I searched the hell out of this, plus have had several recommendations
in posts to other threads. I'm going to install TR5s gapped at about .040"
based on what I have read.

So, what is there to lose in the way of performance by gapping smaller,
like .035? I have heard that idle quality may suffer with a smaller gap but
don't know if there are performance impacts. I think I have a pretty good
idea on what too large of a gap combined with the wrong plug does, but
it's a guess for now. The proof will be on the next dyno run with the TR5s.

Comments???? Suggestions????

And yes, I'm dreading the plug change. It's about my least favorite thing
to do.

 

I have read that a bigger gap is desirable. however I have read here that someguys go for the smaller gap.

For supercharged or nitrous I think its mandatory to have a smaller gap. I have read it somewhere in here. Anyway. I think it has to do with how strong the voltage spike is when it arrives at the plug. If your opty is beggining to flash over the other cylinders then I bet little to no spark gets to the plug. By gapping it smaller logic dictates that you create a shorter path for the electricity to flow, thereby creating the spark at the plug and not inside the opty.

Im not an expert so I today I bought a set of TR5.s to replace my 7 tr55/s and that one Bosh Plat. My car runs good but not as smooth as it used to be. I hope the new plugs help. I know there is something wrong with the ignition but its just too tiny a problem for me to figure it out yet.


Trial an error for me. I have an old opty so unless my car smoothes out of that random tiny misfire I wont know for sure if the plugs are any better...

Marvin

 

You want to run the largest gap possible *without* snuffing out the spark. For your average LT1 there's no point in going outside of .045-.055. If you run nitrous, forced induction, or a really big "bumpstick", then ignition upgrades and a smaller gap (and colder range plugs) are in order. A smaller gap on a stock car may cause you to lose some performance (it's probably not a lot) and gas mileage (which I consider vastly more important now that gas got expensive).

 

http://web.camaross.com/forums/showthread.php?t=292132

 

Ken,

Thanks for the link. Not much was said about performance in comparing
a narrow (i.e. .035) gap to a stock (.050) gap, other than you will need
a tuneup less often. Mindgame alluded to performance in his response but
was not specific. I do appreciate the opinions of the experts. I'm just an
occasional hot rodder with an extremely mild car so it's not the same
league as a big HP car.

Another consideration I have is CA smog. I wonder if a narrow gap will work
against me on the sniffer. It generally sounds like a gap in the .040 range
is a good compromise.