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Boost Creep? T04E turbo going nuts

pwaes

pwaes

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Mar 22, 2009
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Just got my MOT (in Dutch APK) so she is again allowed on the road (legally) since 2 years, good times!

But now the following has occured, engine so far:

b230ft
531 ported - flowed
ck1 camshaft
siemens deka 660cc injectors
90+ manifold ported
t04e turbo
full 3 inch with v-band exhaust
m90 gearbox
stock intercooler (npr on the way, i know)
tloa chips, ezk and ecu

Picks up from 2200 rpm to 0.9 bar (so 13 psi) untill around 5200 rpm and then goes banana's (upwards 2 bar/ 28 psi) untill the redline of 6500 rpm which I have not reached because I don't keep flooring it.

Is this the famous boost creep I am experiencing? The turbo should be capable of this kind of hp/boost with relative ease.
 
Haven't checked the internal wastegate :oops: it's on the car now so that's a bit hard.

It's this turbo, new and should be capable of this kind of setup, I've talked with the supplier a hour ago and he has never had anyone telling him that the wastegate was not sufficient:

COM WHEEL : 50.5 / 76
TUR WHEEL : 65.5 / 55.9

Is there a way that the wastegate does not fully open or .. :???:

It does deliver enough power because it goes like crazy now, so that is a good thing !
 
Simple thing- unhook the wastegate actuator from the arm and let it flop and see what it does. If it still builds boost over 5000 rpm (excessive boost) then the wastegate is probably sized to small.

I had a similar problem with the GT3071R on my old T5R. Even with the gate locked open, it'd make 18psi from 5500 rpm on if I wanted it or not.
 
Hank Scorpio said:
Simple thing- unhook the wastegate actuator from the arm and let it flop and see what it does. If it still builds boost over 5000 rpm (excessive boost) then the wastegate is probably sized to small.

I had a similar problem with the GT3071R on my old T5R. Even with the gate locked open, it'd make 18psi from 5500 rpm on if I wanted it or not.
Click to expand...

This is it. Wastegate hole to small, ****.

Should a ATP ultimate wastegate housing fix this, combining it with making the wastegate hole slightly smaller than the flapper? I don't want to go external because of the plumbing (ditching the 90+) and the costs..
 
Appears to be the standard Ford/Volvo 5-bolt housing, so you should be able to run the ATP housing for sure if that is the case... May be a different sized V-Band.
 
That ATP wastegate housing is good. As I recall the bypass hole is in the turbine housing. Not the wastegate. So you'll want to spend some time making the hole larger to allow more exhaust flow. I had boost creep when I went to a three inch exhaust with the stock 240 turbo housing. Cherry turbos made me a wastegate housing that flowed better and cured it. But with a compressor as large as what you're using you will want something done to the hole in the housing.
 
Thanks for all the good advice. Turbo should be a replica of a garrett gt2871 and have a wastegate hole just as big as the original garrett one. I've never seen an original Garrett gt2871 but this is the hole (around 25mm):

wastegate2.jpg


wastegate1.jpg


Flapper is 32mm so I think the boost creep can be fixed by making the hole 30-31mm. I'll report back when this is done and the test driving is done.. Fingers crossed
 
When cherry turbos made my better flowing wastegate. He ground just a tiny bit on the outlet pipe lower area so the exhaust gases can take the bend. That is the main problem with this stock style wastegate. It forces the bypass exhaust to make two turns before it gets to the downpipe. Grinding the hole will definitely help and should cure your problem. But as you go for more performance and more airflow you may want to consider either a better flowing exhaust housing or some type of wastegate replacement that will merge the flow without the two turns.
 
Problem fixed. Very happy about it.

Solution was that the hole needed to be bigger (now around 29-30mm, increase of 40-50% of the original hole) and put it back in the center. Now the boost stays even until the max of 6800 rpm. This weekend i'm going to up the boost, now on 7 psi and see what she does. I'll update back here because I expect a lot of fun :)
 
So im glad i saw this. I have a new GT2871r and i just measured the hole and its 1" so 25mm and the ATP ultimate wastegate is 1.3" so 33mm which is what this gentleman was having issues with.

So im taking i should do this now before i get the thing coated and assembled?

Anyone else had this specific experience?
 
I did similar porting on the WG hole on my gt2871r turbine housing. One concern I have about mine is that I feel like I may have cut away too much on the part nearest the flapper, such that the flapper might catch the edge of the hole and hang open. I've always had some issues with response, and I don't know if that could be part of my problem. So be careful when enlarging the hole and don't try to go for the maximum size possible.

I also opened up the turbine outlet from just after the wheel to the edge of the turbine housing. Made it match to the ARP housing with a gradual increase

http://www.pbase.com/towerymt/gt2871r&page=all

And some photos of the 3" outlet ARP housing:

http://www.pbase.com/towerymt/atp
 
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