As most of you cam guys with no programming know, the idle surge is a common problem....

I'm wondering how hard this is on the engine...the engine drops down to 100 rpms like 4 or 5 times for about 5 mins until the car is fully warm...sometimes it will shut off, most of the times it will stay alive...is it bad when it gets this low in the RPM's and then staggers back up??

The oil PSI goes from 40 at idle to about 30 when this happens...when it happens with a cold engine it goes from 60 to 40....

Sometimes it feels like the crank is really struggling to turn...and also shakes the hell out of the car...

I would just like to see what some of your guys thoughts are on this..

Thanks,
Brian <img src="graemlins/gr_cheers.gif" border="0" alt="[cheers]" />

 

How big of a cam do you have for it to surge so badly on a M6 ?
I have a TR 224/224 on a 114lsa and the lowest my rpm's drop on cold idle is 600. And that is when I first turn the key and is only for a second or two. After that it idles aggressivly at 850rpm and does not drop. I don't have any tuning and the throttle body isn't drilled either.
You must have a really big cam.

 

Use a drill bit and slowly go up in sizes until your IAC counts drop to 35-40. Drive around between drilling to allow it to settle.
This will fix your issue.
Cheers,
Chris

 

I've already drilled to the max size, I don't want to go bigger....

My cam isn't as big as you might think...


222/222 .563/.563 112lsa