Phantom_GTO

I am about to put headers and a x-pipe on my car and I’m wondering what will happen if I don’t tune it right now? Will it run ok still?

LS1Formulation

iTrader: (13)

It's not going to run very well, because you're placing the O2s further back in the exhaust stream. They're set at a certain distance so they can react to changes in the air/fuel mixture, and moving them farther back increases the distance of the feedback loop. It may run well enough to get it to a tuner, but I wouldn't plan on keeping it that way for long. Not to mention, you're greatly increasing exhaust flow out of the engine, so in turn your engine's ability to ingest air will increase. If untuned, the air/fuel mixture could become dangerously lean.

99 Black Bird T/A

iTrader: (4)

You'll be leaving a lot on the table if the car isn't tuned.

Here's my bolt on 02 Z28, automatic from several years ago. The pulls don't start at same rpm etc but clearly big gains with tune.


Green is baseline, Red after header & 90mm LPE LS6 intake install before tuning, Blue is tuned.

Note all of the area under the curve the blue (tuned) graph gains vs the red (untuned).

DUSTYWS6

For only headers, consider doing a mail-in tune instead of dropping big bucks on a dyno tune. I did a Frost mail-in tune for my stalled and bolt-on car and it turned out really well.

Phantom_GTO

What’s a mail-in tune?

DUSTYWS6

Do a google search for “tuned by Frost”. Basically you remove your PCM and mail it to a tuner.

LS1Formulation

iTrader: (13)

FWIW, I have a mail order tune on my Camaro with headers, high flow cats, and a BTR stage 4 LS3 cam, and it rips. I second doing a mail order tune, it's too cheap not to.