Track Time Limited due to High CHT

[bnightstar]

A built, caged Coyote/LS swapped Fox with square 325 Hoosiers would also do circles around that.

There's always something bigger and better out there.

and if you want a dual use track daily a Porsche GT3 will do circles around all of this options

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[NeverSatisfied]

A built, caged Coyote/LS swapped Fox with square 325 Hoosiers would also do circles around that.

There's always something bigger and better out there.

LOL note I said budget weighs into the equation in my formula. I don't see many LS S550's that you can buy turn key for ~$25K. Not to mention the cubic difference in consumable costs.

You'd be surprised at how close a sub 1-ton car with modest power, aero, sticky rubber, and significantly better suspension design can perform. Your described modified S550 would not be doing circles around it.

And now we're way off topic.

 

[EFI]

LOL note I said budget weighs into the equation in my formula. I don't see many LS S550's that you can buy turn key for ~$25K. Not to mention the cubic difference in consumable costs.

Besides consumables (which is really only 325 vs. 275 tires) buying a cheap Fox and a junkyard 6 liter then caging it is not going to be anymore than buying a Miata, K24 and caging it.

But I digress, the racing world doesn't revolve around Miatas unlike many people make it out to seem like.

 

[nbjeeptj]

I was just brinnging up that point because of the number of hrs of sleep I lost trying to decide if removing the AC was a good idea. In my case it was, but no 2 people on this fourm have the same goals or budget, so I was just proposing the other side of the I would never do it or I wish I had not done it.

Now to get back on topic, I have no way to know for sure since when I did mine it was a lot of changes at once but I think removing a beat up AC condensor was a big help on this. Mine had about 5000 on track miles before removing it and there was probably not a lot of air getting thru it easily. I have since wandered if I would have replaced the condensor with new and installed some sort of screen to protect it if I would have had good results with that. I think some sort of oil cooler would have still been needed but it is something to think about if you are not redy to not have AC.

 

[nbjeeptj]

and if you want a dual use track daily a Porsche GT3 will do circles around all of this options

This

When budget is not a issue and you want a turn key factory car that is not modified, to use as a dual purpose car I dont know if there is any better option. The GT3 and C7 Zo6 are the only 2 cars that are consistanly faster than mine on HPDE days with factory ish cars. Full race car builds all that goes out the window, and a ragged out looking miata may be the fastest thing on the track for that given day, another day you may get passed by a mind blowing fast Radical SR10.

 

[NeverSatisfied]

Besides consumables (which is really only 325 vs. 275 tires) buying a cheap Fox and a junkyard 6 liter then caging it is not going to be anymore than buying a Miata, K24 and caging it.

But I digress, the racing world doesn't revolve around Miatas unlike many people make it out to seem like.

You've clearly not track driven or maintained a properly built 1950lb car with 50/50 weight distribution and 4 wheel double wishbone suspension nor an overpowered V8, 1970s tech, stick axle/mcpherson strut car on steam rollers and shaped like a brick.

It's like comparing apples to oranges in both performance and costs despite your tire and build cost analogy attempt.

Don't get me wrong both are a riot to drive.

 

[Jstang23]

Just spent the greater portion of an hour reading this entire thread, wow! A lot of information. I am an automotive engineer and work closely with the engineer responsible for the team that designed the coyote engine. I've sent an email over to him asking what's the target temperature for tracking a mustang with a Gen 3 coyote (this is what I drive). I'll keep you all updated as to what he comes back with!

Cheers

 

[Jstang23]

Update:

This is what he said!

"That's somewhat of a loaded question. The coyote's fan initiates between 212-215 degrees CHT. This is by no means an indicator of what the normal operating temperature is. Depending on where you live, the nature by which you drive, or a slew of other factors, there isn't a standard operating temperature. Also, we tend to avoid using terms such as normal operating temperature in the industry as normal is such a wide term. Some may say normal is anything that's not damaging your car. Others say normal is daily driving your car to work and back. Use that information as you will."

"If you're hitting ~240 degrees CHT the coyote will pull your power to preserve the engine. If you hit that then you really need to slow down. Unfortunately the GT, PP or otherwise, was not meant to be a track car, so if you bring it to the track and drive it hard, don't be surprised if you activate limp mode. We were aware of the GT's ability or lack thereof to track well. Which is why we developed the M1. If you want a track ready mustang out of the box, go buy an M1 or a Shelby."

"I can't comment as to what's a safe range for the coyote, especially if there are any modifications. ~270 degree CHT is where you will start to lose gaskets and deform head studs, if you don't burn your oil first. ~250 degree is where limp mode comes into question, assuming no other failures occur. I would highly recommend avoiding these temperatures."

"Generally the road going versions of engines typically can run "hotter" as the internal parts allow for more fluctuation in tolerances with regard to heat and cooling cycles. The race engines are highly sensitive to heat differences, hence why the are preheated and cooled before and after the races. I can't speak to the design and function of the race engines, but I can guess the "lower" operating temperature is related to keeping the tolerances correct."

Hope the helps you all!

 

[GTP]

...

"If you're hitting ~240 degrees CHT the coyote will pull your power to preserve the engine. If you hit that then you really need to slow down. Unfortunately the GT, PP or otherwise, was not meant to be a track car, so if you bring it to the track and drive it hard, don't be surprised if you activate limp mode. We were aware of the GT's ability or lack thereof to track well. Which is why we developed the M1. If you want a track ready mustang out of the box, go buy an M1 or a Shelby."
...

Hope the helps you all!

To that I would add that us GT owners need to add an auxiliary oil cooler that has at least the cooling capacity of the M1/Shelby cars.

I'm still waiting to hear if any M1 owners also overheat the engine on track. That oil cooler is not really high capacity, but it certainly will help.

 

[tosha]

Update:

This is what he said!

"That's somewhat of a loaded question. The coyote's fan initiates between 212-215 degrees CHT. This is by no means an indicator of what the normal operating temperature is. Depending on where you live, the nature by which you drive, or a slew of other factors, there isn't a standard operating temperature. Also, we tend to avoid using terms such as normal operating temperature in the industry as normal is such a wide term. Some may say normal is anything that's not damaging your car. Others say normal is daily driving your car to work and back. Use that information as you will."

"If you're hitting ~240 degrees CHT the coyote will pull your power to preserve the engine. If you hit that then you really need to slow down. Unfortunately the GT, PP or otherwise, was not meant to be a track car, so if you bring it to the track and drive it hard, don't be surprised if you activate limp mode. We were aware of the GT's ability or lack thereof to track well. Which is why we developed the M1. If you want a track ready mustang out of the box, go buy an M1 or a Shelby."

"I can't comment as to what's a safe range for the coyote, especially if there are any modifications. ~270 degree CHT is where you will start to lose gaskets and deform head studs, if you don't burn your oil first. ~250 degree is where limp mode comes into question, assuming no other failures occur. I would highly recommend avoiding these temperatures."

"Generally the road going versions of engines typically can run "hotter" as the internal parts allow for more fluctuation in tolerances with regard to heat and cooling cycles. The race engines are highly sensitive to heat differences, hence why the are preheated and cooled before and after the races. I can't speak to the design and function of the race engines, but I can guess the "lower" operating temperature is related to keeping the tolerances correct."

Hope the helps you all!

Interesting, thanks for sharing. so keeping it under 225F seems to be reasonably acceptable and well below 240F "warning" zone. 270F would be really crazy

 

[Jstang23]

Interesting, thanks for sharing. so keeping it under 225F seems to be reasonably acceptable and well below 240F "warning" zone. 270F would be really crazy

Interesting, thanks for sharing. so keeping it under 225F seems to be reasonably acceptable and well below 240F "warning" zone. 270F would be really crazy

I'll definitely be keeping it under 225 just to play it safe. At the end of the day the goal is to come home safe and sound! If anyone reaches 270 then I guess they deserve to deform their head studs lol!

 

[GTP]

FYI, 270-280 is oil temp range. 200-250 is CHT range.

 

[Jstang23]

FYI, 270-280 is oil temp range. 200-250 is CHT range.

I was referring to CHT! The engineer also only used CHT as well

 

[Knockdown]

To that I would add that us GT owners need to add an auxiliary oil cooler that has at least the cooling capacity of the M1/Shelby cars.

I'm still waiting to hear if any M1 owners also overheat the engine on track. That oil cooler is not really high capacity, but it certainly will help.

I was hitting the RPM pull back in a M1 at 84deg ambient at Sebring after about 5-6 laps with an A10. I boxed in the radiators with silicon rubber sheet and RTV and didn’t have any RPM pull back at 92deg ambient last track day.

 

[67Fast_V]

Update:

This is what he said!

"That's somewhat of a loaded question. The coyote's fan initiates between 212-215 degrees CHT. This is by no means an indicator of what the normal operating temperature is. Depending on where you live, the nature by which you drive, or a slew of other factors, there isn't a standard operating temperature. Also, we tend to avoid using terms such as normal operating temperature in the industry as normal is such a wide term. Some may say normal is anything that's not damaging your car. Others say normal is daily driving your car to work and back. Use that information as you will."

"If you're hitting ~240 degrees CHT the coyote will pull your power to preserve the engine. If you hit that then you really need to slow down. Unfortunately the GT, PP or otherwise, was not meant to be a track car, so if you bring it to the track and drive it hard, don't be surprised if you activate limp mode. We were aware of the GT's ability or lack thereof to track well. Which is why we developed the M1. If you want a track ready mustang out of the box, go buy an M1 or a Shelby."

"I can't comment as to what's a safe range for the coyote, especially if there are any modifications. ~270 degree CHT is where you will start to lose gaskets and deform head studs, if you don't burn your oil first. ~250 degree is where limp mode comes into question, assuming no other failures occur. I would highly recommend avoiding these temperatures."

"Generally the road going versions of engines typically can run "hotter" as the internal parts allow for more fluctuation in tolerances with regard to heat and cooling cycles. The race engines are highly sensitive to heat differences, hence why the are preheated and cooled before and after the races. I can't speak to the design and function of the race engines, but I can guess the "lower" operating temperature is related to keeping the tolerances correct."

Hope the helps you all!

Thanks for reaching out to the engineers and posting info, JS23. Appreciate that. I have been severely distracted in regards to my track efforts and have yet to prove out my "final" cooling configuration. Definitely have learned a lot from the Forum and the modelling/testing I have done. I'm ready to put a check in the box for sure.

Just a few quick thoughts. As Knockdown mentioned, the M1 is not fully ready for the track under higher ambient conditions. Although the grill size of the M1 helps the cooling, there is still way too much leakage around the radiator to effectively cool the engine under track loading and higher ambients. I have to believe the engineers know this. But sealing takes design time and adds to production costs, so I get it.

My GT data shows that at around 242F CHT, the computer takes over in a more intrusive way (above and beyond pulling timing) ... by changing redline. The calculated oil temp is the limiter for the GT. Now I'm not sure what limits the M1 (oil temp, ECT/CHT, etc), but one of these days Knockdown and I will meet at the track and I will hand over my laptop for him to run a session so we can better understand what the M1 is doing. This assumes he will want to do that which I have not discussed w/ him.

Will certainly report back when I have my "final" track proven data and if Knockdown and I can meet-up at the track and are able to share some data. Thanks again for the input. Cheers.

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