# LS2 Compression



## TrueRedGoat (Oct 19, 2006)

Hello...

I am thinking about purchasing an '05 M6 GTO. It has just under 11k miles. However, I'm a bit concerned because the dealer said that the tires look new. (He estimated 80% tread.) A friend suggested that I have a compression test done on the engine to see if it had been ragged out. Does anyone have specs for the acceptable range and compression for the LS2 in the GTO? Is there anything else I should look for?

Thanks...


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## MrGrandNational (Jul 12, 2006)

I don't think that's a big deal. I think the stock bfg's suck and I don't need to rag my car at all to turn the tires.


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## 05GTO (Oct 6, 2004)

I have 12 k miles on my 05 and the stock BFGs are in good shape,


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## CPO's GTO (Jul 1, 2006)

I would venture to say that 80% tread after 11000 miles on the stock 
tires means the car has not been dogged any harder than they 'should
be' as GTO's. Did you drive it? Did it throw you back in the seat really 
hard and put a big smile on your face? If so, I would say the compression
is fine. I can't remember the compression numbers of the LS2 but I think
they are on the pontiac site, or the GM crate motor site.


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## C5ORGTO (Dec 30, 2004)

I replaced my bald stock tires at 13,900 miles. So if that car still has 80% tread with that many miles, I would guess that someone did not abuse the car.

Compression ratio is 10.9:1


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## TrueRedGoat (Oct 19, 2006)

C5ORGTO said:


> Compression ratio is 10.9:1


Do you know what the psi (? - correct unit of measure) per cylinder should be. I found a motor on eBay that had 195-200 per cylinder.

I have not driven the car yet. I plan to this weekend.


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## kwiktsi (Apr 5, 2006)

TrueRedGoat said:


> Do you know what the psi (? - correct unit of measure) per cylinder should be. I found a motor on eBay that had 195-200 per cylinder.
> 
> I have not driven the car yet. I plan to this weekend.


Mine was in the 215-220 range with 5k miles, and is 205-215 now that it has had the daylights beaten out of it for 4500 miles @10+ psi.

It is damn near impossible to hurt the LS2 in any way in stock form within 11k miles with proper break in. If it had nitrous or FI on it at one point, that is another story.
Joe


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## TrueRedGoat (Oct 19, 2006)

kwiktsi, thanks for the info. The dealer sold the GTO before I could get to San Antonio. So the hunt is still on...


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## kwiktsi (Apr 5, 2006)

No problem. If you have any questions, just shoot me a PM or something. There are plenty of other GTO's out there, so you'll find one . It's best not to jump into one too quickly and shop around a bit anyway- I made the mistake of believing the dealer when they gave me the "this is the best we can do" speech. I found an IDENTICAL one about 3 days later for almost 4k less ...
Joe


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## aintmisbehavinn (Feb 9, 2006)

05GTO said:


> I have 12 k miles on my 05 and the stock BFGs are in good shape,


By the looks of your picture, must be drag radials? I need tires like yours if they are in the good shape!:lol:


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