2018 GT PP2 Rear Differential Overheating Issue

[t44tq]

That's what I did in my car. You are going to want to buy the diff cover, though.

I only said that because currently, the diff cover is out of stock- I think you have to buy the diff cover to install the GT350 setup.

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[Hack]

I only said that because currently, the diff cover is out of stock- I think you have to buy the diff cover to install the GT350 setup.

I think you could make the standard cover work, but IIRC it will need some holes drilled and tapped for the additional plumbing. I didn't want to pay for a second cover, but after looking at both of them I decided to replace mine. I think if the GT350 cover is no longer available it will still be possible to add a GT350 system using the factory diff cover, but there will be some extra work needed.

The two covers looked like they were the same casting to me, but the GT350 version had more features machined into it.

 

[accel]

I'm trying heat shields as shown in post #82 above, should be easier and more effective than header wrap, not much more cost if any.

Been slammed with work, as soon as I can get these on and figure out how to access the diff temperature sensor output (going to try a BDX first), I'll post some results.

FYI based on a conversation I had with a few other guys who track their cars with Torsen diffs, and two who did Formula SAE when we were in college and used a spec Torsen diff in their FSAE cars, I'm pretty confident the real issue is heatsoak from the exhaust and not heat generated by the diff. To that end, anything that helps keep heat off the diff should improve the situation.

any update?

 

[t44tq]

I think you could make the standard cover work, but IIRC it will need some holes drilled and tapped for the additional plumbing. I didn't want to pay for a second cover, but after looking at both of them I decided to replace mine. I think if the GT350 cover is no longer available it will still be possible to add a GT350 system using the factory diff cover, but there will be some extra work needed.

The two covers looked like they were the same casting to me, but the GT350 version had more features machined into it.

Hack, it shows that you have a GT350 in your profile- so your car didn't come with the diff cooler?

 

[Hack]

Hack, it shows that you have a GT350 in your profile- so your car didn't come with the diff cooler?

That's right. The 2015 and 2016 tech pack cars didn't come with coolers for the transmission or rear diff. The first time I went to the track (on a relatively cool day) I hit limp mode very quickly. So I ended up buying a track pack transmission, cooler and lines for that, plus the gear for cooling the rear differential. I was very upset at one time that Ford left those parts off my car, but I am grateful that they let me purchase the components to add the coolers to my car. It works really well on the track now.

 

[t44tq]

That's right. The 2015 and 2016 tech pack cars didn't come with coolers for the transmission or rear diff. The first time I went to the track (on a relatively cool day) I hit limp mode very quickly. So I ended up buying a track pack transmission, cooler and lines for that, plus the gear for cooling the rear differential. I was very upset at one time that Ford left those parts off my car, but I am grateful that they let me purchase the components to add the coolers to my car. It works really well on the track now.

You had to buy a new transmission?!? It looks like these same parts will fit a GT, just don't know if the mounting points are there as well.

 

[Hack]

You had to buy a new transmission?!? It looks like these same parts will fit a GT, just don't know if the mounting points are there as well.

I could have added a cooler to the tech pack transmission, but I chose to purchase a track pack transmission so I'd have a full OEM style solution. I know I could make something that would work, but I really value reliability in a car that will be driven on track. Losing a bunch of transmission fluid and having it dump under your tires could ruin your whole day.

 

[93tankus]

Hi All,

This may be a stupid question, but has anyone thought about a side exhaust system to avoid having the hot exhaust so close in proximity to the rear diff? Something along the lines of the 2012 Boss 302 system with removable restrictor plates which could be removed for track use?

I guess a side exhaust can have drawbacks as well - annoying drone? Leg burn? But it seems like the Boss 302 used this system with pretty good success?

I think Cervini has a system as well...but it's not cheap.

I'm sure a rear diff cooler is the way to go...but I was just thinking of alternatives that don't require wiring!

 

[Norm Peterson]

Routing wiring and hoses is probably a lot simpler than relocating mufflers and rerouting exhaust tubing. Running without any muffling is no longer possible at some tracks already, and the trend will be toward more tracks requiring this rather than fewer.


Norm

 

[1 old racer]

Try wrapping the exhaust pipes as a first step. Change the lowest cost/easiest method and move up slowly from there testing the results of each
That is unless you are made of money and just like adding things to you car that you just dont need.

 

[93tankus]

Try wrapping the exhaust pipes as a first step. Change the lowest cost/easiest method and move up slowly from there testing the results of each
That is unless you are made of money and just like adding things to you car that you just dont need.

Nope. Not made of money. Just asking the collective for input on ideas.

 

[Hack]

I don't think the exhaust is the heat generator that causes a problem. Otherwise your diff would overheat in stop and go traffic.

It just doesn't logically make sense IMO that exhaust is the problem. I think heat wrap on the exhaust is fine if you have extra time to waste doing things that are unlikely to help. However, I'd go straight to a rear diff cooler. I just don't have that much extra time to wrench on my car, so I would plan out ways to get the most of my time.

 

[Norm Peterson]

I don't think the exhaust is the heat generator that causes a problem. Otherwise your diff would overheat in stop and go traffic.

It just doesn't logically make sense IMO that exhaust is the problem. I think heat wrap on the exhaust is fine if you have extra time to waste doing things that are unlikely to help. However, I'd go straight to a rear diff cooler. I just don't have that much extra time to wrench on my car, so I would plan out ways to get the most of my time.

At idle and very low rpms there isn't going to be nearly as much exhaust heat as there will be at high rpms and WOT. Or as much heat generated internally by gears and such.

But heat gained out of the exhaust-heated air around the diff almost certainly isn't the real problem (even though that's what will appear to be "obvious"). The bigger effect is going to be the reduction in heat flow out of the diff into that heated air. Heat transfer depends on the difference in temperature between the hot thing you want to cool down and the fluid around it that you want the heat to move off into so it can be carried away.

I say "almost certainly" because although I have no thermal data for this particular heat flow situation, I have had some experience in heat transfer and thermal transient analysis.


Norm

 

[Gearz]

Gale Banks engineering are working on diff covers that passively cool the diff fluid. They've been researching the problem for big trucks and find the high shearing action from the ring/pinion gear really heat up the oil with normal use. Under high loads the diff fluid overheats easily. They have some videos showing the churning and what their solution to the problem is. I heard on a podcast that they're going to make a cover for the S550 Mustang. If so, it should be a pretty simple fix that doesn't require wiring, plumbing or anything else. Probably a little early to get hopes up but the research is interesting. Point is the problem is internal to the diff, not primarly due to exhaust proximity although it probably is a factor.

 

[MagnaFlow]

Try wrapping the exhaust pipes as a first step. Change the lowest cost/easiest method and move up slowly from there testing the results of each
That is unless you are made of money and just like adding things to you car that you just dont need.

I don't think the exhaust is the heat generator that causes a problem. Otherwise your diff would overheat in stop and go traffic.

It just doesn't logically make sense IMO that exhaust is the problem. I think heat wrap on the exhaust is fine if you have extra time to waste doing things that are unlikely to help. However, I'd go straight to a rear diff cooler. I just don't have that much extra time to wrench on my car, so I would plan out ways to get the most of my time.

Not the cause of the problem, but one contributing factor for sure. It wouldn't hurt to wrap the rear sections with header wrap and costs <$40. We have heard from more than one owner that doing this in addition to using a quality gear oil like Lucas/Amsoil/Red Line did make a noticeable difference.

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