ignition/spark problems

[Disturbed1]

hey everyone

i own a 7mgte which is pretty heavily modified but running stock coils.

im running an ems 8860 ecu with ems 3 channel ignitor.

when the car was tuned last, i seem to be having some boost dependant spark or ignition problem which ressults in the car "hitting an early rev limit" as such.

as u can see from the following dyno runs, the more boost i run the earlier it dies in the ass yet i dont have any hicups/missfires during the power runs - only at peak revs


*please note* rpm scale on dyno sheet is slightly off - the pink runs roughly corresponds to 6800-6900rpm (soft limiter is 6800, hard is 7k).. and yes i know its laggy



anyone had any experience with these symptoms?

is it time to purchase some aftermarket coils or there are some basic things i can check first (bad earth etc etc)

was thinking of going ls1 coils with built in ignitor orelse bosch or M&W coils. would ideally like to keep the setup simple and cost effective as i dont plan to ever run more then 500 rwhp (assuming if i reved out to 7k atm id make roughly 430 hp (on 20 psi so another 2 psi and slighlty more agressive tuning on race fuel will see me there)

any help/suggestions or ideas are appreciated

im running champion race series plugs from usa (apparently shit hot but no idea) they are a number 8 im pretty sure with 0.7mm gap. and msd 8.5mm leads. dwell on coils currently set to 3m/s which the tuner didnt get around to playing with if cranking that up to 4.5ish would make any diff other then burning them out quicker

cheers

[JustCallMeOrlando]

Glen's 7M made the goods with factory coils. When wiring my old car up, we tested the 7M coils and shot a nice healthy spark 5cm across the bay. I'd be surprised if they're a problem

[Disturbed1]

peewee got a spare set of coils so when i ever get around till grabbing them back off him (before i go spend 600 on replacxement coils) will see if i have better luck with that set

[Jayem]

I have exactly the same problem. Although I have 1G but it has same coils and numbers are at the same wall too. I also have no misfire, hicups or anything like that. Car works like a clock but it just dies at high revs just before the rev limiter and the problem is most definitely boost related. It's really annoying.
I'm ditching the wasted spark system and retro fitting the distributor with Summit CDI box right now.
I still hate distributors!

[Disturbed1]

nobody have any ideas??

[Norbie]

My 2JZ had similar problems when the ignition was too retarded. It hit a wall at about 5500rpm and nothing I did would get it past that point. I thought it was dodgy coils too but when I wound in some more timing it all came good.

It looks like you're running a pretty big turbo there but only 413hp at 20psi? My GT35R comes on earlier than that but it made 442hp at 15psi. Maybe you need to have a close look at the iginition map, retarded timing would explain your ignition problem and the relatively low power output.

[Disturbed1]

im blaming low power output on 3mm mhg yeilding fairly low compression (145 across all cylinders)

[boxh34d]

What does it feel like when it starts blowing the spark out??
I have a similar but different problem at the moment, but it only happens on the track when its getting an absolute hiding. Street, or shitloads of back to back dyno runs, and it won't do it. I'm putting it down to heat related, but not sure what the exact culprit is yet.

[Disturbed1]

feels/sounds exactly like hitting the rev limiter - no difference at all

[boxh34d]

Hmm ok then, sounds different to mine. Mine starts missing / coughing from lower rpm, but will keep climbing in revs if I persist.
Sorry, no helpfull input from me then.

[Disturbed1]

to add to that - the autometer monster tacho neddle goes crazy (bounces all over the place)