Boost spike on a external wastegate (Tial 38mm)

[VWTUNING]

Is it normal? Im running ~9psi right now and I've seen spikes up to almost 15 when slamming the throttle in higher RPM's. I dont remember ANY spike with my old 2L setup, but this wastegate has a lot more miles on it and my old one i installed brand new. I was thinking about re-doing the vacumn line to the wastegate and maybe even taking apart the wastegate to check for/clean out any carbon buildup.

I tried doing some searches on google and vortex and didnt come up with much.

[USOPHUNKE]

thats a pretty big spike. I would check for a vacume leak. I have not read anyone having a normal spike like that. maybe 3 psi.... but 6....

how long does it spike for?

[USOPHUNKE]

try a bit bigger vacume line.. maybe better quality. or try and shorten it if possible.. these seem to be the things that help.

other possibility is the w.g. is to small!!!

[VWTUNING]

spikes for a split second, like a 'flash' of boost. some of it might be momentum from the needle (its a mechanical guage). I'm gonna re-do the vacumn line tonight and secure all the ends.


Also any one have a tial 38mm flange gasket I can use, or know where I can find them local?

[USOPHUNKE]

you should secure the ends no matter what... thats exactly how corradojoe blew his engine... popped the vac to the w.g.

[B4passatglx]

pete I think I have a 38mm wastegate gasket you can have, I will let you know by tonight, I need to go digging in the garage

[VWTUNING]

thanks dude, I appreciate it!

[B4passatglx]

do you have a manual boost controller? sometimes they can help prevent boost spikes, if not I have an extra one too that I dont use. Its in my car in a minoa garage, if you want to try that out i can get that to you by tommorow

[BUNNYLOVE]

I was going to say the same. A MBC will help settle down spikes. Also you shouldn't need gasket unless its on the dump side.

[VWTUNING]

I do have a MBC installed; it was installed by the previous owner so Im gonna check the orientation tonight.

Not sure if this helps diagnose, but if im sitting in lower RPM's (say 2200) and I floor it, boost will steadily grow to ~9psi and stick (no spike). But it does flutter from 3-6psi as it builds.

[BUNNYLOVE]

the mbc might be gummed up. Clean it up and re install, I've had to do that.

[boostin20v]

maybe its too long of a vacuum line to the wg?

[evolveVW]

I think i have a gasket too if you need it. Ideally vacuum lines should be as short as possible, especially WG/MBC lines.