Can't get the boost down!

[paintitblack]

I can't seem to lower the boost. Let me start from the beginning and tell you what I have done because I am stumped. After the car sat for 8 years I bought a complete intercooled motor from a friend and got the car running. It had hooker headers, 3in downpipe with a deltagate, turbonetics boost controller, and I had it running with a open dump (didn't have the money for a full exhaust yet). Everything ran fine with no problems. Went to the track and had a transmission problem and had to pull the pan. Thats a different story, but I had to pull the crossover pipe to get the pan off which is a pain in the ass with the hooker headers. It ran a 13.30 in the 1/4 killing the street tires to the 60 ft. After that and the ride home with the open dump I decided I was putting stock headers, crossover, and full exhaust on. I ordered the T/A stainless stock replacement header kit, 3in testpipe with dump, and a hooker 2 1/2 dual kit ( aero muffs ). Put everything on and the car seemed to run way better but would over boost. Not changing the controller (set at 17psi) it would go way above 25psi. Turned the dial all the way down and would still go really high. So I removed the controller and disconnected the vent side of the wastegate to get the base line or spring pressure, which was 10psi before. It still climbed high. I figured it was the wastegate, and wanting to replace the old rusty downpipe I ordered a gn1 3in downpipe with a 46mm external gate. Before putting it on I ported the exhaust housing on the turbo to match the wastegate pipe so there was no question there. Put the controller on with fresh vac lines and all the way open and there was no change. Pulled the controller off like before and no change. So I then checked the line from the compressor housing to make sure it wasn't plugged and it was fine, but to be sure I ran it from vacuum block on the intake to the wastegate and no change. Then I called gn1 to find out the spring pressure and they said it should open at 8psi. From there I hooked up an air line with a ball valve and a gage to the wastegate to make sure the valve opened correctly. It opened at about 9 1/2- 10 psi. Running out of ideas I went through everything I changed and decided to run the car with the cutout open to eliminate the catback, still no change. Also when I go WOT from idle it kind of bucks or pops like the gate is opening then closing, opening then closing then runs up through the rpms normal. That happened with both gates after changing the pipes. The car runs fine and strong otherwise with no codes and problems as long as I roll into the throttle and don't go farther than 3/4 petal. I'm out of ideas and dont want scatter my motor all over the road. I plan on putting the engine on race fuel when I go to the track but I dont want to run it on the street, not to mention I should be able to control the boost pressure anyways. Sorry this was so long but I wanted to get all the info out. I cant do anything right now because it's put away for the crappy Ohio weather but it's weighing on my mind pretty heavy. Any ideas will be greatly appreciated. Thanks, Brian.

 

[AllMotor85]

On my car with the deltagate I have to adjust the boost controller opposite.

So in other words..to lower the boost I had to turn the boost controller like I was anting to add , to add boost I had to turn it to lower..

 

[bison]

Remove all sources of pressure from the top of the gate while leaving pressure to the bottom and back off the spring tension on the gate as far as it will go and test it like that. Then report back

 

[paintitblack]

Remove all sources of pressure from the top of the gate while leaving pressure to the bottom and back off the spring tension on the gate as far as it will go and test it like that. Then report back

Thanks for responding. I have done that and it's still climbing. The deltagate was backed off all the way. The GN1 gate doesn't have a tension screw (the new one I have on now) but I did run it with the top port open to atmosphere. Both wastegates are good and functional but wont control boost. I can't understand how it was fine and did exactly what it was supposed to do with the crappy hooker headers and now it's got good designed headers and I can't control it.

 

[GNVYUS 1]

If I had to guess, it's the DP tube to the wastegate.

Can you check the old DP tube to wastegate for an I.D.?

 

[bison]

Thanks for responding. I have done that and it's still climbing. The deltagate was backed off all the way. The GN1 gate doesn't have a tension screw (the new one I have on now) but I did run it with the top port open to atmosphere. Both wastegates are good and functional but wont control boost. I can't understand how it was fine and did exactly what it was supposed to do with the crappy hooker headers and now it's got good designed headers and I can't control it.

Apply compressed air to the bottom of the wastegate and verify its not seized.

 

[pacecarta]

but to be sure I ran it from vacuum block on the intake to the wastegate and no change.

are you still connected this way ?, did you try running the gate tuner style ?

and you dont have the gate on upside down do you

 

[paintitblack]

If I had to guess, it's the DP tube to the wastegate.

Can you check the old DP tube to wastegate for an I.D.?

I will check this weekend. I would say it's probably an inch or bigger.

 

[paintitblack]

Apply compressed air to the bottom of the wastegate and verify its not seized.

I did, it's not.

 

[paintitblack]

are you still connected this way ?, did you try running the gate tuner style ?

and you dont have the gate on upside down do you

No I have since changed it back to the correct routing, and the downpipe and gate was preassembled from GN1. Not sure what you mean by running it tuner style?

 

[bison]

I did, it's not.

Remove the gate and hook up a piece of flexible ex tubing and see what it does.

 

[pacecarta]

No I have since changed it back to the correct routing, and the downpipe and gate was preassembled from GN1. Not sure what you mean by running it tuner style?

tuner style = run a hose direct from turbo compressor to the bottom port of the wastegate (make sure the top port is open to vent) , if the plumbing to the gate is not too small this should result in boost within a lb or two of the rating of the spring in the gate

use new hose and zipties , you'd be surprised how many overboost issues were from hoses with holes or cracks in them that the op swore the hoses were checked

 

[TR Custom Parts]

Which Turbonetics boost controller are you using? Hopefully it is not the little billet one as I never had any luck with one of those. I am using the black plastic Turbonetics on my external gate DP. Both ports hooked up like in this picture. Make sure you are turning the dial the correct way!

Had trouble controlling boost when I went to a 6262 bb turbo and ported the crap out of the wastegate hole with a lot of work laying back the hole in the exhaust housing of the turbo. Also ported the flange on the downpipe to the size of the wastegate pipe. I have solid boost control now. If you are still having problems after that contact me and will see what we can do for you.