you guys know where i can find the calculator for setting the dwell on two rx7 coil packs wasted spark. i think my dwell is stupid high and is causing the MS box to get really hot so i stop before it does dmg.

this is the 3rd MS car i got running . but is the first piston engine though with rx7 coil packs to run as spark.

here is a vid of the car i still have a lot more tweaking to do . but want to get this fixed first before i continue.
car is a MR2 with a jdm 20v
ms1 v3.0 ms2 processor
2 rx7 2nd gen coil packs wasted spark
fuel and spark controll


enjoy sorry on crappy phone vid.
http://www.youtube.com/watch?v=PW604...feature=search

 

Dwell settings are the same as on an RX-7 assuming you are using the FC coils with ignitors. I think 3.6MS for "maximum dwell".

The MS box shouldn't be getting hot as it is essentially supplying a logic level signal to the ignitors, which then fire the coils. Incorrect dwell will cause the ignitors to overheat.

 

oh i have the coils with a switched 12v volt source. and the MS outputs as grounds. i dont have ignitors in this setup.

 

What IGBTs are you using to drive the coils?

Ken

 

vb921's if i remember correctly ill have to double check on that .



http://www.diyautotune.com/tech_arti...megasquirt.htm

 

Those hit current limiting mode when you're dwelling too much. They can get hot and are very electrically noisy when they do that. I would just reduce the dwell until they don't get hot.

You might want to give DIY a call and ask about the BIP IGBTs... they're a lot more bulletproof than the vb921.

Ken

 

had some time to mess with the mr2 and took the case off and yes i have the BIP373's installed

so its just my dwell set really high. so all is good now thanks again guys. shes not getting hot anymore.