Holset Turbo Application

[Power Surge]

Greetings to all here. My name is Sal, and I need some Holset turbo advice.

First off, I do not own a DSM car. I found this forum doing extensive searching on Google for good Holset turbo info. I found all three parts of the big Holset turbo discussion, like here: http://www.dsmtuners.com/forums/turbo-system-tech/274459-holset-turbos-part-3-a.html. I was very impressed with the knowledge on the people on this site, and no other forums or Holset info I could find seemed to be anywhere near as impressive as what I've seen here.

With that said, I am hoping you guys here can give me some info. I have a DOHC 3.0 liter V6, with a Holset H1C on it. The problem that I have, is that the car will make 6 psi by about 4000 rpms, but after that, it drops to 2 psi all the way up to 7200. Everything has been checked on the car from exhaust leaks, to the wastegate, to the blow off, and nothing seems to be the cause. At this point, I am questioning if this turbo is just too small to continue to move enough air to make boost on a DOHC 3.0 after 4000 rpms. I know that this turbo was OEM on a big diesel, but that never saw over 3000 rpms on that motor.

So if any of your Holset guys could give some advice, it would be very appreciated!

Thanks!!

 

[iluvmy4g63]

this has to be a wastegate problem.or boost controler.

 

[GORBS88]

Greetings to all here. My name is Sal, and I need some Holset turbo advice.

First off, I do not own a DSM car. I found this forum doing extensive searching on Google for good Holset turbo info. I found all three parts of the big Holset turbo discussion, like here: http://www.dsmtuners.com/forums/turbo-system-tech/274459-holset-turbos-part-3-a.html. I was very impressed with the knowledge on the people on this site, and no other forums or Holset info I could find seemed to be anywhere near as impressive as what I've seen here.

With that said, I am hoping you guys here can give me some info. I have a DOHC 3.0 liter V6, with a Holset H1C on it. The problem that I have, is that the car will make 6 psi by about 4000 rpms, but after that, it drops to 2 psi all the way up to 7200. Everything has been checked on the car from exhaust leaks, to the wastegate, to the blow off, and nothing seems to be the cause. At this point, I am questioning if this turbo is just too small to continue to move enough air to make boost on a DOHC 3.0 after 4000 rpms. I know that this turbo was OEM on a big diesel, but that never saw over 3000 rpms on that motor.

So if any of your Holset guys could give some advice, it would be very appreciated!

Thanks!!

That turbo will definetally flow enough for that engine. The first place i would look is for boost leaks, you have to presurize the intake and all piping from the turbo to check for leaks.

 

[Power Surge]

this has to be a wastegate problem.or boost controler.

No boost controller. And it should not be a gate issue. I am running a Tail 38mm gate. I have tested it in various configurations (on my dyno) such as with an 8 psi spring, 12 psi spring, the vacuum line disconnected (which should produce spring boost) and I have also tested the gate off the car for proper psi opening point and all is as it should be.

 

[Power Surge]

That turbo will definetally flow enough for that engine. The first place i would look is for boost leaks, you have to presurize the intake and all piping from the turbo to check for leaks.

I have checked everything multiple times for obvious leaks. However, I have not actually "leak tested" everything under pressure. I suppose I can rig something up to check from the throttle body into the motor, and then work my way back down the piping back to the turbo to see if there are any leaks. I really don't think so, but it's worth checking.

 

[iluvmy4g63]

thats good idea. a few guys on here make there oun boost leak testers. iam not sure where the page is but if you look around iam sure you will find it.

 

[Power Surge]

think about it. the only thing that would stop the turbo rpm would be the wastegate. and the controler would make it boost. also you getting enough oil flow to the turbo?. lack of oil can slow turbo speed. to much can also.

Well, I tested the seal of the gate seat, and it doesn't leak one bit. It also opens precisely at 12 psi.

The oil feed issue is a good one. I actually have tried several levels of oil input using a special inlet fitting I made that uses nitrous jets with various sizes for oil control.

My last feeling on this was that the turbo was not spinning at a certian point. I pulled it apart and found that the rebuilder (I bought it as a freshly rebuilt unit) had done a bogus repair to the shaft where they machine the piston groove on the turbo side double wide and then try to use two piston rings. The problem with that is that the second ring rides up the shaft lip and does not seat into the housing. I thought that was the issue with no spool. I had a custom wide single piston ring made to fit the groove, but it didn't seem to help with boost at all.

On my dyno, the boost level and power graph is completely repeatable. I've tried blocking off the blow off (gotta be careful on the decell with that one), I've even tried NOT using the gate and blocking it off with a plate, and the dyno graph and boost log is IDENTICAL no matter what I do.

 

[iluvmy4g63]

thats crazy. with no gate. if i tryed that on my car the turbo would probly blow in to a hundred metal fragments. u would think the turbo would just spin out of control.

 

[Power Surge]

thats crazy. with no gate. if i tryed that on my car the turbo would probly blow in to a hundred metal fragments. u would think the turbo would just spin out of control.

That was the point of that test . I can watch boost during the dyno pull, so if it was going to go crazy high I could just abort the run. But it made no difference.

As for boost leaks, if I had some kind of leak in my intake stream, why would it make 6 psi at one point, but only hold 2 psi after that? If it can hold 6 psi, it should hold 6 psi all the time, no?

 

[iluvmy4g63]

well my turbo dose the same thing. it spikes then settles back to right boost psi. it gos from 20 to 18 . but i will be honest i have no clue why mine dose it. buy any chance you think the wheel in the turbo is hittin the comp. cover under boost?

 

[Power Surge]

Could somebody with regular board status, please post a link to this thread in this thread:

http://www.dsmtuners.com/forums/turbo-system-tech/274459-holset-turbos-part-3-a.html

I'd really like those guys to see this, but I can't post in there due to my "newbie" status, and I don't think any of those people check the newbie forums.

Thanks!

 

[billman]

Check for boost leaks. How does the turbo sounds? How is the shaft play? Do you have pictures of your turbo? Can it be that something restrikts the inlet (a hose before the that is sucked toghether during boost)?