booboo782

Need some help from all the plug reading gurus. Please chime in.

After nailing my A/F ratios, I moved on to doing a little street tuning of my ignition maps. I want to get a rough idea of where she needs to be so as to minimize the amount of time I'm on the dyno. This is an 84mm, Precision 5857, 1000cc Inj., running E70 if you didn't get it from my sig.

I did 3 pulls back to back @ 12psi, with 15, 19, and 25 deg. of map timing respectively. Each run was done with a brand new NGK "8" heatrange plug in Cyl. 3 (I just happen to know thats my trouble cyl.). No signs of Detonation on any of the plugs, and porcelain is bone white.

To me, these timing numbers seem really low considering E70, but I need opinions on which looks BEST at this boost level before moving on. I tried to get a good shot of the ground strap's "bend" in each pic. Thanks guys!

Errol Aguinaldo

i think 19 is better

booboo782

Thanks. I'm modifying a previous pump gas tune, as I'm on E85 now. What's weird is, I'm having to LOWER my map timing to get my plugs to look like in the 19 Deg. image, which is about 6 deg. lower than my previously dyno tuned pump gas tune in the 12psi column. Anybody ever seen this?

Do spark plugs ever lie? Why would I have to pull timing back that far after switching to E85 to get the plugs to look like this? My impression of E85 is that I would be able to run MORE timing than pump gas, not less.

Any more opinions?