mcar00

Made a couple of changes to my C6 Z06 at the same time. Added breathers to the valve covers and made some PCV changes. Also added a lightweight clutch assembly. When we started up the car it did not want to idle and surged from 1,000 to 2,000 RPM continuously. We assumed we made a mistake to the PCV system and put it back to stock but the car still did not idle and surged.

Is it possible that taking off 40 pounds off the clutch/flywheel assembly could cause the tune to need adjustment at idle or do you think we just created a vacuum issue somewhere messing with the PCV system?

Thanks for any help.

sspeed30043

Lightweight flywheel can cause false misfires and choppy idle
all the weight helps the engine maintain its idle smoothly.
Even though there is nothing wrong....... the breathers probably caused a lean condition, maybe higher than normal idle, all air entering the engine needs to be metered by the mass airflow, even crankcase venting air. Do a battery reset and see if the idle comes back to normal.

travisnd

When I put a Luk Stage II clutch with a Fidanza aluminum flywheel in my old C5 Z06 the car had a harder time finding an idle when coming to a stop. Never had an issue idling when started, but when the rpms were dropping the throttle/idle programming couldn't deal with the reduced mass perfectly. Had to tweak the tune to get it to catch idle properly.

Last C5

Fidanza aluminum flywheel and lightweight 7.6 dual disk set up and I can't just blip the throttle and have it settle by itself to idle anymore. I have to catch the rpms and let them down slow or it will surge till it dies.

travisnd

A good tuner can fix that

Bink

Pretty simple fix. Adjust "Throttle Follower Airflow" and "Throttle Follower Airflow Decay Rate".

Last C5

Not with the cam and intake I was running, but now I've changed to the converted upgrade for the Haltech and I'm going to have it retuned. (Crossing fingers here)

mcar00

I would have never guessed that changing the clutch/flywheel could impact the idle. Amazing. Thanks for all the info!!

Rednels

Yeah, you will also be amazed by how much quicker the acceleration is out of low speed turns.

It feels like you added a bunch of HP...

mcar00

Looking forward to it!

LSOHOLIC

Post some weights....light is a relative term..... RPS alum flywheel is like 11lbs and McLeod's is 31lb...huge difference. Matter of fact RPS's steel flywheel is 4lbs lighter than McLeod's alum. IIRC, of course.


Thanks....and whats a Tilton alum flywheel weigh ??


.

mcar00

RPS twin carbon here. 25 lbs for total assembly. Removed a 64 lb ZR1 assembly.

LSOHOLIC

Yeah, I'm running the BC2 steel setup. 34lbs total...for steel.. Great for "stored energy" and light enough for a HP gain. I read horror stories about the tuning issue with alum flywheels, so I went with a light steel setup. Plus they rate the alum setup at 800hp or less and I'm afraid my torque spike would be very close to that...


Thanks....

.

Screamin Z

Mike, yeah it will make a difference. We did the same swap as you. With the clutch depressed in the car it has a very difficult time trying to idle when cold.

Leave it in neural and let out on the clutch it should get better. But not much. Our tuner worked a good part of the day just getting it to idle pretty smooth and reduce the "bucking" while idling in gear to 0.

Once it gets warm is purs like a tiger.

alextz

you can get random misfires P0300 code on all cylinders that goes away above around 1200 rpm (just detune the index misfire counters a bit, and the codes go away).

also for idle, you should do an idle relearn which includes base running airflow, then throttle cracker and follower including decay rates. Also, if the car has a non stock throttle body, the tune needs to recalibrate based upon the blade area etc.

can all be fixed via tune.

Superbee

Can anything be done in the tune for problems with either stalling or spinning the tires when trying to start off from a stop with a liteweight clutch assembly?

newschool

No your tuner sucks. A good tuner can correct that.

SouthernSon

BIG LG camshaft in LS6 with quartermaster clutch pack (no flywheel). Car hunts idle constantly, no way around it. Tuner has engine running OK when abruptly coming to a stop with clutch in but starting from dead stop requires some clutch slipping. No problem at the track but am unable to drive on street without burning up the clutch. No misfire codes or any other DTC problems.

rustyguns

it adds about 11 hp!!

rustyguns