hi. im running a all motor fully built 13.8 compression on 110 octane gas motor. i use the ngk size 10 spark plugs and 35 mm gap. my problem occurs after i use the plugs for like 30 miles and it starts to detonate at high rpm first then slowly to lower rpm as time goes by. but if i put new plugs the problem goes away and it repeats over. what can it be.? the motor is properly tuned on the hondata s300. i tuned it with spark plug ngk v power size 9. the guy who tuned it told me to use size 10. either way it detonates with both. all the parts are new in the motor and the spark plugs are black after i take them out.

 

It's probably because the plugs are being destroyed by the detonation. What is a "size 10" spark plug anyway? Get the car properly tuned or you'll be building a new motor if you haven't yet.

 

"Size 10 spark plug?" I hope you don't mean heat range...
Are you aware of how to read plugs? What do they look like when you pull them out? Are they completely black; other than the detonation? Pictures of a set of your bad plugs would help.

Is this the engine with the nitrous that is in you sig? Scratch this; it was a mistake...

 

Id try a little less timing. Sounds like your getting some heatsoak in your engine. If colder plugs dont help, try routing the intake for cooler air...

 

a 10 would be the coldest plug in that heat range.

He doesn't have a sig in his post so which engine with nitrous are you referring to?

 

Ha, I must of saw you sig and thought it was his. My bad...

I know what heat ranges are which is why I asked him that. He shouldn't be running no "10" though should he?

 

10 is the coldest plug they make that i'm aware of..maybe someone makes colder?
I'm still on heat range 7 in a 12.8CR motor on pump and i have no pinging..
Whats your timing / AFR look like..

 

Usually running a colder plug can help with detonation assuming that's what's causing it. If he's running a 10 heat range and using 110 race gas and still detonating like that, I'd say his timing/tune is WAY out of whack. He probably wouldn't need to run anything colder than an 8 range, properly tuned.

 

you need a tune or if you already tuned it theres to much timing there

 

NGK Part # 4554
Gap at .22

would be my suggestion, also do away with some timing if your getting up there with that.

 

why.

 

I run 13.5:1 on on NGK 8's and 90 octane daily with NO signs of detonation whatsoever. Its in the tune my friend

 

Now thats pushing the limits of pump gas..lol
Hope your AFR is alittle richer then normal..



still hasn't answered my question
Why would he need to go to a lower heat range "h22ej8"

 

yeah the motor is properly tuned on the hondata s300. i tuned it with spark plug ngk v power size 9. the guy who tuned it told me to use size 10. either way it detonates with both.

 

oh yeah the motor was rebuilt and all the parts are new. also the plugs are black after i take them out

 

Sounds like the tune bro...
What size injector?

 

Retard the timing and try to get cooler air to the intake...
What are your coolant temps looking like?
Depending what your tuning with, you can change the ECT vs. Ignition advance map....

 

what is the setup....stock cams?

 

really. dang. umm im on 440 injector

 

im on the skunk2 stage 2 pro camps. everything is new in the motor

 

skunk2 stage 2 pro? or skunk2 pro 2's?

what the hell is a spark plug size anyway? we are trying to help you out here and we don't seem to be getting any answers. any motor that is detonating with 110 octane, even decently tuned with hondata s300, has some issues.

 

10 heat range plug it too much in my opinion. Try a better fuel.
Also have you ever tried reg 7

 

same thing.

 

lol

 

skunk2 stage 2 with a pro at the end of it doesn't necessarily mean skunk2 pro 2's. what if he meant skunk2 stage 2's but was confused?