Hi guys, I'm having trouble with my idle. I currently have a 2k GS-R with AEM CAI, ITR cams, and skunk2 gears. I was playing with the cam gear settings and tried +3 intake, -1 exhaust, and found the car would not idle properly. It would sometimes almost stall (drop below 700 rpm) and then rev back up itself again.

At 0, 0, the car runs fine. At +2 intake, 0 exhaust, the car runs okay. Is it normal
for certain cam gear settings to affect the idle?

Oh yeah, and I have a V-AFC installed, should I try changing the fuel settings?

Any help is greatly appreciated. Thanks.

 

Yes, cam settings can effect the idle and running condition of your motor. That is why you need a dyno to properly tune them. With extreme conditions, your engine may not run at all or possibly self-destruct due to contact between the valves and pistons. cam settings have a much bigger effect than timing settings where you can try just about anything without too much consequence. And due to the nature of every motor being different, no setting will perform the same on any 2 engines. Find a dyno and try tuning it there.

 

Hi, thanks for the reply. +3 in, -1 ex is a pretty common setting though. I don't see why it would make my idle bad. Is there anything I need to do to make the car idle with those settings? Adjust fuel in anyway? I know I have a maximum of +-6 degrees on my car before contact between valves and pistons.

 

Did you adjust the ignition timing when you made changes to the intake cam timing? Whenever you advance the cam timing you retard the ignition timing, the two are physically tied together. Did you degree the cams? Timing marks on cam gears are notoriously in accurate, on Skunk cam gears especially, so 3 degrees on your cam gears may actually be much more than the marks lead you to believe. +3 and – 1.5 on my 93 GSR B71A1 with ITR cams and Skunk gears does produce a significantly greater amount of overlap and some idle roughness.




[Modified by DB1-R81, 5:26 PM 8/24/2001]

 

Hi.

I didn't think it was necessary to degree the cams because it fits in the cam holder holes. And no I didn't adjust the distributor back to 16 deg BTDC, I had no idea. In a 2k GS-R, I know that the timing is automatically set to 16 deg BTDC no matter what I do to the distributor, so does this still apply to me?

Thanks for all your help.

 

Yes it is necessary to find true zero. Like I said if you adjust the intake cam timing you must readjust the ignition timing, look at their physical arrangement they are connected together.

 

That is true about the intake cam being linked to the ignition timing.

Every 1 degree of cam timing = 2 degrees of ignition timing.
So if you advance the intake cam 2 degrees...the ignition timing automatically advances 4 degree...so it must be retarded 4 degrees to get it back to 16.

I didnt degree my cam either (and probably should have) but on the dyno I dont think it really matters. Just tune the cam gears on the dyno for where they make best power at.

 

Ok, thanks a lot guys, this has been very helpful. I'll get my hands on a timing gun and redo the settings on a dyno. This board is great.

Thanks.