gnx7

iTrader: (28)

I tried running NGK TR55's before and it felt good... and then stepped up to TR6's and I couldn't really feel a difference after a buddy said that is what I should run. I feel like it should be making MORE power. I ran them as they were gapped out of the box.

What do you guys run with LS7 heads? What plug gap?

My setup:
11.25:1 compression on 91 octane
QM600 cam 243/256 .650" lift approx
WCCH ported heads, ported LS7 intake, 90mm TB
1 7/8" long tubes (non equal length), dual 3" into single 3.5" exhaust

I've never dynoed it. Running Holley HP efi. 26* timing up top I believe.

If I run a 91/e85 blend (e30 approx) should I change plugs?
I ran this before and added 3* timing and it felt very strong.

ramairws6

iTrader: (33)

The TR55's would be perfect for that setup. 6's are too cold IMO...

good2go

I'm running an earlier version of the same cam, decked heads, ported tb and intake, AR headers. With TR6's @.040" I dyno'd 572 sae with 24 degrees of timing. These heads are very efficient and don't want/need a lot of timing. We gave it up to 28 degrees but it didn't make any more power, so we left it at 24. Now, with a 100 shot I'm running Br7's @ .034" and making 682 SAE rwhp.

I think you'll be fine with the TR6'.

ramairws6

iTrader: (33)

He's not spraying so why the colder plug? Only hurting his power for no reason but whatever.....

LS6427

iTrader: (2)

Well, first....unless we're talking about an LSx build that is 650 RWHP plus and spraying nitrous and/or running boost........the LS7 engine is absolutely the same exact engine for all practical purposes as the 1997 LS1. They are all identical engines when it comes to things like spark plugs and other basic parts.

You should use TR55 plugs gapped at .050

That's the best plug and gap for any LSx engine that is a mild normal daily driver engine like yours.

And never install spark plugs that you yourself do not check for proper gap with a gap tool before you install them. Using them out of the box isn't a good idea....you have to check them all to make sure they are all the same gap and the proper gap.

.

Alvin@PCMofNC

YIKES!

There is no way I would run a 55 in that application. I would run absolutely at least a 6 or even side on a 7.

Here is a really good write up on how to read plugs and decide what your engine is actually in need of.

http://www.pcmofnc.com/index.php/blo...ad-spark-plugs


Typically E85 will take a warmer plug. TO give you an example we have a car that made 900+rwhp on 113 and it took a 9. With E85 it barely has any heat with a 8 at 1000 rwhp.

good2go

With the spray use a 7. He has higher compression than stock, the 6's at slightly less gap will work fine, won't cost any power.

ramairws6

iTrader: (33)

Whatever, that was my cam in basically the same build. If your not using spray TR55's will be fine but whatever he wants, it's his car....

good2go

Going by the article Alvin@PCM posted, the TR6 is just right, the annealing mark is right at the bend.

ramairws6

iTrader: (33)

Seriously, the 6's are to cold for an NA build of this nature. Especially running E85 in the thing which runs cooler yet. My tuner is one of the most respected tuners in the U.S. so i will def. listen to him.

ramairws6

iTrader: (33)

Exactly, so if he is running E85 why the hell would he need a colder plug!? You know the 6's are colder then the TR55's?? I would think you know that much at least