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? :confused: 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. :confused: :boxing

 

Was the lobe seperation correct for the cam? Sounds from your description like its more 112 than 115. Of course I'm only a novice :skep:

 

Yeah the cam specs agree exactly with the cam card. 220 @0.050 and 220@0.050 opening and closing events are exactly right on. 0.581 lift intake and exhaust. It all there like it should be. It is tuned and all. Checked with a techII by Lou himself. I don't know what else to try? This car is way beyond a Chevy dealer!!! Way too many mods.

 

You still didn't say what the Lobe seperation is, or is supposed to be.
I have a 220/553/114 and the idle was literally like stock, and this is Without tuning.
After I put on the Shaner TB, it picked up a very mild lope, and rythmic shake like you describe, but very mild, not like yours at all.
The only difference in our cams is the lift and the ramps, these should not cause any idle problems.
So I think the lobe seperation is not ground in correctly, or your cars' ECM is not dealing with the idle normally. Maybe you can borrow another stock one and try that?

 

This is a very interesting and timely post because I have a '04 C5 Coupe and wanted to do a "Cam Only" upgrade since the LS-1 heads alreadyflow very well and I want to minimize internal modifications to the new engine.

I have most of the "bolt-ons" and was seriously considering the MTI "Stealth" cam (220 220 .581 .581 115) since it is suppose to maintain a "stock-like" idle while increasing HP/TQ. The purpose being to not raise suspicions at the GM dealerships when I need warranty support.

Who else have installed the MTI Stealth Cam and what were your experiences? Is this typical?


[Modified by AlohaC5, 12:36 PM 11/8/2003]

 

I have heard from some LS1 guys on another forum that the Stealth cam i fine until you improve the exhaust flow. For example removing cats and intalling pro long tube headers and aftermarket cat backs will make the stealth cam lope. Seems there is a guy on LS1 tech that had an SS camaro with a borla exhaust that had the Stealth cam installed and to MTI's apparent suprise...it loped. Seems as long as you run a more restrictive exhaust it will idle like a stocker. But an aftermarket or freer flowing exhaust will make it lope.

 

What other cams did you consider? I'm staying with the 114 even though my car is a 6-speed and could easily handle the 112 with tuning. My concern is that most cams cost around $400 and if I install something too "mild" and don't realize much of a hp/tq gain, then I basically wasted time and money... Then again - there is always the force injection route, i.e., ProCharger, Vortech or Magnacharger that allows me to keep my LS-1 stock during the warranty period.

 

I considered the TR (ThunderRacing) 220 and 224 cams and the MTI SS2 cam and LG's milder G5 cam. If I can't get this car to idle closer to a stocker I may just rip out the Stealth cam and go with the G5 cam and a Fast intake combo. What a waste of money. Stealth cam that isn't stealthy at all. :cry

 

X_03, There has to be something wrong somewhere! The specs on that cam just will not allow it to do what it is doing within the range of normal deviation. So there is some unfound problem somewhere in the system. I suspect the computer. Did you try having it reflashed?

 

My best advice would be to yank that MO FO out and install a 224/224/581/114 cam... No matter how many times you mess with your setup it is not going to get better. :(

VR :cheers:

 

Ah the MTI C2, but if you really want stealth how about one of the Lingenfelter cams? Of course the baby 220/220 Thunder cam would be a good choice as well, for stealth aspects.

 

My stealth cam idles great but I don't have the A4. What does MTI have to say about this? Good luck with your problem :cheers:

 

It rocks back and forth in Neutral as well as in Drive. It actually seems to idle smoother in Drive or with a load on it. some people say it idles great. But great is subjective. Some people think my car idles great. I don't like the bucking and rocking at idle speeds. MTI guys say that catless cars with freer flowing exhaust are lumpier than cars with cats and more restrictive manifolds and mufflers. Apparently a gun on LS1-tech had a smooth idle until he put exhaust on the car and then it started to lope. This may be why mine lopes and others don't. I am not sure. I am sure the mechanicals are ok and I trust that Lou got the tuning right. So its gotta be the combination I have.

 

Have you considered the chance that you may have some bad plugs/wires?

 

Hello...

I don't think it is an issue with the cam as well....too many others have installed it with great results and a fairly smooth(almost stock like) idle.

I would look for a broken plug, bad wire, faulty O2 sensor, or as others have suggested, something with the "tune" of your combination.

I am curious what Lou has had to say about the idle quality...does he think it is "normal" for a stealth cam install?? (assuming he's heard enough of them to comment on it).

I seriously doubt buying another cam is the way to go...you might end up right where you are now or worse....it would be one of my last choices to remedy the situation.

Good luck...
Tony M.

 

I have the same set up as I have mentioned before. I love the way my car behaves and I was very picky. I am the second car with the stealth cam. You mention that you have been dealing with lou but what about Jayson at MTI? I would not go to MTI with a LG header problem and don't understand why you would go to LG with an issue concerning an MTI problem. I have found Jayson to be very informative and helpful. Call him and give him a chance to look at your car. Not having ever seen or heard your car I have no idea about what you are experiencing but can tell you that there is no such thing as a completely undetectible cam. The stealth cam is more stealth than any other that I have seen and heard. Was just at the drag races and there were many LG cars and others. All commented on how well mannered my car was and could not believe I had over 400 hp. Maybe your expectations were too high.....had you ever seen or heard the stealth before you bought one?

 

Yeah I have checked the plugs for cracks ... changed them all twice. Changed the plug wires too and the coil packs and both O2 sensors. Still idles exactly as before. Checked for vacuum leaks too. none. Lou's impression of the car was it is the wrong cam that was in the box. I verified it by degreeing it Saturday that it is indeed the SS1 stealth cam. I don't live in an area where there are many if any modded Vettes so the only modded Vettes I have seen were at Lou's shop. The GX2 cam idled identically to mine if not a bit smoother. The initial impression I got from Lou was that I crossed the O2 sensors when installing the headers...that was the reason I brough it back to Lou's shop to have them check that out and install a looser converter and gears. I will stick with one tuner as I love 13 hours from Houston and 10 hours from Dallas and don't have the resources to be taking the car back and forth over such large distances. Surely there is another guy out there running the stealth cam and LG long tubes that can chime in with his idle quality.

 

If your cam install, vac leaks, etc. check out okay, two options remain: 1) an intermittant spark problem, or an intermittant fuel problem. From my experience it tends to be the former.

Cannot LG find it?!!! It seems that it is missing while it is "rocking." So, think about the above. Should be able to identify which cylinder(s) is(are) at fault.

I know this can be frustrating--been there on other FI and supercharged cars.

All the best.

 

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.

 

At which crank degree is max lift for both lobes--so you can calculate the lobe center. Most cams are something like 108 & 116. At what lobe center is yours degreed in? Does the cam have ground in advance? Did you set it at zero on the chain?