First HPDE today and the car started running hot??? Ac was on

[5.0calypsonotch]

Hi Guys:

I have a 2020 Musta g GT. Not a PP car. Anyway, went to an HPDE evebt today at Sebring and had a blast. For some reason, the track guy told me told me to leave my ac on. It was on at like 62. The car has a CAI, Roush Tune to go with it and and X Pipe and is otherwise stock. The car has never overheated before.
So I’m five laps in or so and I look down. Only doing 80-100 and my temp gauge is moving toward H. I’m like huh? I immediately shiznit the ac off. Temperature came right down. Windows open obviously. As a drag racer, I never use ac on the track and I was surprised when he told me I could. Maybe he just meant the air. Anyway, I turned it on again and again thr temp came up and then went right down when I turned it off. Ram another 7 laps with no issues and had a blast. I was paddle shifting and staying in high rpm range. Never do that on the street. Was the ac the cause of the over heat? Or the arming I should say? No check engine lights no limp mode, not even a loss of power. Glad I looked at the gauge. Not sure if it would have kept climbing or not. I was in track mode. Any ideas? My theory is running ac on the track was stupid and put way too much load on the ego r at high RPm. It only cuts ac at WOT and I was never at WOT, being my first time out and pacing myself behind the instructor car and a car behind me. Car an perfectly with air on the whole two hour ride home. Is this just because I was revising the help of it chasing this guy down? Would love advice from some guys who actually know. I’m a pro at drag racing with thousands of passes, but this is new to me.

 

[Bill Pemberton]

No sure why he told you to leave the A/C on and with most performance cars the A/C kicks off under full power . Your simple answer is leave it off since it never ran hot then and if you want to use the air conditioning , flip it on on your cool down lap after the your session is over. I use my A/C on every hot track day, but only when my runs are over , I am going around the track to cool everything down and the A/C is to do the same for me!

 

[5.0calypsonotch]

No sure why he told you to leave the A/C on and with most performance cars the A/C kicks off under full power . Your simple answer is leave it off since it never ran hot then and if you want to use the air conditioning , flip it on on your cool down lap after the your session is over. I use my A/C on every hot track day, but only when my runs are over , I am going around the track to cool everything down and the A/C is to do the same for me!

Yeah I agree. Mine kicks off at WOT. But we weren’t going fast enough for that. I never whacked it all the way. This was my first time out and they kept us pretty slow. As soon as I killed the ax, came right back to normal. Was a hell of a good time though. Thanks for your advice!!! I really appreciate it.

 

[5.0calypsonotch]

No sure why he told you to leave the A/C on and with most performance cars the A/C kicks off under full power . Your simple answer is leave it off since it never ran hot then and if you want to use the air conditioning , flip it on on your cool down lap after the your session is over. I use my A/C on every hot track day, but only when my runs are over , I am going around the track to cool everything down and the A/C is to do the same for me!

I knew better. I should have left it off lol. Not sure what Inwas thinking, but I guess you gotta learn somehow. On thr street it’s fine. But we aren’t running like that on the street.

 

[blacksheep-1]

I always turn mine off, even though it kicks off at WOT, I can't imagine that poor compressor clutch kicking in at just under WOT.

 

[5.0calypsonotch]

I always turn mine off, even though it kicks off at WOT, I can't imagine that poor compressor clutch kicking in at just under WOT.

Yeah idk why he told me to run it. Maybe he just meant run the air without ac. Idk. Not doing that ever again.

 

[Mad Hatter]

Yeah idk why he told me to run it. Maybe he just meant run the air without ac. Idk. Not doing that ever again.

Maybe his friend was at the event in a Camaro??

 

[5.0calypsonotch]

I always turn mine off, even though it kicks off at WOT, I can't imagine that poor compressor clutch kicking in at just under WOT.

What kind of cylinder head temps do you see? I’ve never seen my temp gauge move that way before ever. I was paddle shifting and I guess leaving at too high and rpm for too long and combined with ac, probably just overloading it.

 

[ScottD]

I was just at a Chin Weekend at Sebring. Temps outside were around 85F. I was running the A/C while sitting on the grid just to be comfortable. Forgot to turn it off. Once on the track maybe 5 laps into the session, the engine started governing itself at around 5000 rpm. I was at WOT and when it hit 5000 RPM it just cut the power and barely accelerated further. No warning lights, all gauges were normal , cylinder head temp was showing 217F. I was like “WTF”!. I slowed down and did a slow roll through the pits, realized the AC was on, turned it off, and all was ok. Back in the paddock I ran a scan and it showed an engine oil overheat code. I cleared the code and ran the next day with AC off and no issues or codes. Don’t really know what’s going on there. Just don’t run the AC while on the track. BTW, best lap (AC off) was 2.26.8. Sebring is a fun track! Can’t wait to go back.

 

[Bill Pemberton]

On warm days S197s can run hot on occasion, which is why many folks have gone with Boss 302S grills or others to cool things down. Two very effective fixes are to get a vented hood (like offered by chicane23.com ) or to buy a vent kit and cut your existing hood. Lastly, it sounds simple , but I have had great luck sucking out some anti-freeze and refilling with 2 bottles of Water Wetter. I have done this on my cars for 20 years and it really seems to work well.

PS -- the hoods from chicane23 are often called Tiger Hoods by other aftermarket sellers, but keep in mind they all buy them from him. Jonathan Blevins ( owner of chicane23 ) may sound familiar as he has won the Ultimate Streetcar Challenge 4 times in his yellow GT500.

 

[Paul McWhiskey]

After installing Race Louvers is it a good idea to open up the stock grill for added airflow or does that just increase drag and lift?

 

[Bill Pemberton]

Good question, and AJ might pop on here to answer that question, I can only answer for two of my cars , a 2013 Boss 302S and a 21 Mach 1. The Boss S has a more open grill and with a chicane23.com CF hood I would run 30-40 minute races and it would seldom run over 200 degrees. With the Mach 1 I removed both of the covers for the driving light areas in the grill , opening up more air , and with the Anderson Composite CF hood, water temp was identical --- hard to ever get the car to run 200 degrees , it sat in the 195-198 area almost always.

....and yes, I had 2 bottles of Water Wetter in both machines, ha!

 

[Tri-bar]

I never run with the A/C on, it's never a good thing at the track. J/K , Don't have A/C. Work on unblocking the grille area, air flow is key. Hot days, 108* at Button Willow Ca, I run about 220-230 at 7800 RPM's and like Bill said 2-3 bottles of water wetter and distilled water in the radiator.

 

[EF1]

High rpm’s tends to eat ac clutches and leads to overheating I always turn mine off when on track. A bigger radiator, better cooling fan and a less restrictive grill didn’t do much to lower operating temperatures on my car. More air in didn’t help until I installed race louvres to give it a path out.

 

[TMSBOSS]

Be sure to turn off A/C on track. The clutch will disconnect every time you go to full throttle. This may burn up the A/C clutch and will definitely dump heat into your cooling system.

 

[Bugs]

On hot track days, I use A/C on the grid and on the cool-down. However, several times on-grid, I've forgotten to turn the A/C off. I now use a mnemonic to assist.

Can't be 100% positive if it's causation or correlation, but I've maimed two A/C compressors so far - both during a track day (there's a strong indicator for you).

Both failures were covered under warranty. The first under my factory warranty and the second under my FordProtect Extended warranty.

 

[TMSBOSS]

I forgot to turn off the A/C a few years back. My instructor (Bill) was very comfortable, both because the car was cool while on grid and because the Boss over heated less than 10 minutes into the run. During the cool down laps the A/C was on providing Bill with additional comfort. Now I never run the A/C on a track day. What did Forest Gump say.... Stupid is as stupid does.

 

[Bill Pemberton]

One of the coolest student runs I ever had, what a considerate guy!

 

[EF1]

And you didn't point out that he should turn the air off when on track?

 

[TMSBOSS]

And you didn't point out that he should turn the air off when on track?

What he said