Bmurray

iTrader: (5)

So Saturday at the drag strip I was experiencing what I believe was spark issues (have in car vid if wanted) I am pretty sure my plugs are bad. Checking them tomorrow. Anyways, I recently switched to e85 / 93 dual maps. Needless to say I won't be using 93 often. Anyways. I'm about to be making 450ish whp. I read for every 100hp more than stock to go a degree colder but also read that e85 like warmer plugs.

Should I just use the stock plugs??

Bmurray

iTrader: (5)

Buump

e_kobz

iTrader: (36)

NGK ILFR7H Gapped at .20

Bmurray

iTrader: (5)

Awesome thank you

Coppi5151

like e_kobz mentioned...NGK ILFR7H

I've been at 443whp and E85 for 4 years using those plugs (replacing them when necessary) I don't take it racing, but still have some fun. You should be all good...

kaj

iTrader: (60)

I've tried stock and colder plugs and never noticed a difference. My tuner says not to worry about it and use stock plugs. My power levels are

Bmurray

iTrader: (5)

Thanks guys. Replaced plugs. Think plugs this bad could have caused bad hesitation issues on the dragstrip? Or is my problem more than likely somewhere else

Abacus

iTrader: (9)

I've used IKH24 ( one step colder from stock) from 330whp to 600whp. Below 500whp for me I gapped them at .020 and above I've got them at .018. I've always been conservative and ran low boost on pump gas and left high boost for E85. E85 is cheap insurance for knock protection .

Here are some of the things I've learned over the years.

E85 is harder to ignite so you may need to gap the plugs lower or make sure you have enough ignition. Good functioning stock coil packs/wires will go pretty far. Most people shoot for 11.2-11.6 for E85 AFR. I'm a big fan of running a car on the dyno to see the difference in power on 2 back to back pulls at a richer and leaner mixture (4 total ). Its better to have it on the richer end of things if it makes the same power to cool the cylinder and fuel the cylinders enough in the shorter gears. Same idea applies to timing. More is not more..

Here is what I would check if you haven't changed anything in awhile and car has been running well.

Check physical timing
Leak down and compression test
Check the coils and/or try stock coil packs /wires as a test. Check wiring to coils.
Any large amounts of oil in the intercooler pipes or coming out of the BOV?
Boost leak test
Lower the boost and check AFR/timing.
If its still not solved then bring it to a local evo shop with a dyno to test it.

4b11slayer

Bpr8es gapped to 21

evo8426

iTrader: (27)

Doesn't apply to Evo 9...

Stay on the factory plugs, they work great even at levels over 500whp

Pal215

iTrader: (12)

I'm running IKH24's gapped to about 0.020" as well. No spark plug blowout when gapped properly for 28lb of boost on e85.

-pal215

kaj

iTrader: (60)

OEM for me.