Does A/C cutout at high RPMs?
Thread Starter
Drifting
Joined: Jul 2000
Posts: 1,661
Likes: 4
From: Phoenix, Arizona
Does A/C cutout at high RPMs?
I know it does on C5, but does the A/C automatically cutout on C4s above a certain RPM? What RPM? I am wondering about both my LT4 and my '89. Thanks in advance, Paul
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Re: Does A/C cutout at high RPMs? (oldman)
Reviewed both sections, electronic & manual air for the '93 in the GM manual, no mention of rpm cut-off. That doesn't mean there isn't a cut-off. It just means I have exhausted my single digit IQ.
Melting Slicks
Joined: Jun 2000
Posts: 3,215
Likes: 6
From: Tampa Florida
Re: Does A/C cutout at high RPMs? (NavyVet)
I don't believe it does on a 96 LT4. I know mine definitely feels strangled with the AC on compared to AC off. And there doesn't seem to be any release as I rev the engine (accelerate) thru the rpm scale.
Even older cop cars had that...seems like it would be standard on Corvettes-good idea.
:confused:
Even older cop cars had that...seems like it would be standard on Corvettes-good idea.
:confused:
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 60
From: Fremont Oh
Re: Does A/C cutout at high RPMs? (No Go)
The compressor will turn off for 10 seconds depending on load and throttle position. Generally WOT is anything above 60% throttle... so at WOT the compressor clutch will disengage for about 10 seconds then kick in again. This is from the Corvette fuel injection Manual... It is part of the fuel enrichment cycle.
Mo
Mo
Thread Starter
Drifting
Joined: Jul 2000
Posts: 1,661
Likes: 4
From: Phoenix, Arizona
Re: Does A/C cutout at high RPMs? (oldman)
My LT4 ('96 obviously) and '89 are both electronic. I ran a three flying lap High Speed event last weekend (actually more like four 1.1 mile laps becasue we had a half to warm up and half to "cool down." However, I forgot to turn the A/C off and left the track with coolant at 251 and oil at 293. It was about 113 degrees out, but it got much hotter than I expected in that distance. Ran good, but didn't seem to have its normal power - me stupid :bb
It's fine now, so I think the A/C didn't cut out. It did puke :U some coolant after I got off the track. I always just "assumed" the A/C compressor would cut out.
Oh, 24 years in the Navy - retired LDO - what's the Lone Sailor Memorial Foundation?
[Modified by NavyVet, 10:01 PM 9/6/2002]
It's fine now, so I think the A/C didn't cut out. It did puke :U some coolant after I got off the track. I always just "assumed" the A/C compressor would cut out.
Oh, 24 years in the Navy - retired LDO - what's the Lone Sailor Memorial Foundation?
[Modified by NavyVet, 10:01 PM 9/6/2002]
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: Does A/C cutout at high RPMs? (NavyVet)
I think this is more of a 4-cyl thing. My brother dyno'd his 99 Z-28 with the defroster on. We wondered why his dyno graphs looked a little low. Thing is a dyno pull only takes about 10 seconds, so if it was going to cut out it would have and you would have been able to see that in the actual graph.
Out of 4 pulls there was no evidence of the compressor kicking off. I wish we would have noticed that the defroster was on at the time! :smash: :smash: :smash:
Out of 4 pulls there was no evidence of the compressor kicking off. I wish we would have noticed that the defroster was on at the time! :smash: :smash: :smash:
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Le Mans Master
Joined: Dec 2000
Posts: 7,839
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From: San Diego, Ca
Re: Does A/C cutout at high RPMs? (NavyVet)
It's suppose to, dependent on throttle position. In order for the A/C clutch to engage, circuit has to be completed through the low pressure and high pressure cutout switches which then sends a signal to the ECM. Dash assembly needs a completed circuit to the ECM to engage clutch. ECM removes ground with full throttle signal from TPS opening circuit. Verify with scan tool. A/C request should be "NO" at full throttle. If so, and clutch remains engaged, dash assembly is probably at fault. If scan shows "YES" at full throttle, could be the TPS needs adjusting - check scan voltage - or its the ECM.