Track Time Limited due to High CHT

[TeeLew]

208 is CHT and yeah I really need to see how it goes at the track. I’ve been over 220 before on a 92 degree day and the car has been fine.

I was hoping I’d see some noticeable decrease and have not.

If you haven't changed the thermostat, you never will.

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[bnightstar]

If you haven't changed the thermostat, you never will.

also 208 is the standard running temp of the engine if he push the car on the street in a canyon and after 20 minutes of running hard up a hill is still 208 I wouldn't call it a waste. On a hot day in a canyon I see my CHT rising all the way to 221 F. So if he is staying in 208 that would be great. But yeah you need better thermostat.

 

[slowdown]

If you haven't changed the thermostat, you never will.

Yeah I was thinking that’s pretty obvious and was just trying to decide if I’m going to do a 160 or 170.

Ended up going with the 160 Mishimoto and will be here Thursday. Hoping that’s the simple solution.

 

[GTP]

Nope just driving the back roads. 208 degrees on an 82 degree day. Not pushing the car really that hard.
Bummed.

I’m getting all sorts of feedback from people. One dude says wrap my headers, another says maybe my timing is too advanced on my tune.

I’m inclined to get more air to the radiator so leaning in the direction of pulling out the unit in front of the radiator

Well then that explains it. Your car temps will be normal until your first track session of at least 20min. Even then you may not reach max CHT for your setup until the next session.

You did a good thing putting in both of those kits.

That doesn't sound right.

Dumb question: Zero drop in temps while on track right?

I guess my question wasn't so dumb after all!

 

[GTP]

Yeah I was thinking that’s pretty obvious and was just trying to decide if I’m going to do a 160 or 170.

Ended up going with the 160 Mishimoto and will be here Thursday. Hoping that’s the simple solution.

You don't need a different Tstat. When the car heats up (from track use), the Tstat will be fully open, whatever the rating.

 

[Hack]

Cold water will help make more power, but it also reduces engine longevity. I would avoid a colder thermostat just for that reason.

 

[Egparson202]

Cold water will help make more power, but it also reduces engine longevity. I would avoid a colder thermostat just for that reason.

Please elaborate on how a colder thermostat reduces engine longevity. TIA

 

[Hack]

Please elaborate on how a colder thermostat reduces engine longevity. TIA

I don't know what TIA is, but friction is higher at colder cylinder liner temperatures. I would assume it's somewhat common sense that oil gets thinner at higher temperatures and so you will have more friction in your engine if you reduce the engine's operating temperature.


However, common sense might not satisfy you, so I looked for more info online. I remember reading about it in an engine rebuilding book years ago that had a really nice plot showing faster cylinder bore wear at lower engine operating temperatures. I did a search today and didn't find something super easy and clear to show you, but here's something you can peruse if you would like.

https://www.sciencedirect.com/science/article/pii/S0306261917301022

And a quote from the article that should address your question somewhat.

 

[slowdown]

It was explained to me to think of a ratio. If the fluid enters at 180 and say the car runs at 210 that’s actually proportional to how much the coolant can do relative to the temperature that it began the cooling process. So if an engine is 20 degrees colder when that process starts the theoretical temp will be lower because the coolant began 20 degrees colder.

So with my new radiator and cooler and more fluid in the system allowing it to open at 180 is defeating the purpose because the engine is going to hit 208 regardless. But if it opens at 160 the engine won’t be allowed to heat up that much. This has been the same answer I’ve gotten from a lot of people.

I’ll be a good test pilot to see if it makes that much difference.

 

[Biggsy]

I don't know what TIA

“Thanks in advance”

That will probably be my best input of the day lol

 

[TeeLew]

You don't need a different Tstat. When the car heats up (from track use), the Tstat will be fully open, whatever the rating.

Sure, but if you can run lower engine temps, it's an advantage. When racing, these engines run about ~185*F on coolant, so maybe 200 CHT. This is better for engine life & power. A car doesn't have to go into limp mode to be running too hot. That's just the point where the ECU can't compensate any further and it's saving you from yourself.

 

[GTP]

On track, any Tstat will be fully open at some point. Max temp is reached pretty quickly. Giving it a "head start" with a lower Tstat won't make any difference, unless maybe for the first session of the day. But the engine heat soaks and doesn't cool off completely between sessions anyway.

I assume Ford designed the coyote to use a 180 Tstat for street driving, and (as was just pointed out) making the engine run a bit cooler with a 160 Tstat is not optimal to them.

Personally I don't think it matters much whether on track or on street. There are other places I would spend my money than for a lower Tstat.

 

[NeverSatisfied]

It was explained to me to think of a ratio. If the fluid enters at 180 and say the car runs at 210 that’s actually proportional to how much the coolant can do relative to the temperature that it began the cooling process. So if an engine is 20 degrees colder when that process starts the theoretical temp will be lower because the coolant began 20 degrees colder.

So with my new radiator and cooler and more fluid in the system allowing it to open at 180 is defeating the purpose because the engine is going to hit 208 regardless. But if it opens at 160 the engine won’t be allowed to heat up that much. This has been the same answer I’ve gotten from a lot of people.

I’ll be a good test pilot to see if it makes that much difference.

I’d skip the tstat and add ducting. My pile runs so cold on the street I finally covered up the grill to get oil over 200. With a stock tstat

 

[slowdown]

On track, any Tstat will be fully open at some point. Max temp is reached pretty quickly. Giving it a "head start" with a lower Tstat won't make any difference, unless maybe for the first session of the day. But the engine heat soaks and doesn't cool off completely between sessions anyway.

I assume Ford designed the coyote to use a 180 Tstat for street driving, and (as was just pointed out) making the engine run a bit cooler with a 160 Tstat is not optimal to them.

Personally I don't think it matters much whether on track or on street. There are other places I would spend my money than for a lower Tstat.

It’s $63 shipped and a few nuts to swap. Not that big of a deal considering I have a lot more into new radiator and oil cooler.

If it doesn’t make a noticeable difference then I’m going to remove the AC condenser from in front of the radiator. If that doesn’t do too much I’ll probably go back on the dyno and see if they can pull timing to cool her down. Also may have the headers heat wrapped.

 

[slowdown]

I’d skip the tstat and add ducting. My pile runs so cold on the street I finally covered up the grill to get oil over 200. With a stock tstat

I was out on the street again today hammering around and reached 212CHT

But yeah I’m going to pull off the fascia this week and have a look at helping the air flow.

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