toughy v8

hey guys im just wondering what plug and gap to use on my motor,
its an ls1 with vic jr 650dp edelbrock box and headers, standard everything else. its 50/50 street strip.

thanks

ZONES89RS

iTrader: (25)

TR6 NGK would work great, .050 gap.

speedtigger

iTrader: (16)

I think some NGK TR5 plugs gapped @ .040 will stay cleaner than the TR6 plugs. If you crank up the compression or drastically increase power, then the TR6.

ZONES89RS

iTrader: (25)

I have run tr6 is all my stock apps, never fowled, the ignition is hard core on these.

Tr5....might recommend for stock 5.3 with 317 heads maybe.

toughy v8

ok thanks chaps ill try tr5s first

GC99TA

iTrader: (30)

Concur! TR6's were a bit too cold for my LY6 and liked to foul if they saw too much idle time. Granted my LY6 is about 1/2 a point less compression than a stock LS1.....but I'm also running lower octain fuel. I run TR6's in my 11:1 LS1 with good results.

ZONES89RS

iTrader: (25)

Wow, i have never seen a LS motor foul plugs like that, interesting, how fat is the idle?

GC99TA

iTrader: (30)

This was before I had the wideband......so I'm not positive. But it was actually so lean at that point that the car would die if I would go WOT and then lift quickly. So I had to fatten it up little by little until it stopped doing that. Now (with a wideband) the idle is around 14.5 or so in gear but has to idle a little fatter when in park/neutral.....so I'm seeing mid to high 13's during no load idle to be able to maintain mid 14s idling in gear/idle circuit cruising (below 3000 on my set up).

ZONES89RS

iTrader: (25)

Crazy, never had any fowling on any I own/work on.

3pedals

iTrader: (3)

I ran TR55's on my 11:1 setup and I gapped them between .030" and .035" cant remember exactly. I do know that if you are making real good cylinder pressure, you should tighten up the plug gap to ease the strain on the ignition.
No signs of the tr55 being too hot.

GC99TA

iTrader: (30)

Yeah.....but admitedly there could be any number of factors at play. One variable is that my high RPM cruise (above 3000 when I'm out of the idle circuit) is pretty rich right now; like mid to low 12s. I've got 76's in the mains and would have to drop it down to 70s (and then drill the PVCRs to compensate at WOT) to get the high RPM cruise inline. I just haven't done it yet because I'm moving back down to sea level later this year and don't want to redo it there.

I know cruising above 3000 sounds uncommon for some combos but with my convertor and gearing.......it's pretty common. 3400 rpm is about 55mph .
So spending time cruising at that kind of AFR could've certainly contributed to the fouled TR6's as well. All I know is that the TR5s stay nice and clean for me all the time and are no where near being too hot......even with 87 octane fuel at my altitude. Plus I'm almost 100% sure the TR5 is the factory recommended heat range for an LS1. I'm not sure if the higher compression LS motors got a colder factory plug?