[evil_eagle]

Ok, a buddy of mine has a 95' gst with these mods
big 16g
wallbro 255
hallmen boost controller
3" down pipe
o2 dump mod housing
3"cat back (turbo back)
upper and lower innercooler pipe with 1gen bov

Now the problem is that we found a bunch of boost leaks, fixed the leaks and now we have boost creep
1gear 15 lbs
2 gear 15lbs then after 4500rpm it rises to 18lbs
3 gear 17lbs and climbs to 20lbs, not sure if it keeps going up or not cause we let off the gas..lol we have the boost set at 15lbs

But we figured with the o2 eliminator housing that we wouldnt have boost creep, but now we do how do we fix this? bigger flapper? or is there an easier way around this?
thanks....
-Jake

 

[joereitman]

I am experiencing the same type problems especially as the weather is finally cooling off and I tend to build more boost. When I get a chance I will pull the turbine and open up the wastegate exit under the flapper. I should have done it when I ported everything else...

 

[venom42]

What I want to know is how much do you have to open up the WG hole? Can you get away with widening the area around it (on the side that the exhaust gasses would be passing through), but not porting the actual hole under the flapper?

 

[Flowgoode]

What I want to know is how much do you have to open up the WG hole? Can you get away with widening the area around it (on the side that the exhaust gasses would be passing through), but not porting the actual hole under the flapper?

Probably not, your most likely gunna have to port behind the flapper so you can let more exhaust gases flow thru there letting your boost stay at the level you set it at. I have the same problem...I ordered the FP BIG 16g ported and w/34mm wastegate flapper upgrade. Should take care of it (once it get to the damn shop...freakin west coast shipping strike.) I didn't think it was worth the money porting out my stock turbo because I was going to upgrade soon anyway. just my .02.

 

[turbo90awd]

Yeah, I have a big16 with the TRE exhaust housing w/34mm flapper. I've never seen boost creep before. Even at 20 Psi.

 

[joereitman]

What I want to know is how much do you have to open up the WG hole? Can you get away with widening the area around it (on the side that the exhaust gasses would be passing through), but not porting the actual hole under the flapper?

Hey Venom- I did exactly that- it helps some but not enough for a big16g. One trick is to port where the flapper door bumps into as it opens, to let it open further. Another trick is to open up the opposite end from the hinge as much as possible to smooth out and enhance flow. Both these (in conjunction with serious O2 porting) helped a lot until I did more MAS mods and started letting the 16g really breathe.

When I next pull the turbine I may see if I can get a local milling shop to open up the actual WG hole to almost the size of the flapper door.

Joe

 

[venom42]

I am still running the 14B with a 2.5" O2 housing w/external dump and 3" exhaust. I have my boost set at 16 psi, but creep to 20 (maybe farther, but I back out of it) in the top of 3rd, 4th, etc... Thats why I am thinking I might can get away with just porting around the flapper?

 

[Flowgoode]

I am still running the 14B with a 2.5" O2 housing w/external dump and 3" exhaust. I have my boost set at 16 psi, but creep to 20 (maybe farther, but I back out of it) in the top of 3rd, 4th, etc... Thats why I am thinking I might can get away with just porting around the flapper?

I have basically the same exhaust as you. And I have serious boost creep at higher rpm in 3rd and up. I made a post a couple weeks ago about it. Go here:

http://www.dsmtalk.com/forums/showthread.php?s=&threadid=67231

Maybe that can help you.

 

[whiteGSX]

One trick is to port where the flapper door bumps into as it opens, to let it open further.

I don't think this works because the door will still open the same amount due to the lenght of the wastegage solenoid's arm.

 

[venom42]

I don't think this works because the door will still open the same amount due to the lenght of the wastegage solenoid's arm.

That seems to be the case from all that I have read as well.

 

[16g-95GSX]

Yeah, I have a big16 with the TRE exhaust housing w/34mm flapper. I've never seen boost creep before. Even at 20 Psi.

First off the lower the PSI you run the more creep you will have. The idea is the lower the PSI you desire to run, the more the wastegate must bleed off in order to keep the turbine from getting anymore gases and therefore spooled at the slower speed.

To tell you the truth your best bet it definately a 34mm wastegate flapper. www.turbotrix.com and www.teamrip.com both have this flapper. It really is not that difficult to replace, I did it by myself and then ported out the hole to now rematch the flapper. I am only 19, and I have some tools, but nothing serious like a true garage, just my dads extensive collection from his lifetime, so dont think that I am a major mechanic as I am not. I cannot explain to you how much this flapper has helped reduce my creep. I used to go from 17 to 22+ psi around 5500rpms with the setup I have. After putting on the new flapper, and porting the hole to the point where the old flapper will literally fall completely through the new hole, meaning I have about a 8mm larger diameter or so, I can honestly say that with my profec B turned off my lowest boost I can reach is 9psi, yes that is right, 9psi, with no creep even at the top of 3rd at 9psi. Get it, it costs 30 bucks for a flapper, take a little time porting the turbo out then a quick spot weld to get the new flapper on and you're set. I can honestly say you will have absolutely NO creep problems afterwards.

 

[BoostedTSi]

Yeah, I have a big16 with the TRE exhaust housing w/34mm flapper. I've never seen boost creep before. Even at 20 Psi.

I also have the TRE Big 16g w/34mm flapper and I haven't had any boost creep either.

 

[joereitman]

I don't think this works because the door will still open the same amount due to the lenght of the wastegage solenoid's arm.

I think you are right if the actuator rod, and the flapper arm length, are both stock. The actuator of my old 14b moves the rod 13mm, and the 16g actuator looks like it moves the rod even less, though I could not measure it since it is on the car and not easily measured. Does anyone know if the 16g actuator differs from the 14b actuator?

I noticed the actuator rod on my 16g was already extended about 3mm while the wastegate flapper was closed. First I considered straightening the rod to allow full travel, but I instead decided to bore the 6mm hole in the rod for the flapper arm stud to 3/8" (about 9.2mm). This was pretty easy by removing the heat shield, then rotating the rod for the correct drilling angle. I started the enlargement with a conical carbide grinding bit, then finished it with the 3/8" bit. There is enough metal left around the hole for structural integrity, as far as I can tell.

The wastegate flapper arm stud now "floats" in the enlarged actuator rod hole when open, allowing for a noticeably increased open angle, probably a 10* improvement due to the extra 2mm or so of travel (the enlarged hole allows more travel of the flapper arm both horizontally and vertically). The flapper still seals tightly when closed, but even if it does not seal quite as tightly that is no big deal because the 16g with my ported 6cm turbine housing spools so quickly.

I just finished the mod and will test it tomorrow, weather permitting. I am also considering shortening the flapper arm from the current radius of 21mm to 13mm or so to ensure full 90* opening. Has anyone done this? If so, was the difference noticeable?

Thanks,

Joe

 

[Motohead1]

Thank you search button!

Thansk for the info guys. gess i need a 34mm flapper to fix my boost creep.

 

[joereitman]

FWIW, the actuator rod mod described above changed my 17 to 22 creep to 15 to 19 slower creep, with no other changes. It still spools just as fast. I will cut the flapper arm and shorten it then reweld next. I want to see how much improvement I can achieve without having to pull the turbine again. I expect I will still need to port the turbine pretty soon.

Joe

 

[Motohead1]

Hmmm so Joe you havent done the 34mm flapper and porting mod? From what i read it seems to solve the creep problems all togther. Its really not hard at all to pull the exhaust housing on the 14b. When my flapper comes in this week i will let yall know how much it helps. with my mods i am hoping to eliminate creep totaly. BTW for referance mine will not boost under 14psi right now with the MBC set as far out as posible.

1st gear 14-15psi
2nd 15psi till 6000 then slams to 19 and fuel cut
3rd is a joke and starts to creep instantly.

So soon will see exactly what the 34mm flapper does for me.