Diff Cooler, how do I know I need it?

spearfish25 · 04-12-2009, 09:41 PM

Sorry if this is the wrong place to post, but I saw a thread about oil coolers and figured it's worth a shot.

Knowing you need an engine oil cooler is pretty straight forward when the temp gauge rises and the RPMs get limited. How do I know if I need a rear differential cooler though?

Thanks.

ssqpolo · 04-12-2009, 09:46 PM

if it aint broke...dont fix it!
u probably dont need one, but maybe the track guys on here can say more.

spearfish25 · 04-12-2009, 09:50 PM

You're probably right....so far I don't need the engine oil cooler either. Just curious how to know your diff needs better cooling.

Otherwise I'm going to focus on more functional changes for my Chicago Z...like heated side mirrors.

RCZ · 04-12-2009, 09:50 PM

I can't know for sure, but I didn't notice any change in the steering at any point during my last track day.

And its definitely not the right forum section.

spearfish25 · 04-12-2009, 09:55 PM

Figures it's wrong, but there are other oil cooler threads that haven't been moved. Doesn't really fit any specific section...maybe the DIY

RCZ · 04-12-2009, 10:09 PM

no no.... its good that its in the engine section. But not under forced induction...

Its a diff cooler... would've been fine in the main engine/drivetrain section.

imag · 04-16-2009, 01:11 PM

When your diff blows up all over the track, you know you needed it.

Honestly, whether this thread is in the right place or not, I'm thinking about it too. My thought is that if you're not tracking the car, don't worry about it. If you are, it's probably worth getting one (or just step up to a new diff, which is what I'm seriously pondering). Nissan didn't put them on their press cars for no reason...

Maybe the best option is to just leave it as is, let the stock diff melt down, and replace it when it does...

Anyone know how much a quaife costs fully installed?

ChrisSlicks · 04-16-2009, 02:33 PM

When the diff oil gets too hot on a viscous differential it will have less lock up ability. Had the same problem on my G35, it was like driving an open differential when it got too hot. You will only notice it after repeated auto-cross runs or extended track sessions. Given that your engine would probably overheat first, it's probably not a problem.

KLRCADI · 04-22-2009, 12:44 PM

The NISMO diff cover has cooling fins and provisions for cooler lines. They cost about $150. Some of the magazine demo cars had them, but for everyday, mild track driving you should be fine.

AK370Z · 04-22-2009, 12:47 PM

I saw this in a JDM Z34

Z34/370Z air-cooling fin equipped diff. rear cover

KLRCADI · 04-22-2009, 01:45 PM

Thanks. Thats the one I was thinking of...

rbratton · 10-30-2009, 03:31 PM

My diff felt like an open diff toward the end of each session last weekend. I'm changing the fluid and going to run it again and specifically look at diff action at the beginning and end of each run to see how heat is effecting performance of the VLSD. Looking at the GTM cooler kit pricing (over a grand), I think I may just upgrade to a mechanical LSD.

Z1Performance · 10-30-2009, 07:22 PM

The majority of the reason for the overheating issue is due to the tolerances things come preset at from the factory. There is a fair amount of variation, that really should be tighter, but for an OEM part being used in normal driving conditions, its not much of an issue. The OEM diff is absolutely useless once things get hot, and it's lockup% is not all that significant in the first place. It's why the aftermarket units provide an immediate, noticeable difference.

The diff cooler certainly helps on a full out race car running slicks. It's not something I'd invest in otherwise

import111 · 10-30-2009, 11:19 PM

I expect to buy a clutch type diff. after the stock diff blows up on the track. I hope the stock diff. can at least handle 1 or 2 track days...we will see.

04-12-2009, 09:41 PM	#1 (permalink)
spearfish25 A True Z Fanatic Join Date: Mar 2009 Location: Naples, FL Posts: 4,117 Drives: to work Rep Power: 1856	Diff Cooler, how do I know I need it? Sorry if this is the wrong place to post, but I saw a thread about oil coolers and figured it's worth a shot. Knowing you need an engine oil cooler is pretty straight forward when the temp gauge rises and the RPMs get limited. How do I know if I need a rear differential cooler though? Thanks.

04-12-2009, 09:50 PM	#4 (permalink)
RCZ A True Z Fanatic Join Date: Nov 2008 Location: Miami Posts: 6,403 Drives: '09 370Z Rep Power: 1118	I can't know for sure, but I didn't notice any change in the steering at any point during my last track day. And its definitely not the right forum section. Last edited by RCZ; 04-12-2009 at 09:53 PM.

04-22-2009, 12:47 PM	#10 (permalink)
AK370Z Administrator Join Date: Sep 2008 Location: NJ Posts: 9,930 Drives: 09 370Z MB Sports M6 Rep Power: 10	I saw this in a JDM Z34 Z34/370Z air-cooling fin equipped diff. rear cover __________________ The370Z Signature Pictures ll Want to rock our forum decals on your car? Then click here! ll How to Embed YouTube Videos In a Post STOP! (Hammertime) ll Become a Premium Member Click HERE ll F.A.Q. Are You a Nissan Dealer? Click Here to Become A "Supporting Dealer" and Start Listing Your 370Zs In Our Inventory Section My Monterey Blue Z ll My Exhaust --> My Intake --> G3 Nissan's Official Response Regarding Oil Temp Issue: CLICK HERE Need a Set of Cheap Winter wheels /Tires? Then Visit The Banner Link Below and Place Your Order. You'll Help Keep The370Z Alive.

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04-12-2009, 09:46 PM	#2 (permalink)
ssqpolo Track Member Join Date: Jan 2009 Location: Florida Posts: 882 Drives: '12 Black Nismo Rep Power: 267	if it aint broke...dont fix it! u probably dont need one, but maybe the track guys on here can say more.

04-12-2009, 09:50 PM	#3 (permalink)
spearfish25 A True Z Fanatic Join Date: Mar 2009 Location: Naples, FL Posts: 4,117 Drives: to work Rep Power: 1856	You're probably right....so far I don't need the engine oil cooler either. Just curious how to know your diff needs better cooling. Otherwise I'm going to focus on more functional changes for my Chicago Z...like heated side mirrors.

04-12-2009, 09:55 PM	#5 (permalink)
spearfish25 A True Z Fanatic Join Date: Mar 2009 Location: Naples, FL Posts: 4,117 Drives: to work Rep Power: 1856	Figures it's wrong, but there are other oil cooler threads that haven't been moved. Doesn't really fit any specific section...maybe the DIY

04-12-2009, 10:09 PM	#6 (permalink)
RCZ A True Z Fanatic Join Date: Nov 2008 Location: Miami Posts: 6,403 Drives: '09 370Z Rep Power: 1118	no no.... its good that its in the engine section. But not under forced induction... Its a diff cooler... would've been fine in the main engine/drivetrain section.

04-16-2009, 01:11 PM	#7 (permalink)
imag Enthusiast Member Join Date: Mar 2009 Location: Oakland, CA Posts: 446 Drives: up the wall Rep Power: 16	When your diff blows up all over the track, you know you needed it. Honestly, whether this thread is in the right place or not, I'm thinking about it too. My thought is that if you're not tracking the car, don't worry about it. If you are, it's probably worth getting one (or just step up to a new diff, which is what I'm seriously pondering). Nissan didn't put them on their press cars for no reason... Maybe the best option is to just leave it as is, let the stock diff melt down, and replace it when it does... Anyone know how much a quaife costs fully installed?

04-16-2009, 02:33 PM	#8 (permalink)
ChrisSlicks A True Z Fanatic Join Date: Mar 2009 Location: North East Posts: 6,203 Drives: 09 370Z Sport M6 Rep Power: 653	When the diff oil gets too hot on a viscous differential it will have less lock up ability. Had the same problem on my G35, it was like driving an open differential when it got too hot. You will only notice it after repeated auto-cross runs or extended track sessions. Given that your engine would probably overheat first, it's probably not a problem.

04-22-2009, 12:44 PM	#9 (permalink)
KLRCADI Base Member Join Date: Apr 2009 Location: Toronto Posts: 11 Drives: 2005 CTS-V Rep Power: 16	The NISMO diff cover has cooling fins and provisions for cooler lines. They cost about $150. Some of the magazine demo cars had them, but for everyday, mild track driving you should be fine.

04-22-2009, 01:45 PM	#11 (permalink)
KLRCADI Base Member Join Date: Apr 2009 Location: Toronto Posts: 11 Drives: 2005 CTS-V Rep Power: 16	Thanks. Thats the one I was thinking of...

10-30-2009, 03:31 PM	#12 (permalink)
rbratton Base Member Join Date: Jan 2009 Location: Vine Grove, KY Posts: 89 Drives: 2009 370Z Rep Power: 16	My diff felt like an open diff toward the end of each session last weekend. I'm changing the fluid and going to run it again and specifically look at diff action at the beginning and end of each run to see how heat is effecting performance of the VLSD. Looking at the GTM cooler kit pricing (over a grand), I think I may just upgrade to a mechanical LSD.

10-30-2009, 07:22 PM	#13 (permalink)
Z1Performance Base Member Join Date: Aug 2009 Location: St. James, NY Posts: 237 Drives: 350Z Rep Power: 15	The majority of the reason for the overheating issue is due to the tolerances things come preset at from the factory. There is a fair amount of variation, that really should be tighter, but for an OEM part being used in normal driving conditions, its not much of an issue. The OEM diff is absolutely useless once things get hot, and it's lockup% is not all that significant in the first place. It's why the aftermarket units provide an immediate, noticeable difference. The diff cooler certainly helps on a full out race car running slicks. It's not something I'd invest in otherwise

10-30-2009, 11:19 PM	#14 (permalink)
import111 Track Member Join Date: Feb 2009 Location: Tucson, AZ. Posts: 622 Drives: 09 Nissan 370Z Rep Power: 191	I expect to buy a clutch type diff. after the stock diff blows up on the track. I hope the stock diff. can at least handle 1 or 2 track days...we will see.