Mark came over and we did some testing with his hand held air speed guage.

Many readings were recorded.
Readings are based on a short pass up to 70mph.
Eventually all the front trunk rubber plugs were removed, large exit holes were drilled and a mock shroud was made.

Air speed right at front trunk hole was 56mph.

All holes open with the meter centered on the trunk floor- 17 mph

mock shround in place with meter over exit hole and gravel guard off- 20mph

With a proper shroud this should work quite well.

KT

holes are 4.5". The same as for the oil filter on the SIX oil tank through driver side inner fender/engine bay under the relay board. ( whew! )

heres a shot of how the cooler will look mounted.

KT

I can just picture Mark locked in the front trunk with his handheld meter while Trekkor's going down the freeway at 70mph.

why so far back? that is gonna be one huge ass shroud then?

why not all the way up front? and out the bottom? AND some trunk space....

Look, it's better to get all the air entering the trunk to pass through the cooler and let it bleed off all over hell & gone rather than the opposite.

To get all the air (plus the ram effect), you need a shroud between the front bulkhead & the cooler. That precludes using those little holes as they are too small & spread out. The holes in the rear (plus leakage) are, in my experience, enough venting.

I think JP and other sare right about the cooler location. It was at the front in all the race cars the factory built and that most all race shops build, mainly for the better air flow and heat control. One thing you have not measured I think is the low pressure under the front trunk area with the front spoiler in place which is probably 40% or so of the force getting the air through the cooler. Since the air is heated, remember it will expand and the vacuum under the car will help it get out, but the further back from the front bumper the exit is, the less the vacuum effect will be. I think Mueller had a thread about this a long time ago?

.914 cents here but I put my cooler uner passenger side the rocker panel. Oil is cooler than when i had a larger one over the trans. (bad idea)

Anyway got rid of the jack reciever and put some louvers in the rocker panel facing forward.

Does it work???? Well air temp today was 98 distance traveled 186 miles one way average speed 85-90. oil temp 225.

I'll probably move it to the front when I get a spare 1/2 a day.

Trekkor probably would have been fine with just mounting the cooler in the trunk and doing absolutely no ducting or air flow. His temps are already fine 90% of the time. I'm glad Trekkor was willing to think beyond conventional wisdom and try something new. We have a plan that should produce enough oil cooling for whatever six he may install at some point. With his design, he'll also be able to install a front trunk board and still have as much trunk space as a stock car with the spare in place. Works for me.

Cooler is now in the car with raw data for you to digest.

The a/x this weekend: I had the air dam over the front vent holes so it was whatever air got sucked out the bottom of the trunk.

never got over 210°.


KT

Just ran all around the Vineyard Lap®...With open ducting and no air dam.

it stayed super cool. maybe, too cool.

160-165°


KT

IMO there is very little air pressure on the face of the cooler located at the rear of the trunk. Once air enters your trunk space at the front it blows all over the trunk before it exits through the cooler.

Look at it this way. Your mother use to put the pie in the window where the air would pass over it as the air blew in. Not on the other side of the room where the door is and the air left the room.

Have you ever seen a race car with the cooler not mounted in the wind stream?

P

Put the air dam back over the holes and it went up to 180°ish.

Mind you, I'm not running at 5000-7000 rpm's for 20 minutes straight


Lastly, I cut matched holes into the air dam.
these can be blocked with tape or the stock rubber grommets to regulate oil temp due to outside air temp, etc.

I even cut holes for future brake ductwork.

KT

Trekkor,
That should really help your temps on the big tracks at higher sustained RPMs.
By the way, what cooler are you using and what size AN fittings?
What size dimensionally is the cooler?

Looks great. Some ducting, maybe just a sheet making a false flat floor to the trunk would be all you need.

No point in debating me...cooler is installed and the data is in.

FYI: I used to get up to 230-240 after the PM a/x runs.
I'd push higher during the fun runs.

Now I ran 210 with no duct work. Two one minute runs back to back, mostly full throttle.

I got close to 250 on the track last week after 15-17 minutes of hard driving ( no cooler ).

I have sneaky suspicion that I will have all the holes blocked except in *very* hot weather.

I'm not telling anybody how to do it. Just sharing what I have done.


Here's the oil lines. "Quick and offensive"


KT

2 q's -

how do the lines enter the cab from the rear...

and, have you shrouded it yet? just want to see some pics to motivate me to get off my ass...

thanks, Dan.

it's a Setrab cooler with -12 line and fittings.
Cooler is 23"l x 5"t x 2"d

Or in other words, really, really BIG.

Aaron, no shroud yet.

here's some more oil line pics, though.
comes in right next to the warm air tubes ( capped ).

KT

...Here it comes right through, below the backpad and along the passenger seat and floor.


KT

I will report back with oil temps after my D/E on Friday...



KT

Trekkor, is there an advantage to having the thermostat so close to the cooler, as opposed to closer to the engine? Longer travel for the oil?

QUOTE (lagunero @ Oct 2 2005, 08:44 PM)

Trekkor, is there an advantage to having the thermostat so close to the cooler, as opposed to closer to the engine? Longer travel for the oil?

i notice you left alot of slack up there......so you can move it to the stock GT style position

JK... looks good and is functional

I only put the thermo up there because the engine compartment was too crowded

Seriously, after the engine heats up, the oil's going up there anyway.

I don't know that it actually makes any difference.


KT

QUOTE (trekkor @ Oct 2 2005, 08:51 PM)

I don't know that it actually makes any difference.

think of it this way ...

with the thermostat all the way up front, the engine has to heat up all the oil in your lines first first before the thermostat will open.

two possible problems:

1. if your thermostat does have a bypass, it's possible that your engine will take forever to get up to operating temps as it now has all that additional oil in your lines for cooling, even when the engine is still cold ...
that could spell death on your first run of the morning after you trailered the car to the track ...

2. if your thermostat does NOT have a bypass, it will take a long time for the engine to heat up the oil in your lines enough to finally open the thermostat which could potentially overheat your engine.

both scenarios are less than desirable ...

that's why most people recommend running the thermostat close to the engine ...
Andy

Porsche installed the thermostat on the engine for a reason. They later changed this on the 993's and everything after that, but it is still mounted VERY close to the engine.

My thought: Why run a second thermostat? I questioned him on this when he called me on Saturday.


B

The only disadvantage I can see is making the oil pump cold oil a lond way and Mocal *appears* to have small orifices in the bypass section.(edit) buts it's worser with none.

Both thermostats have bypasses, both open about the same temperature so the overheat issue is moot...lets face it, they wouldn't be oil theromstats if they couldn't bypass cold oil, eh?

QUOTE (trekkor @ Oct 2 2005, 03:54 PM)

I even cut holes for future brake ductwork. KT

is brake ducting really that necessary?

necessary to the point of me taking a hole saw to my front valence?

It only takes a few minutes to warm up and "cycle".

One thing to take note of: the engine and tank before the cooler had 9.5 quarts in the system. The line adds about 2 quarts and when the cooler kicks in, add about 1.5 more.

The thermostat allows the oil to circulate freely until it reaches 180° when the t-stat cycles and slowly diverts to the cooler.


KT

Cannot argue cold/warm oil with JP. He is the king of blowing up oil coolers with cold oil!!

Two thermostats: two chances at failure. I thought he should have left the MOCAL out. Personal opinion.


B

I guess I don't fully understand. If I eliminate the front t-stat, then the oil is going through the cooler 100% of the time. That would be ok, as my cooler is rated for 25 BAR operating pressure. The t-stat on the engine by-passes the stock cooler only. The oil goes up front and back to the tank, regardless.

Both t-stats will open around the same time.

I trust MoCal.

The beauty of hydraulic pressure is, it doesn't care how long a line is. Pressure is pressure


KT

QUOTE (shaggy @ Oct 2 2005, 09:27 PM)

QUOTE (trekkor @ Oct 2 2005, 03:54 PM) I even cut holes for future brake ductwork. KT is brake ducting really that necessary? necessary to the point of me taking a hole saw to my front valence?

is yours a street car??

if so, no need to cut anything....Trekkor is heavy into auto-x and soon to be hitting the big tracks more often....

remember, the car is 30 years old, there are thousands of them bone stock or near stock with just a few upgrades here and there...save your money and don't do anything "just to do it" unless you know why you need it...just cause someone is doing it or running a particular setup does not mean it'll suit you and your driving needs...

QUOTE

is brake ducting really that necessary? necessary to the point of me taking a hole saw to my front valence?

For high speed track driving with repeated hard braking for 20-30 minutes straight, you betcha.

I only cut the holes in the Sweeper Dam.

Street L.E. dam will remain unmolested


KT

Trek's cooler placement may be unconventional, but I don't think its so bad as some have suggested. Like John said, airflows from high to low pressure areas. The arrangement shown will pressurize the trunk to some degree and the air will flow through the cooler to the openings behind it if they are in a lower pressure area. Modern race cars use ducted feeds to coolers all of the time, but with smoother ducts than the front trunk represents. And this arrangement may help the hot air expansion factor as the hot air leaving the cooler can expand almost iimmediately after passing through the openings and under the car. This arrangement might work better with a rectangular opening in the front and a full size duct from it to the cooler to direct all of the air to the cooler with less drag loss.

QUOTE (trekkor @ Oct 2 2005, 08:51 PM)

The beauty of hydraulic pressure is, it doesn't care how long a line is. Pressure is pressure KT

I am stunned into slack jawed silence.

QUOTE (J P Stein @ Oct 3 2005, 05:20 PM)

QUOTE (trekkor @ Oct 2 2005, 08:51 PM) The beauty of hydraulic pressure is, it doesn't care how long a line is. Pressure is pressure KT I am stunned into slack jawed silence.

so your saying there is NO pressure drop, not even minute at any rpm?

say you had 35 psi at idle.. now you might have 30.....



run 100' of line...see what your pressure looks like then

predicated on the ability of the oil pump to pressurize the increased volume possibly?

As long as there is oil supply coming from the oil tank, engine oil pressure should not be affected by line length.

At least this is my understanding...


KT

Let say you have two garden hoses:

Hose A is 1 foot long. Very little loss in pressure when the water is turned on.

Hose B is 100 feet long. Big loss of pressure.

There is friction in the hose that causes loss of pressure.

You need to think very basic sometimes.

Isn't this fun

In a closed system there is no drop in pressure after working presure is acheived.

If it is an open system...That's something altogether different.

If I burst a line, cooler or seal...Why am I still going on?


KT

But your working pressure in a closed system will be lower with long hoses.

QUOTE (trekkor @ Oct 3 2005, 04:26 PM)

Isn't this fun In a closed system there is no drop in pressure after working presure is acheived. If it is an open system...That's something altogether different. If I burst a line, cooler or seal...Why am I still going on? KT

Depends where you define your system.

But yeah, in any case there are pressure drops over line length. First, and easiest to visualize, is the friction loss from the walls of the lines. Secondly, and probably more important, is the turbulance and direction change within the line. Lastly (what I can think of right now) is elevation change. I dont know how your lines are routed, but if your lines are routed "uphill" both ways, you'll be loosing pressure also through gravity.

I guess the cool deal is that the engine pressure will be the same because it is controlled by a different pump.

BTW...My lines are shorter overall, due to the fact that the cooler is closer to the engine.


KT

QUOTE (trekkor @ Oct 5 2005, 06:12 PM)

BTW...My lines are shorter overall, due to the fact that the cooler is closer to the engine.

so, what are the numbers? before/after?

common trekk, throw us a bone here ...
Andy

pressures or temps?

Temps: way, way, way, lower. I'll have a better idea on Friday morning after the first couple of sessions.

Pressures: don't know.
I just installed the pressure sender and have no basline for comparison

On the 911 combo guage with numbers:

It idles at 20 and gets close to 70-80 when revving...warm.

KT

QUOTE

I guess the cool deal is that the engine pressure will be the same because it is controlled by a different pump

yep 2 stage pump in a 911 -6 engine
scavenge side is doing the up front cooler work .

I put in two of the front tub grommets

Went for a nice little drive down to the gas station.

In dash gauge says 180°...Pyrometer says 190°-200° into the cooler and 180° coming out.

My thermometer out in the yard says it's currently 89°.

It's supposed to be in the 40's-50's in the morning climbing to high 80's in the afternoon at the track.


Seems like sucess.


KT

The results:

Ran five sessions at high rpm's and the motor finally saw 210° by the last session.

I'm always happy when something I set out to do works!

Hooray for me!


KT

I made a removeable shroud a couple of weeks ago...


KT

That looks pretty good Trek...what material did you use?

I did something similar with mine by utilizing the stock trunk board...sealed edges with rubber edging to seal periphery, and put in a couple of brackets to hold it down under +air pressure...
Seems to work well...tomorrow will be a good test.
Temps in the high 70s

See you tomorrow AM

It's fiberglass.

I made a form out of 3/4" rigid insulating foam.
Got the shape right then laminated three layers of cloth and resin.

Pulled the foam away, added dzus fasteners and spray paint.


KT