Finished working on my sons 951 and have a problem.. This is what we put on. First the motor was just rebuilt. We put 55lb injectors, lindsey racing dual port wastegate, garrett ball bearing turbo, has stock exhaust except for no cat.
3bar FPR.. cone filter on stock maf. I have an adjustable boost controller.
max berry tuned chips.
The problem is we cannot get more than 10lbs of boost. So I brought it to a shop with a good track record and they checked everything and even they are baffled.
They tested the turbo, wastegate,leaks in vacuum lines. BOV. Even the vacuum line going into the DME... everything checks out ok.. The only other think they said it could be is the chips.
This is driving me crazy. Is there anything else I can check... I cant see this being a big deal.. When I dropped it off at the shop I thought for sure they would find the problem.. HELP!!!

 

Sounds like you have the lines swapped on the DP wastegate. Common problem. 10lbs is the default spring usually in the DP (0.8 bar).

 

Start checking the simple things, like the lines connection to the WG, then the WG itself.

Did you check the X-over pipe, down-pipe and the cat-pipe (if in use) to make sure the internal wall did not collapse.? A collapsed inner pipe could limit your boost.

 

I brought it to a porsche shop that specilizes in 944 turbos and they checked all the basics and did vacuum and tested the wastegate and turbo. John what do you mean by collapes. Are you saying that there is a second wall in the pipes and they could collapes with no signs on the outside of the pipe.
We just did the swap 2 days ago and from what I remember I did not see any problem inside the pipes. I am not using the cat. I have a bypass pipe in there. As far as hooking up the boost controller, I switched the lines and made no difference. I got the schmatic on how to hook up the wastegate and lines to the boost controller right off of lindseys site. One other thing. My son put one of these stupid BOVs that empty to atmosphere. I was thinging that was the problem but they say that is working fine.
One thing I did notice is that the blow off vavle did not work unless I hooked up the lines to theboost controller backwards. That still didnt make a difference in boost thou. I have the top line from the dual port wastegate going to the port on the boost controller that says turbo in, split to the right intercooler pipe.(if looking at the motor). I have the bottom line from the wastegate going to the out of the boost controller. If you go on lindseys site they have a section were it says tech garage. They have a pic of how to hook up the controller. It is very simple.

 

Yes X-over and Downpipe both are dual wall. Inner wall can collapse and restrict air flow. You cannot see the collapsed pipe from the outside!

If the BOV you are using is letting compressed air out under boost, you will not make much boost. For testing purposes only, disconnect the vacuum line from the BOV. Verify it does not open at 10psi pressure.. The goal is to eliminate the BOV as the cause of low boost. Regardless, dumping to atmosphere is not a good idea, and you might still have issues with the BOV as it depends on how you make the WG connections.

Top Port on factory based dual port WG is the pressure port. It gets it's unmodified signal from the IC pipe after the turbo. It does not connect to the boost controller!

- From IC have a hose going to a "T"
- One side of the "T" goes to the pressure port (TOP) of the WG.
- The other side of the "T" goes to the IN on the boost controller
- OUT of boost controller goes to control port (SIDE) on WG.
note: Ports on Tial WG are opposite of ports on factory based DP WG.

If you disconnect (and cap) the line going to pressure port (TOP) of WG, you'll get high boost. Easy test, just make sure you don't overboost. All you are trying to establish if you can exceed 10psi.. Boost will rise quickly, just be careful to lift, you are in uncontrolled boost territory while performing this test.

 

Did the car boost well before the work? If so, I doubt any exhaust has collapsed from sitting, but obviously it could. Your sunroof could also fly off in the garage and land on your shop-cat.

If you don't already own a clamp, such as the one below, it takes all of 5 seconds to clamp the top line to the WG (somewhere easily accessible) and take for a short spin. Pay particular attention to what John says while the top line is off. It'll need a headgasket after "Garrett Gone Wild!". And it will happen in less than 3 seconds. Ease into it and if it starts past 10 psi, you've found your culprit.

The clamp is on sale at Sears for $2.

Good luck!

 

thanks guys. I will do so testing today..

 

its johns son i clamped off the top off the WG and still got 10psi and took the exhuast off and checked for clogging and nothing still only 10psi

 

how new is the boost controller?

 

Are you positive you have the hoses routed correctly for the WG? The top should be getting air straight from the IC pipe (it should NOT be routed through the MBC), the regulator should T into this line before the WG and then route the regulated air supply to the side port.

 

yeah the hoses are all correct .. i hear my turbo spooling up but my boost gauge read negitive boost is that right shouldint it be boosting if i hear it spooling up

 

and i tryed 2 boost contollers

 

Remember that the gauge reads manifold pressure and not pressure from the ic pipes.

 

When I put my manual boost controller in I mixed up the inlet and outlet vac lines.
My car was not producing boost when I drove around the block for the first time.
I figured that I had mixed the two lines up and I was correct.

Try swapping the two lines right at the manual controller just to see what happens. It's easy to miss if you are working like I did.... underneath, under the hood, upside down on the passenger side seat over and and over while putting things all back together.

I swore that mine was correct until taking it for the first run.
[
QUOTE=JBrown;8153669]and i tryed 2 boost contollers[/QUOTE]

 

I clamped off the vacuum line to the top port of the wastegate and still 10lbs of boost. I would assume that means my problem is either wastegate or turbo? Could the chips have anything to do with boost?
The turbo spins fine and has no play.