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-   -   dual oil cooler question (https://www.rx7club.com/race-car-tech-103/dual-oil-cooler-question-672533/)

Turbo23 07-19-07 05:02 PM

dual oil cooler question
 
This does not involve dual FC coolers. But for my FC this year, I want to setup with dual setrab coolers. Doing some reading, due to the FC's short long tube style cooler the oil flows faster causing a higher pressure drop, where as a tall cooler with shorter tubes, you see less of a pressure drop. The problem is, I run a stock FC oil pressure regulator. Im worried as to how much of a pressure drop id see doing this. I currently see 60psi, Im kind of thinking It wont see to much a difference since Im going with 7 1/2x14" coolers, in series. Im open to suggestions, I really dont want to have to pull the pan!

Turbo23 07-19-07 05:04 PM

just a note, Im not seeing high temps are the moment, as long as I have good airflow right now, my temps seem pretty normal, Im worried about when I hit the track. I basically want to have a setup where I dont have to worry about anything

John Magnuson 07-19-07 06:10 PM

Just make sure they are ducted well and you should be ok. I don't think the oil pressure should be a problem.

I'm currently working on installing dual Setrab coolers on my FD as we speak... they're a really good quality cooler...

jgrewe 07-19-07 07:37 PM

If you have temp problems after the install, or if you want to get the most out of both coolers, figure out how to run them in a parallel circuit. That way both coolers have a higher temp differential from the oil to the air.

On the track for any really hard driving you should go with a higher oil pressure anyway. The regulator has the final say on what pressure the system holds, the pressure drop through the coolers being lower than stock won't be a problem or even matter.

Turbo23 07-19-07 08:37 PM

i believe FD regulators are bypass around 100 psi anyways. I know I should go with a higher pressure unit for racing, but overall, should I worry since I am running the stock regulator

jgrewe 07-19-07 09:51 PM

I'd worry if your are spending a lot of time above 6K rpm. Then go with the FD reg or motorsport adjustable version.

RETed 07-19-07 10:42 PM

Problem with running dual oil coolers on an FC is that the front stock bumper is not ducted good enough to run such a set-up.

I'm assuming this is a turbo FC with an FMIC.
No sense having 3 heat exchangers fighting for the same bumper opening in the front.

You're right - push the FC on the track hard enough, and the oil temps do start to rise.
The stock oil cooler is not adequate.

Running the oil cooler in series (or parallel) will only be determined by the total pressure drop across the system.


-Ted

its66 07-20-07 01:11 PM

If you are going to try the twin cooler set up, and have a FMIC, see if you can mount one in each fenderwell. You could split the air coming through the brake duct opening, and send half to the cooler, and half to the brakes. Soem Porsches have coolers mounted in the same location. Then, your FMIC, and radiator get the same, cool air they are used to seeing. With any oil cooler set up, ducting and air flow is the key to make a good oil cooler actually work.

Turbo23 07-20-07 02:39 PM

I run a fmic, but it is placed back close to the radiator, and my front is cut and the stock cooler at the moment is placed out front of everything else, and is ducted http://i22.photobucket.com/albums/b3...C/100_3908.jpg
The 2 new coolers would be placed where the brake duct areas would be. Im really just trying to avoid pulling the pan, since it was such a pain. I guess once everything is installed this winter, I will just have to wait and see.

RETed 07-21-07 10:13 AM

Really not necessary to be splitting the airflow in the brake ducts...

The oil coolers should NOT see anything over 300F.
Your brakes can hit almost 1000F!
With the temperature differential, running the airflow through the oil coolers and then onto the brakes should be perfectly fine.


-Ted

Turbo23 07-21-07 07:18 PM

The coolers would be in the holes where I would run brake duct tubing. Ive seen alot of racers do this, aka speedsource rx8s. NOT close to the brakes, mounting isnt my problem, its figuring out oil pressure.

KNONFS 07-21-07 08:50 PM


Originally Posted by Turbo23 (Post 7161412)
The coolers would be in the holes where I would run brake duct tubing. Ive seen alot of racers do this, aka speedsource rx8s. NOT close to the brakes, mounting isnt my problem, its figuring out oil pressure.

Unless you are willing to cut "some" metal on the break duct area, you won't be able to fit a "regular auto style" oil cooler in there. I thought I could fit a 11X11X1.5 oil cooler on each side, unfortunately I wasn't able to ( I am not willing to cut any metal on my FC).

If my memory serves me right, you will be able to fit a 9X6 oil cooler on each side without cutting any metal. Here is the problem, you won't be able to find an oil cooler on that size, let alone two that matches the oil capacity\frontal area of two FC OEM coolers.

With that said, I did found a company that makes oil coolers for small airplanes, and they do have them on odd sizes, like a 9X6X3. There prices werent to off from a sestrab or mocal.

jgrewe 07-21-07 09:04 PM

Oil pressure won't change at the bearings with two coolers. The pressure is controlled by the regulator after the oil goes back into the engine after the coolers. Having a huge pressure drop through coolers can cost you HP but the pump is capable of producing a couple hundred PSI at the RPM's you will be running. The regulator is letting pressure go at pretty low RPM's, look at what RPM the pressure stops rising when you rev the engine. Above that point, its all regulator controlled.

Turbo23 07-22-07 04:45 PM

Cutting doesnt bother me, its just metal. The car wont see prolonged track events. Mostly time trials, and 20 min sessions here or there.


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