Diff

[f1race79]

We had an endurance race this past weekend (LeMons) and our 180 diff was running hot and failed. We switch another 180 in it's place and within 20 laps was getting hot and starting whining.

We where using Red Line MTL 70W80 oil.

Is this oil to light for racing?

We also have dropped driver’s floor ~3 inches and installed a front spoiler, would this block enough air to make it get hot?

We have another race in a couple of months and are scratching our heads.

Any help would be greatly appreciated.

Thanks,

Julius

[Zs-ondabrain]

Maybe it's time for an R200?

Maybe make a cooling duct from the side to move air to the diff for proper cooling?

I wouldn't think that dropping the floor would stop all air but apparently it is doing that.

[Ron Carter]

R-180's will work fine, but will need cooling, and can't handle such a long time in the car without aux cooling. I run redline Heavy Duty Shock Proof, and I would run a differential cooler. This will increase the amount of fluid you run in the diff, and keep it at a reasonable temp.

There is also a finned cover available for a Subaru that will help as well...but the pump and cooler is the best way to go.

Are you running an LSD? what are you running for tires? What track configuration are you running? What gear ratio in the R-180?

[f1race79]

R-180's will work fine, but will need cooling, and can't handle such a long time in the car without aux cooling. I run redline Heavy Duty Shock Proof, and I would run a differential cooler. This will increase the amount of fluid you run in the diff, and keep it at a reasonable temp.

There is also a finned cover available for a Subaru that will help as well...but the pump and cooler is the best way to go.

Are you running an LSD? what are you running for tires? What track configuration are you running? What gear ratio in the R-180?

It is an open diff.

195/60-14 Falklen RT615's

Running Eagle Canyon 2.5 mile course

Stock 3.36 ratio.

What type of pump?

[Ron Carter]

I am surprised you are having trouble with an open differential, as they do not generate as much heat as a clutch style LSD.

What did the fluid look like that you took out of the Differentials you were running?

Tilton makes a Differential pump that will work. You'll need a small radiator and fan with the pump.

[preith]

Take this with a grain of salt as I have no experience racing with an open 180, but I'd play around with different gear lube first before going with a cooler. As Ron mentioned, try a heavy duty shock proof oil, I'm partial to Amsoil's severe gear, I run their SAE 250:

http://www.amsoil.com/storefront/srt.aspx

[Ron Carter]

I agree with Phillip, try the fluid first, but...for an endurance race you are going to use up any oil if your running really hot temps. The other thing is to install a diff temp gauge, you'll know right where you are and be able to make corrections based on temp.

Ron

[f1race79]

The oil would be black and burnt.

The diff was getting so hot it would boil the oil and blow the vent out and throw oil everywhere.

I was black flagged for the smoke.

The diff cover would be almost blue.

Would a half shaft putting too much pressure on gears cause this?

We will have to get it on a lift and really check things out.

The first diff had a noise and we thought it might be a bad diff but the other diff sounded good when we first put it in.

An hour later it was howling and blow oil out also...

Thanks for the input guys.

Julius

[Jeff G 78]

Hey Julius, welcome to the LeMons club!

Been there, done that!!! Follow my LeMons Facebook link in my sig for pics of us swapping our failed R180 with an R200 mid-race. We didn't have an R200 mustache bar with us, so we made one at the track in the rain at 3am. The bar came out so nice that we decided to keep running the fabricated bar even though I have an R200 bar in my garage.

Send me a PM to discuss the fun.

[Ron Carter]

It is possible that this is a half shaft problem, it also could be a bearing issue in both units. That is excessive heat for sure.

it could be a problem with the ring and pinon being too tight too. But since this repeated, I have to think that it is a serious cooling problem, and an R200 while it might help some, is not the silver bullet.

I would look at your suspension geometry, half shafts, Rear "A" Arms and differential mounts. I would run a temp gauge and drive the car around with a new differential and see where you stand. Clearly something is binding and generating a lot of heat.

[260DET]

It would seem appropriate for LeMons that a backyard fix be considered, maybe weld a finned extension onto the cover to increase oil capacity and run some air ducting to help cooling. There is no reason I can think of why a R200 would run cooler except it has more oil capacity plus a bit more metal to act as a heat soak and dispersant.

Edited June 9, 2010 by 260DET

[Jeff G 78]

Richard, you seem to get the whole LeMons concept. It's not that we race cheap cars, it's that we never give up and find creative solutions to engineering problems. It's easy to throw money at a problem, but it's more fun to backyard engineer something that works just as well for very little money.