LS Coil Dwell

[Mcstiff]

Who's using what?

I was at 3ms with a MAP scale of 5 but I'm peaking at 4ms since I'm only running 200kpa. I've been chasing a missfire above 5k which I attributed to fuel richness and low advance but now I am thinking it is just dwell.

Seems the LS coils (EFI Express) are fine with more dwell but should I simply increase the base or the scale?

After more reading, nothing is to be gained after 5ms @12v but do you still need more to deal with CR, KPA, and E85?

Also, need some new plugs these BKR7Es are about a yr old.

[SEStone]

I would get new plugs, copper plugs get eaten alive in applications like this. I usually only get 7-9k miles out of the FR5DTCs, and the NGKs typically don't last as long.

That being said, do you actually have control over dwell with those TTL coils? I thought I remembered that many of them control dwell on their own, always running at a fixed duty cycle per-se. The trigger from the ECU just tells them when to go.

Sam

[Hank]

e85 needs more dwell typically. I had Marc cut me a custom fireware so my multiplier was 200% vs 140%, that way I could run 3ms on cruise, 6MS on boost. That was on the 034 coils that kick ass, but I think the LS coils aren't far behind.

[turboskipper]

At only 200kPa 4ms is probably enough from those coils. As Hank said you could push towards 6ms and see what happens but I'd look elsewhere for the problem.

[UrSobsessed]

Ed, try either Bosch FR5DTC's or the NGK equivalent(5509). They seemed to work much better for me. I never had any luck with the BKR7E's, although I'm running 034's HO coil kit so that might have something to do with it?

[Mcstiff]

Yeah, I am trying to isolate the issue to fewer variables. Going to try and get a good pull on the WG spring and see if it still goes lean over ~4800 (regardless of ve map) then work my way up.