No More Boost Spike!!!

[trbotaln]

Well, I was thinking about how I have a lot of vacuum line going from the top of my BOV to my boost controler, and I was thinking that this could be causing my horrible boost spikes. I removed the long line going from the BOV and used the nipple off of the compressor housing instead as a boost source and I used really short vacuum hose. I went out and took it for a drive and I get absolutely no boost spike at all! It holds boost perfectly and doesn't even spike 1psi over. Before, I would spike 18 then drop down to 13psi. Now, It just pegs to 13 and stays their the whole time. The car feels better than it ever has. I know that their is going to be pressure drop from the turbo to the manifold and that the manifold might see less boost then the compressor housing does, but at least I don't have that horrible spike anymore.

 

[AWDrift]

"You HAVE to use the intake manifold is you want proper boost control. Why is that? The manual boost controller regulates the amount the wastegate is open based on the pressure at its source. Since you want to control manifold pressure, you want the MBC and the WGA to be recieving pressure directly from there.

Using a source off the turbo or intercooler pipe can cause you to have boost that changes with weather, load, and engine speed, and can also slow down boost response. By comparison, a manifold source will be fairly steady, solid, and reliable."

http://www.dsmtuners.com/forums/showthread.php?t=105573

take that into consideration...

btw, your car looks nice. What controller are you using?

 

[trbotaln]

My car does feel like it doesn't spool up as fast but I like it better because my T25 spools up too fast anyways. My car runs better than it ever has so I think I am going to leave it like this and see if it changes under load, engine speed, ect. I think the problem I have is that when I have the MBC hooked up of the manifold, my T25 spools up to fast so that by the time the wastegate sees the pressure and opens, the turbo is already past the set psi. Having the shorter vacuum lines makes it not spike at all.

By the way, I am using the Boostvalve.com boostcontroler, and I have a lot of friends with the same one and they never get boost spike. They all have the boost controler pressure source off the turbo compressor housing but they are not DSM's.