ustolemyname??stevieturbo

iTrader: (1)

The pics dowser has presented do look interesting.
But dont forget, it states it fits a US Impreza, which will be left hand drive. Id take a wild guess and say that that setup will hit the steering linkage. As many already know, some twin dump pipes run very close already on rhd cars. It would be a gamble to purchase it.

dowser

Stevie, I'm in Swissieland, lol

MorayMackenzie

Hi Alan,

It's my current turbo. Very pleased with it. It's currently on a UK 97 block sitting in an STI 3 Vlimited. Power production is smooth and strong, like a _big_ N/A. Boost control is extremely good, which is a function of the turbo setup and the ecu controlling it.

Moray

David_Wallis

blurb says.. improves lag..

also looks to have an internal w/gate too.

dowser

It's an external wastegate system for a turbo with an internal wastegate - I guess you'd need to wire the internal one shut.

Richard

Andy.F

Alan

You only need to do as JB suggested in the second post. Port out the wastegate by approx 2mm.
The 20G wheel is more efficient than the Tmi Garrett wheel, hence the boost creep on some set ups.

Do you run a splitter ? With a splitter my car will boost creep, without a splitter I can run 1 bar to 7500 rpm no problem (unported WG)

Andy

AlanG

Andy

I don't run a splitter at all.

John seems to recall a boost control issue when the turbo was originally a TD05 and he tried to re-map the JECS ECU on that turbo. I think i had a splitter in the downpipe then, though.

I don't remember the boost creep problem at the time but either way i'm not sure porting will help sufficiently in this instance since with the wastegate held as open as far as it can go and way further than the actuator can give, i see positive boost from 4700rpm and a heady 1.6 bar of boost at 7000rpm.

If you think taking a couple of millimetres will be enough, then i'm willing to give it a go.

Going back to JB's comments when it was a TD05. Do you think there are other variations of 05 exhaust housings with a more restrictive wastegate path? And i may have a roque one?

Alan

[Edited by AlanG - 10/23/2003 11:49:45 PM]

Andy.F

Alan

There may be slight differences between the castings but this will be minor.
Porting the wastegate by only 2mm will increase its area by approx 17% This will kill the creep

This is an inlet/exhaust system specific set up issue, some cars with an identical turbo fitted can have the opposite problem ie boost tailing off at the top end. That's why I don't port them as standard.
Í'd rather have your problem as that is a sign that the inlet/exhaust system is working efficiently at high rpm.

Andy (back to the beach )

AlanG

Cheers for the advise Andy.

Not quite sure i understand the logic. Can you explain how that is the case?

Alan

john banks

Andy's TD05 did not boost creep. When he changed the compressor cover and wheel it did. The higher efficiency compressor wheel resulted in enough extra airflow at high RPM that it overpowers the standard internal wastegate's flow capacity, so more goes through the turbine making the situation self sustaining = boost creep. A boost creep in the last 1000 RPM should be amenable to a small porting job wherever it needs it - doesn't take much to start a boost creep, not much to stop it. I may still have the logs of your top end boost creep on your TD05 - I don't think we could get it below 1.3 bar at the top IIRC, so once you change to the larger more efficient compressor I think you are stuffed hence the present problems. If I find them I'll post them up.

What Andy is alluding to re intake/exhaust restrictions is that if you have little pressure drop at high airflows in your intake then then you are going to get more exhaust gas flow to go through a restrictive wastegate, so it will divert through the turbine. A free flowing exhaust will also result in lower pressure drops so the pressure gradient across the turbine will be steeper and the turbine wheel will do more work.

You have developed a mismatch between limited wastegate capacity and the rest of your breathing which is far less limited, hence the boost creep.

AlanG

My head hurts trying to take that in...


Alan

Scoty

Alan, did you get this sorted?
Did porting the wastgate help?
I'm getting boost creep similar to what you are/were getting

I have a splitter fitted in the downpipe and not sure wether to remove it or port the wastegate?

Scoty

Top

Pavlo

port the wastegate, make it bigger, and gently radius the entry into it from the turbine housing inlet side.

Andy.F

Hi Scoty

I ported the wastegate for Alan and that sorted it. Yours may be adjustable by slackening the wastegate linkage, I'd try that first.

cheers

Andy

AlanG

With no porting of wastegate my boost crept to 1.8 to 2.0 bar depending on situation. (1.6 bar with no wastegate attached at all!!

Andy gave me a ported exhaust housing (thanks Andy) and this helped reduce my peak boost to just over 1 bar at 7000rpm.

Allowed the boost controller to do its job properly

Alan

Scoty

Cheers

Was about to hack out my splitter in the downpipe tomorrow morning

Andy I'm still on a big learning curve here mate, how would I
slackening the wastegate linkage; there is no ajustable nut or thread on the bar between the actuator and the penny bit?

Andy.F

Ah, Yours is one of the non adjustable wastegate linkages. You can space the wastegate actuator back with a couple of washers just to try it though. The WG linkage should need only a few millimetres pull out to fit on to the pin at the penny (just enough to keep the penny tight shut)

I'd also take the splitter out, I had to remove my splitter to get the top end boost down once I fitted the Gruppe-s headers. That was even with the wastegate ported !

I can port the WG for you no problem if thats the way you need to go.

Andy

Scoty

Right Andy, so take the actuator bolts out that hold it onto the bracket and fit 2 washers on each bolt, and try it?
I'll remove the splitter while the DP's off too then mate.
Planning on doing this tomorrow afternoon, if I could bring the turbo accross to you tomorrow afternoon could you port it for us please?

Thanks in advance

Andy.F

No Problem - you have mail

Scoty

YHM mate