I beg to differ.

Exact same turbo, 2.5" V-band downpipe to 3" no cat... Ran into creep as well,
I even disconnected the wastegate entirely to trouble shoot but realized that the out of control creep still existed, so the problem is traced down to the turbine housings port being way to small..

Exact same housings, before and after. Yes I have 2 of these turbos, one is a spare so a perfect opportunity to showcase them side by side.

Note the black soot outline on the used left housing! Its a good idea since your in there to gasket match it to gain better flow, less lag which is exactly what I did as per right side ported housing.

You don't have to go to the extreme as mine and polish the housing (promotes higher exhaust gas velocity btw) but definitely should at least do what Braineack did on his, which has a similar shape to channel the gasses into the wastegate port.

Its hard to see this from my pic since I polished and smoothed mine out but the idea is the same. Keep in mind I am running a upgraded 1.5" flapper (yours is 1.25") and a Kinugawa billet wastegate : Results: boost creep? Whats that?!!

 

I'm pretty sure he meant making the hole larger in diameter.

He clearly showed porting his housing, but not hogging out the port itself.

Dann

 

Note the larger diameter on the ported housing (right)

 

And?

 

Lol. Dumping a fixed amount of gases through a 1.25" diameter hole vs. 1.25" hole . Which one will evacuate the gases first! ..

Go ask companies that make variable size wastegates why they don't just use one size pistons and you will get your "and"

Or

Ask yourself why a 3" exhaust makes more power over the stock 2"...

Sure opening up the hole .5-1mm is trivial ok
But .250" makes a difference

You have your answer.

Nobody has to do what I did, the above method and pictures I posted is to help others see the merits of:

Simple fluid dynamics

 

Huh? Is this a riddle?

 

that turbo had a severely undersized outlet to begin with. Look how much bigger the flapper area is compared to it. I've never dealt with a turbo like that, where I'm used the flapper just being maybe 2-4mm or so larger in diameter than the outlet.

There's also fear that if you do enlarge the hole that it's possible the extra exhaust gasses/pressure could force the wastegate open faster; but that sounds like a long math equation that I don't want to tackle.

also my comments were directed to that specific turbo itself: I have the same turbo; I don't have creep. The outlet doesn't need to be enlarged and there's little wiggle room to do so anyways.

 

is it not just pressure over area?

 

plus the negative pressure of the wastegate actuator.

 

That's why I'd only go with external wastegate.

 

OH COOL STORY!!! YOURE SO ******* AWESOME!

 

Expensive EWG setup for a $150 turbo. Makes sense.

 

The 2 housings i posted are the exact same turbos, same specific one as you, and OP. the one on the left is untouched, the right one was after I ported it.

Yes I agree with you 100% that a channel is all thats needed on this turbo, the process I did would be considered the "ultimate internal gate mod" lol, the step one would take if they don't want to go down the external wastegate route, but still want the same flow capability of a 38mm external gate, (exact same size) .

 

I love your heat shield! I have an old stop sign that I cut up and use for random things.

 

Thanks lexintexan!

I blew my turbo inlet gasket yesterday so while I have the turbo off I plan to get it fixed up like the picture brain posted to rid of the boost creep. Brain, do you use the same flapper?

I am getting like extremely bad gas mileage. I talked to the tuner about it because I am running around mid 11s to mid 12s AFRs when cruising and he told me that it is like that because I would have a constant light load misfire when cruising (trying to stay the same speed) so he had to richen (that's not a word) it up to prevent that. Has anyone encountered this before and know of a fix or what's causing it?

 

I cruise around 15.5 to 16. I get extremely good gas mileage and the car runs beautifully. I also don't use a "tuner" (unless you count VEA).

 

Haha, I was just referring to the guy who tuned my car because I don't trust myself enough. I had it running around there before I took it to him, it just misfired when I tried to cruise around

 

You should not be misfiring at those AFR's. Is your WBO2 accurate? Have you done a free air calibration lately?

 

it only misfires at very light throttle, goes lean, no matter the RPM. As far as I know it's accurate. No I have not done a free air cal.

Edit: Sounded wrong

 

The misfire honestly would worry me more than your other problems. Figure that out and fix it.