External Wastegate Problem

[CM boyd]

Ok, I thought that I had all the "bugs" worked out of my remote turbosystem. The muffler shop found 5 of 6 header bolts loose which caused an
awful squealing noise and loss of boost. There was a separation in my intake tube as well. Got those both fixed. We installed the external wastegate and took her for a spin. Before the turbo was spooling and making boost well into the
midrange of the RPM gauge. You just cannot put
your foot to the floor because you can hit well past 6psi. Now I have to place my foot all the way to the floor and the turbo lags like crazy! Here is what I discovered: There is alot of exhaust leaking out of the discharge port of the
wastegate. I was under the impression that it was supposed to be fully closed until boost threshold hits. The piston does not seat all the
way down in the inlet, and there is a slight gap that contributes to the exhaust loss. Is this how the wastegate is supposed to operate? I could
use a little advice before I call up (or email) turbocalculator.com and find out if it is defective. I should have bought a Tial instead of the generic brand ;)

[Teufel Hunden]

The wastegate is supposed to be fully closed until you hit the boost level you want. Before doing a whole lot, you might want to take it off, and take it apart to see if you have any corrosion in there that would be causing this. I'd guess you DO have corrosion with the entire system being back with the cooler exhaust gases, where the water vapor condenses into drops. If you take the gate apart only to find there isn't any corrosion, or other reason for it to be sticking open, you've just got a defective one. Wastegates are pretty simple in construction and operation, so you shouldn't have a problem figuring it out.

[CM boyd]

Thanks, I concurred that theory with someone that
knows alot about turbos as well. There is no corrosion at the gate. That is what I get for buying a "generic model"

[T-Punk]

yeah, tial is expensive but they are reliable durable units. The cheapies are usually ok but a couple of the dsm guys i know have had problems in the long run with them.

[CM boyd]

Yup, Called Turbocalculator and was told that the
"generic" brands have a slight gap around the valve seat. Damn, it always seems like something
wants to fall apart when you get it together! I am ordering a Tial today and sending back the other unit. Who wants to have exhaust leaking out of the wastegate with it not being in boost
anyway? What a waste....

[CM boyd]

Fixed the gap leak problem. The metal ring was supposed to seat directly in the inlet path (they
did not get me any installtion instructions). I am only hitting about 3psi now. What else could it be?

[yellowfbod]

man, sounds like your in the same boat as I am. I don't know what the deal is, I have tried eveything and nothing is fixing it.

[T-Punk]

i'm so glad i wont have to bother with wastegates... i just have to worry about vacuum lines popping off and causing the turbo to overspin and grenade.

[CM boyd]

How much PSI are you getting? I was making too much boost before the wastegate. I am going to connect the boost controller and up the bleed.
Worse case scenario I can order a .43 A/R Exhaust
housing for $125.00 from East Coast Turbo. I
notice that when I used the .63 that the turbo lags more and does not make the same high pitched
whine when you rev the engine in park. I don't have as much backpressure though. I do not think there is a problem with the turbo this time and there are no leaks. Tell me what you have set up
yellowFbod.

[Teufel Hunden]

The high pitched whine doesn't mean anything except that you have a wastegate dumping to the atmosphere, or you have a very short downpipe or both. You can't hear my turbo when i rev it at idle at all.

I'd stick with the .63 housing, but that's just me. The thought of going to a .43 would make me cringe. You've probably just got a vaccum leak somewhere, and i'd go through all other possible scenarios before switching housings.

[GN-T66]

.43 housing?!?!?!?! :eek: :eek:

Wow, I cant imagine choking off a 3.8 that much, be it in a GN or a camaro. Moreso in a camaro I guess, since they start off with such better heads.

[T-Punk]

i have vnt's so they control themselves to a point. i might have to add a wastegate later but i'll try without first. as for housings the 63 is a better choice but i would think something in the 57 area would be a better choice because of how your turbo system is designed. as for the whine... again your turbo setup is a little different and has a very short exhaust run after the turbo so you might just be hearing the turbo whine if you arent using a muffler. good luck.

[CM boyd]

Thanks for the input. I had a .48 before and the
whine was actually the noise of the turbo spooling at revs. It sounds cool, but like you said; It does not really mean anything. All the STS turbos make the same whine. You actually hear it from the air intake filter. I was using an integral system, so I know it was not being dumped into the atmosphere. Although the bearing leaked lots of oil, the turbo still spooled quickly. I did not get much boost at all, but I
thought it may have been the turbo not a vacuum
leak. This gives me more reason to keep searching for the problem.
I am going to keep the .63 because if this project does not get good results then I know it is something I have done incorrectly. I can always move the entire turbo further upstream or
construct a front mount kit seeing as how I already have a pair of header flanges from PACESETTER. I hope the weather here lets up some
so I can get cracking on my problem.

[Teufel Hunden]

You can hear the STS kit's turbos, but you can also hear all the FFF turbos as well (re: the teaser vid that was posted on here a while back). The only commonality between all of them is either a wastegate being dumped to the atmosphere, or a very short DP. It's not necessarily the turbo spooling either... just spinning, and effecting the air around the blades.

[kahouna23]

CMBoyd....do you have pictures yet?


I also sent you and email....