Ignition breakup help needed.

[HondaDrag]

Hi,
This week i tuned the car on our dyno and just to check everything and get to use the S8 i filled her with normal 92oct Gasoline, 10psi and 9000rpm and engine worked perfectely.

Infact I am very happy with the Syvecs S8, its power and safety when you have the boost/knock/limps maps etc all working you start appreciating what a controller this is, and also thanks alot to Ryan and Paul
for all the help they gave me.

Then today I switched the fuel to 100% Ethanol and on the dyno severe ignition breakup started when applying some load like 0-5psi, idles perfectely, only on load the issue
comes up. Tried different fuel/ignition settings but no better.

I tried different spark plugs, iridium, normal, different heat ranges, different gaps upto 0.5mm but did not make a difference also.

I went back to 100% gasoline and worked perfectely, so it seems that for sure the Ethanol needs more energy to fire and not sure whats going on here.

I am using the M&W Pro14 CDI and AEM CDI Coils.

I have bought this ignition setup for alot more boost than this so why could this happen?

Any help would be appreciated.
Thanks.

[pavlo]

It could be that you might need to tweak the dwell a little. A CDI should work with almost no dwell but it could be the ignition outputs are taking a little time to go high before being dragged low.

Can you scope the ignition outputs to check you are getting a sensible square wave?

What lambda are you targeting on boost?

I presume you are using 4 ignition channels with fully sequential? Most CDI units can't fire 2 out of 4 channels simultaneously as they share some of the components. So if you are using wasted spark you need to use 2 outputs and fire double ended coils rather than 4 outputs with 2 firing seperate coils at the same time. BUt I wouldn't expect it to run at all if it was wrong.

[HondaDrag]

Hi Paul, thanks for your time.

Scope attached of ignition output.

Yes its on sequential each cylinder is on an output from the M&W CDI.

Coil charge time is on 2.5ms from 13v onwards.

Lambda target I tried from 0.95 to 0.75 nothing seemed to make a difference on Ethanol, even timing +/- 20deg
no difference at all, don't forget that on gasoline it works perfectly so the power to ignite the ethanol is the issue probably.
Idles perfectly on 0.95Lambda.
Thanks.

[pavlo]

That looks fine on the scope and 2.5ms is fine for CDI.

I would check your CDI wiring and setup in general as I have used the Pro14 with an S8 no problem at all. Check you have a good +12v supply and good grounds for the CDI and all the normal things.

It could be the coils, personally I tend to find OEM coil on plug units to be very good and I would be sceptical of any aftemarket stuff.

[HondaDrag]

So it seems that the AEM CDI coils are no good with M&W just been emailed from M&W unbelievable!!!!! he said that
the AEM coils will damage the CDI unit so have to throw them away, he even said that the new pdf is written in red not to use them!!!........and there are websites selling this exact combination.

So now my options:
1)Fit stock K20 COP coils which apparently didn't know are very good up-to 900bhp but not sure if they handle 98% Ethanol on big boost and not sure if I can fit the M&W CDI on them???

2)CBR954RR coils are short for a K20 so not good or I have to make plug extensions.

3)EVO guys use the Chrysler 300M COP coils with great results 50psi on Methanol but I think they are thick to fit the K20 plug holes as EVO use larger spark plugs.

4)MSD coils with High tension leads but I don't like this setup bulky and fitment issues.

Any ideas?
Thanks