Waste gate wide open still have serious boost creep.

[My96z]

I have some huge boost creep issues. I have removed the G-valve, backed off the tension on the actuator and finally I disconnected the waste gate actuator completely from the swing valve. Its still building boost to way over 20PSI. This is a fully open wastegate port.

I had no problems with the stock head. I had it set up to run at 19PSI. It held it rock solid. I recently installed a ported head and now I cant keep the boost down. I didnt think that this would flow enough to do this.

Has anyone else had this problem?

I know people have ported thier wastegate port. But how much have you guys opened it up? I intend to do this only one time. Are there any write-ups or pictures around?

I think that since I have a wide open gate and it still creeps up over 20PSI in a hurry, I can open it up a good bit. I talked to Chris at TU and he said to open it incrementally. But how much should I take on the first go? 1/8"? 1/4"?

My set up:
1989 Caravan
2.5 w/built A413
Tyler's +1mm G head
Hybrid TO4E 46 trim w/ .63 stage one turbine
3" TU SV
full 3" exhaust

Thanks guys,
Jeff

[Juggy]

I Hybrid TO4E 46 trim w/ .63 stage one turbine

this is your problem. all that flow and little exhaust wheel. i opened up my wastegate hole no more then 1/8" perside

some guys have opened them up to the size of the wastegate puck. most of these guys seem to be running smaller turbines, because obviously you cant move as much air through a stage 1 as you can a stage 3, so you need to find another way, for the air to exit

champher the edge of the wastegate puck while your at it, will prevent hangup.

[Vigo]

Sorry to hear it came down to this, but hopefully you only have to do it once. And hopefully since you have an aftermarket turbo the bolts are still seperate pieces of metal and will actually come out without breaking

[My96z]

I am going to try to get the turbo off without removing the head. Simon says its possible. But I dont remember it being all that easy with the head off!

[t3rse]

It is possible with ratcheting box swivel wrenches. Done it in a CSX before. I tried on an omni one time and gave up...

[turbo84voyager]

Take your time. If you used the hardware from Chris they are 12 point bolts and there may be 1 6 point. I needed to grind a socket very thin to get this off. If you do this, go to Fastenall and get cap screws so you can use an allen to reinstall them. It makes it much easier. I did it twice on my shadow. It was far easier the second time with the cap screws. Make sure you use good anti-sieze. I did it all from on top. I moved the power steering pump and was able to get to it.

[My96z]

Justin, since you have pretty much the same set-up as I do, did you have boost creep issues like I have?

[86Shelby]

If you enlarge the wastegate hole do it in steps. I went too far on mine. No boost without helper springs; but they hold the wastegate shut too much for 4th gear pulls and I get creep. I have a choice between low and slowly rising boost in 3 gears while 4th gear is a party. Or have good quickly rising boost in 3 gears and have to let out in 4th.

[iTurbo]

What kind of tool are you guys using to port the wastegate hole? Would a Roto Zip and some kind of grinding stone work OK? I've never tried to port anything in my life.

[My96z]

Well I am going to use a drill and a stone made to grind metal. Its all I have, I dont have a die grinder.

[86Shelby]

What kind of tool are you guys using to port the wastegate hole? Would a Roto Zip and some kind of grinding stone work OK? I've never tried to port anything in my life.

I used a nice carbide bit. Afriend let me use old pieces from his his head porting kit to get the job done. It would be doable with a drill & stone, long time to finish but doable. Be sure to not overheat the motor!

[turbo84voyager]

I have never had this problem but I believe my BOV is leaking. I have to throw the new one on. I also have a very similar setup on my shadow and I dont have the problem on that one. The only time I had a problem like this was when my 3" SV was sticking on my shadow.

[Juggy]

I have never had this problem but I believe my BOV is leaking. I have to throw the new one on. I also have a very similar setup on my shadow and I dont have the problem on that one. The only time I had a problem like this was when my 3" SV was sticking on my shadow.

+1


when the wastegate arm was disconnected from the swingvalve....were you able to move the puck arm freely????

maybe the wastegate is stuck, and you dont really need to port the hole?

[My96z]

+1


when the wastegate arm was disconnected from the swingvalve....were you able to move the puck arm freely????

maybe the wastegate is stuck, and you dont really need to port the hole?

Yes it moved freely. I just have to grind!

[My96z]

Fixed!

I ported the snot out of it and now it holds boost solid now. I set the wastegate to where it barely has any tension on it.

I used the SV nut with the big flat piece of metal on it as a template. I seen that it was barely smaller than the hole by maybe a 1/16". So I took my drill and the stone I bought and went to town. I enlarged the hole substantially and also took out the bumps inside the wastegate and smoothed out any sharp edges. Now I can fit that wastegate nut in there all the way down and wiggle it by about a 1/8" to each side in the hole.

I also put a bevel on the edge of the wastegate port and on the SV puck itself. I noticed somtimes when I worked it by hand it would jam open. This took care of it.

I have been told that you can take too much out so I might not reccomend taking out as much as I did. Only reason I took so much out as with a completley open wastegate, actuator disconnected I got over 20PSI of boost before I let out of it. So I felt safe to go a bit bigger. Also when I checked the wastegate actuator via my air compressor set at 10PSI my wastegate only opens maybe 3/8". So mine is pretty stiff.

Thanks for all the help guys!

Jeff

[t3rse]

What is your min boost now?

[My96z]

About 5-7 PSI.

[Juggy]

I have been told that you can take too much out so I might not reccomend taking out as much as I did. Only reason I took so much out as with a completley open wastegate, actuator disconnected I got over 20PSI of boost before I let out of it. So I felt safe to go a bit bigger. Also when I checked the wastegate actuator via my air compressor set at 10PSI my wastegate only opens maybe 3/8". So mine is pretty stiff.

Thanks for all the help guys!

Jeff

like i mentioned earlier. the stage 1 exhaust is really limiting your flow. so you need to find an alternate route to dump all that exhaust pressure. your 2.5 is fairly modded, and a stage 2 wheel would prolly have been more appropriate.

so how does she run?? is the 2.5 laggy with a G head like everyone says?
with the forged slugs you can really run alot more aggressive timing. im pretty sure that 84 voyager guy was having probs with too much timing from reading some threads. might be mixing him up with someone else tho. but matt really had his stuff set for max timing and some of the other setups didnt like it so someone made a revision and tuned it down some

im sure matts self ported head/exhaust/intake manny had something to do with it. ive had 2 of his exhaust mannys in my possession, i owned the 1st one he ever did for TU, then got ahold of another one about 2 years later, and i can tell you he wasnt slacking off on his work. def blows away any other vendor manny ive seen with the FM one coming in 2nd but still not nearly as nice as matts