'87 944 turbo that had a manual boost controller installed. the boost was set at 18 with larger injectors and vitesse chips.

to sell the car we took off all mods and turned the boost all the way down so we could slowly turn it back up to 12. well, it still boosted to 15.

so i completly removed the MBC and tied the lines together. still 15 psi...WTF? the wastegate opens with boost pressure right? thats why the signal line is on the pressurized side of the turbo. well the whole thing was hillbilly rigged so i zip tied every spot that looked like it could leak a boost signal and tried again. still 15psi.

with the line unhooked it boosts past 15 which i didnt let it do and lucky for the cold weather georgia is getting i got no knock during these test.

now.....Im geussing i need to replace the wastegate right? busted diaphram?

 

Hey - unbolt the banjo bolt on the hard line - it might be jetted.

 

whats jetted?

 

Unbolt the banjo bolt from the hard pipe - if it has something inside the bolt, remove it.
Thats how autothority chips got 15psi...

 

ok it was jetted...didnt make a difference though. still 15.

 

Sell it that way the car will feel stronger... ??

 

Check to see if the wastegate has shims on the bolts, this is sometimes used to increase the spring tension on the valve and thus increase the pressure at which the wastegate opens.

 

brad (ilikemy944) says that it was shimed. but the thing is....would just the shims mean it would boost that much more. could i sopmehow rig a little hand pump in the car to try and open the wastegate?

 

Campeck if you want a wastegate you can have my old one for free. It worked fine but I put on the lindsay one.

 

It would, depending on how thick the shims are.

 

if the wastegate was not working you would be getting alot more than 15psi!

Sounds like you have just about every boost raising mod there is on that car....the cycling valve is probably drilled also.

 

cycling valve is deleted. and if i go in fourth gear it will get more than 15. but i dont want to blow up the engine so i let off. the turbo is old and wont boost more than 18 becuase the MBC was set as high as it would go....ive heard other k26's get 20 but this one wouldnt.

anyway im going to swap out the wastegate today and that should fix it. ill keep yall updated. thanks

 

It is not the turbo limiting boost...it is the wastegate spring.
When you swap the wastegate you are going to need something to control the boost or you are probably going to end up with more boost or with a straight line going to the wastegate and opening it prematurely.

 

well

we went to josh B house today and found the problem when we got the car on the lift. right above the wastegate nipple the line had a huge crack in it and about a foot of it was crusted and cracked. no wonder got a line at napa and put it on. no boost control. 4psi! :jumping:

put the lindsey boost enhancer on their. its set at 9 but every once in a while boosts to 12 and sometimes as low as 5.

im sorry but what a piece of junk. it could just be because its sat for so long. i cleaned it up and it works a little more consistent now. so lindesy racing dont kill me.

thanks for the help everyone! and check your vacuum lines!!!

 

IIRC the Lindsey BE needs the cycling valve inline to work correctly.