dealer06

Can anyone clarify whether I would need a tune on a 2008 coupe if I replaced my exhaust system with a 3" system from a Z06? I'm talking about manifolds, cats, h-pipe and mufflers.

I've followed several threads on the matter, and asked a few questions, but I feel like I get answers split about 50/50. Half say "don't need tune," about half say "must get tune." Can anyone say with certainty one way or the other? I think I get the rationale for a tune after long-tube headers--difference in breathing should be pretty great there. But is the change from C6 to C6Z manifolds still a big enough difference to through the air / fuel mixture off at WOT?

Again, to be clear, the question is do I need a tune if I replace my (completely stock) car's exhaust system with a 3" Z06 system from manifolds back? The car is a 2008 M6 Z51 coupe.

Appreciate any input.

Delbert

First off, let me say that "I am not an expert" and am only offering my opinion here based upon my own personal research and studies on EFI tuning......

The installation of a freer flowing exhaust reduces back pressure and cylinder temperatures. You have increased the size of your exhaust 1/2 inch. This in turn buys a little greater knock margin. Timing can be increased slightly to move closer to the MBT (Maximum Brake Torque). There are some adjustments that can be done with the tables.

To answer your question more directly, NO a tune is not required. The small error built into your current tune will work fine, however, if you wish to tweek as much from your engine as possible, a tune will improve the output.

dealer06

Thanks Delbert. I've heard lots who put the system on say they didn't tune, but I frequently hear people suggest that the freer flowing exhaust will lean out my air/fuel ratio to the extent that it could cause problems. That's the last thing I'd want to do.

Eventually I'd like to wring every ounce of power out of the car. Right now, I'm really interested in improving the exhaust sound, and a 3" Z06 system without tune appears cheaper than a 2.5" NPP set up. If I have to add a tune to that, that changes the equation, and I'm not sure if I want to risk potential dealer hassles with the tune, as that issue seems far from settled.

jon6.0

If you are worried about it running lean, install a wideband in the car. I like having one to glance at when I'm at WOT.

danieloneil01

If you're worried about it running lean off just that mod then you worry to much.

MLCZ51

dealer06

Well, you're telling me what I want to hear, but not very convincingly. It's like just repeating an argument more loudly but not offering any insight or anything useful.

Still, thanks.