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.

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....

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.)

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

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 -

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

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

At least we aren't stupid!

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

Group Hug!


M

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...

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

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

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...

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

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.

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.

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

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 ?

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

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.

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

Did some internet searching on radiator airflow design.

Here's a college student study to glean though
http://www.tfd.chalmers.se/~lelo/rvad/repo...ing-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

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.

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

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.

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

yeah, finned copper oil lines

Aaron, why don't you just shut up?

<---it's my avatar


M

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

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

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

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

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.

Another phot of the box up front.

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.

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!

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.

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.

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?

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 ...

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

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

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.

Here's a couple of pictures of my setup.

more...

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.

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.

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.

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!

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

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