cm870 ISX Turbo Screech Monroe/Charlote, NC

[wrenchwabbit91]

no i watched the sample video you uploaded it was identical to what i had going on. it would go away if i pryed the arm up. truck also built way too much boost while cruising, do you have quickserve? they have the spec for how much air pressure should be applied to vgt in warmup mode. i wouldnt advise disabling the vgt. i tried that while i was testing, jakes were shi#t and had poor low end power.

[Rawze]

(04-08-2023 )Magnum1 Wrote:  ... it'll have stationary turbo.

Removing the Vg turbo and putting a fixed type turbo is one of the worst things that someone can do to an ISX. It is the very device that sets the proper fuel-air-mix, is responsible for a large portion of the engines efficiency, and is used to help properly keep in check, the internal engine friction, which directly effects engine lifespan by a lot.


Removing it significantly shortens the engine life, causes lower than normal fuel miles by thousands of dollars a year. -== there is no gain whatsoever in putting a garbage fixed-vein turbo on it and costs more in fuel mileage losses each year than simply replacing the VG if it is bad.

Also.. like I mentioned already, the screeching IN ALL OF THOSE VIDEOS ... is the gasket(s) causing the screeching and not the turbo itself.

DO A TURBINE INSPECTION. Remove the boot off the cold side, Check that it spins freely, has no in/out play, and check the side-play of the turbine with your fingers. It should have about 0.045" of side-play max (a very tiny amount but usually not zero) .. and if it were loose enough to actually cause that kind of noise, then it would be pouring oil out of it too.


As far as screeching goes ... Simply put .. If the turbo positioning is set to a higher position then higher pressures are driven thru the turbo. If it screeches .. then it is simply revealing that there is a mounting (or exhaust manifold) gasket issue. -= The Screeching itself IS ALMOST ALWAYS,.. 95% OR MORE --- NOT THE TURBO!.


(back to your comment about removing the VG permanently)...
- Seems you are not listening to anyone on here. -== seems you are also drinking the cool-aide from some seriously ignorant people somewhere who are bunch of complete idiots if they are suggesting you remove the VG and replace it with something far less efficient that will also contribute towards shortened engine life.

This last post of yours also brings into question that maybe you already have a delete program in the engine too. If so, then you need to also start assuming that the program is bad as until you get it reviewed properly. More than 90%+ of all delete programming for the ISX engines is absolutely horrible and significantly shortens engine life .. causes dropped liners, head gasket failures, and/or turbo problems, and all sorts of other component life-shortening issues.

If you in fact do have a delete program in it then the next move is to copy the program out of the ecm and e-mail it to me for a proper review of what someone did in there. See what is good, bad, or downright harmful to the engine. It is absolutely nothing to take for granted at all.

....

AND replace the squealing gaskets + have the manifold removed, re-surfaced, filed flat, etc. where necessary etc. so that it will not leak again while you are at it too!> instead of assuming it is the turbo itself.


how does the saying go ?/... "you can lead the horse to water ..."?

[Bengy88]

(04-08-2023 )Magnum1 Wrote:  Thank you everyone for your replies. If I will come to the conclusion that it is either vgt or controller - it'll have stationary turbo.

It’s your truck so I’m not gonna tell you what to do with it but take what I’m about to tell you and do what you want with it.

When I first started doing this shi#t I was all in on vgt deletes, who wouldn’t want to buy a $2000 kit and put a simpler, cheaper turbo in place of a $3500-4000 turbo? Hell it even makes 45psi of boost right? Not to mention the entire passenger side of your engine looks nice and clean…… well after about a year I started realizing every truck that my customers wanted a vgt delete done on had cracked a head, wasn’t long after that came the excessive blowby from collapsing rings, oil consumption etc. it was a chain reaction with all of these trucks….. not just one but every one. Not only that but the engine brakes were weak and there was extreme turbo lag in lower rpm’s. (The shi#t nobody tells you about their engines after they have made this mistake). Well I took one of these trucks “my brothers” and I played with making it as dependable as I possibly could. I lowered torque, set rpm limiters, did everything I could think of to keep the stress down….. that was 2 years ago. I’m now tearing the engine down to replace a cracked piston.

Isx engines can not safely handle these turbos. 45psi of boost is entirely too much. You can no longer control fuel/air mixture properly. Usually the exhaust gas back pressure sensor will be deleted, this monitors missfire conditions, you actually loose power from too much boost, loss of engine brake performance, lower fuel mileage, cannot properly tune, the list goes on. So why would you want to do this to a truck? You save 2000$ that cost you 25-30,000$. Saving a penny just to spend a dollar huh? This isn’t a 14l Detroit or a twin turbo cat where you can get away with making changes like this and not seeing an issue from it. These engines are far more complex and sensitive to doing stupid shi#t to.

Instead of trying to beat around the actual problem why not ask “well how come when I move that little arm the squeal stops”? It’s because that little arm controls the vanes in the turbo which controls boost which in turn increases or decreases pressure in the intake, manifold, turbo, and exhaust. When you move that little arm the pressure is decreasing. Kind of like when you whistle if you don’t blow quiet as hard the whistle will go away. This is what’s happening with your truck.

Say you pull your turbo, pull your manifold, check for blown gaskets, replace them, disassemble your turbo just to see that nothing is wrong with it, reassemble your turbo, (rawze has videos on this I believe), and reassemble your truck. If the noise stops you have fixed it, if you find an issue in the turbo you can fix it… either way the problem will be fixed and worse case scenario you loose a couple hours of labor and a gasket. In 18 years the absolute only thing I’ve heard cause that sound is turbo gaskets/cracks and exhaust manifold or egr gaskets. Not to mention if you scroll the comments in the video you sent you will see where people were fixing this problem by replacing gaskets. We are here to help you but if you won’t take the advice given then there is absolutely nothing else this forum will do for you. Good luck in figuring the problem out.

[Magnum1]

I've been looking for soot and can't seem to find it anywhere around the gaskets... Is there a smoke machine option that could be used to pressurize the exhaust or that is a poor option as well ?

[Bengy88]

https://rawze.com/forums/showthread.php?...21#pid8321

Check this out

[Magnum1]

{post removed by rawze .... trolling}

[Bengy88]

Because metal expands when it’s hot. Also if your tune isn’t locked in chi4 properly it could be changing operating modes because it’s looking for your exhaust filters to heat up but they are missing. This would cause added intake and exhaust pressure. Now I’m not saying 100% that it’s not your turbo giving issues…. I can’t put my hands on it. All I’m saying is minor exhaust leaks and egr leaks is literally the only thing I’ve ever seen cause this issue you are having.

It also would seem that the volume of exhaust gases wouldn’t change but when you move that arm and increase the air flow into the engine where does that added air flow go? Air that goes in must come out…. All a turbo does is force air…. It wouldn’t be forcing if nothing was there to restrict it. . If you increase the amount of air that goes into that engine then you are gonna increase the amount of air that comes out. This will cause increased pressure on the inlet and exhaust.

[Rawze]

(04-09-2023 )Magnum1 Wrote:  {post removed by rawze .... trolling}

this person has been muted to save them from embarrassing themselves further. They ask for some help and only want to argue everything away and make idiotic replies.. this is not tolerated on the forum.

Take that trolling style of attitude back social medai where that kind of garbage-manipulative trash belongs.

[Bengy88]

I was starting to get aggravated but I hadn’t made the decision whether he was being a clown or actually a clown. One contradicting comment away from me catching a ban for myself lol. Thank you sir