Alternate wastegate vacuum source

[imdrax]

So I just picked up a 91 GVR4 that has a fair amount of mods. It runs pretty decent however it has a severe boost spike. Its running an E3-16g running off of the wastegate pressure. My question is the owner has the wastegate vacuum sourced from a tee in the BOV line which I am certain is not correct, however there is no J-pipe nipple so I am not sure where to draw from for my source. Can running the wg off the BOV line cause boost spiking? And what would you recommend as far as a source for the WG?

 

[coryf1233]

I ran into the same problem, put a j pipe on with no boost source. So i T'd mine off with the bov, not proud of it. I am just welding a nipple onto my j pipe. Or you can drill and tap and thread a fitting into it.

 

[imdrax]

Have you noticed any issues running tapped into the BOV?

 

[T9S1i]

Pull off the j-pipe and install a nipple. Make the line as short as possible and you shouldnt have any more spike issues.
The best way to do it is to have someone professionally weld a bung in place and get the correct fitting to screw into the bung. I had a piece of brake line brazed onto my old j-pipe back when i had to mod "thriftily" but it is way better to do it once and do it right.

One other thing, you worded you title as the WG seeing vaccum, you dont want it to see vaccum, you want it to see boost pressure. Pulling off of the BOV line is definitely not the correct way to give the WG a pressure source, because you are exposing the WG to vaccum, and you are taking some away from the BOV thus reducing its potential performance... how much? we dont know exactly, but they each require a dedicated line.

 

[imdrax]

Thanks, I guess I just refer to most pressure lines as vacuum lines because 95% of them are sorry for the confusion.

Just noticed your in SF btw. Anytime you feel like coming to the valley I have my gvr4 I just picked up and my roomates 93 built GSX as well as I'm finishing up my turbo IS300 so we always have stuff going on.

 

[coryf1233]

I havent had any problems, i just dont like using it that way