2015-2016 Tech Pack and Base GT350 Cooler Solution Discussion

[mattlqx]

Are there any reports of having a trans cooler installed and the car going into limp mode because the differential over heats?

Even with my '17 with both coolers, I pushed the car pretty hard on a day with long sessions this week and managed to get the diff fluid up to 315 degrees, which is the early part of the red zone. The car didn't limp at that temp, but it may have if it got much hotter. It wasn't something I wanted to prove out so I ducked in a little early on that session. It was high enough I'll be changing my diff fluid soon.

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[SchultzLT1]

Even with my '17 with both coolers, I pushed the car pretty hard on a day with long sessions this week and managed to get the diff fluid up to 315 degrees, which is the early part of the red zone. The car didn't limp at that temp, but it may have if it got much hotter. It wasn't something I wanted to prove out so I ducked in a little early on that session. It was high enough I'll be changing my diff fluid soon.

How long were those sessions? That is concerning.

 

[Hack]

Are there any reports of having a trans cooler installed and the car going into limp mode because the differential over heats?

There is no differential temperature sensor on the Tech Pack cars, so the computer doesn't monitor the rear end.

Which shows that Ford knew very well that transmission temps would be the initial performance limiter. If a transmission cooler is installed, a diff cooler should also be installed - otherwise there's a significant risk of destroying the rear diff.

 

[firestarter2]

Rear differential coolers are pretty rare in cars I suspect they can run pretty hot and be fine. Or at least I wouldn't assume any temp you saw was too hot. At a glance 315 does seem quite high but most people seem to measure externally.

http://www.kaazusa.com/80w90.html

How often should I change out my differential oil?
It depends, our recommendation for street vehicles rarely driven on tracks should be changed every 3,500 to 5,500 miles or every other motor oil change. Racecars may need more or less oil changes, this is dependent on vehicle usage as well. Some general enthusiast may not know that differential oil can sometimes reach temperatures of 350F/180C at which point most oils will breakdown. Once operating temperatures reach this degree, viscosity levels will lower therefore not providing sufficient lubrication for differential operation. Do not be fooled by others suggesting oil's should not be changed for 20,000 miles...like your engine, differential's produce friction and wear, provide your differential a clean and healthy operational environment.

 

[5.0 435]

According to GM the Z/28 after a track event should have the fluid changed in the diff. The fluid can break down @ high temps that's the reason to change fluid.
Taken from the manual...........
(Rear Differential Fluid 75W-90 Limited- Slip: GM Part No. 88900401, in Canada 89021678)
AFTER THE TRACK
• Return the tire pressure settings to factory (see the Tire and Loading Information label located below the door latch with the door open)
• Return the wheel alignment settings to factory
• Replace oil
• Replace brake fluid
• *******Replace rear axle fluid *******

 

[mattlqx]

How long were those sessions? That is concerning.

25 minutes. With roughly 50-60 minutes between. Basically my sessions for the day went:

8:55am, 25 minutes
10:10am, 15 minutes (pulled in early for fuel cutoff)
11:25am, 20 minutes (pulled in early for high diff temp)
1:10pm, 25 minutes
2:25pm, 15 minutes (pulled in early for fuel cutoff)
3:30pm, 20 minutes (full session)

With all the high speed, high G turns, the fuel gauge was confused as hell, but when it started to read down near a quarter, I'd get throttle cut from the fuel pickup sucking air. This was very immediate and pretty dramatic power loss and takes a 3-10 seconds to repressurize and resume so that's not something you want to be out on track with. The car didn't have any minor stutters prior to that. I just came in immediately if I got that. With a full tank, I could probably get two full sessions, but I was filling from cans so I just put enough in to get the fuel gauge reading high.

Diff temperature was only a problem during one session before the lunch break. It was getting warm around 90 degrees and there wasn't much of a breeze. The wind kicked up after the lunch sessions and while it got up to 275 or so, it didn't make it past 300 again.

Thunderhill East is a pretty high speed track as well. I would've hoped for better cooling while moving at a good clip.

 

[SchultzLT1]

25 minutes. With roughly 50-60 minutes between. Basically my sessions for the day went:

8:55am, 25 minutes
10:10am, 15 minutes (pulled in early for fuel cutoff)
11:25am, 20 minutes (pulled in early for high diff temp)
1:10pm, 25 minutes
2:25pm, 15 minutes (pulled in early for fuel cutoff)
3:30pm, 20 minutes (full session)

With all the high speed, high G turns, the fuel gauge was confused as hell, but when it started to read down near a quarter, I'd get throttle cut from the fuel pickup sucking air. This was very immediate and pretty dramatic power loss and takes a 3-10 seconds to repressurize and resume so that's not something you want to be out on track with. The car didn't have any minor stutters prior to that. I just came in immediately if I got that. With a full tank, I could probably get two full sessions, but I was filling from cans so I just put enough in to get the fuel gauge reading high.

Diff temperature was only a problem during one session before the lunch break. It was getting warm around 90 degrees and there wasn't much of a breeze. The wind kicked up after the lunch sessions and while it got up to 275 or so, it didn't make it past 300 again.

Thunderhill East is a pretty high speed track as well. I would've hoped for better cooling while moving at a good clip.

That seems kind of odd. Obviously we know the Track pack cars for the track attack program run all day. You didn't really have any "long" sessions. With the cooler I would think you wouldn't have to worry about it.

 

[mattlqx]

That seems kind of odd. Obviously we know the Track pack cars for the track attack program run all day. You didn't really have any "long" sessions. With the cooler I would think you wouldn't have to worry about it.

There's a number of different variables. The TA cars have long breaks in between and shorter sessions. I think people are prone to be monitoring temps there less. It's cooler at UMC than (the desert-y parts of) California usually. The drivers at the TA are mostly newbs. On and on.

In three days of driving on three different tracks, only that one session was a problem. My point is conditions can be right to get the diff too hot even with the Track package's stock cooler. Just something to be aware of.

 

[SchultzLT1]

Thanks. After a successful install of a trans cooler, I'll look further into a diff cooler. No time before this track day though.

 

[lemers]

Cost wise, what does it run to replace a diff vs a trans? And it the track diff different than the tech diff or can to just add the track cooler bits to the tech diff?

 

[barstowpo]

From what I've read, it is about $1200 worth of parts to add the factory diff cooler. Problem is wiring it into the system as there is no harness in the tech cars. I haven't looked at mine but I suspect this is true.

 

[Optimum Performance]

Are there any reports of having a trans cooler installed and the car going into limp mode because the differential over heats?

A Warning I believe in the center stack, no limp mode but it should come on at around 290F. If you get the oil that warm a fluid change is a good idea.

There is no differential temperature sensor on the Tech Pack cars, so the computer doesn't monitor the rear end.

I believe all 3.73 equipped Mustangs 2016+ have a rear differnential sensor. GT's will give a center stack warning to slow down for over temp. All Shelby's have a transmission and rear axle virtual gauge unless my information is incorrect.

When I was driving my 2015 GT year round the transmission still wasn't fully warm 5 miles down the road when I was getting onto the interstate. Now add a cooler - I'm just saying that I'm not as confident as you. You also have no reason to worry about your transmission not warming up during driving any more now that you are in Florida. I do.

If it's cold out I usually let my car warm up 15 minutes before driving it. I usually have to get the frost off the windows. This is why I moved. Heat is generated in Neutral with the clutch engaged.

Pump comes today and just ordered the BG fluid from [MENTION=22413]Optimum Performance[/MENTION] this morning. Install will probably start Wednesday and hopefully have the car back on the road for pre-track testing mid next week.

Thank you Sir!

According to GM the Z/28 after a track event should have the fluid changed in the diff. The fluid can break down @ high temps that's the reason to change fluid.
Taken from the manual...........
(Rear Differential Fluid 75W-90 Limited- Slip: GM Part No. 88900401, in Canada 89021678)
AFTER THE TRACK
• Return the tire pressure settings to factory (see the Tire and Loading Information label located below the door latch with the door open)
• Return the wheel alignment settings to factory
• Replace oil
• Replace brake fluid
• *******Replace rear axle fluid *******

Ford states after the first hour of track time and every 12 hours of track time. It's in the owners manual.

Rear differential coolers are pretty rare in cars I suspect they can run pretty hot and be fine. Or at least I wouldn't assume any temp you saw was too hot. At a glance 315 does seem quite high but most people seem to measure externally.

http://www.kaazusa.com/80w90.html

How often should I change out my differential oil?
It depends, our recommendation for street vehicles rarely driven on tracks should be changed every 3,500 to 5,500 miles or every other motor oil change. Racecars may need more or less oil changes, this is dependent on vehicle usage as well. Some general enthusiast may not know that differential oil can sometimes reach temperatures of 350F/180C at which point most oils will breakdown. Once operating temperatures reach this degree, viscosity levels will lower therefore not providing sufficient lubrication for differential operation. Do not be fooled by others suggesting oil's should not be changed for 20,000 miles...like your engine, differential's produce friction and wear, provide your differential a clean and healthy operational environment.

We sell more 75W-140 than our 75W-90 (3-1) for the S550 chassis for track Customers. It does help keep the temp down longer without a cooler plus offers more protection when on track.

Even with my '17 with both coolers, I pushed the car pretty hard on a day with long sessions this week and managed to get the diff fluid up to 315 degrees, which is the early part of the red zone. The car didn't limp at that temp, but it may have if it got much hotter. It wasn't something I wanted to prove out so I ducked in a little early on that session. It was high enough I'll be changing my diff fluid soon.

Exhaust radiant heat causes a lot of heat soak in the rear axle combined with the too light of a gear oil for the use. 75W-140 is better for track use, plus we have a harness to help flush the system completely.

Very true.

Funny though (and maybe this has been explained already) but we can get an 'error' code for our read diff overheating. Fellas at the dealership pulled it up after a track day and limp mode occurred and boy were we all confused.

P188A Differential Oil Temperature Too High / Too Low
This DTC sets in continuous memory when the differential oil temperature
exceeds 145° C (293° F).

 

[Optimum Performance]

From what I've read, it is about $1200 worth of parts to add the factory diff cooler. Problem is wiring it into the system as there is no harness in the tech cars. I haven't looked at mine but I suspect this is true.

This relay is on Track Pack / R Models. This is the box on the RH inner Fender. Open and see if that spot has terminals in the holes. You should not have a relay inplace on a Tech Car but Ford may have run the wires to it. The spot to the right of this relay should be one for radiator fans. You can see the terminals in the picture. If it is not wired it will just be empty white /black plastic sockets.

PLEASE Let me know.

 

[Hack]

If it's cold out I usually let my car warm up 15 minutes before driving it. I usually have to get the frost off the windows. This is why I moved. Heat is generated in Neutral with the clutch engaged.

My car sits in an attached and insulated garage, so it's not frosty, but it still takes time to warm up. When it's below zero outside it's often slightly below freezing in the garage.

It is better to drive the car to warm it up. Idling so much can glaze the cylinder walls.

 

[PintoBoost]

Hope this helps. 2016 Tech Package

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