BoostGuy951

OK, Today I cleaned out the intercooler and subsequent piping. They were soaked in oil. Now the turbo no longer smokes, but it will not boost above 14 PSI with the MBC all the way open, and trust me, the wastegate is shimmed to hell. It also seems like a somewhat weak 14 PSI. My friend and I did a roll on from first gear, and his Corvette totally smoked me, and that has never happened. A turbo upgrade was on my list for eventual mods, so I guess now looks like a good time eh?
I just want to get a consensus that it is probably the turbo and not something else.
Opinions would be appreciated.

Mike Buck

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by OZ951:
<strong> </font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by Mike Buck:Why are you using a MBC, LBE, and a shimmmed WG at the same time?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Running a LBE and shimmed wastegate along with a MBC is not a problem. They all work together doing their bit. MBC sets the boost limit, LBE allows boost to build quickly and shimmed wastegate enables the wastegate to hold a higher level of boost.

QB]</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">It is my understanding that the LBE is a "band-aid" for a weak wastegate spring. Therefore if a WG is shimmed "to holy hell", it would not be needed. Seems redundant to me.

BoostGuy951-
If you decide to get a new turbo . . it is not just a matter of bolting a larger unit on. Any turbo bigger than a K26/6 will require lots of other things. Exhaust, intake, injectors etc...whomever you buy from would tell you this.

BoostGuy951

The wastegate in the 951 is a progressive Spring wastegate. That means that it doesnt have 2 settings, open or closed. If it is set to hold boost at 15 PSI, it may start to open a little bit at as early as 3 or 4 PSI. The LBE prevents the wastegate from opening at all until 10 PSI so that the time it takes to go from 0-10 PSI is greatly reduced with the LBE, than without it, even if the wastegate is "shimmed to holy hell".

Shims: Ablilty to hold High Boost
MBC: Ability to set that boost to a predetermined level
LBE: Affects the speed of the Spool up

All three work in conjunction, and all three play their own specific role.

Mike Buck

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by BoostGuy951:
<strong>The wastegate in the 951 is a progressive Spring wastegate. That means that it doesnt have 2 settings, open or closed. If it is set to hold boost at 15 PSI, it may start to open a little bit at as early as 3 or 4 PSI. The LBE prevents the wastegate from opening at all until 10 PSI so that the time it takes to go from 0-10 PSI is greatly reduced with the LBE, than without it, even if the wastegate is "shimmed to holy hell".

</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">The LBE is adjustable, why haven't you dialed it up to 19psi also?

BoostGuy951

If I did that, the wastegate opening point would be 19PSI. In the time it took to take the wastegate from barely open to completely open the turbo would overboost to around 24 PSI before boost fell back to the LBE set 19PSI.

BoostGuy951

I understand the further implications of installing a bigger turbo.

Mike Buck

Sorry for all the questions. Your car is the first i've seen to use a LBE, MBC, and a shimmed WG all together. I've looked at a lot of turbos at the track, hadn't ever seen the combination you are using. Whatever works for you works for you. No hard feelings.

I bought a testpipe to help my spooling, best mod done to date. Now sorting out the suspension and rebuilding the engine - then i will turn up the boost.

TonyG

Quit messing around with the stock wastegates.

For the cost of a good electronic boost controller, you can get a Tial 46mm wastegate, and a manual boost controller.

That's what I run, and the boost is rock stable. No boost creep one way or the other.

BoostGuy951

Tony- does the boost level stay the same in every gear? I thought that with the same wastegate setting the car would boost progressively higher in each gear due to a higher load. Thats why I wanted to get the AVCR to get gear based boost control.

TonyG

Yes.. the boost is the exact same in every gear. Very stable.

So much so, that I never intend to go back to an electronic boost controller (and I've had a few in the past)..

BoostGuy951

So my boost increasing in each gear is due to the wastegate?
I am definitely replacing that along with the turbo.

Edman951

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva"> OK, Today I cleaned out the intercooler and subsequent piping. They were soaked in oil. Now the turbo no longer smokes, but it will not boost above 14 PSI with the MBC all the way open, and trust me, the wastegate is shimmed to hell. It also seems like a somewhat weak 14 PSI. </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Maybe you now have a boost leak and thats why you can't boost higher and it feals weak.
What did you use to clean out the intercooler and piping?
Double check all the rubber fittings and clamps. maybe one of them cracked when removing them or someting...
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