Auto trans oil cooler on the track blues....

[Tom Wells]

I'm using a C-6 auto trans on the track. As I learn to go faster, cooling the trans becomes a problem!

I have a 2000-2200 stall converter and have tried several aftermarket coolers without success. The present cooler is a B&M 70297 with a SPAL fan ($200++). At the track day last Saturday, the fan shroud melted stopping the fan. The trans temp shot up, then smoke.....

B&M was no help. They won't RMA just the fan, but need the whole cooler, meaning I need to buy another cooler anyway to use in the meantime, so no real help there.

The trans guy suggested I put the radiator cooler into the circuit after the add-on cooler. The guy at B&M says the radiator cooler should go before the add-on cooler, not after.

Here's the question: how can I cool this trans?

Tom

PS: When it is working it is an absolute joy to drive on the track: right=GO, left=STOP

[bobcowan]

Oil has an operating range. Too hot or too cold and things don't work the way they're supposed to.

For a year round daily driver, you would want the add on cooler before the radiator cooler. That will provide good stability of the temps even when it's really cold. It will shed most of it's heat before hitting the radiator, and the radiator will provide additional cooler or add some heat if needed.

For a summertime fair weather fun car, probably put the coooler after the radiator, so you can shed as much heat as possible.

[bobcowan]

Sorry, double post

[Gatorac]

You can get a replacement fan from http://www.the-fan-man.com/

[Burnd]

Tom:

Have you had the trans tricked, beefed or modified for track by someone other than a local Aamco repair service? I used to race with a C6 and they take a beating BUT not in stock condition. You need a RACING Trans Shop to do that for you if you are going to continue to race the car. [BTW:C6's eat up a ton of HP (55HP-60HP loss, contingent upon drive train; (reference data; TCI, Inc.; July 1991 Hot Rod Magazine)]. I am assuming that your definition of "track" is road racing and not drag racing? Consequently your heat issues are related solely to redundent stop/go and down shifting?? Those are questions. Frankly; if the trans hasn't been beefed for "race", you are probably going to burn it up anyway under continued track conditions. I have been to that movie too. FWIW: temps should be in the 180 to 220 degrees range.

Going on the assumption that you are road racing; a 2200 stall is not tight enough and you are constantly "slipping", which is generating major heat with "stop/go" not including any down shifting. A custom converter at about 1600/1800 would lock up quicker with less slippage and address that issue for you. On the other hand: "IF" you are Drag Racing then your stall is too tight for launching. That being said; if you're running a trans brake, then you are talking serious heat. With a trans brake locked; trans temperature rise between 50 and 75 degrees PER SECOND depending upon stall. PER SECOND!!!When the fluid regularily exceeds 300 degrees you can plan on reaching for your wallet at some point. I use some expensive voo doo, hokus pokus fluid in my trans that was developed for race and high heat conditions. The stuff doesn't break down under heat and is so good that we just filter and reuse it when we change trans filters. On another note: (The trans cooler goes in front of the RAD regardless of the configuration). I don't know why someone would tell you otherwise. You did not mention the CFM on the radiator fan nor did you mention if your engine typically runs hot. Is your radiator shrouded all the way around? Those issues may be a part of the equation. I am leading up to sumpin but i'll get to it later if it appears to be appropriate.

I am not sure I understand this right? I don't understand how you cooked a shroud? I can see cooking a few motors, but melting a shroud??? I don't get it. Was that from engine heat? I custom built an aluminum shroud but I can't imagine an engineered plastic shroud not being seriously heat tolerant. I need a little more information to offer more meaningful suggestions.

Bernie

[Tom Wells]

Bernie,

I seem to have omitted a few relevant facts, so here goes:

The trans was built by Carl Rossler, a real pro! Here: http://www.rosslertrans.com/ It's a full roller, full auto race trans - no trans brake. I just put it in drive and go. If it downshifts, it does it without any input from me.

The tracks are road race tracks ranging from ~1.6 miles at Gainesville to 3.7 miles at Sebring, where I have done numerous 1/2 hour sessions at full chat. The trans has exceeded my expectations to say the least, as it is still working fine after amazing abuse.

The engine has always run cool, no problems there.

The latest cooler to meet its maker is this one: http://www.bmracing.com/index.php?id...subcat=&pid=75 It is the model 70297 that has a 500cfm fan. The fuse blew and the fan shroud melted. The fan and shroud are labeled SPAL, made in Italia.

Both the B&M and the Derale tech folks told me to put the fluid through the radiator cooler first, then into the add-on cooler.

I put the add-on cooler behind the radiator about a foot because I couldn't find any space anywhere else to put it!

All experience welcomed.

Tom

[Tom Wells]

Jim,

Thanks! I'll contact them tomorrow.

Tom

[Tommy]

Tom -
I don't have any answers, but I do have a question that may be relevant. Which sequence of events do you think happened?
1) Fuse blows, fan stops, temperature of cooler increases, shroud melts, or
2) Cooler temperature increases, shroud melts and obstructs fan, fuse blows.
If it was the first sequence, the solution would seem to involve the electrical system. If it was the second sequence, it would be very useful to know the temperature of the fluid coming out of or going into the transmission. Perhaps, as was mentioned earlier, an aluminum shroud is the answer.

[Tom Wells]

Tommy,

ahhhhh....

I wish I knew whether the egg or the chicken...

Seriously, I don't know what went first. The fuse blew when I had a lesser cooler installed, but I failed to check the condition of the cooler fan. Wait a minute! I gave it to a guy with a Chevy! And he says it works fine.

Maybe you're onto something here. Maybe the fuse went first.

I'll do some detective work there - maybe I'll pull that wire and run a new one from the switch directly to the fan.

The cooler has a 160 degree thermostat built in. I'll try to make sure it doesn't have a short.

Thanks for the different perspective.

Tom

[Burnd]

[quote=Tom Wells]Bernie,

I seem to have omitted a few relevant facts, so here goes:

More than a "few" facts omitted Tommy. Looks to me like you're set up pretty well. I didn't realize it was an integreated cooling system. If a Pro Shop with proven credentials can't solve your dilemma, then I am not going to have the magic either. I inquired from my shop:

http://www.fbperformance.com/NewSite/Default.asp

And they thought that that the converter may be slipping to much and increasing the heat. Lower stall with a quicker lockup would address that issue. You never did say what the fluid temperature was in the trans.

Check your voltage @ the fan motor! I think you need to be getting close to 13 volts AT the fan motor. If you are not, then the Spall rpm's will be down and it will not cool worth a dam. Check with the manufacturer and find out how many volts you need to be getting "AT THE MOTOR". It took a lot of wasted time to figure that out on my setup. My second thought was whether you were recirculating hot air from the engine bay back through the trans cooler and not able to capture any cooling properties. I am struggling for a spot to put an oil cooler so i can appreciate your fight for room. Sorry; I don't have any other suggestions, but it's sumpin to chew on. Good luck with it.

Bernie

[Tommy]

Tom -
If the fan were still turning when the shroud melted, perhaps it would have left marks on the inside of the shroud, or be wedged into the shroud. If the fan stopped first, I'd think the inside of the shroud would have no fan marks.

[Tom Wells]

Tommy,

Good thought but I think we'd need CSI to establish the fan marks/no fan marks. The melting just seems too extensive

I ordered another fan yesterday from the "Fan Man" ( http://www.the-fan-man.com/index.html ) since B&M were no help, and plan to run a "clean" circuit for its 12V.

I also plan to run the radiator cooler, then the add-on cooler, then back to the trans.

Then it's off to the track to see if that works!

Tom

[Plums]

Originally Posted by Tom Wells

I put the add-on cooler behind the radiator about a foot because I couldn't find any space anywhere else to put it!

All experience welcomed.

Tom

The cooler should really be out the front in clean air. Whilst racing, the air coming through the radiator will be up over 70 deg. C. The poor little cooler is starting behind the 8 ball, (or radiator as it were)...

[Tom Wells]

Jim,

New fan arrived today. It's the correct one, too!

Thanks for the pointer to this supplier!

Tom