Track Time Limited due to High CHT

[tosha]

I really think starting with either a GT350 or GT500 front bumper & fenders makes things so much easier. There just isn't enough real-estate on the other noses to really keep things cool. Yes, you can start shooting air under the car, but you probably don't want it there for lift reasons. At the end of the day, you probably want to shoot the cooling exhaust out of the sides or back if you can. The side nose intakes of the 350/500 make this much easier. Pull through the front and exit though fender vents. For the center rad, you exit though hood vents. You don't really want heated air to go around the greenhouse, but this is kind of a take-what-you-can-get scenario.

For 2018+, I would pick mach 1 bumper, mainly for almost direct fit reasons. As far as those knockoff chinese gt500 bumpers for s550, I wouldn't trust them for track duty. Or figure out how to get those cutout grilles from roush max cooling kit without buying the whole thing)))

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[67Fast_V]

Yes, my other concerns I have not yet posted about are what you say.

1. Grille area is only half the HX stack area
2. Airflow restriction due to HX's covering each other
3. The accepted practice of keeping the HX's close to each other (no gaps)
4. Airflow losses due to side leaks
5. Loss of the water/oil HX requires large oil HX, which covers up the stack thus causing more flow restriction.

#1 can't be helped without a different bumper. (non starter for me)
#2 can't be helped without nixing the condenser (also non starter)
#3 is an issue because the gap between rad and cond is too small for standard thickness coolers. So we put a big oil HX in front of the stack, which leads to problem #5.
#4 can be addressed.
#5 has no clear solution.

The solution to one issue always seems to exacerbate a different one. Argh!

My current thinking is to choose a wide oil HX and mount it vertical and low in front of the condenser. So that's 3 HX's in the lower half of the stack, but with a 2" gap between condenser and rad. (And 3 in HX's still in the upper half). If oil cooling is solved, but trans remains a problem, then I would upsize the OEM trans cooler to a Setrab SLM to fit in the narrow gap.

Regardless, I just can't give up the AC.

I can't shake the feeling that Mach1 owners will be complaining about insufficient cooling next year.

A lot activity today. Let me add some mostly worthless info into the mix. I can't drive, so let me do some calculations .

@GTP, as promised ... I ran the calc's on the benefit of removing the stock GT water to oil cooler. Glad you pushed me to do it. It's an interesting study. See attached.

First, the stock oil cooler is a lot smaller than I thought. I took external dimensions off of mine and it's tiny. So my 30k-60k btu/hr guess from previous post was way off. No way it can shed that much heat. I think it's in the 15-30k btu/hr range. Best guess at this point is 23k btu/hr which provides a 15F reduction in CHT w/ the assumptions specified. Overall, I think this is pretty solid benefit.

Next up, is the "summary" chart. I dropped the oil cooler delete in the previous chart I posted to see how it compares. Basically 50% sealed + deletion of stock oil cooler gets you roughly equivalent to the Fully Sealed all-stock condition. To say it another way ... 50% reduction in leaks = stock oil cooler delete. ... that's how powerful leakage reduction is w/ a stock grille.

What this also means is that for a fully sealed system, the goal of 235F Max CHT can be reached by either... (1) opening the grille or (2) removing stock oil cooler and adding an air-oil cooler away from the radiator. (1) has an aero hit and (2) has a weight hit. Decisions decisions

Hope this helps a little w/ your decision making ... and maybe a few others that might be on the fence or struggling in general w/ cooling issues. Cheers.

 

[TeeLew]

Your goals never cool the car sufficiently. 235* is still probably 40* too hot.

To do this at normal engine temperatures, a ton of heat has to come out of both the water and oil. This is not a simple, "stick an oil cooler on it" type of a fix. Separating the oil and water is a way to use more cooling air, so I suspect it will be a gain. Having said that, the heat transfer rates of oil aren't that great, so it's tough to shed enough heat from an oil cooler to influence water temp much. Cooling the oil 10* might buy you 2* of water temp.

At the end of the day, if you want the water to run cooler, you have to get more heat out of it. Get a big, racing radiator which is boxed in and has a clean airflow exit path. That will help the water 10x more than simply playing with various oil coolers. I still don't think it will be enough. I think it will take a smaller aux radiator as well to keep temps in check.

 

[EFI]

Your goals never cool the car sufficiently. 235* is still probably 40* too hot.

Your reference/comparison to highly modified Ford 4 valve engines raced professionally is not really relevant here. Those engine clearances are significantly different than a mass produced engine, and their expected life is measured in hours not hundreds of thousands of miles.

The target temp for a stock Coyote is 212*, so there's no way in hell you're keeping that engine at 195* after 20 minutes of racing. Heck, that is too cold even for street driving according to the Ford engineers, they designed this engine to run hotter than that.

Ford a stock engine and amateur HPDE racing, there's nothing wrong with 235* CHTs.

 

[67Fast_V]

Your goals never cool the car sufficiently. 235* is still probably 40* too hot.

To do this at normal engine temperatures, a ton of heat has to come out of both the water and oil. This is not a simple, "stick an oil cooler on it" type of a fix. Separating the oil and water is a way to use more cooling air, so I suspect it will be a gain. Having said that, the heat transfer rates of oil aren't that great, so it's tough to shed enough heat from an oil cooler to influence water temp much. Cooling the oil 10* might buy you 2* of water temp.

At the end of the day, if you want the water to run cooler, you have to get more heat out of it. Get a big, racing radiator which is boxed in and has a clean airflow exit path. That will help the water 10x more than simply playing with various oil coolers. I still don't think it will be enough. I think it will take a smaller aux radiator as well to keep temps in check.

Regarding ..."Your goals never cool the car sufficiently. 235* is still probably 40* too hot."

To add something to EFI's point (which is not necessary by the way because he is 100% correct in my opinion) but maybe to put an exclamation point I will add this ... a 195F CHT goal is totally unnecessary from an engine health standpoint and very expensive and costly from a weight standpoint.

On the health point, Ford doesn't even think they need to turn the cooling fans on until 212F. I think that message is clear. And 195F doesn't even fully evaporate the water moisture in the oil. And the cost and weight penalty are clearly unavoidable. Cheers.

 

[EFI]

For last time the OEM oil cooler has a very tin aluminium plate between the oil and the coolant that because of heat have a tendency to brake. And as we know mixing oil and coolant is not great idea for any motor. So if you can get rid of that thing better do it.

How many of such failures happened? I have yet to really see any on the GT/Boss setup. I've seen more GT350 failures which have the air to oil cooler.

Yes anything can happen, but I have a hard time believe the issue is as big as they make it seem. I mean, this is coming from a company that's trying to sell you an expensive "fix". One line they say failures are bad, and the next line they say that solving this is to buy their kit. I smell a little sales driven bias here.

 

[TeeLew]

Ford a stock engine and amateur HPDE racing, there's nothing wrong with 235* CHTs.

I know WTF I'm talking about, but I'm not going to argue the point. Run it at 300 for all I care. For the record, the stock elevated running temperatures are for emissions, not performance.

 

[EFI]

I know WTF I'm talking about, but I'm not going to argue the point. Run it at 300 for all I care.

Not sure why you're so angry, I just said your experience is not relevant here. You getting mad at this makes me think you really don't know wtf you're talking about. Cooling requirements are different between a highly built tight clearance race engine that's meant to last a few hundred miles before a rebuild and a mass produced street engine meant to last tens of thousands of miles.

And who said running it at 300*? How did you turn 235 into 300? Where did I ever say 300* CHT is fine?

 

[NeverSatisfied]

Your reference/comparison to highly modified Ford 4 valve engines raced professionally is not really relevant here. Those engine clearances are significantly different than a mass produced engine, and their expected life is measured in hours not hundreds of thousands of miles.

The target temp for a stock Coyote is 212*, so there's no way in hell you're keeping that engine at 195* after 20 minutes of racing. Heck, that is too cold even for street driving according to the Ford engineers, they designed this engine to run hotter than that.

Ford a stock engine and amateur HPDE racing, there's nothing wrong with 235* CHTs.

It would be nice to get some Ford engineering guidance on running at full tilt ~225-230CHT which equates to ~210-215 ECT in the block and ~260 oil temp. I know TeeLew thinks we're on the brink of disaster, but I'm probably 30 hours+ running like this now and bumping 10,000 total miles on the car. She seems to be holding up well.

As a side note-- it's crazy how hard it is to cool these cars. Coming from a N/A miata with similar hp/Liter but pushing more Lb/hp, I followed the exact same steps as on my GT. However, the result was locked at 180-195F coolant and 240max oil temp @ 95F+ ambient when beating the dog crap out of it.

I found a picture of the radiator opening—it was probably 15-20% of the size of the radiator surface area and zero cooling issues.

Such a head scratcher.

 

[TeeLew]

Dude, I'm not mad. I've given my opinion/experience. If you don't want it, don't take it.

Yes, there are differences between a race engine and a street engine. In terms of bearing clearances, the street engine will want to run at a lower temp than the race engine, because it will necessarily have larger clearances (you don't preheat a street engine, do you?). CHT (or coolant) temp is a big determining factor when it comes to spark knock/detonation. The higher CHT is, the less power you're going to make, because the ECU will pull spark lead.

So, if you want to keep your bearing clearances reasonable (bearings and oil pressure don't like large clearances) and be able to make good power, you have to cool the car. But, hey, you do you.

 

[EFI]

I've given my opinion/experience. If you don't want it, don't take it.

And that's exactly what I initially said, before you threw your hands up in the air telling us how you know what the bleep you're talking about.

I just said your experience, while I'm sure is extensive, is not relevant to these engines and scenarios. You continually pushing the 195* CHT or else it will blow up scenario is not relevant to most if not all people on here. So yes, we're not going to take it because it's not ever going to happen on this vehicle and you peddling it on here is wasting your breath.

 

[TeeLew]

the result was locked at 180-195F coolant and 240max oil temp @ 95F+ ambient when beating the dog crap out of it.

Yep. BTW, this is the same engine as in the Eco and the same engine that has been used in several racing series. Those numbers are *exactly* where you run this engine when racing. Are we saying this is a coincidence?

 

[TeeLew]

And that's exactly what I initially said, before you threw your hands up in the air telling us how you know what the bleep you're talking about.

I just said your experience, while I'm sure is extensive, is not relevant to these engines and scenarios. You continually pushing the 195* CHT or else it will blow up is not relevant to most if not all people on here. So yes, we're not going to take it because it's not ever going to happen on this vehicle and you peddling it on here is wasting your breath.

You're right.

 

[Scootsmcgreggor]

It would be nice to get some Ford engineering guidance on running at full tilt ~225-230CHT which equates to ~210-215 ECT in the block and ~260 oil temp. I know TeeLew thinks we're on the brink of disaster, but I'm probably 30 hours+ running like this now and bumping 10,000 total miles on the car. She seems to be holding up well.

As a side note-- it's crazy how hard it is to cool these cars. Coming from a N/A miata with similar hp/Liter but pushing more Lb/hp, I followed the exact same steps as on my GT. However, the result was locked at 180-195F coolant and 240max oil temp @ 95F+ ambient when beating the dog crap out of it.

In the absence of input from ford engineers we can make some reasonable conclusions based on what they have done previously. I think the best comparison would be the FP350S. That engine makes more power than most of our 5.0 coyotes and they determined that a big radiator and a Setrab 960 oil cooler both ducted and with hood vents provided sufficient cooling for road racing with 50hr engine life between overhauls. What temps does that yield in harsh conditions? Is the 50hr expected life due to cooling temps or other wear variables? Not sure. But with a similar setup in my car in 90* temps with a fairly small hood vent yields ~215-220CHT and 250 oil temp. A number of guys on TMO have run this setup for many thousands of track miles without issue. So I think its at least a fairly well laid out path to relative success. Can better be done, I'm sure. What cost and how many iterations if done otherwise? A number of people in this thread are on a path to finding out!

Just throwing it out there again since there's what feels like a lot of wheel re-inventing going on here.

 

[paulm1]

Your goals never cool the car sufficiently. 235* is still probably 40* too hot.


Get a big, racing radiator

That's what i said and was told to "please stop".

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