I bought a 93 twin and I get full boost out of both turbos just fine, but when i let the car rev all the way to 7k then shift I get capped @ 5psi untill I let the car go back below 3k rpms. Now here is the really weird part the guy who owned it before me removed the vacuum chamber out of the car and blocked off all the vacuum lines and added what looks to be like a home made bov or something, my only thoughts are was he trying to do a homemade non seq conversion or was he just a complete idiot. Any ideas at all anyone I really dont wanna have to hunt lines for 6 months rofl.

 

im no genious when it comes to the turbo stuff but i think there is a weird boost sequence that the turboes run. i cant remember what it was but i do remember it is like high then low then high again

 

Replace the vacuum chamber. You need both the vacuum and pressure chamber to operate the solenoids and get proper boost function.

(That was easy)

Dave

 

vandamage gets owned on his first ever post. FATALITY!

 

The boost sequence is supposed to be 10-8-10, and in reguards to the vacuum pump I had assumed that but with the home made looking contraption he has under the hood im a big chicken.

 

In all seriousness, several rats nest systems have nothing to do with making correct boost. You can eliminate, block off, or replace these without affecting the boost:
- double throttle
- FPR
- Air Pump/ Secondary Air system
- EGR
- PCV

If you eliminate these emissions components you'll cut down a lot of rubber plumbing. Moreover, if you install a boost controller you can eliminate the precontrol and wastegate solenoids (the two green ones).

There is a right/wrong way to go about this, so if you want take your time and research what you have, where you want to be, and what it takes to get there.

 

We will see if it works.

 

I would also suggest returning everything as much back to stock. Once there if problems haven't been solved it will somewhat make things easier to troubleshoot. First get rid of that whatever bov setup it's got and put some stockers back on.

The turbo boost pattern is high - low - high due to the transition from primary to secondary turbo.

connect all the vaccum lines back too, seeing if he just capped them off and left the sensors still connected without the use of a PFC then yeah you're gonna have issues.

 

I hope this works I want to buy a good bov ill search here now to see what people have.

 

on a stock engine and turbo's you would actually not benefit at all from an aftermarket bov, using the stockers will do just fine plus save ya some money.

 

Ill take some photos of what this guy did this weekend please watch this forum to see the craziest stuff ever rofl.

 

Vacuum chamber is correct sir. Still a leak somewhere but we have full spool in all gears on both turbos now. THANKS GUYS IM SO HAPPY.