X_03_Cobra_guy

I have posted about my idle woes before. This is an update on my progress with it. I have had the car tuned by Lou at LG Motorsports and the car made 403 at the wheels (A4 with 3.42 gears and an SS3600 converter...in locked mode on the dyno. My engine mods are unported Z06/LS6 Heads and the MTI stealth cam with LG Longtubes) I have had the cam degreed...again to make sure it is installed right and I checked all the specs on each lobe of the cam except the rear most cylinders...the dial indiator wouldn't fit under the cowl. The cam is indeed a 220/200 .581/.581 cam like the card says it is and the intake and exhaus opening and closing events are right on the money. So that rules out it being the wrong cam. While I had the rockers off....I got the bright idea to pressure test the intake manifold for a vacuum leak. I used a vacuum tester and it held 10 inches of vacuum for 45 minutes. No vacuum leak! I had changed to O2 sensors ... still no luck.
The car idles at 900RPM and gets into and out of a rhythm of rocking back and forth enough to spill a drink in a cup that is 1/4 from being full. Then it smooths out for a second or so then back to rocking again. It is noticeable from outside the car as well. The exhaust sounds like I have a 230/230 cam in it, as does the lopey idle. HAS ANYONE WITH THE STEALTH CAM HAD AN IDLE LIKE THAT? I bought the Stealth cam with the impression that it idle better than the "bigger" cams. Now I am thinking I should have just got the X2 or X3 cam anyway since they idle the same if not better than mine does. I heard an X2 at Lou's shop and it idled BETTER than mine does. WHAT COULD CAUSE THIS PROBLEM? Or is is just normal. I don't want to throw money at parts I don't need. Lou's impression of the car was that it was probably the wrong cam in the box because of the power it made and the idle it has ( with unported LS6 heads). But it IS the right cam, I double checked that. The O2 sensors are installed right, I went over that with Lou. So I am puzzled as to how guys with 224+ cams can idle better than mine does.

Pro Stock John

iTrader: (34)

That cam should not be too too lopey, maybe you are really rich at idle and the plugs are loading up?

A really easy way to play with the idle, once you have gone through the obvious stuff like vacuum leaks, fouled plugs, etc,. would be to borrow a MAF-T and play with richening and leading out the base to see what you need. IMO when a motor shakes big time it's rich, and you either need more air or less fuel.

Scalpel

iTrader: (4)

The SS2 cam WILL lope if the car is not flowing through a stock catback.

X_03_Cobra_guy

The car was running rich before the tune. Now it runs perfect A/F wise and the plugs are nice and clean again. I thought this would fix the idle but it didn't. When you start it cold it idles good...though it idles a bit high like 1200 or so. But once it goes into closed loop it starts to lope. I hear some guys say they installed this very cam and "claim" it idles like the stock camshaft. I find that somewhat hard to believe. I do have a catless car with LG pro long tubes. And a 3.42 gear with SS3600 Yank converter and unported Ls6/Z06 heads. Car make great power but the lope gives it away. I wanted stealthy but got beastly. I just want to know it is normal for it to do this so I don't keep hunting in vain for a cause.

Scalpel

iTrader: (4)

Yep, it's normal, it will lope through anything that isn't a STOCK catback. MTI found this out on a recent customer's car. It had a Borla catback and it loped. This is what they told my brother after we had already installed it and all. It will lope unless you have a stock catback.

Your options are a stock catback or take it out.

All this data I posted is regarding an F-body.

X_03_Cobra_guy

thanks for that tid bit. That make me feel better that something is screwed up mechanically. I don't mind the lope as long as I know it is to be expected. Buying a Stealth cam one would, well, expect stealth. I have long tube headers too and am catless with aftermarket cat backs.

4thGENRETARD

iF YOU HAVE A 220/220, .581/.581 115 lsa you have a SS1. The SS2 is 224/220, .581/.581 116 lsa. I have the SS1 and a Hooker cat back, pacesetters and 2.75/3' Y. GMAF, BBK TB, FIPK GEN II, TCI SSF 3500, Patriot LS1 stage II etc...
The SS1 does lope, but nowhere near a TR224 or TR220 for that matter. Shoot, the only thing I had to do with the stock tune was to adjust idle and it does so at 650rpm in drive. Im pulling 391rwhp/378tq and over 500 with NOS 5177. This cam is the pimp for street. And check my sig, if i wasn't sleeping at the wheel, I know I could have got low 11's, my R/T for that pass was 1.03 (Yeah i know, no need to say it)

highgear

First time I ever heard about the type of Catback effecting or making a radical idle. Hope you get it fixed.

X_03_Cobra_guy

I am confused at this point. Some say it it lumpy some say not. I know mine rocks the whole car back and forth quite a bit. More so than some of the cars at Lou's shop with much healthier cams in them. Something must be awry with my car. I makes good power though, just won't idle very good. I don't have ported heads, just factory Z06/LS6 heads but I do run the long tube headers without cats. I have tried new O2 sensors, Lou at Lg Motorsports tuned it and idle it up to 900. Could it be a bad injector or bad MAF meter? Wouldn't this show up on a TechII? Wish I knew someone that would donate a PCM to try just to see if something is wrong with mine.

MaximusPrime

How does R/T have anything to do with E.T.?

Scalpel

iTrader: (4)

It doesn't. The timer doesn't start until you cross the beam.

99 Black Bird T/A

iTrader: (4)

As far as cat-backs go for hiding lope the SLP dual/dual can do a very good job of hiding stuff in most cases.

Isn't their an idle control sensor or something like that on the TB? Is the voltage to the Throttle position sensor correct? Checked the TB to make sure the blade isn't sticking etc?

Trojan T/A

iTrader: (1)

Dont know how to help you out but that sucks. I bet if you put cats back on the car it will stop most of the lope and sound more stock-like. I know a car with no cats and a very high flow system with the stock cam that lopes, so the catback does effect it. I also know a guy with a TR220 114 with stock cats and manifolds but with a loudmouth and his sounds almost stock i.e. if you didnt know what a stocker sounded like you wouldnt know. However, I think that these labels of stealth cam are false advertising and I'm sorry you found out this way. Any cam over 220 without cats, at stock idle, and with a catback is going to be very noticeable. As highgear, who posted above, even a 216/220 cam lopes with a free exhaust system. The only two choices I have heard for a real stealth cam are the LS6 cam and the GT2-3 from LPE.

I agree with Pro Stock John though, that your rough idle probably means you need more air or fuel at idle.

4thGENRETARD

Nothing, except for the fact that I was tired (I had been up for 21 hours straight) and that I activated the NOS too late, and my 60 ft sucked. that's what I mean't by it. I couldn't concentrate for ****. Sooory .

X_03_Cobra_guy

It had a hint of wanting to lope when it was stock. Every now and then it would rock a little bit...enough to make your leg shake a little. Bit since all the upgrades (all done at once) it is much worse. But runs smooth until it warms up ... after about 10 minutes or so ... and goes into closed loop mode. I am certain it has something to do with electronics. Since in open loop mode it idles fine. Blasted electronic gizmos. Sometimes I just hate fuel injection.

X_03_Cobra_guy

I can't believe Colonel's car. I believe it I just can't believe mine doesn't idle like that. I dont' care if the exhaust gives away the cam but I cannot stand the whole car shaking and rocking when it idles. I tried this test: I put a cup of water on the center console. The cup is 1/4" from being full...at idle the water will splash left and right and out of the cup! That is lopey! I am thinking the problem stems from the MAP sensor. I bet some are more sensitive than others. The map sensor detects and erratic vacuum and messes up the idle. Any larger cam will have more overlap and a more erratic vacuum signal I think. So it stands to reason that would impact idle. Now when mine is cold on startup....it idles great...that is until it hits 150 degrees...and goes into closed loop mode...it starts loping.

Scalpel

iTrader: (4)

There's something else going on with your setup Cobra guy, there's no way the cam should shake the whole car. Are you getting any codes?

Colonel

I talked to Jayson about this today...

I asked him if he thought there was any chance that some Stealth cams were being ground different than the others. He said he REALLY doubts it since they are CNC ground.

I asked him if it might be that the SS2 cam idles smoother than the SS1. He thinks maybe...possibly.

I asked him if he thought my LS6 heads and my 11.1:1 compression ratio might have something to do with why mine sounds stock. He thought that might be a possibility.

I think there are other issues here somewhere. Cobra_guy is describing such a large difference that I don't think it is explained by a difference in heads, a small compression ratio change, and a slightly different cam. I wish I had an answer. I bet I could install his cam in my car and it would idle like butter.

"However, I think that these labels of stealth cam are false advertising"

I don't think it's false advertisement. I think if you heard my exhaust at idle in person (like several at the Thunder Shootout did) you would swear it had the stock cam. When we heard my cam idle the first time, there was nothing we could call it but "Stealth" since "stock" was already taken.

Colonel

Thinking about it a little more... The fact that your car idles smoothly in open loop but not in closed loop tells me that there is a tuning problem of some sort. Mine, if anything, idles smoother in closed loop.

X_03_Cobra_guy

Even after a whole day of dyno tuning it still idles with an amazing lope. I have to agree with others that there is something going on with different cars reacting differently to the cam. I has to be sensor or computer related. I tried changing my plugs/wires and O2 sensors but that did nothing to stop the shakes. I runs dang good...just idles like crap. There are no vacuum leaks! I pressure tested the whole intake with a tester and it held 10 inches of vacuum for more than an hour...so its safe to assume no vac leak. The only thing that remains suspect is the MAP sensor. It throws no codes but I bet some are more sensitive than others.