Ok, so about 3 weeks ago, I bought a new Buschur 20-g-9, to put on my 2005 EVO MR. My MR already had:3" turbo back exhaust, large front mount, 264/272 cams.

I re-used my hotside, so I got this turbo as a cartredge, & compressor housing, with the adaptor kit.

I port matched the exhaust to turbo's hotside. I port matched the hotside to o2 housing.

I added a test pipe, air intake, & intercooler hard pipes.

Before the turbo swap, the boost would rocket up to 22~23 psi, with the stock actuator, no problem whatsoever..

AFTER the turbo swap, I've been running low boost till this Saturday, when Al of Dynoflash is comming to Colorado to tune like 10 Evos. (I have 780cc injectors that will go in the day of the tune also)

Anyways, I got my methanol kit installed & working, so I tried a momentary hit for high boost, to make sure everything is working correctly, but dangit. It doesn't make more than about 17 psi or so..

I was using a Profec B boost controller.. I know they are limited, but remember, it controlled boost up to 23psi no problem with the stock turbo.

I also ordered and installed a forced performance high pressure actuator.. Still doing the same thing.

Here's what I've done to try to figure it out:

1. Hooked up a Hallman style boost controller.. Same problem.
2. Disconnected the hose going to the boost actuator.. Same problem.
3. WIRED SHUT THE WASTEGATE alltogeather, so that it CANNOT open at all.. (Very carefully applied throttle in 4th gear to control any overboost.. SAME PROBLEM! It won't go over 17psi!)
4. After this, I did ANOTHER pressure test on the intake system.. Capped the intake hose at the throttle body, & capped the inlet to the turbo, & then pressurised the system with a boost gauge to test pressure.. I made it to 17psi before one of my plugs shot across the shop! haha.. BUt, It would hold 17psi, so NO BOOST leaks in the intake system.
5. Last night, I removed the turbo, & re-installed the stock turbo again.. Still need to take it for a ride, but once I had the turbo removed, there were no exhaust leaks to explain anything.
6. I examined the wastegate flapper, & wastegate holes.. No problems.. It seats perfectly, & moving the flapper around cannot expose any of the wastegate hole at all.

I even checked where the hotside band clamps to the cartredge, in case they wern't seated correctly, leaving a lot of air-gap around the turbine wheel.. No problems there.

So. Obvyously i need to go for a ride with the stock turbo, to check the difference, but does anyone have any more ideas? I have to get a customer's job done this morning, but once I have 30 minutes to finish the job up, I'll go for a ride.. If boost & everything are great, then I guess I got a gimpy turbo & just need to exchange it, but geeze.. There's not a whole lot that can go wrong in the turbo itself, that usually keeps it from working at all, right?

??

 

did u check to make sure the blades were spinning after u put the turbo back together??????

the mbc you're using might need a stiffer spring.
recheck all your i/c connections.
turn the w/g turnbuckle all the way down to reduce boost taper.
check for any kinks in vacuum lines.

 

The turbo is making 15 - 17 psi.. The blades MUST spin to make boost, right? But yes, As I was installing the center cartredge to the hot-side, I was gently moving the turbine blades to make sure nothing was binding.. It spins very freely.

I re-checked the IC connections, & pressure tested the system.

I did tighten the WG turnbuckle all the way to the bottom, & even wired the wastegate shut..

Once I wired the wastegate shut, it eliminates any problems that might be in the wastegate control system. It should go past 30psi of boost if I allowed it to by continuing to step on the gas pedal, but it would go to 15 or 16 psi, leaving the wastegate out of the equasion.

 

i would recheck the blades to make sure they're not rubbing or anything...

 

Ok, I now have the stock turbo back on the car, & it's doing the same thing.. I can get to 17 or sometimes 19psi.. NO MORE.. That's with the heavy wastegate actuator on there, with the turnbuckle tightened all the way down.

Here's a bit more info though...

If I give it about 10% throttle, & allow the turbo to come up, it gets up to about 19psi.

If I floor it, it usually stops at 16psi, & drops off pretty bad.

This is with the stock turbo.

Now, with adding the intake, hard intercooler pipes, & test pipe, & the cams, could I simply be outflowing this turbo too bad?

I guess I'll put the 20-g back on tomorrow, & go ahead & get it tuned, & see what happens. But even being out of tune, it should have no problem making boost.