Rear Diff Temps

[THRAPY]

Anyone know the optimum oil temp range for th rear diff? I think I read the Track Pac GT 500 turns the cooler on at 200 but is there a temp that it should warm up to before pushing it hard?

 

[Grant 302]

I wouldn't worry about warm up at all unless you're on track and it's 30s-40s out.

 

[steveespo]

The oil should be about 100 degrees before putting any shock loads through it. In really cold weather it's good to take a few laps at 50% and try not to put full torque through it. Torsens are great diffs but the worm gears need good lubrication to live long. Typically I see about 130 after a 15 minute cruise on the highway. I switch my diff cooler on at 235.
Steve

 

[Boss_302]

I installed a temp senor in the diff of my Spec Iron race car, data is recorded on an AIM MXL Pista.

During my last race at Daytona the sensor maxed out at 270 degrees (is should read to 302 degrees so I have something wrong because it only reads to 270).

Well as you can see when it started to record the lube was at 80 degrees and then quickly climbed to 270 max by lap 7.

It does cool down a bit each lap but the low temp slowly increases each lap, (heat soak I guess).

I wonder if a diff cooler is needed in by application.................others racers have said for sprint races a cooler isn't needed.

Thoughts?

 

[steveespo]

The "need" for a cooler depends on a few things, what lube do you use and how often do you change it. You are based in Florida so ambients are on average pretty high, the car is heavy with a lot more power than a Miata or E30 so there is more load, 270 is the upper limit I like to run but I think your peak is higher as you stated. I have seen 295 on my car with no cooler. I would say get one, but in the end it will cost about the same as rebuilding the rear with new gear, Torsen T2 and bearings. Choice is yours.
Steve

 

[THRAPY]

Wow those temps are quite a bit higher than I expected. I was under the impression that 220-230 was the upper limit for synthetic lube before it starts to break down. Are you changing fluid each race?

 

[steveespo]

Wow those temps are quite a bit higher than I expected. I was under the impression that 220-230 was the upper limit for synthetic lube before it starts to break down. Are you changing fluid each race?

Conventional GL-4 lubes are good to 275, Synthetics are good to 300+ but lifespan decreases as the temps go up. I run Miller Oils GL-4/5 synthetics that are used in Indycar and Prototype racecars and I change every 8 track hours or so. Redline and even the stock Ford lubes are very good quality. The good thing about torsens vs Traction Loks is there is much less debris in the fluid because there are no clutches, Traction Loks especially hate sustained high temps as the clutches wear faster the higher the temps get. Really not suited for Road Racing. You can do it but be prepared to re pack them often.
Steve