diff seems to be my weak point

[jamsilvia]

So I've been doing a lot to try and keep the diff cool enough to last and not burn the fluids. Someone mentioned that they just change the fluid after every weekend. Well, I kinda don't have that luxury in an enduro!

After about 1 hour on track, the temps are in the 250 range. The diff temp gauge only goes that high, so I don't know what the peak is - only there's still 11 hours to go and the gauge is maxed out!

I run Red Line 75w90 with a Cusco LSD (packs setup for full lock) and a 4.6 rear end. The car is an ITS 240SX.

Anyone have any thoughts about how I can keep the temps down? I had considered running the redline 80w140 and see if that helped any. Anyone run any different fluids and had better experiences?

Thanks!
Joe Mac

[murphyd]

Besides the temp what other problems are you experiencing. Do you notice anything when the temps are up that is different from start up? Do the temps drop if you back off? Could it be a gauge problem? Have you been able to verify the temps with some type of pyrometer. When you break the diff down after the events how do things look? Just food for thought to help in the diagnosis.

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David Murphy
Murphy Motorsports
ITS 240sx
Carolina Cup Pro Series
www.murphymotorsports.net

[Ron Earp]

I suppose diff coolers are illegal, I'm pretty sure.

I imagine that airflow in the diff region isn't what you think it is. So, some NACA ducts carefully placed to duct to air to the housing should help somewhat. Even if it pulled it down 30F it'd help.

I would think that using a Quaife might drop temps a bit since it isn't a friction type LSD.

R

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Ron Earp
NC Region
Ford Lightning
RF GT40 Replica
White Jensen-Healey ITS
Silver "Skull" 260Z ITS
Email: "rlearp at gt40s.com"

[kthomas]

BG Gear additive.

On the 240Z's when we went above 3.70 ratios we twisted the needle off a 325 degree guage in 10 laps. Tried every fluid known to man. BG fixed it.

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katman

[jamsilvia]

Originally posted by murphyd:
Besides the temp what other problems are you experiencing. Do you notice anything when the temps are up that is different from start up?

Other than the smell, the terrible smell?? No - not really.

<font face=\"Verdana, Arial\" size=\"2\"> Do the temps drop if you back off? Could it be a gauge problem?</font>

They do not come down unless the car is pretty much parked. I think the gauge may be accurate, given the significant change of smell the fluid goes through when it starts to break down. Did I mention the smell?? :-)
That's almost caused me a divorce a couple of times...

Have you been able to verify the temps with some type of pyrometer. When you break the diff down after the events how do things look? Just food for thought to help in the diagnosis.

I have NOT verified the temps with a pyro. But I definitly will. That's a good idea that I had not considered.
When I have taken the diff apart before, things LOOK fine. I haven't taken apart the clutch pack yet, but the gears look fine, there's no significant amount of metal on the drain plug, and other than the fluid being blackish, things look and move normally.

Thanks for the help!!
joe

[This message has been edited by jamsilvia (edited June 07, 2005).]

[jamsilvia]

Originally posted by kthomas:
BG Gear additive.

On the 240Z's when we went above 3.70 ratios we twisted the needle off a 325 degree guage in 10 laps. Tried every fluid known to man. BG fixed it.

I'll try it out! Which one of the BG additives do you recommend? I noticed they have a LSD one (LS-2 Lim Slip Add) and a Multi-Gear concentrate....

My gauge only went to 250 - so I have no idea if I'm getting as high as you were. Sheese. Are the Nissan's known for these diff issues?

Thanks!
joe

[This message has been edited by jamsilvia (edited June 07, 2005).]

[This message has been edited by jamsilvia (edited June 07, 2005).]

[kthomas]

MGC

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katman

[Tom Donnelly]

I've cooked the paint off mine before with a 3.90, smells real bad, doesn't it?.

Tom Donnelly
1970 ITS 240z