. you have 250F oil and 100F freestream air.

since the coolers are very efficient, the first cooler reduces the temperature of the oil from 250 to 101. AT BEST the second cooler can cool the oil only one more degree. you have twice the cost, twice the weight, and yet you cooled the oil only one more degree. that's not efficient.

for the same Delta-T, you will be able to use smaller coolers in parallel.
or - two coolers in parallel will reject MORE HEAT than the same two coolers in series.

(serial coolers may eventually result in lower temperatures, but it is not efficient to do so.)

Posted by: TimT Sep 15 2004, 07:32 PM

My copy of "Tune to Win" disintegrated years ago

Actually there is a GT3RSR at my friends shop now, ill have to take peek how the radiators are plumbed

Posted by: theol00 Sep 15 2004, 07:34 PM

Hi Trekkor - is your engine an "S" spec engine - if not you might get away without an oilcooler - I run a 2.2 ltr "e" spec without any additional oilcooler - and even on the track going fast the temperature remains perfectly fine - I was told by a very reliable source - my trusted Porsche Factory Race Engineer and Engine Builder - that unless you run an very hot "S" spec you don't have to go without all that plumming - that is good enough for me - I like to keep it simple -

Posted by: trekkor Sep 15 2004, 11:01 PM

Nobody's biting at the oil cooler/heater, eh?

I will look at this a little closer later.

Good posts thus far, thanks for that.

Still have a few more a/x's and may have a DE in Nov before I tear it all down.

KT

Posted by: SpecialK Sep 16 2004, 12:25 AM

Actually did that with a '70 Baja Bug I owned 20 years ago in Colorado. I had two remote oil coolers, one mounted on the rear fiberglass, and one mounted in a box I made out of sheetmetal (HVAC stuff), an old blower motor out of the junk yard, and a couple of valves to switch between the two depending on the weather. It did keep the back window clear in the winter, but not much more than that.

Should've mounted them in "parallel", might have been more effective

Posted by: redshift Sep 16 2004, 12:32 AM

At least we aren't stupid!

(well... Rich isn't stupid..)

Group Hug!


M

Posted by: ArtechnikA Sep 16 2004, 03:26 AM

for sure it had at least half a good idea - i have seen oil coolers mounted in the high-pressure area of the cowl where the ventilation plenum is, ducted through the structure and exhausting out the bottom of the car.

but i donno why you'd want a heater in an AX car, and most engines don't make enough oil temp in warmup and cruise to even open the thermostat, much less actually heat the car...

Posted by: trekkor Sep 16 2004, 08:20 AM

All those cones give me "the chills"!

Really, this car is mainly street. I drive it several times a week.

Heating me is really not important at all. I never use the heater now.
I'm just thinking of having heat available for a very cold day or for the wife

Since the headers will knock out the heat, it'd be nice to offer *something*.
I like the idea of running the hot air out the back through the longs.

If I truly wanted a functioning oil heater, the copper pipe idea might cool the oil too much? Can you cool it too much?

Ten feet of thick wall 3/4 inch pipe exposed to the air might exchange a lot of heat.

KT

Posted by: brant Sep 16 2004, 08:48 AM

Trekkor,

I personally know 2 people in colorado with a cooler mounted in that location.

One is a 1.7/4 race car.
the other a 3.0/6 street car.

both have had good results.
Its not the optimum place.
I re-did my cooler 3 times on one car just to get the optimum exit...

I highly suggest that you stick to what is proven.
straight frontal air flow will give you the most efficiency and Paying A LOT of attention to the exit is VERY important.

neither of the guys I know are using the exit for heat.
I think this is very problematic. Exit flow is one of the main keys to efficiency, and having the exit air go through flapper boxes and twist and turns seems to be a definite set up for failure...

I would seriously recommend you learn from my mistakes and not have to re-do the set up 3 times like I did

brant

Posted by: Brando Sep 16 2004, 09:58 AM

straight-shot, through the front/spare tire well and down is best (at an angle). lift factor wont come into account until you maybe break 150/160 mph...

Posted by: trekkor Sep 16 2004, 06:36 PM

Here's the Patrick louvered floor pan.

I know, doing it the way everyone does it is the way.

I just like to toss ideas at all of you.

One day I may come up with something good.

KT


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Posted by: East coaster Sep 17 2004, 09:06 AM

I like the idea of the louvered exit area, but it apears the exit area is far less than the entry area. It really should be at least a 3rd larger than the entry area unless your counting on fans to give you all the flow. 2X entry = exit is really the shiznit for flow.

Posted by: Joe Ricard Sep 17 2004, 09:37 AM

just sat here and read like all the comments. Hmm
So now here is my.914 cent worth. I notice that the car temp is cooler when Autocrossing than running down the freeway. Oil temp is higher head temp is lower.

I normally start car and and leave it running from when I pull onto grid till I complete all the runs.

On the freeway the car runs hotter head temps with higher oil pressure @75MPH 3400 RPM till the oil is warm. Once oil is really warm the oil pressure runs 40PSI and head temps drop 25 degrees or so.

BONE Stock 1.7L So I think to myself if I cool the oil will the car run hotter???
Been running 35 years like this maybe I should leave it alone. I do run Synthetic oil 20W-50.

Posted by: lagunero Sep 17 2004, 02:33 PM

I agree with Eastcoaster. Joe Ricard, that is very interesting. I hope some of the big dogs can answer your question.

Posted by: ArtechnikA Sep 17 2004, 02:46 PM

at what temperature does the cooling air thermostat open ?
does that only direct air away from the oil cooler, or does it affect headflow too ?

Posted by: synthesisdv Sep 17 2004, 02:54 PM

I remember Jake saying something about stock configurations and camshafts make these motors run much hotter than they need to. I think the OEM cams are crap.

So maybe a better combination (cam, heads, etc) would run cooler head and oil temps.

dr

Posted by: McMark Sep 17 2004, 04:18 PM

Correct, you could set your oil and head temps to almost any degrees if you knew enough about cam selection and didn't care about horsepower or fuel economy. My point is that head and oil temps are related to the overall cam/engine combination.

Posted by: synthesisdv Sep 17 2004, 04:55 PM

Right, but you can have good (low) head and oil temps and have great HP and torque. That is the goal in tuning a motor, efficiency.

dr

Posted by: Cloudbuster Sep 17 2004, 05:15 PM

Did some internet searching on radiator airflow design.

Here's a college student study to glean though
http://www.tfd.chalmers.se/~lelo/rvad/reports/rva2002_gr13_cooling-systems.pdf

The pic is from page 8. Don't know of diagram is to scale or correct. If so, the rad/cooler surface exceeds the inlet area. It is actually desirable to have a plenum-like situation that slows down the air in front of the rad/cooler. The outlet seems to be smaller than the inlet.

It is also interesting to see the optimum angle of incidence for a rad/cooler is best between 30-50 degrees.


Other info.
http://www.enjoythedrive.com/content/?id=8302


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Posted by: ArtechnikA Sep 17 2004, 05:24 PM

that's all covered in good detail in Tune To Win.
IMNSHO, anybody considering vehicle modification or race-prep should have all the Carroll Smith books.

Posted by: synthesisdv Sep 17 2004, 05:31 PM

I agree,

I have the complete library of smith books and many others but I mostly use them to put under my butt so I can see over the dash better.

dr

Posted by: Joe Ricard Sep 17 2004, 06:44 PM

Well pretty sure the air flaps are wide open within the 1st few minutes of running. I'm talking 15-20 minutes down the freeway at speed. Running around town I never see this phenomenon.

Been kicking around the idea of gettig a oil temp gauge. then I'll as dangerous as the rest of you guys. As hard as I run this car I am always amazed at robustness of the stock motor. I imagine I won't have this motor in the car after Christmas as the 44IDF 2056 I want to build should be ready.

Posted by: trekkor Sep 17 2004, 09:08 PM

Copper oil lines in the rockers.
I thought somebody would say something about that.

I will...If thin copper strips were soldered on as heat sinks/cooling fins. Even better.

How would you like to have a ten foot long oil cooler?

KT

Posted by: Aaron Cox Sep 17 2004, 09:14 PM

yeah, finned copper oil lines

Posted by: redshift Sep 17 2004, 09:23 PM

Aaron, why don't you just shut up?

<---it's my avatar


M

Posted by: redshift Sep 17 2004, 09:31 PM

Now I have to change my avatar, it's got crap on it.

Ok, I cleaned up my act, I got a job, and now I am selling AmWay.

Thanks Aaron.


M

Posted by: trekkor Sep 17 2004, 09:40 PM

I'm thinking out loud here.
If the lines are in there any way, why not make them work for you. Little air scoop and everything.


other question was, can you cool the oil too much?

KT

Posted by: Howard R Sep 18 2004, 01:53 AM

I have been working on the front cooler setup for the last few weeks while the engine is out being serviced and the clutch replaced. Cooler lays flat in the front boot floor with a fan on the top of it inside a carbon fibre box that I moulded up


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Posted by: Howard R Sep 18 2004, 01:55 AM

Added a factory thermostat while I was at it. The lines run through the sills on the left hand side.


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Posted by: Howard R Sep 18 2004, 02:00 AM

This is the new clutch. Modified in Brisbane by Jim Berry at RaceClutch. 2400 lbs of clamp with 5 button carbon metallic facings and solid centre.


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Posted by: Howard R Sep 18 2004, 02:10 AM

Another phot of the box up front.


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Posted by: Howard R Sep 18 2004, 02:15 AM

This is a bit OT but you don't see these very often. Repco Brabham V8 fitted to an Elfin sports car; kind of like a baby can am car. 3.5 litres and 380 hp. This was at the historics at Eastern Creek last week end.


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Posted by: SpecialK Sep 18 2004, 02:48 AM

Okay, I wasn't going to say anything about my plans for routing my oil coolers for fear of getting slammed by all of the fart smeller's....I mean....anyway, the guy's that now there "shizzle" when it comes to effective set ups on these cars, but here it goes. Please be warned I can tell you about it, but then I'll have to kill you


It all started with my air conditioner condenser coil location...hate the stock location and set up for numerous reasons, and hey, that's where I was planning on originally sticking my RX7 oil cooler anyway. So I decided to fab my own condenser coils out of three concentric spirals of soft copper (I do a lot of HVAC stuff), 4' long each, with varying tubing dia. to prevent/reduce any restrictions. There'll be one coil each mounted in CAT ducting in both rear fender wells, with an inlet in each rocker panel (was to be X1/9 side scoops, but that's still up in the air), and exhausting behind each rear wheel kind of 996 like.

"But what if you're not moving Kevin", already thought of that. I've got two 240 cfm 4" marine (read: cheap, water resistant) bilge blowers that'll mount in the inlet of the 4" CAT duct upstream of each coil, controlled by a sail-switch (HVAC item) mounted in the front bumper. I can adjust the spring tension of the sail-switch to "deactivate" the bilge blowers when I get to about 25 mph or so (they'd only run if I'm sitting in traffic, or barely moving...gotta keep Daddy cool in the summer out here). This got me to thinking of possibly doing the same thing in a smaller 3" diameter (still 3 concentric spiral tube) mounted in the front fenders for oil cooling .....

My '73 has the 916 front and rear bumpers which I really like the look of, but didn't particularly like the idea of cutting a big hole in my front trunk to accommodate an oil cooler (especially since it's the only car I have that has a solid front trunk). The "driving light" recesses in the bumper were not in a particularly good location for me to duct to my front fenders, so I'm going with cutting (neatly) the top and bottom out of the little wing thingys on each side leaving the leading edge of the wing/spoiler, and using a spare engine lid mesh for protection. I'll fab a FG insert to fit on the back side of the spoiler to duct the air to the outside where the 3" CAT duct and oil cooler(s) are located. The exhaust location I'm still over. I was originally going to bring the duct over the front wheel and down to louvers in the rocker panel, but that would trap the heat if I wasn't moving (no blowers up front with this plan....yet). The "plan 'B'" was to exit higher on the fender, kind of Z3ish, which would allow the heat to "draft" through the duct, just like a flue on a furnace, if I'm standing still (I know, not much...but better than nothing...3" bilge blowers? ). There are a hundred little details I'm omitting (like the oil cooler drain hidden behind the front license plate) to keep from boring you do death...if it's not too late already , but in a nut shell, that's it.

Blast away!

Posted by: ArtechnikA Sep 18 2004, 03:30 AM

few issues going on here ...

oil can be too cool, which is why you must have a good (factory or Troutman, same Behr element in a different container) thermostat if you have a cooler. so - supposedly - the oil will not be sent on its merry way through the plumbing if it's not already warm enough. aftermarket oil thermostats seem to be set right around 180F, which i think is too cold for this purpose; the factory T-stats seem to be set higher. i saw a couple of different numbers this week and i'm still trying to sort 'em out.

so the theory is that if the oil's cold, it won't be cooled. so you just barely hit 181, a big slug of oil is released to the cooler, where it (and all the already cold oil in the cooler and oil lines) has heat removed. it's no longer going to be 180F when it returns from that trip. so the thermostat closes again... clearly, if the oil's REALLY hot you're fine.

the first factory coolers (911) used tinned steel oil lines and a trombone at the front that basically just turned the flow around -- most of the cooling was in fact performed by the lines which-- on a 911 - are in the airstream all the time. put the lines in the rockers and now you have no free airstream cooling. Elephant has finned lines that the HiPo 911 guys like -- but if you put a finned line in a box it hasn't bought you anything. Scoops? get serious... they pick up debris, grit, and water, and add drag you don't need. anyway - a good exit for the airflow is probably as important as getting the air in...

copper (and aluminum, so don't go there...) will work-harden from the vibration and crack eventually. if you mount it in nice rubber Adell clampswill that occur in your lifetime? who knows... but the factory used steel and/or brass when they did metal lines...

so - in theory, yes, you can overcool the oil, but one of the reasons we like good oil is that it'll lubricate well even at suboptimal temperatures (although it won't be as efficient...) in practice, what it means is that you can spend too much time, money, effort, and weight making oil cool, and that's not efficient.

MHO is that plumbing should be reliable, and coolers should cool. looking for additional cooling capacity in the lines when you already may or may not need a cooler seems effort mis-spent. (Porsche did it because they were trying to avoid the cost of actual radiator oil coolers...) lines run through the rockers will be reliable, but i wouldn't count on them to be a significant part of your heat rejection package.

i don't think i'd have much heartburn with straight runs of rigid wall copper in grommets and Adell clamps run through the rockers. (yes, this means i am mellowing on this issue...) but you also have the issues of attaching flex lines to the rigid pipes, and there are issues there. solvable issues, but stuff you've gotta deal with.

Posted by: maf914 Sep 18 2004, 06:42 AM

Are typical oil thermostats modulating or on-off. In other words, when the oil reaches the set point does the thermostat open slightly and continue to open as temperature rises or does it open completely? I assume they are on-off.

This makes me wonder how often they cycle. I know this would be based on the combination of cooler and line sizes, but I can't quite visualize how this all works together. It seems that an oversized cooling system will cycle excessively and an undersized system will remain open continuously. How do you size the system properly? Lots of variables.

Posted by: maf914 Sep 18 2004, 07:02 AM

Howard,

Is that the same engine that Jack Brabham and Denny Hulme used in the middle 60's to win the championship? Wasn't it a DOHC V8 built on the Oldsmobile aluminum block? If I recall correctly it was the first year for 3-liter F1 engines and Repco-Brabham built this because there were no established customer engines available yet.

BTW, your oil cooler installation is very neat. Any problems bleeding air from the system with that horizontal coil placement?

Posted by: ArtechnikA Sep 18 2004, 09:47 AM

you spend some time looking at the heat rejection rates published for the coolers you intend to use, and how guess how much more you'll need than you've got. you discount the cooling effects of the lines - anything you get there is bonus.

then, you discover the benefit of testing.

if the car hits the red before the end of the session, you do not have enough. if you don't have a bigger cooler on the truck, you either decide to risk the engine and race anyway or you decide to pack up and go home. if the engine won't reach operating temperature within a few laps, you have too much. this is usually easier to correct at the track with a few strips of tape.

this is but one reason racer's tape comes in so many colors ...

Posted by: trekkor Sep 18 2004, 11:26 AM

Now we are having that open discussion!
Remember...A bunch of guys in the garage, throwing ideas off each other.

Thanks for the input!

With the copper, I'm not worried at all about cracking.
You'de have fold it back and forth over your knee to break it.

Why I know this? I have folded it over my knee and I have two copper coolers on my boat.
One is 1 1/2" pipe with a 1/2 " pipe inside. The oil flows through the 1/2" pipe while fresh water jackets the oil line as it flows to the raw water pump on the engine.
This set up is available in all the marine catalogs.
I made my own custom to fit my boat for $50 in copper schtuff. The pre-made ones are like $100 and about 16" long, mines six feet long.

Engine cooling? Yes, copper fresh water heat exchanger.
A large copper tank with a pipe splitting it internally down the middle. As hot coolant passes next to the cold sea water heat is exchanged through the copper wall.
Thus, my Corvette boat motor stays below 175 all day long. And no crud or squid or sea weed in my motor.

Copper is an excellant metal for heat transfer, one of the best, no one will dispute that.

KT

Posted by: J P Stein Sep 18 2004, 11:33 AM

The 9eleben engine thermostat ....which is also used in the Troutman unit... opens gradually starting at around 185 deg and fully opens at about 212. I've tested these in a pan of water on the stove.....the wife loved that
They cycle continuously in response to heat input.

These thermos also have a pressure bypass .....excessive back pressure is bled around the cooler to protect it.....that save my motor when I screwed the pooch plumbing the system....blew the cooler tho. Fluidyne replaced the ex cooler FOC......which gets them kudos from me. Good parts are a blessing to dumbshits like me

Posted by: StratPlayer Sep 18 2004, 11:40 AM

I have a front mouted oil cooler, hot air venter through fender well. I put a Mocal thermostat in mounted close to the engine. 180 degree thermostat. My cooler works just fine I don't think I would go without one now that I've had this installed. Going up steep mountains on a hot summer day and my temp stays put... I've had a front mounted cooler now for almost 4 years without any problems or leaks.

Posted by: Series9 Sep 18 2004, 02:02 PM

Here's a couple of pictures of my setup.


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Posted by: Series9 Sep 18 2004, 02:03 PM

more...


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Posted by: Howard R Sep 18 2004, 02:06 PM

Mike, very loosely based. The blocks were a different casting and the heads were sohc, but yes same type of engine. This one grew a bit. They also came in 2.5l for the Tasman Series if you can remember back that far.

haven't tried the cooler yet. Waiting on a guide tube for the gearbox which wont get here until Friday week after next. I expect that whatever is scavenged from the case will find its way through the cooler when the thermostat opens. It doesn't have any choice.

Posted by: Howard R Sep 18 2004, 02:13 PM

JP, my wife was not particularly happy with me washing IDA's in the dishwasher (without anything else in there) but she really went off a bit when I preheated a bunch of (clean) cylinder heads in oven of her new stove. So much easier to weld when they are hot.

Posted by: J P Stein Sep 18 2004, 03:06 PM

Whenever I carry car parts near the kitchen the wife says "Now wait a damn minute. Whadaya gonna do with that".

Gotta add a dishwasher & stove to the shop......or a cot & pillows

BTW, Nice set-up for the cooler.

Posted by: SpecialK Sep 18 2004, 03:49 PM

Got busted myself curing the cylinder coating in the oven , luckily she didn't catch them in her new dishwasher . She was supposed to be shopping with her sister all day but came home early (couldn't find a single piece of clothing in an entire mall that she liked )....definitely need my own dishwasher and oven installed in the garage to match the "beer only" refrigerator!

Posted by: SpecialK Sep 18 2004, 05:28 PM

Totally agree! If properly isolated there is no danger of work hardening. It's also very easy to bend into shape for routing, can handle any pressure a car can throw at it, and best of all it's cheap!

FYI: Soft copper used in HVAC applications uses different fittings than the kind you'd get at a hardware store. Soft copper sizes are measured by O.D., rigid copper (for household plumbing) is measured by I.D.. Another advantage of using refrigeration copper fittings is that you can get them in larger radius "sweep" elbows which will help reduce restrictions. It can be easily flared for use with fittings....and did I mention it's cheap!!


Kevin

Posted by: trekkor Sep 18 2004, 06:54 PM

Flared soft copper...nice.

I had thought to just sweat on threaded fittings for the braided lines to attach to.

Here's something new. Louvered rockers to get air in there for cooling the lines.

KT

Posted by: SpecialK Sep 18 2004, 07:41 PM

Everything you ever wanted to know about 'copper', but really couldn't have gave a shit less.

Do check out the "typical uses" section at the bottom of the site's page.


http://www.copper.org/resources/properties/db/CDAPropertiesResultServlet.jsp?alloy2=None&alloy3=None&alloy4=None&alloy5=None&alloy6=None&alloy=C10800&property=All&unit_type=Both

Posted by: ottox914 Sep 18 2004, 10:15 PM

couple weeks ago I started a thread "heating with headers" that covered the your thoughts of something up the existing heater spaces in the rockers. If I knew how to paste the link I would...

Posted by: SpecialK Sep 19 2004, 01:45 AM

Go to the thread you described, right click on the 'address' at the top of the page (browser), go back to this post, add reply, right click again and 'paste' the link. There's probably an easier way, but I'm a computer DA.

Posted by: synthesisdv Sep 19 2004, 05:58 AM

I came across this image a long time ago. Someone's GT project. Nice copper lines.

BTW, does anyone know where I can get tube clamps like these?

dr


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Posted by: SpecialK Sep 19 2004, 09:30 AM

Wow! That's clean looking!

I haven't seen clamps like that before, but you can accomplish the same thing (securing and spacing) using two of these clamps, and one common attach screw.

They're available at Aircraft Spruce for like $0.39 each.


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Posted by: street legal go-kart Sep 19 2004, 10:14 AM

First I am putting the cooler in the rear alongside the tranny.
Reasons are shorter hose length , less chance of damage and I need my trunk as the car is a driver.
Types of plumbing are all debateable but the old guy who helped us with various boats including a top fuel hydro and both the roundy round cars would never use hard lines unless they were steel. He also did not use solid wiring/single strand for the same reasons. One break and you are done. The chances of something severe happening are just too great. He also would frown on the use of steel braided covered hose in anything but a pure race rig as you cannot inspect the hose from time to time. The choice was always 300psi high temp Gates green stripe .

JT

Posted by: J P Stein Sep 19 2004, 01:12 PM

Funny thing about old guys......I know a shit load of em'.

Some have 30-40 years of experience.
Some have 1 year's experience 30-40 times.

The trick is tellin' which is which.

Posted by: McMark Sep 19 2004, 10:54 PM

Plus you get free ambient heat from the engine, exhaust, and tranny! Yippee! But seriously, you can get a little bit of cooling back there, but not a bunch. Even with an electric fan. If you need a lot of cooling, you might want to consider other options.

Posted by: ottox914 Sep 20 2004, 06:01 AM

here's the link to heating with headers (hopefully)

http://www.914world.com/bbs2/index.php?act=ST&f=2&t=16460&hl=heating+with+headers

how about using the factory a/c condenser in the front trunk location? it comes with a box, fan, air scoop, a path for air in and air out, all in one self contained box.... I tallked to a guy at a track day in TX who was using the factory a/c box w/holes cut in front, the front behind the bumper plugs out, no ducting between the 2, and one large radiator w/thermostatically controlled fan, oil thermostat from the engine to the cooler. He said that set up dropped his temps 50 degrees!

I do think for the best cooling, hard to beat the factory GT system, but thats based more on observation than experience. How about it? Use the A/C option for those of us who like the stock front end.

Posted by: Randal Sep 20 2004, 09:01 AM

This is beautiful work. How many cfm's is the fan?

Posted by: Series9 Sep 20 2004, 09:19 AM

I don't know about the fan volume, but then engine (3.6 with no on-engine cooler) doesn't run hot at all. The fan is a Spal(?), I think. I can check when I get home. My design is a little different, but I wanted the fan to not only pull air across the cooler, but also remove heat from the tank and filter. I has worked fine so far.

I'll be happy to post specific pictures and/or answer questions.

Joe

Posted by: Brad Roberts Sep 20 2004, 11:42 AM

I have spoken to Chuck Moreland more than once about doing the finned copper lines for a 914 (he sells them for early 911's..Elephant racing). If I can get more than 6 orders.. he will do them.

B

Posted by: d7n7master Sep 20 2004, 12:37 PM

At The Boeing Co. we call those "marriage clamps". We use them all over the place where you need to maintain separation between the tubes. Look in any MaMaster-Carr catalog.
G

Posted by: Dr Evil Sep 20 2004, 12:47 PM

"marriage clamps" = wedding rings, no?

Posted by: J P Stein Sep 20 2004, 01:08 PM

AUGGH.......another troll from the lazy B. This BBS....er ...forum is going down the tubes. Boeing of Poland is the bridge I live under.

Posted by: itsa914 Sep 20 2004, 02:22 PM

Ok I know NOTHING about any of this but..... I ran AX Saturday and there was a 74 -6 conversion owned by Richard Gonzales and he has his cooler mount along the passenger side long. Looked to be two finned cooling tubes with the outer rocker panel cut to fit exposing the fins. I asked him how well that worked and he said no problems around town and AXing. He did say that when he ran a DE event with the PCA guys the temps got hot. It was a 20 min session and he left the track after 15min. He did say it was 95+ outside that day. I asked why he did it this way instead of a front mounted cooler and he told me that he didn't want to lose the front trunk space.
Anyway it looked slick. Sorry, I didn't have my camera with me, I will next month.

- Garold

PS - he sells 914 parts, you can find him in the classified section in pano. Maybe he could email you some pics of his setup

Posted by: d7n7master Sep 21 2004, 07:46 PM

Hey, JP,
I'm at the McDonnell Douglas - Boeing in Long Beach, Ca.
We don't play troll games... We ROCK!!! Takes ten northern boyz to do my job & then they send it to "engineering-check".
Really liked your reference to "tubes" though.

Posted by: SpecialK Sep 21 2004, 09:25 PM

McDonnell Douglas/Boeing St. Louis....F-15K

Posted by: trekkor Sep 22 2004, 06:28 PM

Those copper tubes in the rockers were bold looking.
I thought I would be the inventer of the copper cooling tubes

Always, too late.

KT

Posted by: trekkor Dec 2 2004, 11:07 PM

Anything else you'd like to add, before I go with the 1/2" soft copper tubing with flared fittings?

KT

Posted by: 9146986 Dec 3 2004, 01:30 AM

I used a 25 row Mocal cooler and put it in the right rear wheelhouse, opposite side of the 914-6 oil tank, and it worked pretty well, and was fairly easy to plumb. The most difficult part was getting the right mounting location and reaching up into that slim area to bolt everything up. I had mounted a Spal fan directly to the cooler with a thermostat that didn't work right and burned the fan out after a while.

That was with a 3.0 with Webers, and it never ran hot, even on long trips in the summer. I never did any autox or DE stuff with that car though (unfortunately).

Posted by: ClayPerrine Dec 3 2004, 08:37 AM

A friend of mine here in the DFW area is a PCA club racer. He runs a 914 2.0, and he has a very nice oil cooler setup. He put a cooler at the rear next to the transmission, and ran it into the oil filter adapter. It's mounted vertically, with a duct on the front side of it that tapers it down to the size of the heater hose used on a 914 (the flexible orange stuff). He then took to shop vac ends with the wide nozzles, and replaced the flaps on the front of the engine compartment with them. They hang below the front edge of the engine compartment, and they force cold air into the cooler at the back of the motor. He runs 190 degree oil temp on a 100 degree day with track temps in the 140s. He does not use a fan on it either. The heating on the engine happens when the car is moving, not sitting still.

I have a full setup of what he runs that I will put on my car if the temps run too hot.

Posted by: dflesburg Dec 3 2004, 10:39 AM

Duh,