bplemmons

I just had a comp cam (907-304-8) installed in my car a few weeks ago and I found that it is causing my t56 gear box to make noise at idle. If I idle the car up to about 1000 rpm.s the noise goes away. I just read on a website the the recommended idle for a cam with these dimmentions is 1000 rpm's.

Do I have to have the chip flashed to change the idle? I have the datamaster software but it's not letting me change it. Is this only for the 93?
I see a threaded stud on the throttle body that looks like it could be a mechanical adjustment.....

sssalah

Fisrt of all the CC304 is a small cam and the motor doesn't need to idle that high with it. I'm running a crane 210/224 on my impala which is slightly larger than the CC304 on the ex. side and set the idle to 700 rpm.
I don't think you can maintain the desired idle speed with the adjuster screw on the TB, if it's same as later years it must be reprogramed by LT1-Edit, Tunercat, or have a mail tune from pcforless or ion.

96capricemgr

A cam without programming is highly foolish anyway GET IT TUNED and all will be much better. I don't care if Comp says you don't need a tune get the thing tuned. A cam requires different spark and fuel curves and this is handled with tuning. Also Datamaster is a logger not a programmer.

shoebox

Idle speed is controlled by the computer and must be adjusted with programming.

bplemmons

Comp cams own websit says it all......

stock idle 800
this cam 1000
http://www.compcams.com/Technical/Cu...ML/198-199.asp

If it wasn't for the gearbox noise, I wouldn't worry about it

N2O93Z28

Get a louder exhaust. The trans will make noise with an idle that's any rougher than stock.
If you really want to change it it must be programmed, if you just turn the screw the IAC will just compensate.
BTW, in my last motor I had a Cam Motion solid roller with duration in the 250's at .050 and it idled rock steady at 800 with the ac on.

sssalah

I don't see them state 800 stock and 1000 rpm recommended for this cam. They mention the operating rpm range for that cam as 1000-5000. BTW The stock idle rpm is 550 in nuetral and 650 in gear.

Dave '97 Z28 M6

That's with an auto, though, and with the #'s reversed. With a 6-spd, I think 800 is the right #.

jsetzer

My clutch chatters like an sob. But my cc306 (much bigger) idles at 600 with no problems whatsoever.

I tried 500 but the knock sensor went crazy for some reason.

atljar

What are your IAC counts on dataMaster at idle?

The PCM controls idle, so you need to have it tuned. However if you max the IAC motor out, the PCM cant compensate. Once the desired idle has been programmed into the PCM, you can adjust the idle set screw to get IAC counts of about 30-40 fully warm with AC off.