UPS delivered my BR inline MBC today. This is their newest MBC that has the ceramic ball bearing and stainless spring that is not interchangeable. The box came with the MBC, a T fitting, and approx 3 ft of vacuum line.

I installed it earlier and must say my knuckles are a llittle banged up. I removed the UICP, air filter, and radiator fan. I followed the directions posted by drb titled
"MBC Installation Procedure"; it has some good pictures and diagrams.

Here are my results after the install... Out of the box with no changes made to the settings I started the car and it immediately went to 2k RPM with the clutch in. When I let out the clutch the RPM dropped to 1500 and went to 900 when warm. It struck me as odd since it normally doesn't do this when I start the car, but I did disconnect the battery. Just something I noticed.

With no increase on the MBC 2nd, 3rd, and 4th gear went right to 12 PSI and held. I turned the dial 2 settings ( not 2 full turns... the round knob has 4 dashes per turn; so it would be one half turn). Now it's holding 16 PSI... So being the math genious I am I figure 3 more hashes would set me to 22PSI and I'd be good.

Well my boost gauge showed 21 PSI tapering to 19 PSI. One more hash... Now I'm spiking 23-24 PSI for less than a second immediately settling to 22 tapering to 19 in 2nd and 3rd gear... 4th gear spiked the same and immed settled to 22 PSI tapering to 21 at 5500 RPM and down to 20 PSI from 6K to redline. I figure I may have a small boost leak somewhere. I've bought all the stuff to make a boost leak tester but haven' t put it together yet. So when I get some more time I'll check for leaks.

That is where I left it... The temp is 32 Deg outside and it's dark now so I'm going to run it a little more tomorrow. Redlining 4th gear on back country roads at night is a little scary!! I'll hit the HWY tomorrow and check it a little more.

 

The boost taper could also be from your wastegate actuator.

 

No, the taper is par for the course for the stock turbo.

 

All stock turbos w/ MBC's will taper, although it's usually not as prevalent on an VIII.

I wouldn't spike 24psi unless you're tuned... otherwise just try not to exceed 21.

EBC, Stock BCS w/ modified pill, or a stiffer WGA is the only way to fight taper

 

This is the normal ECU calibration procedure when you disconnect the battery or pull the ECU fuse. Normal.

 

Turbo Trix dyno tuned my car almost 2 years ago... He tuned it for a MBC set at 22 PSI, I just never put it on. When I go drive on the HWY today I may turn it down 1/2 click or so to see if the spike decreases any. Last night felt like it was much stronger in higher RPM. Didn't feel like it "fell on it's face" like it used to.

 

The car is no longer a quitter at high RPM!! Running on the highway today the car felt totally different. It no longer felt like it was falling on its face close to redline. The car pulls and pulls until a shift. VERY NICE!! Boost Held strong around 22-22.5 psi and slightly tapered close to redline. I didn't see the spike to 23-24 in 4th gear today. I'm going to turn back knob about 1/8th to 1/4 turn to try to get the boost to 21-22. That won't be till next week though... I'll repost my results when I mess with it more

 

Glad it worked for u. My Buschur MBC did not work, period.

 

care to elaborate?

 

just picked one up as well for my 35r setup, i love it

 

I just installed mine this weekend. Here's my question. I was setting it with 3rd gear pulls. Initially, it peaks and plateaus at 14 psi, then once I reach 5500 rpm it starts boosting up to 21 psi (where I want it to hold, and it does hold). Is this initial plateau normal, or does this sound like a leak? I have it hooked up between intake/BOV---wastegate.
Supporting mods are: (still stock turbo)
* BR 2.5" Mandrel Bent Stainless Steel Downpipe
* BR 3" Mandrel Bent Stainless Steel Catback Exhaust
* BR Air Filter Kit
* Oil Pan Heat Shield
* BR Polished Exhaust Manifold Heatshield
* BR 2.5" Upper Intercooler Pipe w/ stock BOV
* BR Mini Battery Kit
* Ported Exhaust Manifold
* Ported Turbine Housing
* Ported 02 Housing
* 3" testpipe

 

It sounds like it's set too low and you're creeping to where you actually want to be.

Keep turning it up until you can hit 21psi @ 3500rpm. Don't worry, the stock turbo can't really overboost in the upper RPM ranges.

 

I'll try that thanks!!

 

yea i am having a hard time with mine as well... I will have to spend more time with it and figure out what is going on

 

Nevermind, I was just being a 9u$$y. I didn't have it turned up high enough. It works perfectly. I have it set at 20 psi and holds perfectly until I let off throttle. Another Great Buschur product in my opinion!! BTW, I have it set up between the Intake/BOV and wastegate. Thanks for the advise!!