[Joshua Lee]

No matter what I do I cant get a clean plug on my current setup...

830hp carb with a 71/72? jet and 3.5" PV's
Timming locked out at 36*

After I make a pass these plugs stay dark... Any ideas?

[oldbogie]

Originally Posted by Joshua Lee

No matter what I do I cant get a clean plug on my current setup...

830hp carb with a 71/72? jet and 3.5" PV's
Timming locked out at 36*

After I make a pass these plugs stay dark... Any ideas?

Are the plugs wet or dry? And what kind of run 1/8th, 1/4 mile or something else? Is this electric or push start? Where do you shut off and do you or not drive back to the pits?

Bogie

[richard stewart 3rd]

Hi,
To continue with Oldboggie's questions
have you tried hotter plugs?
rich

[Joshua Lee]

wet
1/8th
drive back
electric start

I dont know of a hotter plug in the NGK XR series?
anybody know the difference between the XR series and the 5670-8 type plugs???

[F-BIRD'88]

Look at the MPH on your time slips, not the plugs.
Jet it for the best MPH. What you're looking at is near meaningless.

[Chevrolet4x4s]

Try shutting it off after the run, dont let it come back to idle, and towing it back then check the plugs.This will get a better reading.
Shane

[oldbogie]

[QUOTE=Joshua Lee]wet
1/8th
drive back
electric start

Wet says there's too much fuel somewhere in the process or the plugs arn't hot enough. This could happen on the drive back or the back off after the traps. 1/8th drags don't get the engine very warm either, it could just be a situation where the engine temp needs to come up more. Being too cold for drag engines is a common problem. Everybody wants a cold engine for power, but cold engines really aren't doing as well as they could. You want cold induction into a warmed engine, where the clearances are optimized and the oil heated.

Race engines are hard to id where these problems originate but your operating cycle allows you to make some changes to localize the problem. I'd suggest shutting down and disconnecting the engine from the drive line after the traps rather than coasting down then towing back, this should tell you if the wet plugs are a result of coasting after the traps and idling back to the pits or whether it's occurring during start up, staging and the run.

Bogie

[Joshua Lee]

THANKS GUYS... I have done some research on the plugs and they ARE the hottest plug NGK makes they are a heat range 4 so the hottest race plug they sale is a heat range 5 so should I upgrade to the race plug @ a 5 heat range or stay with the hotter range 4 plug setup for the street cars?? Would the 1 range temp cooler hurt me in a BETTER plug???

I also am running a 3.5" PV x's 2 so a guy suggested a 2.5" x's 2 and maybe I have a blown 3.5" in the front and it's loading up at the lights???

I run almost 94 mph on motor but, CAN NOT get a better MPH out of the truck... I tried leaning it out thinking it was flooding and ran the same MPH??? I also can cut anywhere from 1.55-1.60 60' times and still run the same ET/MPH??? Wouldnt a 1.55 net more MPH/ET than a 1.60 60'??

Any help again is appreciated! I will also watch the engine temps and try to keep them the same every pass to pinpoint that as a prob./no prob.!

[Chevrolet4x4s]

What is your vacuum at idle?Your power valve should be 1/2 of your vacuum at idle so if its 10 inches of vacuum you need 5 power valve do you have the power valve check ball?(if the carb is post 1992 it should be in there from the factory)
Shane

[nitro_baller4692]

what size engine do you have this 830hp on?and what rpm's r you turnning?

[carsavvycook]

When you stated 830HP is that the engine output, or carb spec's? You might be over carburetored, or under carburetored. A lean miss-fire will give you a darker looking plug. You just might need a larger air volume carburetor. Try locking the timing @ 38 degrees to see if it cleans up a little.

[Joshua Lee]

Thanks guys! I will try some of those things..

I make 6-4" at idle so I swaped in 2.5" PV's and it didnt seem to help.... I am getting some black/brown liquid out of the mufflers??? It leave a spot on the concrete when idling??? what is that?

[carsavvycook]

It's TOOOOO Rich.

[tdkkart]

Start by taking the air cleaner off and looking down the carb while the engine is idling, you should not see any fuel in the throats at idle, the throttle plates should be dry or very close to it. If you see fuel drizzling in you need to fix that first.

[BBCMudbogger]

I have been told that you will see fuel dripping in a race carb......