dowser

James,

You need to fix this problem before going any further, but I guess you know that really?!

If a pipe directly between turbo output and wastegate actuator is showing boost creeping ever higher (how high does it get - does it level off anywhere sensible?) then you have a problem. With this scenario you should see no more than .7 bar with OE actuator. Your wastegate, for whatever reason, cannot bypass enough air from the compressor.

Your EBC needs the actuator/wastegate to be functioning correctly to stand a chance of controlling boost....

Richard
Edited to add: when you connected a pipe between nipple and actuator - was the pipe clean? Could you see through it?

[Edited by dowser - 12/11/2002 6:49:12 AM]

jameswrx

iTrader: (4)

Hi all,

Getting an avc-r soon but wondering whether fitting it is wise?

As some might know and/or remember I have trouble with me boost, when I tried a dawes (pipe between turbo nipple and actuator with dawes in) the boost reaches a level (as it does with the standard solenoid) but then it climbs up with the revs (as apposed to leveling or tailing off). I tried without the dawes (just pipe between turbo nipple and actuator) and it reached 0.5 bar and climbed again with the revs. I put the solenoid back in place and everything is fine, I do get slight overboost (down to HKS with decat and HKS induction) but it holds and slightly tails off as every other turbo car I've owned. I have tried actuators, checked for leaks, checked wastegate operation etc, and can only attribute to possible HKS D/P not flowing as well for the wastegate gases as the exhaust turbine gas speed due to closed neck design (plate of D/P covering wastegate, D/P bore behing exhaust turbine).

After the history lesson, just wondering if the AVC-R is gonna control the boost well enough (like the standard solenoid)?

Been told the way to fit avc-r is directly between turbo nipple and actuator (as I had dawes and trouble).

Will it be able to keep my desired boost setting level?

Sorry bout the old ground

James

Turbo_Steve

Not wishing to state the obvious, but your boost guage is ok, right? I mean, it is not reaching a certain (higher) level of boost and starting to mis-read badly?

I am sure it isn't cos you must be able to feel the car keep accelerating harder and harder, but I just thought I'd suggest it?

jameswrx

iTrader: (4)

Nah mate not the gauge, and like you say the car does start accelerating harder. It's weird but doesn't do it with the boost solenoid plumbed in.
Don't understand why it doesn't do it with the boost solenoid plumbed in, at full chat it stays level (in 4th say) but with a pipe between nipple and actuator it (like I said) hits 0.5bar then climbs up to about 1bar near the limiter.

It's well strange the more I think about it even now because the solenoid ultimately controls boost using the wastegate so I don't understand why it doesn't climb like this if something is wrong?!

I can only put it down to the D/P, but then I don't see why it doesn't climb with solenoid if it's restricting flow.

James

jameswrx

iTrader: (4)

Richard,

Yeah pipe was clean tried different ones, got two actuators etc.
Can only think it's down to the design of the downpipe where it bolts to the turbo.

Someone out there must have a HKS downpipe?, fancy putting a pipe between the turbo nipple and actuator? I need to know this is it for sure before I change the downpipe.

People have said why doesn't the oe D/P do it, but it must be cause the HKS system flows better(apart from wastegate area) thus creating a higher gas flow speed through the exhaust turbine and the wastegate gases can't get out quick enough past the plate of the downpipe and into gas flow.

edited to say: Why the blinkin eck does the standard boost solenoid manage to control boost, looking yesterday I get a good 0.9bar in 4th and slightly tailing off towards the top of the revs. Thats why I wondered whether the avc-r would do the same?, it's gotta be better than the standard one anyway.

James

[Edited by jameswrx - 12/12/2002 8:12:38 AM]

dowser

I think any boost controller would be fine....as long as it keeps boost below .9 bar!

Any higher and I reckon you'll run into problems. But as you say, there must be people running with HKS d/p and over 1 bar without problems....

Richard

jameswrx

iTrader: (4)

ok so I'm mad as a box of frogs

The boost DOES still rise with the solenoid in place, didn't notice it because boost comes in at 0.9bar and only goes to 1.0bar as it hits the rev limiter. Been studying it today.

Witout the solenoid (just the pipe between actuator) boost comes in at 0.6bar and then creeps up to 1.0bar at the rev limiter which is why it's more noticable.

Still, what I should be getting is (without solenoid) 0.6bar coming in and holding this boost or tailing off, and (with solenoid) 0.9bar coming in and holding or tailing off, but i'm not.

I need help before me avc-r gets here...

James

JIM THEO

Sorry if hijack your thread just to ask if you know where Dawes Device should be connected between turbo exit and "T" piece of solenoid, or between "T" piece and wastegate?
Is for a friend but as never have fitted a DD I have no personal experience!
Thanks
JIM

Turbo_Steve

I suspect your wastegate may be overtightened: espcially if everything you do results in too much boost that simply cannot be bled away.

Jim...DD goes between bleed nipple on turbo housing, and actuator. All the solenoid piping and everything gets disconnected from turbo: Dawes replaces computer control.

[Edited by Turbo_Steve - 12/13/2002 8:11:28 AM]

Katana

Yup I'm still inclined with Steve's reasoning. Its either that or its leaking somewhere on the way to the actuator which was discounted by you.

jameswrx

iTrader: (4)

Turbo_steve, are you meaning the actuator preload?, if so i've hardly got any preload on. From a postion the actuator arm would slip on the wastegate arm without preload i've got one maybe one and a half turns of preload on the actuator, is this too much?

Or are you suggesting that the actual wastegate itself is sticking?, I would discount this as the boost (when coming in hard) will level at the desired setting for a second before it starts to rise and I've felt the wastegate action and it is free and light.

James

Flat Four Impreza Club

Sorry to hyjac, but we have had members when using the Dawes that the boost hits a point (1.1 bar) and tails off to .9 bar. Surley it should hold 1.1 bar accross the range!! As it says on the packet!!

jameswrx

iTrader: (4)

You won't get that sort of control with a dawes mate.
Your gonna lose boost because it relies on a number of aspects one being engine load which when the engine is revving higher is less, this is one reason the boost will tail off. Unlike mine.

Anyway back to my problem

EMS

James,

Look at this: http://www.scoobynet.co.uk/bbs/thread.asp?ThreadID=124996

(my) conclusion about this subject: enlarge the wastegate diameter in the turbo housing and/or use an exhaust system with more backpressure. (in some cases an "open neck" downpipe will help)

Mark.

[Edited by EMS - 12/13/2002 9:32:39 PM]

JIM THEO

Thanks Steve!
JIM

jameswrx

iTrader: (4)

Thanks Mark.
I might try an open neck D/P anyway.
I'll check the thread out
James

jameswrx

iTrader: (4)

Wish I'd seen this before, didn't realise I wasn't alone.

Well in my quest to solve this over the weeks I've tried all the methods apart from enlarging wastegate.
I've had the wastegate wired open and it still went up with the revs so guess it's not flowing enough.

One interesting point is that when my car came to the UK it had a Hiper system (decat) and the guy who imported it put a standard exhaust on.
The interesting bit though is that the wastegate actuator was actually adjusted to have the wastegate open slightly which I guess would mean it open further round. Perhaps the Jap owner was getting the boost creeping up and wa susing this as remedy?
But thinking bout it it still moved up like this so guess it's down to enlarging then!

I have since buying the car bought a full HKS Hiper again.

It could still be the closed D/P though I suppose, that was one of my earlier thoughts (turbine flow great due to flow of exhaust etc and wastegate flow poor coz of restricted D/P)

How do I do this enlarging mod or porting??? Anyone got pictures?

I bet there are people out there with this problem that don't even know about it.
James

Turbo_Steve

Sorry I cannot remember, but what spec is your car? MY etc etc?

If you have a TD04 it is probably worth sticking a different turbo on there rather than messing with your existing one! Depends if you are doing it yourself, or getting someone else to do it.

Glad to hear you have found the problem though: Insufficient wastegate flow.....never would have though of that.

EMS

Steve,

I donīt think James has a TD04, because with that one you whould like to have boost creep! Itīs very hard to acchieve more than 1,0 bar at 6.000 RPM with a TD04.

Mark.

Turbo_Steve

Looks like a larger wastegate is in order then! (Hmm...weekend with a powerdrill ahead for jameswrx)

Steve