I currently have a 383 ci LT1 with the stock timing tables still in the PCM. I am havign a problem with it idling at any kind of decently LOW RPMs. (around 1000)I know the long duration soild roller cam is not helping it any but what in LT1 Edit can I do to help it idle better at lower RPMS ? Would increasing the 200-2000 RPM spark advance help? BTW the cam is a 260/250 @.050 lift, 113 LSA and .617 lift solid roller. 12.2:1 compression.

 

you should have a table that is closed TPS spark advance.
You will probably have to do quite a bit of playing in there with the 400, 800, and 1200 rpm data points. Might have to play with the maf table to get the idle fuel correct if the injector constant doesn't do it.

 

I'm not if that cam is similar to the CC306, but I just got done fixing this problem for a buddy with a 383 that had cam surge at 1600 to 2400 and problems with idling. I raised his idle speed to 1000 RPMs and added 1* of timing to the 800-1000 RPM range. That smoothed it out quite well, although he only had the problem with the car in drive, not park. I can send you a copy of his final file if you want, see if it helps you out. You probably want to check to see if the cam is similar to the CC306 first, though.

 

That cam isn't anything close to a CC306.
I'm suprised you had that bad of cam surge with the 306...must have been in an M6 car?

 

sorry the CC306 cam is tiny compared to the cam I have. Since my post on this I have increased the spark advance to 30-35 at idle and crusing speeds. This has helped tremendously, however ive done the best I can and will be going to the professionals at the local performance shop to use their chassis dyno and have them help me tune with the wideband.

thanks for the help guys

 

yOU NEED MORE "CLOSED THROTTLE SPARK"
Theres a lot of blow thru at low rpm with that bump stick.
I would start at 40 degrees with a vacuum guage on the motor.
I ended up getting my highest vaccum running 45 degrees on closed throttle spark.
Talk about cleaning up idle quality .

I'm running a comp custom extream hyd-roller nitrous grind with a rev- kit.
585/620 , 242/254@.050 , 112 cl, 114 lsa.
in gear @ 950 rpm the motor/ camshaft makes 10~9 inch's of vacuum, in park its 12" @ 1100 rpm.

 

im using a solid roller and I have ZERO vacuum at idle. the closed throttle spark advance is at 32, do you think i would benefit by bumping it up to like 38 ??