diff & geaqr box temps
 

Has anybody on here tried putting a thermocouple into there gear box and diff. I am concidering a cooler for these parts but was unsure if it is really worthwhile

Scott

If you are running hard on track for more than 30-40 minutes at a time it is something to check into. I've heard some of ITS FC guys putting rear diff coolers in because they run 90min enduros but I know many that don't have an cooler. It depends on what kind of diff you have, some generate more heat than others. Make sure your exhaust isn't heat soaking your tranny and diff first.
I'd just get under the car with one of those cheap infrared guns and see what the cases' surface temps are after a hard run. If they are up around 200F-225F then I'd dig further.

engine oil and gearbox lube will break down at about the same temps. any oil temp gauge will work in the trans or diff. no real need for a thermocouple but it would work. If using a straight cut gear gearbox or one of the 512 ring and pinions then a cooler would be useful.

Cheers guys.

I was thinking more of conecting it to my fc datalogit so i could play back the data.
I never thought of it before untill i looked over a friends GTR. he had added some to his set up.

Scott

hhmm..I hope not because that isn't legal(for IT). I just use synthetic and change it way to often.

its66, when did something not being legal stop an IT guy from doing it? :rlaugh: I know the front runners keep a close eye on each other though.

:rlaugh: true. You got me there.

I actually haven't seen one on any of the ITS cars I've been under, but that certainly doesn't mean nobody has one. There is a thread on a certain road race-autocross forum about a ITA miata whose diff cooler was visible after his rear bumper got ripped off in a metal-to-metal incident. It apears to have caused quite a stir.

You gonna be at Daytona? How about Ed?

It is too bad nobody goes and asks for this rule to be changed. I mean some people spend a lot of money on their diffs & trans rebuilds and just running a cooler may add a little longevity/money saved. I have been thinking about adding a diff cooler for a while now because every time I change the diff fluid, it is really dark. I run a 4.88 with oversize friction discs and it was one of the biggest expenses on my car. Of course I am not in ITS yet so I don't have to follow the rules right now.

-Jack

jrx13, write a letter to SCCA,maybe get the ball rolling.

its66, I know Ed isn't planning on it. He's planning on the three Sebring races in a row. New engine etc etc he should be a lot faster than at the national. We're going over the car for him this week. I won't be there, my wife is about to pop, she's scheduled for a c section on Aug 1. Got a little boy on the way and I have to shop for a go-kart for him :wink: You should see the looks she gives me when I bring THAT up! Plus I'm pushing my luck already, I'm headed up to Mid-Ohio on the 16th to help run a bunch of Alfas at a vintage event, and her birthday is on the 19th...I guess I'll call her on that day or not come home at all. Guys, if your not married yet try to find one like mine!

depending on the diff/trany combo, could you just run a pump rated for that viscosity fluid and conect the trany to the diff with some SS lines and AN fittings....then plumb a cooler into the line and locate it where you can get good airflow. You could also rig up a thermostat to activate the pump at a specific temp, so its only running when the temps reaches 98*C or whatever. You could be cheap and run the inlet/outlet in the fill/drain plug, but I think a large ammount of the fluid would just go in and out quickly and not circulate thru the gears/diff. You would use one of the exiting fill/rain plugs but would want to fab in a new fittting on the opposite side of the box...that would provide max time in the gearbox for the fluid.

That would no only cool both the trany and diff with 1 cooler, but would also add a large volume of fluid to help combat heat soak. The pump would only run when the temp reached your preset point, so it wouldnt delay the warm up of the fluid when cold.

If your running a fluid that meets the needs of your trany and diff....what are the downsides...other than the cost.

You could also throw in one of the larger diff covers to add another qt of fluid to your total ammount, along with the close to 2 qts you could have in the lines/pump and cooler core you would be running close to double the ammount of fluid.

This is something I did with my miata, and am thinking of doing it in an FD when I get one.

I have now purchased a diff cooler set up. Im going to see how it goes ( when it turns up )

I will update the thread when i have completed the job.

Scott

http://i30.photobucket.com/albums/c3...linecooler.jpg

I made a quick picture in MSPaint to help show what im talking about.

Putting the cooler before the pump would help lower temps at the pump inlet...possible helping extend the pumps life. The trany also gets the cooler oil first, as I think the i remeber the transmission has higher operating temps than diffs (could be wrong).

Also the diff would see higher temps as the trany get the oil first, you could put in another cooler in that line, but that would be more stress on the pump, more cost and also more trouble to fab up. I think the overall drop in temps would be fine for the diff and it also is less prone to heatsoak from the engine since it sits outback by itself it also gets more airflow.

The biggest trouble with installing this would be proper placement of the cooler core. If your running a diffuser you could stick it in he opening on the opposite side of the muffler next to the licence plate, i belive that area gets good airflow

Cool.
The cost is not an issue. Im using 200sx diff coolers. I can get them for £20 a pop complete. I understand where you are coming from with the order things. I dont need the oil frying the pump now LOL....

Do you think that joining the gearbox and diff together with this setup could also aid in the warming up process since they will both generate heat. also there would be a much greater amount of fluid to pass through the system with the extar in the lines and cooler etc.

Scott

Yeah, i think linking both units together would also help air the warmup process (I never thought of that before)

I think with the lines, pump and cooler core you could get almost double the ammount of fluid in the system, also adding one of the larger diff covers (like the one greddy makes for the FD) would give you maybe more than double the capacity.

The extra volume of oil would help keep the poil from getting heat soaked, same idea with a larger oil pan for the engine.

The expensive part will be the oil. im using royal purple at the moment. Double the capacity EEKKKKK........ £££

Scott

The problem I can see will be getting the oil to leave the tranny and go to the diff and not out the breather or front or rear seal. You need to scavenge the oil from the tranny some how which may require another pump.
Also, some inline filters would be nice so if something blows you don't take out your whole driveline.
I don't know about the oil requirements that may be ignored by picking one type of oil for both units.
I would run seperate systems myself.

I was thinking about some inline filters. The rear diffuser is a good idea to get the airflow up round that area but i dont want to upset the balance of the front of the car by doing so.

I think the easiest way is gonna be to copy the R34 GTR and run 2 cooler set ups.

I might be lazy to start with and draw the oil out from the drain and back up into the fill hole.

Scott

good points! the filters is a good idea! I see what your saying about the scavenge...but were not moving the oil under a lot of presure...i think as long as the system didnt have any big restrictions, the system could work under a pretty low (or 0) pressure and just flow the oil around....but maybe not. Many cars with LSDs use the same weight of oil and not all LSDs require a friction modifyer.

A tiwn system with a pump/cooler for each unit would be the ideal setup...but it would run double the cost and almost double the weight of a single system.....but that might not matter anyway, since this is a setup only people who need it will be running...not for the average joe.

the only problem i could see with running the in/out from the fil/drain hole is that they are pretty close together......esp on the diff and you might make a current that just circulates the fluid in and out along the edge of the case and not thru the whole unit....although this might not be a problem as the gears inside will circulate the fluid somewhat.

The tranny and diff coolers must be two independent systems because if they're not you cannot ensure that the tranny and diff maintain their proper fluid levels.

For instance looking at the diagram above there's no way to prevent the pump from emptying the diff of it's lube and sending it all into the tranny. No matter where you put the pump you'd have the same problem. Even if the pump were not running you'd need valves in the lines so that the fluid wouldn't empty from one to the other as the car accelerated and slowed. They have to be two seperate loops. You can't combine them into one without it being stupidly complicated.

I also wouldn't bother to worry about cooling either until I knew I needed to cool them.

I want to do this becsaue of the state of the oil that i pull from my diffs. It looks completely dun... also i have chewed through 3 diff in 12 months. I think the oil is over heating and going to pot.

Scott

My cooler and pump arrived today

Based on 3rd gen d.e. track experience, after about 4-5 track days on new synthetic oil, the trans oil came out looking new, and the torsen diff oil came out black. For endurance racing I'd cool the torsen diff ... lots of high load metal-to-metal rubbing in there on corners under power. They work based on friction.

^ I doubt the heat from 4-5 track days is what causes the diff lube to break down, but rather the shearing forces from ring and pinion along with the worm gears in the Torsen.

I am running a KAAZ 1.5 now.

Scott