jameswrx

iTrader: (4)

Hi all

As some of you may have read i've posted bout boost troubles before.

My car has decat Hiper and HKS induction, 94 wrx.

I ventured into the dawes route and had trouble with my boost. At the moment i'm running as standard with the boost solenoid, I get a small spike and then around 0.9bar in 4th and tailing off slightly towards the top.

But I want to hold 1bar, this means dawes, and this for some reason means boost climbing.

I had a pipe straight from turbo nipple to actuator with the dawes in line but with this setup boost comes in at 0.8bar@4,000rpm in 4th and then starts to climb with the revs til it hits fuel cut! It drove me mad, changed pipes, actuators etc, still no joy!

Obviously with dawes in line with solenoid get too much overboost, very tempted to try a normal bleedvalve, someone on here said not reccomended, why?, i've run one on my gti-r for 2 years, doesn't overboost and is fine.

Just wondered if anyones had this problem? I need more speed

James

Katana

Still the same problem mate? Why not take it to a specialist for now since you've replaced the actuator and everything.

jameswrx

iTrader: (4)

Thought there might be some 'specialists' offering free advice on here mate

Plus I'm not gonna have any time to give the car up for ages coz i'm too busy at work. Gotta start working all weekend now til after christmas.

Thing is it's just weird, if it was a leak somewhere i would think it would be noticable in standard form, but it's not.

As it only does it when i'm running the pipe direct to actuator from turbo I would think people that have put the dawes on had come accross this.

dowser

What does it do if you just connect a pipe between turbo output nipple and the wastegate actuator (without the dawes)? Should see boost of around .7 bar (cracking pressure of actuator).

Faulty Dawes?

Richard

jameswrx

iTrader: (4)

Richard,

Tried it like that mate but it still creeps up.

I'm gonna have another play with it sunday(ooo errr)

James

dowser

If it creeps up like that, what happens with no pipe connected to actuator? This should see boost go through roof until fuel cut.

I'd guess you either have a problem with the wastegate itself or the d/p blocking the exit. Can you jam the wastegate full open?

Richard

jameswrx

iTrader: (4)

Wastegate moves freely, I did wire the wastegate open, when i done this there was no boost til the top of the revs where it all starts to come in, I kept one eye on the boost gauge and backed off the throttle when it got to 0.9bar, should have kept going more to find out what happened but I was holding the car on the brakes to try and build the boost up more gradually as it can all come in too fast for my liking.

I did ask the question if it's feasible for the downpipe to be restricting the wastegate flow (ie exhaust past turbine wheel flowing fine thus raising boost and wastegate not able to flow well enough to level off the boost) but this theory got rubbished.
Does seem poss to me as the HKS DP lines up with the exhaust turbine and a plate is in front of the wastegate.

Pavlo

I think the HKS can restrict wastegate flow, especially as the main outlet in for the exhaust will flow very freely with the large exhaust.

One way to fix it would be to port the wastegate, so it can flow more freely. Another way is to possibly get an open neck downpipe like the scoobysport, TSL or H&S designs, and a twin dump will probably do as well too.

If you don't mind removing the turbo, you can port the wastegate yourself if you can use a dremel type tool, as there isn't much material to remove.

Paul

jameswrx

iTrader: (4)

Yeah this is what I thought, but has anyone experienced this with the HKS DP??

Don't know anything about porting the wategate mate, never heard of this, but if it's the DP then the answer would be to change this.

But why does boost act normal when the solenoid is plumbed in?

Can't be the DP then coz if the solenoid keeps the boost to say 0.85bar then it does this ultimately using the wastegate, aaaaarrrrgggghhhh, what fun eh?

dowser

Sounds like an issue with the d/p then - strange though, never come across this before (except Mark at EMS with a specific twin dump d/p design on the STi7). Is it a td05? I would be checking the wastegate operation while you've got the d/p off - maybe it's partially blocked somehow?

Richard

jameswrx

iTrader: (4)

I've had the DP off before and it was all working fine.

Think I might get an open neck DP when my credit card cools down

jameswrx

iTrader: (4)

This is my problem I reckon (thanks waggy do, nicked your pic)

Looks a bit 'blocked' don't you think?

James