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Differential Cooler


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So I'm finding a weak point in the car (finally) With 500hp and 315s, the diff and axles arent taking the heat very well on the road course. Does anyone have any experience with diff coolers, or any other ideas to help keep things cool? I can only get a few laps in before things heat up and it needs to be addressed. Ideas?
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I see some newer heave duty diesel trucks and stuff now are coming with aluminum ribbed rear diff covers. Maybe just an idea? Could probably get one machined. Won't cure all your problems but might help with a little heat Edited by LSQuest88
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also the 3000GT awd system had a pump built in to the diff housing for the rear wheel steering.

 

maybe apples to oranges but rather then powering a steering unit just use it to run diff fluid through a cooler.

 

http://www.supercar-engineering.com/rubberducky/FS/VR4/DSC08294.JPG

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Simplest is to use a thermal dispersant coating on the diff cover, it would act like a ribbed aluminum cover as it helps reject heat about 25% faster. The monster truck guys also use Techline Coatings Cermalube thin film lubricant coating on the ring and pinion, they were routinely breaking them until they tried the coating according to the report. That application reduces friction which reduces heat, coupled with the increased heat rejection it would probably be enough.

 

http://www.techlinecoatings.com

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Something like this,

http://www.summitracing.com/parts/til-40-524?seid=srese1&gclid=CIbIgvyf9MUCFROUfgodNC0AuA

 

With a small cooler and fan on a switch inside the car. Those pumps are meant for intermittant use so turn it on for a track run then off for normal driving.

 

 

Stock car racing uses or at least used to use a pinion flange with a pulley on it. That way they could mount a pulley driven pump for the diff cooler. Works good but SQs don't really have the ground clearance to use something like that unless you mount it where the rear seat should be.

 

 

http://image.hotrod.com/f/10533626+w660+h495+cr1/ctrp_0402_12_z%2Boff_season_stock_car_maintenance%2Bguide.jpg

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What about using an electronic pump and mounting an external cooler behind the diff?

 

Tap the bottom of the cover as a feed for the pump and then tap the top as a return. Hot fluid goes in through the bottom and returns through the top splashing cool fluid on the gears.

Edited by Turbo Cary
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yes! all good info. I can easily do a finned diff cover, the only problem is that the exhaust runs right under it, I do have to wrap the exhaust and or some sort of heat shield...but i dont want the fins to get heat from the exhaust either. A seperate pump system might be in order... kinda wanted to get away without spending a f- load of money on this. That is very interesting Importwarrior, I didnt know they did that...
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What about using an electronic pump and mounting an external cooler behind the diff?

 

Tap the bottom of the cover as a feed for the pump and then tap the top as a return. Hot fluid goes in through the bottom and returns through the top splashing cool fluid on the gears.

 

Tough to find an electric pump that can handle that, gear oil is thick.

 

Maybe a different rear differential, like one off a 350Z or from an RB powered Nissan.

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Simplest is to use a thermal dispersant coating on the diff cover, it would act like a ribbed aluminum cover as it helps reject heat about 25% faster. The monster truck guys also use Techline Coatings Cermalube thin film lubricant coating on the ring and pinion, they were routinely breaking them until they tried the coating according to the report. That application reduces friction which reduces heat, coupled with the increased heat rejection it would probably be enough.

 

http://www.techlinecoatings.com

 

Do that and add fins to the cover. The G80 Dana 44 (and several others) use that combination and it works good under heavy use and high RPM but low vehicle speed.

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Could you get by with just a external reservoir connected with large diameter hose? No pump, let the g-forces do the circulating. The reservoir would have to be at the same level as the diff, but if you could get some airflow on it, I bet it would stay pretty cool.
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Tough to find an electric pump that can handle that, gear oil is thick.

 

Maybe a different rear differential, like one off a 350Z or from an RB powered Nissan.

 

I was talking about using an electric motor to drive a pump like a Power steering pump. Not an electronic pump. I should have been more specific.

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I just looked into pumps.. tilton engineering had one for under 200, but after the fittings, lines and cooler.. it starts to add up. I was thinking of boxing out the cover with fins to add volume as well. I don't have a ton of room though...makes things tough. I will look into the coating more..
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if you have a pump for a dry sump system, or electric hydraulic pump, seeing as you wont have it on until your on the track, you could put a sensor in the diff for temp activation, have the pump kick on at a temperature, once its hot gear oil is as thin as oil
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I think the fins + using some type of duct to direct air flow over the diff is probably a really good way of going about it. Wouldn't cost you much either.

 

If on top of that you use some type of coating like what was suggested I'd bet that would get you where you want to be.

Edited by speedyquest
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If i am not mistaken,s13 and s14 all come with std oil pump and cooler for their rear diff..

Why don't you try and find something from a pick and pull yard?

I don't think it can get cheaper than that and if you manage to find a car and take out the whole assembly,thigs would be a lot easier...

You will see how it works and make it happen easilly in you diff

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Im sure your exhaust routing isnt helpful. What condition are the clutches in? If they are allowing excessive slippage they're not helping the temp issue either.

A lot of guys that race manual trans cars use Tilton pumps. They have like 1-2hr duty cycles so it would be perfect for your setup. I was gonna use one on my R154 but never got around to it. Way F'n easier than a Diff swap. Then just add a stock SQ oil cooler in there.

Edited by Funky Phil
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maybe wrapping the exhaust, and shielding off the diff, and with fins on the cover. then building a couple ducts to help move the air from under the car up across the diff.. that may be just enough to get you through it without spending a load of money and may work great.. you could also maybe look into some brake cooling blowers which can be had failry cheap, to help push air across the diff itself. Edited by 19cturbo
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I just looked into pumps.. tilton engineering had one for under 200, but after the fittings, lines and cooler.. it starts to add up. I was thinking of boxing out the cover with fins to add volume as well. I don't have a ton of room though...makes things tough. I will look into the coating more..

 

I can't imagine you'd need heavy duty AN fittings for this application, it most likely would be low pressure, no? Could probably get away with barbed fittings and hose clamps on rubber line, so long as there aren't rules requiring specific fitting and hose material types.

 

A stock SQ oil cooler would be plenty I'm sure. Smaller coolers from snowmobiles and motorcycles would likely work as well, and would take up virtually no space at all.

 

Have you flat bottomed that thing yet? a NACA duct in the flat bottom with a duct would be killer.

 

Edit:

$40 on ebay, 80's Honda CB1000 oil cooler.

http://i.ebayimg.com/00/s/NjAwWDgwMA==/z/c0oAAOSwRLZUBj2D/$_57.JPG?set_id=880000500F`

Edited by dmyers151
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Do any of the truck rear differential rear covers fit? Are any of them larger capacity?

 

Maybe you can make a rear cover that will handle more gear oil and at the same add some waffles to it for cooling. Run some sort of scoop under the diff to channel air to the back cover?

 

 

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