Custum tune after upgrade

[johnm]

I recently upgraded my 04 coupe's exhaust by replacing the oem cat back exhaust with the corsa pace car catback exhaust. I love the new sound signature, however I really can't say I am able to appreciate the advertized increase in horsepower. I was reading in "VETTE" mag yesterday that the LS6 engine is tuned for a specific amount of back pressure and once you alter that pressure you need to custom tune the car on the dyno to maximize the available performance gains. Is this correct. Is this also true for the LS1. If so, who does this kind of stuff. Does it void the warranty to make these alterations. Can the tune make a noticable difference? thanks johnm

 

[Edmond]

John,

The computer controlled cars have a deviation on modifications. You can actually put a few mods on there without tuning the car because the computer has enough deviation in the stock tune to compensate. That being said, the stock tune is friendly for emissions and gas mileage, unleashing all the potential power isn't what GM had in mind with the stock tune.

As for the warranty, I really don't know. But I believe a tune is easily reversible.

 

[johnm]

Thanks for the reply Edmond. I spoke with an engineer I met that worked on the C6 project. Her reply was very similar to yours. She also added the stock tune is designed to maximize the engine's life span. They want to make sure the motors make it to the warranty's end. Are these custom tunes possible with these hand held devices marketed in all mags, or do you need a lap top and a car computer geek to do it right? johnm

 

[Edmond]

John,

Unless you know what you're changing, I would not mess with the tune. I would let a professional do that. Yes, the handheld devices can change the tune. But a lot of people tune after mods and while running on a dyno to see what their air/fuel ratio is throughout the whole RPM band.

 

[74bigblock]

John,

The handheld units only allow you to change basic functions such as: Rev limiter level, cooling fan turn on temp, shift points. If you are looking to get as much as possible out of your motor, you need to find a shop with a dyno and software to completely map your air/fuel ratio through the RPM range under load.

There is software you can buy out there to plug into a laptop through your OBDII port, but I wouldn't touch it with a 10' pole!!! I have no idea what I am doing there... dunno about you.

Dave

 

[fdxpilot]

I don't know what performance increase was advertised, or you were expecting. The stock C5 and Z06 catbacks are pretty free flowing. Conventional wisdom (at least on all the forums I visit) is a catback should only be bought for sound, not power. When I had LG Motorsports install their headers and tune my car, I still had the stock catback. They said I might pick up 5 hp with a good catback. IMHO, a catback on an otherwise stock engine needs no tuning. A tune might pick up some HP, but it would on a stock car, also.

 

[johnm]

Thanks for the info fdx.., I kinda figured that and I am satisfied with the sound. I would have done it anyway just for the sound. For the record, the manufacturer claims a 12 to 15 hp increase