Camed LS3 and A/C on engine temps
Thread Starter
Le Mans Master
Joined: Dec 2013
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From: Charles Town WV
2024 Corvette of the Year Finalist - Modified
2023 C6 of the Year Winner - Modified
2022 C6 of the Year Finalist - Modified
Camed LS3 and A/C on engine temps
Hey guys, been just dealing with it for the last 2 years but curious if there's a solution. Ever since doing the Cam in my car 2 years ago I've consistently seen temps climb to the "uncomfortable making me nervous" level with the a/c on if I'm not actively moving. I typically will see a steady climb to 220-230 on a hot day if stopped with the a/c on, typically I'll kill the a/c if it gets near 230. Moving with the a/c on I see around 190-195. After burning up a fan module last year I decided to upgrade to a dewitts and have a GC cooling high vol fan on it on its own thermostat... still the same results (maybe a hair better). Is there something I'm missing or is it just the nature of these things to run hot with A/C on? I've tried water-wetter with slight results but still not enough where I feel completely comfortable. a/c off cruising I'm around 178-182 on average. I'd love to be able to enjoy the a/c again without having to constantly gauge watch. Any suggestions?
Burning Brakes
Joined: Jan 2018
Posts: 973
Likes: 268
From: Oro Valley Arizona
Have the ECM tuned for fans to come on at a low temp and on high speed. 230 is okay as long as it cools down when driving. Also I think the fans are set to come on high speed at 230.
Le Mans Master
Joined: Dec 2005
Posts: 6,999
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From: Southeast TX
My last Vette (2013 Grand Sport) had a Dewitts radiator with integral trans and engine oil coolers. Even with a Magnuson heat exchanger in front of the condenser, I could idle it in hot weather with the A/C blowing cold. ECT's rarely got above 210. It would only get that hot idling for extended periods in hot weather. Moving, it wouldn't get over 180 with a 160* stat and aggressive fan settings. I actually thought it ran too cool in cooler weather.
I'd check for an air flow problem. Maybe the condenser has a little trash in it? That Vette had a mild blower cam with Magnuson Heartbeat. I did remove the stock Grand Sport air/oil engine oil cooler in favor of the Dewitts radiator with the integral EOC.
I'd check for an air flow problem. Maybe the condenser has a little trash in it? That Vette had a mild blower cam with Magnuson Heartbeat. I did remove the stock Grand Sport air/oil engine oil cooler in favor of the Dewitts radiator with the integral EOC.
Thread Starter
Le Mans Master
Joined: Dec 2013
Posts: 6,338
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From: Charles Town WV
2024 Corvette of the Year Finalist - Modified
2023 C6 of the Year Winner - Modified
2022 C6 of the Year Finalist - Modified
My last Vette (2013 Grand Sport) had a Dewitts radiator with integral trans and engine oil coolers. Even with a Magnuson heat exchanger in front of the condenser, I could idle it in hot weather with the A/C blowing cold. ECT's rarely got above 210. It would only get that hot idling for extended periods in hot weather. Moving, it wouldn't get over 180 with a 160* stat and aggressive fan settings. I actually thought it ran too cool in cooler weather.
I'd check for an air flow problem. Maybe the condenser has a little trash in it? That Vette had a mild blower cam with Magnuson Heartbeat. I did remove the stock Grand Sport air/oil engine oil cooler in favor of the Dewitts radiator with the integral EOC.
I'd check for an air flow problem. Maybe the condenser has a little trash in it? That Vette had a mild blower cam with Magnuson Heartbeat. I did remove the stock Grand Sport air/oil engine oil cooler in favor of the Dewitts radiator with the integral EOC.
Burning Brakes
Joined: Mar 2014
Posts: 1,238
Likes: 203
From: Lexington South Carolina
I have always wondered why some supercharged vettes have this issue and some dont. I am still running stock radiator and fans, and I never get over 215-220 in traffic with the ac on. 100+ degrees during the summer normal around here. Curious if not running enough timing at idle causing elevated temps if there isn't airflow issues through the condenser and radiator.
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,108
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
The simple solution is to pull off the rubber hood seal on the cowl. The heat will be blown out by the fan at speeds below 20-25 mph and ambient outside air sucked in at higher speeds.
Le Mans Master
Joined: Dec 2005
Posts: 6,999
Likes: 1,685
From: Southeast TX
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,108
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
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Race Director
Joined: Sep 2007
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From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Try taping a 6" long string or yarn, on the back edge of the hood near the center. Without the engine running and the car stopped, the string lays limp. Start the engine and the string will run up the windshield toward the top. Start driving and as you get in the 20-25 mph range, the string will go limp again. If you go faster, the string will be sucked back under the hood. It's basic aerodynamics that you can visualize.
Thread Starter
Le Mans Master
Joined: Dec 2013
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From: Charles Town WV
2024 Corvette of the Year Finalist - Modified
2023 C6 of the Year Winner - Modified
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The coolant fan blows out the upper underhood heat through the gap left when the rubber seal is removed. It works best when the car is stopped, but still assists up to 20-25 mph. With the rubber seal in place, the fan can only push heat out the bottom.
Try taping a 6" long string or yarn, on the back edge of the hood near the center. Without the engine running and the car stopped, the string lays limp. Start the engine and the string will run up the windshield toward the top. Start driving and as you get in the 20-25 mph range, the string will go limp again. If you go faster, the string will be sucked back under the hood. It's basic aerodynamics that you can visualize.
Try taping a 6" long string or yarn, on the back edge of the hood near the center. Without the engine running and the car stopped, the string lays limp. Start the engine and the string will run up the windshield toward the top. Start driving and as you get in the 20-25 mph range, the string will go limp again. If you go faster, the string will be sucked back under the hood. It's basic aerodynamics that you can visualize.
Went ahead and took it off but didnt get a chance to try it with the weather yesterday. Hopefully ittl make a little bit of a difference.
Pro
Joined: Jan 2020
Posts: 623
Likes: 130
From: Az
Hey guys, been just dealing with it for the last 2 years but curious if there's a solution. Ever since doing the Cam in my car 2 years ago I've consistently seen temps climb to the "uncomfortable making me nervous" level with the a/c on if I'm not actively moving. I typically will see a steady climb to 220-230 on a hot day if stopped with the a/c on, typically I'll kill the a/c if it gets near 230. Moving with the a/c on I see around 190-195. After burning up a fan module last year I decided to upgrade to a dewitts and have a GC cooling high vol fan on it on its own thermostat... still the same results (maybe a hair better). Is there something I'm missing or is it just the nature of these things to run hot with A/C on? I've tried water-wetter with slight results but still not enough where I feel completely comfortable. a/c off cruising I'm around 178-182 on average. I'd love to be able to enjoy the a/c again without having to constantly gauge watch. Any suggestions?
I have some prospeed fans and I think I'm gonna go with a Mishimoto rad to see of those two solve the issue.
One more thing. Lots of guys exaggerate or outright lie about their normal operating temperatures. I'm not exactly sure why they do it lol.
Do you still have a radiator shroud? Do you have a varaRam?
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,108
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
My Z behaves the same way in 100* heat. On the freeway with the AC on it will stay at 200. But around town with lots of red lights it creeps up to 230*. This is Phoenix AZ one of the hottest places on earth.
I have some prospeed fans and I think I'm gonna go with a Mishimoto rad to see of those two solve the issue.
One more thing. Lots of guys exaggerate or outright lie about their normal operating temperatures. I'm not exactly sure why they do it lol.
Do you still have a radiator shroud? Do you have a varaRam?
I have some prospeed fans and I think I'm gonna go with a Mishimoto rad to see of those two solve the issue.
One more thing. Lots of guys exaggerate or outright lie about their normal operating temperatures. I'm not exactly sure why they do it lol.
Do you still have a radiator shroud? Do you have a varaRam?
BTW, when was the last time you reverse cleaned your radiator and condenser with a water wand? If it's been more than a year or 10K miles, you're overdue.
Thread Starter
Le Mans Master
Joined: Dec 2013
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From: Charles Town WV
2024 Corvette of the Year Finalist - Modified
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No vararam here, airstream is clear. The fan is shrouded and moves a good volume of air. Not sure if the lying about temp things was aimed at me. I have no reason to lie about it, clearly there's an issue. The car runs perfectly cool and happy until I kick the ac on at low speed or sitting still then it acts stupid. I tried removing the seal and it does seem like its helped slightly.
Pro
Joined: Jan 2020
Posts: 623
Likes: 130
From: Az
No vararam here, airstream is clear. The fan is shrouded and moves a good volume of air. Not sure if the lying about temp things was aimed at me. I have no reason to lie about it, clearly there's an issue. The car runs perfectly cool and happy until I kick the ac on at low speed or sitting still then it acts stupid. I tried removing the seal and it does seem like its helped slightly.
I was referring to a radiator shroud. Definitely need one of those
Thread Starter
Le Mans Master
Joined: Dec 2013
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From: Charles Town WV
2024 Corvette of the Year Finalist - Modified
2023 C6 of the Year Winner - Modified
2022 C6 of the Year Finalist - Modified
Typically without it running i see 180 moving 190 sitting, the radiator does have an aftermarket aluminum shroud though I'm not sure if its sealed enough, could be allowing some air to escape around it. Might be worth looking into.
Thread Starter
Le Mans Master
Joined: Dec 2013
Posts: 6,338
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From: Charles Town WV
2024 Corvette of the Year Finalist - Modified
2023 C6 of the Year Winner - Modified
2022 C6 of the Year Finalist - Modified
235 scares me, i know alot of guys say its fine but to me that just seems like melt **** territory. Maybe I'm just being overly paranoid.
Burning Brakes
Joined: Jan 2019
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From: Dallas, Tx