To tune or Not to tune?
Thread Starter
Teching In
Joined: Feb 2015
Posts: 13
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To tune or Not to tune? I have a question weather I should tune my car or not
I purchased a 99 Z28 a few months ago, it cam with an LS6 Manifold, a ported LS1 throttle body and Long tube headers. I Have removed the LT headers and Put the back the OEM exhaust manifolds, Cats and Muffler.. and kept the LS6 manifold and Throttle body..
I dont know if the previous owner tune the car for these changes, but I figure if he went through all this trouble to make these mods, he had to of tuned the car.. and there is no way to get a hold of the previous owner...
So.. Saying that he did tune the car for these MOD's and I change continue to run the car with the OEM exhaust system, are there any possible problems I may be running into but Leaving it alone? or should I just Tune it?
I purchased a 99 Z28 a few months ago, it cam with an LS6 Manifold, a ported LS1 throttle body and Long tube headers. I Have removed the LT headers and Put the back the OEM exhaust manifolds, Cats and Muffler.. and kept the LS6 manifold and Throttle body..
I dont know if the previous owner tune the car for these changes, but I figure if he went through all this trouble to make these mods, he had to of tuned the car.. and there is no way to get a hold of the previous owner...
So.. Saying that he did tune the car for these MOD's and I change continue to run the car with the OEM exhaust system, are there any possible problems I may be running into but Leaving it alone? or should I just Tune it?
He probably did not tune it, even if he did it would not have been a significant enough change that you swapping the exhaust would hurt anything. But if you dont think its running right or just want to get the tune, it will only make it better.
It's a 99 with a LS6 intake. Unless it's one of the goofy SLP LS6 intakes that they rigged an EGR port on it, it should have been at least setting EGR codes. If it wasn't, then something was done to the PCM. There are other things that could be clues but without knowing more details, I can't say.
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
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From: So.Cal.
To tune or Not to tune? If you can borrow an advanced scanner you can read the calibration CVN (similar to checksum) and then goto http://tis2web.service.gm.com/tis2web and punch in your VIN to see what the stock CVN is.
These cars run rich from the factory. Those mods would probably make the AFR at WOT more reasonable with the stock tune. If it was tuned the fuel was either not adjusted at or or barely touched (maybe even pulled some fuel out). So I wouldnt worry about the fuel adjustments.
None of those mods would change the timing. So dont have to worry about that. You can advance the timing a couple degrees over stock tune. If they did it wouldnt effect anything.
Conclusion: Dont worry about it, unless you want tune spot on for 5 extra hp, but since you went back to stock I would assume you dont care.
None of those mods would change the timing. So dont have to worry about that. You can advance the timing a couple degrees over stock tune. If they did it wouldnt effect anything.
Conclusion: Dont worry about it, unless you want tune spot on for 5 extra hp, but since you went back to stock I would assume you dont care.
