And I am gonna try a couple things out.
1. Insulate the knock sensor with a large plastic grommet. about 1/2 inch thick.
2. Adjust the idle up about 100 rpms.
3. I already have the FPR going to a line on the manifold. To get a better vac.
4. "Reset" the PCM
I have been doing some research. It seems the LS1 guys had some experience with similar problems. Some guys noted that the increased vibrations due to solid motor mounts were causing false knock.
I know the first car with these cams didnt have them. Alot of the cars that did and do HAVE the problem run solid mounts. Think it would help to reinstall the stockers?
I dont want to if i can avoid it.
Any tips besides after market engine management or a SAFC?
2006 Cobalt SS I/H/E ZZP S2 HPT 2.8/60's Etc...13.8@105(I need to learn how to launch)
Anyone have any input?
2006 Cobalt SS I/H/E ZZP S2 HPT 2.8/60's Etc...13.8@105(I need to learn how to launch)
good luck trying to make a 1/2 inch insulator fit the knock seson... telling you to have a back up plan
Damn, thanks for the pics! I see what you mean. You ever get yours running right? Any thoughts on my plan?
2006 Cobalt SS I/H/E ZZP S2 HPT 2.8/60's Etc...13.8@105(I need to learn how to launch)
I got my running very good just not consistant... it either pulled like mad or ran like @!#$ no inbetween, but keep in mind by doing the knock sensor thing you need to run premium all the time, if you do get some knock the car wont know it and won't reatrd timing to prevent damage, so run premium to be safe, bumping up the idle a bit should help, another thign you shoudl do after resteing the ECM is have someone with a Tec-2 do a relearn on the crank sensor once the cams are in. In terms of engine management not many people have messed with it, SAFC would work for small tuning, its worth a shot since they are realtively inexpensive, personally I'd say if you can afford it go with the F.A.S.T. system
Solid mounts and the knock sensor are not the only issue.
The crank angle sensor is also used to determine misfires. When the car lopes excessivly the ecu detects a rapid change in rpm and thinks it's a misfire. The goal is to reduce the lope, which gets harder the more breathing mods you have.
One thing we wanted to try but never had a chance to was a vacum canister on the intake manifold. I know on v8's with hot cams this is a common work around.
Oh and before you adjust the idle, I would say install them and see how they run, if the car is loping really bad and throws a code, then adjust the idle.
Yeah, install it first and see how it is. There are people that didnt get codes. All motors respond differently. You might get lucky.
good luck! I couldn't get the damn things to work. now they're just siiting in the garage, right next to my old engine. Be Careful.
2004 Cavalier
13.2@105........
Mods...
BFG Drag Radials
Saab Turbo kit
2.5 exhaust, w/cutout
Spec Stage 2+ Clutch
Thanks so far for the kind words. I am also going to install a vacuum cannister. I read that the ls1 guys in some cases have had to use similar means. I will adjust the idle as a last resort but I will do all the things mentioned above..........minus possibly the mounts.
Any more input?
2006 Cobalt SS I/H/E ZZP S2 HPT 2.8/60's Etc...13.8@105(I need to learn how to launch)
on question for you... how do you plan to adjust the idle?
the idle adjustment screw under the throttle body (where the throttle cable goes there is a little screw that is a throttle stop screw..........back it out a little and it keeps the throttle body open a bit and voila!)
2006 Cobalt SS I/H/E ZZP S2 HPT 2.8/60's Etc...13.8@105(I need to learn how to launch)
I was wondering the same thing..
Hmm even with uppper/lower mounts, full mandrel 2.5" exhaust/header/ported head, the only code I ever get with the LZM cams is the occasional rich code(0172?) because of the lopey idle, never affects performance though, runs 14:1 off idle to redline afr....
Well I hope my car is ok with them. I mean, the car never felt like a factory freak. Its always a little of both.....fast and then slow.
I dunno.
2006 Cobalt SS I/H/E ZZP S2 HPT 2.8/60's Etc...13.8@105(I need to learn how to launch)
The TB doesn't actually control the idle rpm, the IAC does so you might be cause more problems then your helping, I'll look into it more and see what I can find out
yes you will cause more problems then it will help because it will cause a gap in the butterfly plate and the TB bore which will cause high irratic idle and it will throw a high idle code and it will also make you run really lean.
i bored out my stock TB to 62mm and the plate had a .0025 gap between it and the TB bore and caused all those problems. the idle is controlled by the IAC like Darkstars said. the only true way to change the idle is through the ECU
04 sunfire auto, mid 15's n/a, and still going
