issue at high rpm

[teRcel]

i have a MS-II v3.0... using the VR with thei'm running a 24 tooth cam wheel with 2 opposite teeth grinded off giving me 12/1 wheel.... the car runs very nice and strong until i hit 6700 RPM... it feels like something is holding it vack at that specific RPM, like a cutoff or something of the sort.... the redline on that engine should be at 7400 rpm and the engine is fully built with balanced internals so the engine isn't the issue.... the ignition cut off is set up at 7500rpm so that's not the issue neither... i checked my datalog and i have noticed the voltage is steady until i hit high rpms and it falls by about .5v .... what would cause that??? could that affect something else causing the engine to "stop making power and stop going up in rpm"???? even when i hit 6700 and i keep it floored then rpm won't go any higher... it'll just stay and that and be bouncing around a couple hundred rpms....

here's a log...


thanks alot for the helps

alex

[grippo]

Everything looked good to me - PW going up, AFR going rich with boost, spark retarding to avoid detonation. Still 70% duty cycle on the fuel PW. The only thing I noticed, by looking at the dtach column (time between tach pulses in us), is that this time is approaching 4500 us = 4.5 ms and the coil dwell is 4.0 ms and starts dropping slightly, as it should to provide some time for sparking. I think you may be overloading your coil, causing it to get hot and killing spark. Just a guess, but I would try reducing dwell to say 3.5 ms.

[teRcel]

perfect will try that and will keep you posted

thanks

alex

[teRcel]

seems like it has worked! i can now reach 7400 rpm with the dwell at 3.0... but if you look at the datalog you can see that at high rpm it seems like the signal is really noisy... and i feel it sluggish too when i'm driving.... what would cause that???? just poor shielding??? or something else could be the cause???

thanks alot!!!

alex

[grippo]

There was only 1 instance of a missed tooth at about 525 sec and this didn't lead to loss of synch. It doesn't look to me like this is the main problem. If your coils are still getting hot, you could try dwell of 2.5 ms since it is easy to do. Other than that, it could just need more tuning.

[teRcel]

will try to bring it down some more.... i'm still using the factory toyota coil.... would an aftermarket one would allow me to run more dwell??? and recommandations for a good coil?

[Matt Cramer]

The right coil will depend on your situation - sometimes aftermarket "performance" coils may be hotter than some OEM coils but get out-sparked by other OEM ones. Exactly what sort of engine is this, what type of ignition module does it use, and is it running forced induction?

[teRcel]

it's a toyota paseo 1.5L engine running 20 psi.... i'm running the regular setup on the MS-II version 3.0 board.... with the factory toyota paseo coil..... and ngk sparkplugs and wires....

alex

[Matt Cramer]

it's a toyota paseo 1.5L engine running 20 psi.... i'm running the regular setup on the MS-II version 3.0 board.... with the factory toyota paseo coil..... and ngk sparkplugs and wires....

alex

This coil should be able to get you a very hot spark even at 2.5 ms dwell. It could still have issues if you run too much dwell, but it shouldn't need as much dwell as the OEM coil. Or you could use this one with an MSD box or similar.

[teRcel]

would i get better results using an msd box?

[teRcel]

and what msd box would work best???

thanks

[Matt Cramer]

would i get better results using an msd box?

Quite possibly. The basic 6A would be fine.

[teRcel]

excellent! ordering the coil and box right now !