Bridge_FD3S

Hey all,
I know this has been done to death, but I would like to know what sort of cooling you guys use that are serious about racing. Be it curcuit work, or auto x as long as your car is under stress moreso than 1/4 mile, thats what Im interested in. Instead of it turning into a V-Mount, vs Front mount vs Stock mount, Id rather you just state what you use (Brand,type of coolers,bar and plate ect) and what sort of consistant stress your car is under. Basically Im setting my car up for trackwork/street. I would like my FD to be able to handle 1/2 hour of trackwork at a time, so please help me in the right direction. Would I get away with this using somthing like an Apexi front mount/radiator and Trust oil coolers?
Thanks in advance.

C. Ludwig

iTrader: (27)

On my ITS road racer I use two stock oil coolers. One is in the stock location and the other sits right below it. They are plumbed in parallel. Thermostats are removed and the bypass hole is blocked. Oil temps don't exceed 200*F. It will and should be said that proper ducting is all important. You need to get air on the coolers and the passage needs to be sealed tightly.

Can't comment on intercoolers.

Carl Byck

I use a 33x10x3 Spearco Bar and plate IC, and two stock TII oil coolers in series on my FC. Oil temps rarely excede 210* exiting the plate. This is with an output in the 350hp range, with an oil, and water cooled turbo. I have just switched to an oil cooled only turbo and my output will be up around 150rwhp, so we shall see. I wanted to get my wter temps down a little, and since the turbo sees relatively few miles as a dedicated track car, turbo longevity will not be an issue. If your system is properly balanced your oil, and water temps will be equal under max load. Carl

John Magnuson

I assume by your screen name that you have an FD, 3rd generation RX7.

The main concern with an FD is being able to lap for an extended period at a track without overheating.

First of all. I highly recommend not going with a front mount intercooler. You need every bit of air getting to your radiator possible in order to not overheat at a track day.

After much experimentation I found that the following combo of mods made my car stay cool for any length of track time:

1) Oversized Radiator (I used the Koyo)
2) Waterpump underdrive pulley. I know that slowing down your waterpump seems counter intuitive but if you run at high rpms for extended periods (like at the track) the waterpump spins too fast and will cause cavitation and you will overheat. This is a VERY important mod if you're going to track the car.
3) Dual Oil Coolers. I use the stock dual oil coolers from the R1 model. There are aftermarket options also.
4) Carefully duct the radiator. This means making sure that all the air that enters the nose of the car can't slip around the radiator and has to flow through it. I used some heavy duty foam and duct tape.
5) Larger Intercooler. I think this is the last thing you need to do. The stock intercooler will heat soak after just a couple of laps. I use the M2 Large Intercooler that is mounted like the stock intercooler. Like I said above don't use a front mount. It's very hard to get an FD to not overheat with a front mount intercooler in place.
6) Use a coolant mixture that is about 80% distiller water and 20% coolant.

If you're just going to autocross I think you should be ok with a stock car.

C. Ludwig

iTrader: (27)

Carl, what do you see for oil pressure with your coolers mounted in series? What regulator?

DamonB

I have always heard to mount multiple coolers in parallel?

rynberg

Damon, the stock FD setup is serial!

DamonB

I know, but I've always heard that parallel is more efficient. Cars with multiple radiators for instance are plumbed in parallel and I've always heard the same recommended for oil coolers.

C. Ludwig

iTrader: (27)

That's why I questioned Carl. Not so much from an efficiency stand point but I've always been told, by reputable shops, that there's a greater pressure drop with the coolers in series. Just wondering what the pressure drop would be. Plumbing in series would be easier and less expensive.

hondahater

iTrader: (2)

nm

Carl Byck

I'll have to get back to you guys, car is apart right now, and I cannot remember, but nothing out of the ordinary. I believe I am running the mazda comp regulator, I cannot remember. I must be getting senile I can say i have never had any issues with pressure, or temps. I am going to an oil cooled only turbo as my oil temps at light throttle are only ~150-160...

Gene

iTrader: (1)

My father and I were discussing the parallel vs serial oil cooler issue the other day. It's hard to say for sure without concrete numbers, but parallel should be best. You get less pressure drop, and should get better cooling. When the coolers are in series, one cooler is doing a lot more work than the other, because the oil is pretty cooled by the time it exits the first one, so the temperature gradient between the oil and the ambient air is much lower for the second cooler, so it doesn't cool as much. It's hard to say which is better without actually testing it with real numbers however.

speedturn

iTrader: (1)

I have re-plumbed the oiling system on my road racer several times over the years.

If you do plumb coolers in parallel, then you have to be sure the two coolers are exactly identical makes/models, with exactly identical flow characteristics.

If they are in parallel and are not identical coolers, then the oil wants to flow thru the one with less flow resistance. As the oil gets hotter, it gets thinner, so most of the oil will continue to flow thru the hot cooler, and next to no oil will flow thru the colder oil cooler. I learned this one the hard way.

I currently run two Mazda coolers in series, and both coolers still have their stock oil t-stats. This system is working well. I always warm up my engine before I hit the race track, and even though water temps are at 180 the oil will be cool until I run hard, with my foot in the throttle for a lap, before the oil temp will really come up to 180 deg F. Then, the oil temp will sit steady at 180 deg F for the rest of the long road race. Oil pressure stays good with no problems caused by the 2 coolers in series (oil pressure drop from air in the oil foaming above 9000 rpm is another story.)

As stated earlier by someone else, it is imperative that you have good air ducting in your cooling system. You must not give the air any other choice except to go to your oil coolers and your radiators. A good duct sealing the opening of the air dam and directing the air to the coolers is soooo important that it cannot be overstated.

Bridge_FD3S

Some great info guys.
I thought there would have been a lot more people replying to this thread with hands on experience. Seems there arnt a lot of people tracking their FDs.
Looks like a custom V mount may be the way to go.

cpa7man

iTrader: (2)

Hey speedturn, would you take some pics and post them of your intake duct and you dual coolers mounted in series. Unless it's a secret. I need an upgrade as well. I assume your running 2 stock oil coolers. Mazdamotorsports lists the RX-4 oil cooler as an alternative larger capacity cooler. I've been looking for a used one. But your setup looks like a good alternative. Thanks.

For the FD, I think most of the cars that have been converted into full time track cars use an aftermarket system. Look at this web site http://www.negative-camber.org/crispyrx7/cwrcoolers.htm I know there are other brands and if you search crispy and others have done upgrades similar to this. If I was building a 3rd gen race car the CW dual coolers or the Mazda comp unit would be a must.

edmcguirk

By the way, sealing the ductwork intake to the radiator is most important but getting the air out of the engine bay is also helpful.

Most of the air exits under the car so a good lip spoiler will help keep air from getting under the car and it will also increase air pressure in front of the lip as well.

ed

Bridge_FD3S

Well I have scored myself some racing Trust oil coolers, and have been told a front mount with a Trust radiator should be fine...
If you guys were to go front mount, whats a better option Bar and plate or tube and fin?

80-CU.IN.T

[QUOTE=speedturn]I have re-plumbed the oiling system on my road racer several times over the years.

If you do plumb coolers in parallel, then you have to be sure the two coolers are exactly identical makes/models, with exactly identical flow characteristics.

If they are in parallel and are not identical coolers, then the oil wants to flow thru the one with less flow resistance. As the oil gets hotter, it gets thinner, so most of the oil will continue to flow thru the hot cooler, and next to no oil will flow thru the colder oil cooler. I learned this one the hard way.


“100% CORRECT”

Properly plumbed no significant pressure loss will occur if plumbed in series. The same oil will also be exposed to more surface area for a longer time period. Thus more cooling given equal surface areas. Series / Parallel