They were about 2 yrs with 10K miles on them. I was sure I gapped all of them at .035 but were closer to .040 when I pulled them. I am running approx 12:1 CR, is .035 good?

 

0.035 works well with a high HP setup. If the plugs opened up 0.005 over 10K miles, you might want to consider a colder plug.

 

Congratulations on fixing the problem and doing it so cheaply

 

Fred - I am running TR55s, what would you recommend? This isnt a track car or a DD, but somewhere in between if that makes sense, maybe a mid-life crisis car

Maddog05 - Thanks! It was pretty cheap, except for the $50 I gave my son for helping out He earned it and needs gas money for his car!!

Also, I did recheck the corona last night. It's kinda funny, most of the plug wires still had the corona but the coil did not. Think maybe two fouled plugs? 7 & 8 were black and sooty......

 

If you're running it WOT on the street, the plugs are subject to the thermal loads of a high HP engine. Doesn't matter whether you put your foot in it at the track or not. If you want to run a stock heat range plug like the TR55, use the iridium plug, to resist the gap opening up. But a hot plug can cause detonation issues.

Or look at a slightly colder plug. I run the Autolite 104 on the street, and have no problems with it fouling or eroding. I'm in the same HP range that you are. I wouldn't run a stock heat range plug. The info I have indicates that the 104 1 full step colder than stock, others claim its only 1/2 step. Even when I had the stock engine with a nitrous kit, I ran the TR6, and had no problems with fouling during extended periods of daily driving, and no nitrous use.

 

Thanks Fred. I was kinda wondering why I fouled out after 10k. Wasn't sure if the heat range was to blame or not, I'll put in the Autolite 104. I read a sticky on here ( I think it was a sticky) where someone put together plug recommendations for different engines, CRs, FI, NOS etc... If I recall correctly, a 383 with ~12:1 called for a heat range of 9. Sound right to you?

 

FOUND IT. Here is the link:

https://www.camaroz28.com/forums/sho...plug+reference

 

The heat range 9 is for AFR heads, with gasketed plugs. Not sure where the Trick Flows fit into that. I'm running factory LT4 heads, so that's the only hands-on plug selection I've dealt with. The shop that tuned it optimized the plugs for each application - 104's for running NA, 103's for a 125-shot. I know with the plugs for the 300-shot of nitrous (Champion S57YC) they will foul rapidly in street driving.

 

Fred - are you running ~12:1 CR? I prefer to go with a plug that has been tried and true. Since you and I are close in mods/hp, I'll run the 104s

 

No, I'm only 10.8:1.

Its really a matter of trying a set of plugs that you think makes sense, then taking a look at them after a couple thousand miles to see if they still look good.

 

BACK FROM THE DEAD, this thread I mean. Well, guess I didn't fix this problem. After replacing the plugs, it ran fine for a few days (~20 miles at most). I fired the beast up and heading to work. About half way there, it started to sputter again. Exact same problem. I brought it home and let it sit until I could get my hot rod out of the garage. So, today I began looking at it.........AGAIN. Couldn't find anything obvious. I started it up to check fuel pressure and the battery slowly drained to where it almost didn't turn the engine over. Funny thing too is the engine didn't fire right away like it always does (and did even with the sputter problem). Probably took about 5 seconds to start. Alternator output is ~14vdv and flucuates with engine RPM, in other words, it's charging. I am charging and then load testing the battery.

Question: Could a failing batter cause my original problem of sputtering around 2k rpm?

I recalled reading this a while back and found the link I read.

https://www.camaroz28.com/forums/sho...attery+sputter

What do you guys think?

 

Since I drive my car now once every 5 weeks due to working out of town for 4 weeks at a time I just bought a battery charger. It was a great buy since it rarely gets run and it seems to help the overall running of the car.

I still think the way you re-routed your plug wires is the issue, no offense. Every time I have had that problem with a 2krpm stutter it has been plug wires or plugs. Maybe once it was the opti, but I have had that problem a lot in the 10 yrs I have owned my car.

Key places for plug wires to check:
1.) where it goes under the power steering pump (i think?) to the opti on pass side... here they can get slit by belt and this will cause the stutter.
2.) obviously headers but my main places are the last cylinder wire on the driver side and the first and last cylinder on the pass side.

Have you checked your coil? I still have stock coil, but I have heard this will happen wfor them too.

 

See if one of the plug wires is touching the pulley belts. It happened to me. The ECU recognizes anything like that and makes unnecessary adjudtments. It caused my car to sputter like that under throttle. It idled fine but under throttle those plug wires move a little and if the touch one of the belts, sputtering happens. I took it to a mechanic cause coulnt figure it out either and he took a "zip tie" and tied my wires back away from the pulleys and it fixed my problem. Cost me 10 bucks. Might check that out.