[slimbo5]

i dont run the big numbers like some of you but i need some help with my small tune up. car naturally aspirated runs around a 11.20-40 depending on air and 10.70-11.0 on the 50 shot depending on air. the problem im having is im getting an audible ping as the car crosses the finish line. im runnning 38 degrees total timing and have pulled as much as i can using the digital 6 (9.9 degrees). as i pulled more timing the ping has been happening later and later in the run. the question i have is that i see most only pulling 2 degrees if any for a small tune up like mine. im running ar3911 plugs so i think maybe the plugs are too hot? plug is white with a nice tan ring right at the base so i figure its good as far as fuel go's. pulling about 12.3 afr thru the traps and a 1450 degree egt. i run on pump gas. any help is appreciated. i just dont want to rattle this thing apart. ive been taking baby steps with it.

 

[n20mstr]

dump a couple gals good gas in there at the track, dont play with detonation, that is the worst thing on the engine,

 

[jakesz28]

I would put a colder plug in and try it

 

[Mike Thompson]

That plug should be cold enough. I don't see the need to pull all that timing either. I think the pump gas could be your problem. I know guys spray on pump gas and so have I. You are making good power to run low 11s on motor. Maybe its time to change fuels.

I would run 10.80s on motor with 38 degrees of timing. I would pull 5 degrees for the NX 100hp tuneup and it would run high 9s with no knock. I used Citgo red 110 fuel.

 

[slimbo5]

ill give the 3910 a shot and if that doesnt do it ill go to 110 i guess. looks like race days just got a bit more expensive...lol

 

[Mike Thompson]

Put the 110 in with the 100 shot and go low 10s.

 

[SSOCOBRA]

seriously i would change the fuel before the plugs but thats alot of timming fo 50 hp of n2o

 

[slimbo5]

i first tried pulling two degrees and it would rattle from 1000ft on. as i took more timing out the rattle would move farther and farther down the track. maybe i will set the timing back to just pulling the 2 degrees and run the 110 and see what happens.

 

[slimbo5]

what plug were you using mike?

 

[Tom McDunnah]

Don't use AR3910 or AR3911 plugs in a nitrous engine.Those are PROJECTED tip spark plugs

Use like AR3933 (-9) or AR3934 (-8)

Here is a plug chart posted in Chris U's section
http://www.yellowbullet.com/forum/showthread.php?t=25660

 

[68maro]

switch to a non projected tip(prefer ngk's) put good gas in it and let it eat

 

[Mike Thompson]

Don't use AR3910 or AR3911 plugs in a nitrous engine.Those are PROJECTED tip spark plugs

Use like AR3933 (-9) or AR3934 (-8)

Here is a plug chart posted in Chris U's section
http://www.yellowbullet.com/forum/showthread.php?t=25660

The 3911's are projected tips? Thats a problem waiting to happen.

I use 3932's but would use 3934's in Slimbo's engine.

 

[slimbo5]

yes i didnt mention that they are projected tips. thanks for the help guys i guess ill give the 3934's a shot. car is mainly run on motor. thats probably why my engine builder reccomended the 3911's

 

[gmracing355]

Slimbo FYI. 110 gas is 9.75 a gallon at atco. Hope you get your problem taken care of soon.Ill be needing everyones help in the same area soon.
Greg

 

[excelerater]

you mean you can hear inside the car while racing pinging at the finish line?
Even wearing a helmet???
Dood,I am sure most of the advise supplied here above is solid
better plugs,maybe a fuel change or some additive etc etc
but I would make dam sure you KNOW what you car is doing....
A 50 shot,pinging on the big end audable seems impossible to me
and you describe a sparkplug reading that doesnt sound like a problem.........Perhaps your problem is not what you think it is?


.02

 

[Mike Beck]

I think he is hearing his IPOD inside his helmet, or those voices again!


AR3933 plug is what you should try.
Pull 4 degrees with that pump gas or 2 and use Purple.
I'll have a few empty 5 gallon cans with me you can pump your unleaded into until we're done beating on that car!

 

[slimbo5]

nice mike!

 

[Mike Beck]

No problemo sir!

 

[K*A*B]

Don't use AR3910 or AR3911 plugs in a nitrous engine.Those are PROJECTED tip spark plugs

Use like AR3933 (-9) or AR3934 (-8)

Here is a plug chart posted in Chris U's section
http://www.yellowbullet.com/forum/showthread.php?t=25660

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