Transmission Temp

What is the temp of your transmission at the end of a pass and where is you temp sending unit. I think mine is running hot.

 

I believe 175°F is maximum. Perhaps someone else can confirm or deny?

Are you running a cooler?

 

Ya the biggest B&M super cooler I could get with a 11'' fan

 

Far out! You shouldn't need anything like that! In my last car I didn't have a cooler, just looped the lines. It got hot, but not so that I couldn't put my hands on it.

Assuming you don't sit on the transbrake at stage RPM for too long, something else must be generating all that heat. How much clearance do you have in your clutch packs? Is the band adjusted correctly? What colour is the oil, and does it smell funny?

My sensor is located at the back of the pan near the bottom (under the solenoid), so it's always in oil.

Paul.

 

Temp

Our powerglide gets to 180* at the end of the track and we dont consider it to be to hot. We have approx 1400 hp in a 2000lb dragster running high sixs. We leave from idle. We have a good cooler on it and a 9 inch fan that runs as soon as we turn the car on. We have run it with no cooler when there was a leak but we struggled to keep the temp down later in the day- even when putting a large fan under the trans/converter for 3/4 hour between rounds. We run synthetic oil as the higher boiling point gives us some margin for when things arent perfect. The sensor is in the pan.

thjts - how fast was the car with no cooler?

 

Yes, I stand corrected, my car was not as heavy or as fast as yours (or ALKNOVA's I suspect), but I'm still surprised he needs a cooler and fan that big. If he's getting way more than 180° it makes me wonder if the trans is generating heat where it shouldn't be.

 

Trans temp!

Most of the racecars here in OZ that i've seen don't run a cooler whatsoever!
Some "Loop" a length of tube outside the box and then return it or have the trans modified internally and plug the cooler ports altogether! Having a cooler arrangement mounted outside the box is a disaster waiting to happen if you ask me!! I have a Powerglide behind a SBC with a H/H 14 at only 20 over and a 4800 RPM convertor, after a burnout (sometimes they're long!)stage and a pass the oil in the box was only around 165 degree! Not that hot at all i'd say. Years ago over here in OZ a guy by the name of BOB PRICE conducted a test to find out this exact question. He and another well known trans builder put an inline temp. gauge on a Glide with a 4200 RPM convertor.After a pass(mid 8's in a supergas car from memory)they towed back to the start line and hot lapped the car until the fluid was at a dangerous temp. The car made "THREE" passes back to back before this occured!Remember,this had no cooler at all! Besides,with a blown car of any configuration,by the time the Lash is done, the filter checked,possibly the pan off and the chutes repacked,surely the trans. would've cooled sufficiently anyways...... Just my thoughts Jason.

 

Temp

While we have never done nothing to keep the trans cool, Im pretty confident that if we did do nothing by the end of the day we would be cooking the trans After the morning warmup and 1st run the oil in the pan is about 140*. After the 2nd run 160*, 3rd 170, 4th 180 and we can normally hold it there for the 5th and occasionally 6th run. Jim

 

Trans temp!

Jim, i guess when the temp your talking about gets up that high,yeah! i'd be definately doing something about it.I guess everyone's trans and convertor differs as such and also the turnaround time has a lot to do with it as well.If we get five passes in one day here that's a lot as usually it might be a couple of hours between rounds!I used to have a temp. sender in the pan but after watching it never really climb over 160* i took it out altogether. Anyway, thanks for the insight!Jason.

 

Long winded speech..

Its my feeling that you are going to be hard pressed to remove enough heat from a drag racing transmission to make much difference during a run. A typical temp rise during a 6 second run in a 2000 lb car is around 60 degrees if you have 16 lbs of trans fluid thats 960 btu when you multiply that by 600 you get 576,000 btu per hour. Now when you figure the average high performance automotive radiator removes 200,000 btu per hour it becomes apparent that removing heat during a run is futile.

If you have trouble keeping the temp at an acceptable level you can remove some of the heat after the burnout with a large fan based cooler but it usually is not much, a better alternative is a thermal resevour type like the B&M where you have another gallon of fluid so you increase the heat capacity by around 30 %.

That said if you have a good blower converter and you do not spend a lot of time on the brake then you should not have any heat issues by the end of the run. The only thing you need to do is to remove the heat between rounds just like with the engine. One of the members on here fastavenger who I worked with last year built a really nice unit that he uses to cool the trans, it uses a pump and icewater resivour as the absorption medium and it works very well. You could do the same thing with a radiator and fan but it would be noisy and pump a lot of extra heat out under the canopy and God knows its hot enough already its a lot nicer to just throw in a 10lb bag of ice and pour out the water when your done.

Richard Gavle

 

glide temp, blown alky set up

Just my 2 cents, But we never see much heat in the pan, most of the heat we see is in the converter. At the end of a run we have about 260 degrees on the converter, and about 130 to 140 in the pan, what we have done to get the heat out of the converter as soon as possible is made a 2 gallon water tank,12 volt pump and 2 .030 drop in jets and nozzles and after a run it spays water on the converter on the return road and by the time we get back to the pits it is at about 130 degrees, the air blower does the rest, on most runs we are making about 2400 HP on a 2200 pound rail. it has worked real well for the last few years and we can turn the car around in 45 minutes and the oil temp is under 100 degrees both pan and converter. again just my 2 cents


Good luck

 

Your dragster weighs 2200#?

 

Yes , 2200 #'s both of us need to go on a deit

 

Did you ever think about plumbing a pump into the trans to circulate oil after the run during tow back and in the pits? That should help dissipate heat quite well I would think.