The Correct Spark Plug And Gap For E85?

[devilish64]

Ive been using the one step colder than stock Motorcraft SP471 gapped at .029" on my 20+psi TVS setup and it has ran great on pump gas... but i have now switched the car to E85 and was curiouos what plugs and gaps others run in their setups. Should i go back to the NGK TR6?? Thanks

 

[Phantomhalo]

I'm running TR6's gapped to .028. 14psi of boost. Seems to be working well so far with both E85 and 91.

 

[1320 Junkie]

I run tr7ix's .025" gap at 24psi

 

[stkjock]

yes, go back to the TR6s, I run them for 5 years at .028 for 20-21# here

The corn likes a hotter plug than gas

 

[nxhappy]

The corn likes a hotter plug than gas

interesting. Is it because of the slow burn ???

 

[1320 Junkie]

The correct way to tell what plug your car needs is by reading the ground strap mark. Center is perfect...close to the tip is too cold...back towards plug body is too hot. Thats how you tell what plug you really need.

My car read hot with TR6's on E85

 

[04whitesvtlight]

I run the tr8IX gapped at .028 20-21 psi and it runs perfect.

 

[builttodrive]

I have TR7IX gapped at .032 on around 16-17 psi on E85.

 

[stkjock]

interesting. Is it because of the slow burn ???

I'm not certain, however, corn is harder to ignite in general, one of the reasons the blends change with the seasons. Also consider that the Cooler combustion chamber that E85 creates.
7s

Tr6