Rough idle/Low vacuum/Bogged down accel

[ib_steed]

been trying to tweek the car some. although it is fast, its still not putting out the power that it aught to. the idle has been rough since i started it last week, and it has never had more than 6" vaccum on idle. it still shows 10psi on WOT, and 20-25" vacuum on decel...

swapped my volvo bypass valve with a saab one (it has a tighter spring, and stays closed durring normal running) I have an HKS comming in tomorrow. Just put in a new O2 sensor yesterday, and reset the base timing to 10* earlier this week.

been playing with valve timing today. went to 10*advanced, with wonderful success. smooth and powerful. tried other settings, but when i went back to 10*adv. it was not as good as before. bogged some, and ran better on 90% throttle rather than 100%..... (cam is a Racer Walsh - fairly aggressive - probably too much for a turbo, but i had it running nice for a lap or two, so i know it has the potential)

thats the update. any idea's why it would be idleing rough, and with such low vacuum?
cam timing=0*, vacuum=3-4"@idle
cam timing=10*adv., vacuum=6-7"@idle

Thanks,
-Ryan

(Going to get a new PCV valve tomorrow to replace the one in there - carried over from the old N/A engine - just in case)

 

[Stinger]

Well, a big nasty cam will cause rough idle and low vacuum...

 

[bhuff30]

exactly which cam did you get? Hopefully nothing bigger than the #2. Even the #2 roller is too aggressive, but shouldn't alone cause the problems you describe.
Are you sure the cam timing it accurate? Did you degree in the cam and pulley?

 

[ib_steed]

Current Update

well, i spent a littl more time on it tonight, found out that the ignition timing was about 10*ATC with the spout in!! no wonder! the auxilury sproket must have jumped a tooth or two. i'll keep that in mind next time.

so i got it back on spark base=10*BTC, and valve=10*BTC, and it pulls like its on steroids. thats with only 10psi........ <drool>

...still has a relatively rough idle, and the low vacuum. but as you said stinger, its probably just because of the grind of the cam. since i got it running with that cam, i'll keep it for now, but i'll get a proper grind cam for a turbo later on.
bhuff30, it is a Stage 2 roller cam from Racer Walsh. The cam sproket is the 5bolt ajustable, also from RW. As i understand it, the turbo cams use a lot less duration, but more valve lift.
it would make sense, overlap=low vacuum right?


The question now: is there anything that will make it idle better? It studders pretty badly coming off of throttle. is there any adjustment or part replacement that might make it settle into idle more easily? (TPS is set on 1v exactly on closed throttle)

Thanks a lot guys,
-Ryan