Rossko85

iTrader: (11)

Hey all...LS4 (5.3L) factory long block minus PAC 1218 springs, 7.4 push rods, valve seals, and 160 tstat, a great tuner, and a wing and prayer!! (FWD) E85, N2O, rear mount turbo car

I have done the right thing by combing over just about every thread on here before I posted, and all my google noodles are just about exasperated LOL.

I've seen a lot of good info on what plugs to run in FI, N2O, and E85.

I've see where one of each has been combined and has been commented on, but I haven't seen anything that could give me a solid either way when using ALL 3; I use all 3.

I currently run a BR7EF gaped at .034 and on factory ignition coil packs...I have successfully sprayed a wet 50 shot (which ends up being around 70 under boost) on 8psi and E85.

Tuner is seeing some knock and is a little astonished with pretty conservative timing 16-18* max with only 8psi with out spray with conservative AFR...

He saw some with spray too, so just pulled timing up top a bit...this is in combo with the timing retard box set to pull 4* I have from LPE. Its the 002.

Have successfully sprayed and boosted on this plug and gap with the E85, but going to be tuning Saturday and upping the boost to 10.5psi and keeping my 50 shot.

Tuner told me I should try out the B8EFS...so I bought some and gaped a little larger at .035.

Everything I read makes since for one or two in combination with each of those...but as soon as you add all 3 together...they seem to contradict each other...

**Example would be not to go too cold on the plug with E85 due to it already having a cooler cylinder burn temp and the cooler temp with the 3 heat range colder plug would cause fouling, but on the other hand, E85 has an inherent ability to want to pre-ignite so you would want to run a cooler, non projected plug....but once again...dont go too cold?**

And then you can just put all the knowledge im sure all of you have seen on here; and all that each of you respectively have, and add all those combos together to get the rest of the delimas im facing...

This is not just a track car...not a DD, but hits the street quite a bit...so dont want to foul left and right either with the colder plugs if too cold...I havent had any issues with the BR7EF's fouling at all, even at idle and normal driving.

My tuner thinks i need to go to the colder plug I think to help against the knock we see on the E85; or an answer as to why we are knocking with a conservative tune...

Mechanics check out good...valves and shims and all that junk is in good standing...leak down and compression is good in all cylinders...so nothing in that realm...just saving you the time there...I do have a cross threaded plug hole in the head...but just play with that plug..it will misfire if its not in the head enough LOL...Ive got that finally worked out from about a year ago LOL

There are plenty more details...and I hate having to ask such long drawn out questions...So, if you have any questions, just chime in LOL...

My thought is a 2 way situation/solution here...

1. Go with the B8EFS, the non projected plug to keep cooler for guard against pre-ignition for both boost, N20, and E85

2. Go with a gap of .035 on the B8EFS, which is a tad larger than what my BR7EF's are at right now; in order to help burn up more of the possible additional fuel not getting burned, that could be causing the knock in the cylinder, and that is showing up in the tune. I wont have to worry about blowing out the spark are my thoughts there, due to smaller amount of boost...so bigger is better for more of a complete burn.

There seem to be more pro's than con's with running the colder plug...

Only con is the fouling, and of course IDK if Im going to start misfiring under WOT or half throttle just yet until I put them in and see what they do...?