I run a closed loop system which is great but I am getting some overboost in vtec. The pipe diameter is 1" from my HKS wastegate to the downpipe. The pipe connects right where the downpipe and the test pipe meet. Is the piping too small, should I upgrade to 1 1/2" pipe?

thanks
scott

 

How much is overboost? are you just pushing more then you want? What size turbo? Could be that your turbo just can't push any less then what it's at now. But It's hard to tell with any info.

 

I have a T3/To4E .63/.50 57trim. I have a profec B and a 7lb wastegate spring in the wastegate. needless to say it wont stay at 7lbs. Before vtec it holds boost but when I go into vtec it climbs from 8psi to 11psi.
I am wondering if its the OBX mani or if my wastegate tubing is too small.
scott

 

Damn that's really weird that it jumps up. You could be right with the pipe being too small. Cuz when v-tec comes on more air is getting force at a ridulous amount of speed and volume

 

Maybe the wastegate is installed wrong. I have the same problem, but haven't been able to look into it yet. I have a 7-8lb spring in my wastegate and it spikes to 12 psi!!!

 

yeah could be the wastegate...my deltagate was spiking from 9psi to 15psi for sometime and then all of a sudden it stopped, but it took forever to boost and was making a weird flapping noise all of a sudden. took off the wastegate and it was torn up and not sealing. yup yup...that's why i'm getting a new tial 38mm next week.

 

That is boost creep. It happens when the wastegate cannot flow enough to drop the pressure in the manifold to the necessary level.

I would try upgrading to a bigger pipe, or you could chop the pipe and temporarily run it dumping to atmosphere, to see if that fixes it.

What is the outlet diameter of the WG? If it is 1.5 inches, why would you use a 1 inch pipe?