help with deltagate external wastegate

[1FastCSX289]

I recently bought the 89 CSX from theCSXmachine on turbododge. Ive got the car up and running and want to do some tuning, however, the wastegate has been set for "all of it". Thats a bit excessive for a motor with 100 miles on it. I would like to run just the base boost setting (which I figure should be about 9 PSI) while I get the SDS tuning all set.

THe car has a Deltagate Mark II external wastegate with a discharge tube. I figured if I just unhooked both of the vacuum lines running to the gate, I would get just whatever the spring is capable of holding. THat didnt work. Boost is still WAYYY up there. What gives? How do I get the boost turned down on this thing.

Heres the specs on the car if anyone doesnt know which one I am talking about:
http://www.viplift.com/shelby.html

Any help would be appreciated. THis whole hybrid thing is new to me!

[altered7151]

You should just run to the lower diaphram side without any kind of boost controller in it. That way the manifold pressure will help open the valve against the spring.

[1FastCSX289]

I tried switching between the two vacuum lines (one hooked up and then the other), not knowing which was which. I seemed to get the same result no matter how I hooked it up. Is it not working properly?

[Stinkbox]

i have one of these on my ride too, i love it, absolutly no boost creep. my spring is a 10lb spring but they can come with others, the 10lb is most common. just hook a vac line from either the intake mani or right off the turbo and hook it up to the port on the side that says boost by it, forget about the one on top that says vac. this will give you the least amount of boost that the spring is set for. most likely 10 psi though.

[1FastCSX289]

I am pretty sure I tried this (couldnt really see the gate too well on the side of the road). I will double check today and get back. Should any adjustments be made to the screw on the top of the diaphram?

[altered7151]

If I remember correctly you can back the set screw off on the top of the wastegate to lower the pressure on the valve. It was more of a fine tuning adjustment though, would only give you a few psi either way. Did you see if you can get it to move, maybe it got just a little corrosion on the seat and needs to be popped open once to unseat it.

[1FastCSX289]

If I remember correctly you can back the set screw off on the top of the wastegate to lower the pressure on the valve. It was more of a fine tuning adjustment though, would only give you a few psi either way. Did you see if you can get it to move, maybe it got just a little corrosion on the seat and needs to be popped open once to unseat it.

Could be. I will check. Ive got to get it on the lift later today.

[1FastCSX289]

I took the vacuum line off the top of the diaphram and backed the adjustment screw all the way out and my boost is still way up there. Is it possible that my set up is flowing so much exhaust that the deltagate cant bleed off enough to slow the turbine wheel down to lower the boost? Or is it more likely that its just broken?

[altered7151]

Those wastegates flow quite a bit, I could imagine you getting a little boost creep with a big turbo, but not completely uncontrolled boost. I'd pull it off and check it out. You could have a tear in the diaphram, they sell rebuild kits for them pretty cheap.

[1FastCSX289]

Those wastegates flow quite a bit, I could imagine you getting a little boost creep with a big turbo, but not completely uncontrolled boost. I'd pull it off and check it out. You could have a tear in the diaphram, they sell rebuild kits for them pretty cheap.

Im gonna try hooking the vacuum line directly to the compressor housing first and then, if that doesnt work, pull it off and see whats going on. THanks.

[1FastCSX289]

I went off the barb on the throttle body and no luck. Still overboosting. I hooked a vacuum pump up on the gate and its not holding vacuum and the valve isnt moving. Duh.:rolleyes:

So, I would assume the diaphram is shot.

[altered7151]

Definitally sounds like the diaphram is torn. Did you try pulling vacuum on one port and then putting your finger over the other? If you plug the other port and it builds vacuum its the diaphram, if it doesn't you have a leak somewhere else.

[1FastCSX289]

Definitally sounds like the diaphram is torn. Did you try pulling vacuum on one port and then putting your finger over the other? If you plug the other port and it builds vacuum its the diaphram, if it doesn't you have a leak somewhere else.

Thats a good idea. Before I pull it off, I will try that. Thanks.