napacruzerc5

Got the first all Corvette autox for the year last Sat and Sun. Really heated up Sunday low 90's. On Sunday in a 25-30 car run group I would come in after a run, shut off, then pop the hood. Don't mind other people seeing "what I got" since there's really nothing to see. I noticed only 5-6 other vettes did the same. I always thought that by at least opening the hood you would not "heat soak" the engine. Also when it was time for me to move up the line I would turn on the AC to get the fans going and would notice at least a 10-degree drop in temp. I did forget to turn off the AC on the 4th run (of 5 runs) and it turned out to be my best. Guess it helps to keep cool when racing. Was I overreacting? Opinions please. Thanks

froggy47

All sop when it's really hot, no worries.

TedDBere

First of all you should never be worried about popping your hood at an autox. Compliance to the rules is done by competitor protests and openning your hood and trunk is mandatory at national events while in impound so your competitors can visually check your car for compliance. If someone won't pop the hood when requested then there is an issue.

Cooling the car's engine is up to you. I always kick the AC on when the temp rises above 220 degrees. If that won't cool it down below 220 then I'll pop the hood between runs too.

Corvettes have great ACs and tons of power to spare. On hot days it's not uncommon for the instructors to want to ride with you to cool down. Locally running with the AC on will probably not hurt your times as long as there are no slow elements that you can mash the pedal down and not spin the wheels. I'll even use the AC for conditions where I want less power, ie rain.

Good luck and have fun.

VetteDrmr

Question about running the A/C: I've always thought that the A/C compressor disengages when you're WOT. Therefore I've always run with the A/C off; not because I'm worried about 5-10 hp loss, but because I didn't want the wear and tear on the A/C compressor clutch when it re-engages (typically the engine rpm up close to redline).

Am I wrong?

TIA, and have a good one,
Mike

StealthLT4

I know it disengages at WOT on LT-series motors, so I'm inclined to believe it does the same for LS...

waktasz

If you really want to cool the car off quickly, turn on the heat, not AC.

VetteDrmr

Um, not so sure about that. Turning on the AC turns on the cooling fans, which are going to move a LOT more air than the heater. I guess you *could* run both. Frankly I do the AC because it's easy and it cools ME down.

Have a good one,
Mike

DarthStimpy

in the LS2 and newer the AC NEVER disengages. You can set RPM and TPS disengage and re-enable points with HP Tuners if you want to.

And you can set your fans to come on earlier and stay on after you shut the car down.

68sixspeed

The auto-x and even drag tracks around here frown on using a/c in staging - the water off the systems on the track. The straight line guys are just jealous I figure of not sweating in the lanes, but having run a car on slicks I know the point that even a bit of moisture is no fun.

TedDBere

Matt, just for clarification. The cooling fans are on the radiator. In the C5 there are two fans. Using the AC activates the second fan to move more air through the radiator and drops the water temp quickly.

BrianCunningham

I like popping the hood after a run on hot days

If your in a class that permits it, you can install a manual fan switch.
Keep an eye on the battery, an alternator will burn itself out trying to charge a dead battery.
Leaving an autox on a flatbed really $uck$

On cool days, I need to keep it shut to keep heat in the tires, C4 Clamshell.

napacruzerc5

Thanks for the informative replies. I remember in my younger days running a BP car having to spray the radiator with water from a garden type pump sprayer. Don't know how the car or the wife or I survived those days when we didn't have the forum to ask questions and to learn from.

meldog21

I have a real cheap alternative to a switch for hot days. It's a jumper wire for your fuse panel. I keep the wire stored in the fuse panel. I have the connection points marked. If you connect as shown in the pictures it keeps the fans on whether the engine is running or not. You can also replace the relay with the jumper wire in place, just squish it down over the wire. Everything in the car will function as normal, but the fans will stay on until you remove the jumper wire. Just remember to unplug at the end of the day.

Dog

StealthLT4

Interesting; how much does it cool it down in between runs? I know it helps, but I'd think that without actual coolant flow the stuff in the engine won't see any effect.