boost problems

[boostindoo]

i dont know why but i cant really adjust boost on my car. i have a dual stage man. boost cont. from turbo smart. doesnt matter what setting i have it at, i cant get no more than 14lbs or less than 10, i think its 10. could it be a leak? im gonna check but havent gotten around to it yet. well ill appreciate any info that would help. thanks a lot

 

[nine5raptor]

if you still have the stock BOV (and I didn't see a different one in your profile), it is leaking out all of your boost over 12 psi and you are over revving your turbo. You can't go below 10 because all of the boost is hitting the wastegate diaphragm and opening it. It is as if you have no boost controller at all and have the pos. pressure source hooked directly to the nipple on the wastegate

 

[boostindoo]

i have an hks ssbov. what do u mean about the wastegate thing? i cant boost below 10psi? thanks for replying

 

[nine5raptor]

the wastegate diapragm is pushed open by the boost pressure and thus opens the wastegate. The spring in there applies a certain force to the diaphragm. In order to open the wastegate, the force from the boost must be greater than the force applied by the spring.
If you connected your boost source dirctly to the wastegate, you would always boost to the level of the diaphragm, say 11.5 psi. with a ball and spring boost controller, your are 'blocking' the boost from pushing on the dia. until it is high enough to overcome the spring in the boost controller and can go past and push open the wastegate.
when you open the mbc completey, you boost up to the amount it takes to open the wastegate.
the factory system worked like this except the boost control solenoid 'bled' off some of the pressure to allow you to boost higher.

hope this makes sense.

 

[boostindoo]

cool. it does make sense, ill look into it, thanks. ill let u know. u dont think it might be a leak though?

 

[nine5raptor]

The upper limit could be because of a boost leak somewhere...those are often very hard to track down...

 

[doug]

How do you have your MBC hooked up? And you did take the hoses off the stock BCS, right?

 

[boostindoo]

i have the mbc going between the wastegate and the other spot that the original hose hooked up to. basically like stock. i did take off the stock bcs hoses.

well, i had a leak where that connection was where i hooked up the bcs. the hoses i put on were too short and i guess it was a bad connection.

thanks for all the help anyways.