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bore an LS4?

J

jlt695

New member
Im new here, and notice that alot of ppl have done some interesting things to there GXP's. but there also seems to be a small selection of aftermarket parts. i just recently bought an 2007 GXP, and wanted to know if anyone here has ever experimented with boring and sleeving. from my understanding the outer diameter of the 5.3 sleeve is roughly the same as a 5.7 sleeve, with in a few hundreths of an inch. Any thoughts? I also have an 88 camaro, and have some extra parts i would like to play with.
 


I don't think all the work would be worth it to get a larger displacement, just go FI or spray it. LSX motors go plenty fast on stock internals.

LSX parts don't interchange with the older SBC parts. If you're wondering why the aftermarket is so small for the LS4 is the fact that it's a FWD V8 limited production car. Don't get me wrong, I love the GXPs, but if you want to go fast in these cars you have to stick with the V6s.

I don't think that there's anything out beyond regular bolt ons for these motors.
 


jlt695 said:
Im new here, and notice that alot of ppl have done some interesting things to there GXP's. but there also seems to be a small selection of aftermarket parts. i just recently bought an 2007 GXP, and wanted to know if anyone here has ever experimented with boring and sleeving. from my understanding the outer diameter of the 5.3 sleeve is roughly the same as a 5.7 sleeve, with in a few hundreths of an inch. Any thoughts? I also have an 88 camaro, and have some extra parts i would like to play with.
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Contrary to popular belief there are quite a few LS2 parts that are interchangeable with our LS4.. The crank is an odd ball size eliminating an off the shelf stroker kit without serious modification. Sucks. Punching it out to a healthy 6.2 or 6.3 is a viable option.. fly notched, flat top or possibly domed pistons to raise the compression a bit.. LS2 intake, throttle body, fuel rails and injectors.. Gmpp hot cam, springs, rockers, headers and ofcourse a built trans/converter that can take the abuse.. It could be made into a healthy, reliable car.. but not cheap. This damn car was expensive when I bought it, is expensive to maintain and is expensive to mod, period. JMO:)
 
Sorry about where I first posted. First forum I have ever posted to. And I've talked to a few machine shops that said that you can swap Patsy with an ls2 or ls6. They said to do my research first because there will be snags with doing anything like that. Also anyone know if you lose your displacement on demand when putting on a Turbo?
 
There was a Fiero website that had an LS4 they did a cam and lifter swap on.. Very informative. And yes, they removed the DOD system entirely which also made room for the LS2 intake.
 


Boost IS the replacement for displacement.

You don't technically GAIN displacement from a turbo or supercharger...but they displace a certain amount to create the effect of it.

Hence...what...the GenIII Eaton is a 1.3 liter blower? I think...so...essentially your 3.8 liter V6 turns into a 5.3 liter...or that is how I always understood it.
 
bluegtp91 said:
Boost IS the replacement for displacement.
You don't technically GAIN displacement from a turbo or supercharger...but they displace a certain amount to create the effect of it.
Hence...what...the GenIII Eaton is a 1.3 liter blower? I think...so...essentially your 3.8 liter V6 turns into a 5.3 liter...or that is how I always understood it.
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IMO it trys but there is a difference you can feel when you drive plus you can't buy the sound of a V-8..

You don't gain displacement from forced air induction, it's just that, more air/fuel=more power. Raising compression=more power

It's still a V-6, with balls, til it blows a nut and scatters from the added strain on the bottom end or the air/fuel is off a little, leaning it out, burning a hole in the piston..

All I'm sayin is forced induction requires more maintenance and fine tuning.
A naturally aspirated motor is more reliable plus dumb red necks, like myself, can spend a weekend beefin up a motor and drivin it year round. Most "boosted" cars can't take temps below 50* without retuning.. JMO
 
I'm sure but they are tuned richer to make up for the colder temps. Down here in IL we see 0* as well as 100* friends of mine have to retune for the seasons to avoid detonation.. Again JMO
 
that's only because they are running on the ragged edge. with a conservative tune you can run the car all year round without much issue.
 


gtx3800 said:
I'm sure but they are tuned richer to make up for the colder temps. Down here in IL we see 0* as well as 100* friends of mine have to retune for the seasons to avoid detonation.. Again JMO
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Bio248 said:
that's only because they are running on the ragged edge. with a conservative tune you can run the car all year round without much issue.
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Both are true. Most people with tuners (like myself) are constantly adjusting because when you start pushing, you've got to keep on top of your climate for the best performance. BUT, that being said, you can find a happy medium, get good performance and not teeter on popping something too.

That being said, there's really only so far you can reasonably go with a pushrod engine, and sometimes you can't beat displacement. Even then, those have limitations.

I'm sure there's a reason why we only see a handful of local V6 guys pushing into the 10's, but you see V8 cars like that all day long at the track. :p
 
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