Who has Successfully Eliminated Boost Creep?

[Spln_Hrd]

I have Ported out the wastgate entrance. I have ported to help the flapper open more. I have an external dump 02 housing. I am now considering porting out the exit hole where the flapper shuts, is there any room to increase the diameter without intalling a 34mm flapper. I dont want the 34mm flapper because of losing the potential of the turbo. Then again maybe the flapper will still blow open if I increase the diameter anyway. I dont know what to do. Id rather not spend big bucks on an external wastegate. I want to eliminate it through porting. Id even send it to a shop that is damn good at porting.


Has anyone eliminated creep on a 16g without installing a 34mm flapper running 3" turbo-back exhaust with a testpipe?

 

[1fast97gsx]

I eliminated it on my 16g. I had the wastegate, turbine housing, turbo manifold and O2 housing ported as well as a 34mm flapper installed. No creep whatsoever.

 

[sidoze]

ya if i run 20psi =/

 

[1fast97gsx]

I had a 3" exhaust but I had a HFC and I did have the flapper...

 

[Spln_Hrd]

How low of boost can you run and also what is your max?

 

[coltboostin]

I did on my old colt. you just need to not be affraid and take as much material away from the lip abovt the enterance to the wastegate door. I was able to hold 15psi steady. Boost came quick, on a 7cm housing

 

[Spln_Hrd]

So if I lay into this with my die grinder even more, which im sure there is more that i can remove, It could work without the 34mm flapper or do I have to get the 34mm flapper.

What do you all think about widening the wastegate hole and keeping the stock flapper?

 

[coltboostin]

yeap. Just lay into the housing so exaust can go right out of the wastegate when needed. I have a stock flapper

 

[Spln_Hrd]

another question i have, how severe is my boost creep?

at 3200 rpm i hear the wastegate open(external dump) this is with it set at 16 psi, and by the time i hit 4000 rpm i have hit 20 psi

how bad is the 34 mm flapper w/ blowing open? i would install it, but i hear that you cannot run as much boost when you want to. because i need very little till i can run race gas and run 20+ psi, which i would like to do when i go to the race track, or just really wanna smoke someone.

 

[1fast97gsx]

I never had ANY problems with the 34mm flapper. I had it at 20psi once ( only once cause I had the stock intercooler still ... still no problems with it opening there ) I ran as low as 14 psi and as high as 18 psi on the street. No problems at all. Just keep porting I guess and that could help too but I don't think you will totally fix it without the flapper and / or at least a HFC instead of the test pipe

 

[btrux06]

i have a normal big 16g, ported, and have dead steady boost contol with my 2.5 o2 with side dump, i run 19 on the street and as much as 22 at the track and never had any boost creep at all. mabby your wastegate is bad or mbc or something, sound slike u got a serious not normal case of it.

 

[coltboostin]

No wastegate opens right at the desired boost level (if you want 16psi, it opens earlier) They begin to open 2-3psi earlier to stop the raging turbo from overboosting. Electronic 2 soinoid boost controlers keep the gate shut longer, but to me, it sounds like you just need to turn the boost down a bit. What kind of actuator controller (boost controler) are you running?

 

[Spln_Hrd]

I have an Extreme Motorsports MBC. Ive backed it all the way out and Same scenario 20 psi at 4000 rpm. I have never went past that Im afraid it will only get uglier though. Here is a pic of my turbo, is the porting dexcent?

 

[btrux06]

ya looks real good. sounds like you mbc or actuator is working right

 

[Kevin Jewer]

I didnt have trouble with the 34mm flapper 16g blowng open until I turned the boost up to 25 psi. Dropped to 19 psi by redline. I wired that bi*** shut and it only dropped to 24 psi, and picked up 2 lbs/min flow. Prood that it blows open. Still ran the same 12.0s though.

On my 14b I had boost creep to 22+ psi on a 2.5" turbo back. Without even touching the flapper hole, I got it down to 16 psi. Its all in the wastegate exit area, as tom describes in the vfaq. Just port match the O2 so there is no lip, and its a 2g, cut the divider back so the gasses can get around the O2 sensor (in that shyte location). By just touching up the flapper hole, I got it down to 14 psi or so. Try to avoid going with a larger flapper at all costs. I took the 14b out 4-5 times to port more until it was right. But that thing held 24 psi all day long. Well worth the effort.

Also, an external dump O2 housing did absolutely nothing for my creep.

 

[ShapeGSX]

My experience with the small 16G (TRE ported with a 34mm flapper) was the same as Kevin's. I set the boost at 19psi, and I had 16psi by redline. I set the boost at 23psi, and I had 19psi by redline. The turbo had more in it, but it couldn't hold boost because the wastegate was being opened more than it should have.

I didn't even realize that this was the case until I installed my Evo III 16G (not ported at all, and not clipped). Sure, it creeps to 22psi in the cold. But it also holds 26psi to redline and flows 44lbs/min. I won't install a larger flapper. No way.

For now, I'm just keeping off the gas when I daily drive the car. It isn't that big a deal. Hell, at part throttle the car has more than enough oomph to get me to work. I broke 2 gears on 2 seperate occasions with my small 16G. The Evo III 16G has the potential to break so much more stuff.

I'll be fixing the creep soon enough, though.

 

[Spln_Hrd]

After viewing my porting in the above picture, is it abvious that I need to port it more extensively?

 

[pickens]

on my 14b, I switched to a 7cm housing. No creep whatsoever, but a lil' laggier. Full 15psi boost around 3500rpm I can run as low as 10psi rock steady.

 

[Kevin Jewer]

Originally posted by Spln_Hrd
After viewing my porting in the above picture, is it abvious that I need to port it more extensively?

You're looking at the wrond side of the turbo in that pic. Go read the vfaq I mentioned above

 

[ShapeGSX]

Originally posted by 95GSXracer
You're looking at the wrond side of the turbo in that pic. Go read the vfaq I mentioned above

Actually, the porting on the inlet side of the exhaust housing is very important. When it is stock, the wall above the wastegate deflects exhaust away from the wastegate flapper, and down into the turbine.

 

[coltboostin]

Believe it or not, I even have a bit more off mine, but you are looking good. You have the right idea and clearly understood what I was saying. Yes, dont go with the 34mm flapper, as is obvious, it has too many downsides. With a bit more porting, you should be fine

 

[Kevin Jewer]

Originally posted by ShapeGSX
Actually, the porting on the inlet side of the exhaust housing is very important. When it is stock, the wall above the wastegate deflects exhaust away from the wastegate flapper, and down into the turbine.

I know, I also port that side, but only as a last resort. Or the second to last resort, larger flapper being the last last resort It will increase drag there for the air that does have to go through the turbine.

 

[Spln_Hrd]

Thank you everyone for all of the positive information. I figured I would get hit with the, "Do a Search, this has been beat death". I will port more and follow up with the results.

 

[bigjangin]

hey spln_hard on the 24th and 25th im gonna be porting out my 16g without installing a 34mm flapper. I plan on running high boost so I dont want the flapper to blow open. I have about the same boost creep as you, its pretty bad. It will be all good till right at 4k, then it just shoots up and I shut it down when it approaches 20psi. I'll let you know how it goes.

 

[Enraged78]

Originally posted by 95GSXracer
Just port match the O2 so there is no lip, and its a 2g, cut the divider back so the gasses can get around the O2 sensor (in that shyte location).

Is there any way we can make this a sticky? This has come up so many times, and it seems that everyone I've spoken to with a 2g and upgraded turbo has either partially removed or cut the divider, had head work done, or gone external.

FYI, I have a ported 14b with the 34mm flapper, ported O2, Poted Mani, 3" exhaust with a cat, and I still get creep in the cold. Cutting the divider definately will fix me. If I have the turbo out of the car again, that is getting done.

Matt.