Which A/C compressors are variable rather than on/off with a clutch?
Thread Starter
TECH Addict
iTrader: (10)
Joined: May 2005
Posts: 2,487
Likes: 2
From: Pittsburgh, PA
Which A/C compressors are variable rather than on/off with a clutch? So here's where I am at: The A/C compressor on my G8 is whirring and growling. I think it's on it's last leg. A replacement is north of $400... I think. Most discount retails have it for around $500. The G8 is an Australian car and low production so I get why it's so expensive.
Here's the catch - I believe the G8 compressor does not use a clutch to turn the compressor on and off. It uses a PWM system (pulse width modulator) to control how much the A/C compressor actually pumps. Instead of being all on, all off, it is variable.
With that said, what other GM LS compressors are variable and use PWM control? The G8 uses the "Corvette" spacing. I have heard talk of trying to switch in an LS2 compressor but nobody has done it, and I don't think it will work anyway because I think that compressor is clutch controlled, not PWM controlled.
Any help would be great! Otherwise, maybe a used compressor?!
Here's the catch - I believe the G8 compressor does not use a clutch to turn the compressor on and off. It uses a PWM system (pulse width modulator) to control how much the A/C compressor actually pumps. Instead of being all on, all off, it is variable.
With that said, what other GM LS compressors are variable and use PWM control? The G8 uses the "Corvette" spacing. I have heard talk of trying to switch in an LS2 compressor but nobody has done it, and I don't think it will work anyway because I think that compressor is clutch controlled, not PWM controlled.
Any help would be great! Otherwise, maybe a used compressor?!
98-02 Ls1 Fbody's came with variable compressors and they have clutches. Your compressor should still have a clutch to disengage it for when not in use, high head pressure, and loss of charge situatuons. Have you tried checking Rock Auto or trying to find someone that offers rebuilt models? Also make sure to replace the drier everytime you replace a compressor.
Thread Starter
TECH Addict
iTrader: (10)
Joined: May 2005
Posts: 2,487
Likes: 2
From: Pittsburgh, PA
Thanks! Yea, I know there is the used market. I just don't know how much trouble it will be to put it on. If it's a PITA then I'd rather get a new or reman. I found a reman for $391 shipped on eBay.
I am planning long tube headers next week so now might be the time to do it. If I replace it before it grenades, do I still need to change the drier? Why or why not?
Regarding the clutch, I am not so sure. If you look at all of the LS AC compressors, the on/off wiring leads to the front of the unit where the clutch meets the compressor body, which makes sense for an electronically controlled clutch. On the G8 compressor, the wiring goes to the rear of the compressor body. Weird.
The car does have 187k on it so I can't really complain all that much.
I am planning long tube headers next week so now might be the time to do it. If I replace it before it grenades, do I still need to change the drier? Why or why not?
Regarding the clutch, I am not so sure. If you look at all of the LS AC compressors, the on/off wiring leads to the front of the unit where the clutch meets the compressor body, which makes sense for an electronically controlled clutch. On the G8 compressor, the wiring goes to the rear of the compressor body. Weird.
The car does have 187k on it so I can't really complain all that much.
On The Tree
Joined: Sep 2014
Posts: 115
Likes: 1
From: St. Paul, MN
I've been messing around trying to find an AC compressor for my engine swap. My G8 compressor hits the engine mount. One thing I noticed is the G8 compressor uses a 3 bolt mounting scheme, and most of the other LSx compressors use 4 bolt mounting. So you have change the bracket to the engine as well. And it appears that the G8 uses the Corvette pulley offset.
TECH Enthusiast
Joined: Feb 2008
Posts: 503
Likes: 1
From: Ventura, Ca
The all the early cars have variable compressors. That includes the vettes, camaros, and GTO's. I have a very good GTO compressor for $75 that has the ports in the same basic location. I bought it for my factory ac conversion but it does not clear my side frame. I believe all the ac locations line up no matter what pulley system you are using. It is the rest of the system that has the different spacing depending on the belt system you are using. PM me if you are interested or talk to P Joe.
Thread Starter
TECH Addict
iTrader: (10)
Joined: May 2005
Posts: 2,487
Likes: 2
From: Pittsburgh, PA
I think the G8 compressor is one step past a variable compressor. The early cars still use an on/off switch to run the compressor clutch, and then I suppose the compressor mechanically regulates the pressure. On the G8 compressor, the way I understand it, the wire that activates the G8 compressor is not on/off - instead it is a signal that tells the compressor how much to pump, etc. It is not regulated mechanically, but electronically.
Regarding A/C locations lining up - if you are talking about the belt location, I am pretty sure there are at least some differences across the 3 spacing setups. (Corvette, F-body, truck) I put a truck pump on my conversion (my LS powered Jag, not my G8) and I wound up going to the truck spacing (same as some 2010+ Camaro) so I could have a compressor that would sit far enough ahead to fit.
Regarding A/C locations lining up - if you are talking about the belt location, I am pretty sure there are at least some differences across the 3 spacing setups. (Corvette, F-body, truck) I put a truck pump on my conversion (my LS powered Jag, not my G8) and I wound up going to the truck spacing (same as some 2010+ Camaro) so I could have a compressor that would sit far enough ahead to fit.
Trending Topics
I have a G8 GXP ac compressor that is virtually new for sale if you are interested. $200 shipped to you. It came from a car that was virtually wrecked after leaving the dealer lot when new.
Sent email to you.
Sent email to you.
Last edited by KENS80V; Nov 4, 2015 at 06:33 PM.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
