Chevrolet Cruze Forums banner
1 - 3 of 27 Posts

· Premium Member
1,070 Posts
From Vince @ Trifecta

"It is true there is a discrepancy about what the gap should be - the GM
service manuals say something like .033" or so, and the owner's manual that
came with your car says the gap is supposed to be .028". Based on my
experience tuning turbocharged engines, I believe the .028" to be the
correct gap, and everybody I know that tried to run more than .028" with a
tune ended up with misfire problems."

"I don't believe the "results" people are posting about power, MPG,
drivabililty gains. I believe it all to be placebo.

Short answer: gap them to .028" and don't mess with it. Lol"

- Vince Geglia
Trifecta Performance, Inc.
the largest spark plug gap you can run before blowout will give you the best performance possible. Think of the spark plug as a lighter, and the larger the gap the larger the flame on the lighter. You will get a more complete burn with a larger spark plug gap. I have played with spark plug gap on a few different motors (Supercharged 3800 and LS1) and I personally saw a 2 MPH gain on my Monte Carlo (S/C 3800) from opening my plug gap up from 0.035" to 0.055" (did back to back runs with that as the only difference). That specific setup was running 9PSI boost from an Eaton M90 blower
1 - 3 of 27 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.