Hooray.

I took my 93MY WRX 4 door to Power Engineering on May 29th.

Before the lads at PE put the car on the rolling road they said it didn't sound quite right. Apparently they could hear the wastegate fluttering when they revved the engine. It was not closing properly so bleeding off boost instead of using it.

This was followed with immediate head shaking as the power run started (by Mervyn), he came out saying that he knew straight away what the problem was just by looking at the power/torque curves.

It was showing very little power at all up to 3,800 RPM when it took off rapidly.

Torque = 206lb/ft http://bbs.sidc.co.uk/redface.gif
Power = 245bhp http://bbs.sidc.co.uk/frown.gif

Have booked my car in to PE for next Monday to have the wastegate actuator adjusted and everything else given the once over.

Somebody suggested fitting a stronger wastegate? Any comments?

I am looking forward to a relatively low cost power hike, (£42.00 approx) PE estimate my torque should go up to 240/250 lb/ft, and Power up to 260 bhp?

With the mod's that my car has I would hope that it gets closer to 300bhp but then again I suppose we would all like that wouldn't we. http://bbs.sidc.co.uk/smile.gif

I am lead to believe that a full power run was not done due to the problem and Mervyn only saw 15 lbs of boost?

I don't know how it converts but am lead to believe (by Peter at Subaru Manchester AKA C&K, who previously owned the car) that it can run up to 1.35 bar of boost in relative safety.

It is a Jap (Project X) chip and Peter says that it is the best one he has ever seen, and has even attempted to copy it.

Always run on SUL with repair to wastegate done and running to approx 1.2-1.3 bar, what power & torque figures should I realistically expect to see?


Mike.

Mike,
Apparently Silkolene 'Proboost' octane booster(unleaded) increases SUL octane to 110 RON (£15 a bottle) thus taking it beyond Jap. spec fuel. I haven't tried it yet so I don't what the ratio of octane booster/SUL is (obviously if it's one bottle per tankful then it's a bloody stupid idea), but it should make for safer high-boost running.

Thanks Rob.

Are you suggesting that an octane booster would be necessary to run 1.35 bar (Psi??) safely, or just that it would help.

I will be able to run the car at 1.2 bar and when I want a thrash drop said octane booster in and up the boost to 1.35bar?

Mike,
1.35 bar equates to just under 20psi.

Superchip conversions run at 16-17psi.

I reckon you'd be wise to use the octane booster for that kind of boost pressure just to be on the safe side and I presume your chip must be providing sufficient fueling.
As long as fueling is okay,I think the main thing to worry about is the original turbocharger running way outside its normal operating margins;
The turbo spins faster than it is designed to, thus causing a significant increase in temperature of both the turbo(which may, in extremis, lead to disintegration of the compressor wheel with disastrous consequences) and a consequent increase in charge temperature,thus making it less dense and negating some of the value of having increased boost pressure in the first place.

Nothing a hybrid-turbocharger(larger compressor-wheel and stronger thrust-bearing) couldn't handle though, but we're talking large wads(though maybe not as much as our brakes!)

Lastly, I honestly don't know how much boost you can run on an Impreza WRX without having to start worrying about head-gaskets and pistons,rods,crank,etc.(I'd be interested to know if anyones found the limits-particularly the hard way!).

1.35bar WOW! Whats the exhaust temp. Mike, 900/950 Cels.? (Let us know when yr turbo blades fly into yr engine Mike *touch wood*).

Poor old Mike seems to be taking a bit of a bashing over the boost his cars set up to run.

Firstly dont forget that there are two boost figures give when you do a RR run.

Most of the WRX's/ STi's, have a peak boost of around 17 psi (1.2 bar)@4k rpm,and then hold about 15 psi (1/ 1.1 bar).Standard car.
If you change the exhaust/filter,peak can easily go up to 18/20 psi (1.25/ 1.35 bar)holding 15/16 psi.

PE's Phase 1,is set to 20 psi on some of the WRX's/STi's, and hold 16/18 psi,this is why their mod' gives so much mid' range torque,and holds it longer.

So Mikes HEAVILY modded car,mapped for 1.35 bar peak,is know different to a PE phase 1.

I for one can't wait until they sort his waste gate out.

Mark.

Hmmm, thought it was a simnple task to copy chip programmes these days as I remember back to the heady days of 4x4 Cossie ownership when a mate ran a chipping computer which could read Superchip chip programs and blow them onto a fresh chip; could even call up the map on screen and tune it before blowing the new one and had a laptop plugged in for final on road tuning. Sounds fishy to me (having the PE Phase I and being bloody amazed by the mid/top end) http://bbs.sidc.co.uk/wink.gif

Come on then, anyone got any advances on 20psi/1.35bar? I'm interested to know the maximum peak boost anyone has 'safely' run on standard head gaskets and internals just to provide some sort of bench-mark.

I'm heading for 20psi+ peak boost on an STI II engine+turbo with HKS FCON V/EVC fuel+ignition+boost management,Gp.A intercooler, ERL water injection and 'hot' sparkplugs- basically everything possible to stave off detonation.

The utilisation of the aforementioned octane-booster should enable a further increase but even if detonation is not the problem, you do start to wonder where the limits are of the standard head-gaskets(not to mention the rest).

So, 25psi anyone? Do I hear 30? I bet some mad bugger must have been there(albeit briefly and expensively!).

Speaking to a guy a few weeks ago who prepares rally engines. A UK car can run up to 20psi, but it can cause problems in the long run, he recommended 18psi max. Unless you change to steel head gaskets and gpA bolts.

We have 23psi on our STi3 with 330bhp with standard exhaust. Clutch slips at 25psi but no detting.

Engine failure is usually caused by incorrect mapping not failure of components.

Detonation is a huge pressure spike 20-30 times the pressure normally found inside a combustion chamber, which is enough to break pistons and force head gaskets out from between block and head.

So boost pressure in itself is not dangerous it is what you do with it.

A step in the right direction.


After Mervyn took the turbo heat shield off, he found that the actuator is not adjustable.... So cut a small section out of the rod and sleeved the two parts back together.


After much fiddling managed to achieve 252bhp and 230lb/ft. (17psi boost).

Mervyn thinks that the cat's are restricting the engine (may have broken down and be blocking the exhaust flow)?

So next on the list is removal of cat's.

Interestingly the car was producing 240bhp with only 14/15psi.

David,
So this STI 3 presumably is running standard gaskets and internals is it?(And Turbocharger?) Also, is 23psi run on SUL alone or with some sort of octane booster?
Lastly, is the compression-ratio for the STI 3 8.5:1 or is it lower?

I apologise for all the questions,I'd get down to P.E. and see it all first-hand but for being situated all the way up in N.Yorks.

Mike,(sorry for continually taking your thread off the subject)- how are your brakes bearing up and did you manage to fit the rear discs with the original (small)sliding calipers? Also, have you found that your alloys are almost permanently diahorrea coloured thanks to whatever pad compound Tarox use?

Rob.

The brakes are taking longer to bed in than Tarox suggest, it may be because I have not really pushed them that hard (yet) http://bbs.sidc.co.uk/wink.gif

There are still a few small semi coloured areas on the discs which are not making full contact with the pads?

Yes the rear replacement discs are just that old ones off new ones straight back on, same calipers but new (intermediate compound) pads.

I have noticed with the front discs that with the now shiny large surface area of the rotor, you can now clearly see the inside face of the wheel very clearly.
Bugger, even more cleaning to do. http://bbs.sidc.co.uk/frown.gif

Brake dust, yes it is a very similar colour isn't it.

Mike.

Thanks to all who have sent me direct E.Mails re. the main thread, keep the ideas and comments coming.

Anymore than 15psi apart from the 1994 WRX will spell trouble,. The solution would be to utilise Oil Breather Tank Kit which does not aid power but prevents oil entering inlet of turbo and causing detonation.

Greg
BPM
"The ruthless pursuit of speed"

BPM (Greg) So why is the 94 WRX able to take more, and how much more? Do you mean the japanese wrx or the aussie one? Surprise, surprise, I have a 94 wrx (japanese)!

Come on then BPM, let's have the whole story what is it why is it and how much is it?

Comments are thus:

We as a company have been working with the WRX since 1994 , working closely with possum Bourne with the
Link EFI system and currently claim the fastest WRX on the 1/4 mile.

Now the reason behind my 15psi method. What i mean is do not go over 15psi without dealing with some of the problems that eventuate. When going above boost levels ie 14 psi and above depending on which version you are looking at, this excess
boost level will cause the engine to blow by and thus build up pressure in the engine. This combined with the standard oil breather setup tends to ENABLE oil to be drawn back into the engine via the inlet track. The reason behind the oil breather tank kit is to prevent this when exceeding 15psi since any oil that is blown out of the engine will be caught in the oil breather tank and only air is allowed to exit the tank back into the engine.
As to the WRX 94 , that can be dialled up to 18psi with no real probelms due to the turboit utilises.The WRX 94 is truly the sleeping giant!

Hope that helps

Greg Nikoletto
Boost Performance Motoring
UK Marketing Manager

WRX are using standard head gasket and cast piston. I would advice you to set the boost at 1 bar to prolong the head gasket life.

STI are using metal head gasket and forged piston. 1.2 bar is safe with the original ECU.

STI RA are using metal gasket and higher compression forged piston.

Using Aquamist Water injection to run higher boost would be good.

If you are planning to run higher then 1.4 bar of boost/high compression .... do get the con-rod bolts change to a better grade.

I use Silkoline Pro Boost and i can say it has a good effect on stopping my knock sensor kicking in.(Is this good or Bad?)
I have also noticed a improvement in midrange. http://bbs.sidc.co.uk/smile.gif
I run a 1.5% mix. This use`s 600/700ml per fill up.
I don`t pay £15 a bottle, I pay £7. I also struck up a deal with the shop, I buy 4 cans at once and i pay £6 a bottle. Go to a motor Bike shop. http://bbs.sidc.co.uk/wink.gif(he is also a friend)

I have MY93 is it the same as a MY94 ?
Wishfull thinking.... http://bbs.sidc.co.uk/wink.gif

Dave

Mike

I haven`t checked my seat belts but I do have a Alloy Boot&Bonnet, I will check the wishbones. My car is registered as a `93 K.
(17k miles) http://bbs.sidc.co.uk/smile.gif
I also had my Scoob set up on Interpro`s R/Road They quoted 228bhp @ 5657rpm with 220(ish)flbs.
(Not very impressed)
I have a Jap after market exhaust JASMA. Not sure if it is a Full system or just a tail pipe.
I have just fitted a Pipercross air filter kit. Maybe it gives about 235 now ?
I need to get it back on the rollers. http://bbs.sidc.co.uk/wink.gif

I also have a chance to buy a pre used Superchip for £225. Not sure about that one. Any one got some ideas ?

Dave

Dave,

It's funny you should mention that, from memory I think that the FAQ says that some vehicles although produced in the MY93 for example, actually are to MY94 spec.

My car which I thought to be a MY93 WRX (it says 1993 on the seat belt labels), has aluminium lower front wishbones, an aluminium alloy bonnet and boot, STi parts I thought. Could it be a MY94, it is registered in this country as a 1994 car (L reg).

Mike.