I have a set of TR-55's that I'm putting in my car, and I'm wondering what kind of gap they should have.

'98 LS1
TFS 215's
VRD Cam
FAST 92

 

.055"

 

i thought it was .40

 

i mean .040"

 

.055 is correct

 

With those mods its time to swap over to TR6s. With the 6s running all motor .038-.044 would be fine.

 

well i have to reprogram cause i put a difffernt cam and bigger pistons but i went with .040 is that part the reason it running back

 

well i have to reprogram cause i put a difffernt cam and bigger pistons but i went with .040 is that part the reason it running bad and backfiring

 

I think you should run TR6's gapped @.040-.045
That's what I run.

 

.040 gap on which plug? Your tune is most likely the culprit if you changed cams and didn't tweak it for the new bump stick.

 

I change mine every 10,000-12,000 miles and only when I bumped the compression up to 11.5 did I switch to the TR6 ... I gap them at .050 and they look good before that with the stock compression I ran the TR55 plugs at .055 and they always looked good ... we all have our own poison so to speak ... after 189,000+ miles I have a pretty good feel for what works on this motor.

 

Thanks! That's all very helpful!

 

I'm right around 11:1 scr and was advised to run the TR6's on my currant setup.
When I was cam only all I ran was the TR55's.

 

Okay. I'm around 11.5:1, so I'm assuming I should also invest in some TR6's.

 

General rule of thumb is when you increase base horsepower by ~100 it's time to go a step colder on the plug. Also, when increased cylinder pressure and/or temps are present, like high compression, or nitrous, it is also very advisable.

A lot of people want to keep the hotter plug because they think they will make more power, and this is just not the case.