shiper

MY95 wagon. Full decat s/s exhaust.
Panel filter.
Dawes boost controler set at 16psi.
Full cut lifter set at 18psi.
Allways run on optimax.
Should i have any problems at this psi or is it too high and might i get fueling problems. If so whats the cheepest and most reliable way.
Cheers................

Devil's Refugee

Should be safe I reckon.
When the colder weather strikes, you might want to dial it down slightly, but I see no problems really.

Mo

I'd be tempted to get a knocklink and AFR meter to be sure that you have sufficient fuelling.

Imprezas do run rich from the factory but the mods you have will lean this out.

I had my MY94 fitted with a Unichip and ran 17psi and had to have fuel added throughout most of the map.

shiper

ttt

imprezapm

My 94 wagon (110,000 miles) has simailar mod's but with AFR meter & has been running at 1.3 bar for the last 3 months without any problems. Not sure how that translates to PSI though.

Mo

On standard injectors, fuel pump and map

MurrayZA

1.3 bar = 18.85 PSI

shunty

Guys,
UK 95 scoob with 138,000 miles
I have run 17psi for over a year now with the following mods:

K'n'N induction
full Magnex decat inc dp
superchip (equivalent to Motec)

now upped it myself, via adjustable valve to 18psi in 4th & 19 in 5th....these figures hold steady-ish. Obviously it will spike in winter
how long do you think it will last before it something explodes??
or perhaps it won't no track days, don't do persistant high speeds as this is where the damage is done I believe ??

shunty

Turbo_Steve

Do you guys have any idea how much a full rebuild costs when you blow the crap out of it?

More than the couple of hundred quid you need to check the engine is within safe parameters!

Buy an AFR and knocklink you scary scary people!

David_Wallis

ive got a 94uk wagon and hold 22psi to the redline.. see www.scoobyecu.co.uk for how..

550cc injectors
uprated fuel pump..

Turbo_Steve

Smooth promo Dave

Leeroy

I run around 19psi on MY97 turbo (with AFR gauge showing green under WOT). I have never had a problem with this pressure and run with it for over a year in a previous MY97 without a hiccup. The only problem I had on my current car was the intercooler hose blowing (common fault) which has been replaced with a full SAMCO set.

shunty

scoobyecu....what is that all about then David
some sort of chip modification business that is really cheap & gives amazing results???

shunty

Turbo_Steve

um...shunty.....yep

annointed

MRT is adamant that if you run over 16.5 psi (1.14 bar), its only a matter of time before you blow the motor. Of course, this is in reference to the TD05'd '93-96 jdm WRX's that had an 8.5 to 1 compression ratio. Many UK Impreza Turbos sport a 9 to 1 CR, which would completely change the situation (less boost).

Anyway, they've told me via email that they have at least one of these early generation WRXs per week in their shop due to running over 16.5 psi. I have my jdm '94 WRX set at 1.1 bar (16 psi), and according to my Apex'i Power FC, I hit 99% injector duty cycle at WOT in 3rd gear at redline, which is not good. If you want to run over 1.1 bar (16 psi) on an early WRX, you better plan on upgrading the stock 380 cc injectors...

Leeroy

I was under the impression that a 10-20% boost increase (when monitored with boost gauge and AFR meter) was classed as safe in most instances. With the 97MY set at around 15psi, this equates to around 18psi held. What you are saying about nearing maximum injector duty cycle under WOT is a tad worrying, but if the engine was being starved of fuel, then the AFR gauge would surely indicate a lean mix. In my case, the gauge shows rich at all times under WOT, and doesn't fluctuate too badly.
I have heard of people running 1.3-1.5bar and showing no problems (although uprated fuel pump and injectors may well be needed). AFAIK, keeping a close eye on air/fuel mix, boost pressure and the onset of knock are the main ways to ensure a safe motor.

annointed

Leeroy, do you also have a knocklink? Unless you get an A/F ratio gauge that cost over a grand, you really can't use it for tuning. And if its a light show style A/F guage, its worthless, except for vague tuning and to confirm the O2 sensor is good/bad. Too be accurate enough to tune with, you'll probably need a wideband sensor.

I think the important items if you're going to run 1.3-1.5 bar are a reliable boost controller, fuel pump/injectors, intercooler upgrade, KnockLink, and boost gauge (EGT, coolant temp, oil temp not a bad idea, either).

annointed

Oh, and your turbo will not be efficient at 1.5 bar, further aggrevating the air charge/knock problem. If you have a TD05, it is OK for 18 psi, but beyond that it quickly becomes inefficient, and you'd be much better off upgrading the compressor wheel to a big 16G wheel, which is designed to be more efficient than the stock small 16G at boost pressures above 18 psi. Or take it up another notch, and have the 18G compressor (600 cfm at 1 bar of boost) put in, which is efficient up through 25 psi.

Edit: And if you don't have a TD05, don't even think about 18+ psi, as the tiny stock turbos on '97+ Imprezas are way out of their range at 18 psi. Unless you're going FMIC and/or water injection. Even then, why not just upgrade the turbo?

[Edited by annointed - 10/30/2002 4:50:09 PM]

D8UGF

Annointed,

Bit confused here, can you clarify?, is a TD05 ok for 16psi? as u said in your first post ,MRT dont recommend 16psi.In your later post you say td05's are good for 18psi, anything beyond that they become inefficient.

Regards

Dougie

shiper

So is the turbo on my95 uk wagon a TD05 and is it going to be fine running 16 psi constantly???????????????????????????????

Tone Loc

iTrader: (1)

I'd totally disagree that TD05s are only good up to 18psi......

Tony.

Leeroy

I think the turbo became smaller on the 98 onwards MY. I have driven a couple of MY98's recently, and FWIW they don't seem as quick as the MY97 cars.
As far as inefficient turbos go, would you not expect to see boost tailing off at higher revs, combined with a rough torque curve? I have had mine on the rollers recently (Well Lane), and both the torque and power curves are very strong, with a nice flat section from 3500-5750rpm.
By what people are saying, it seems that uprating the turbo is safe, even though boost may be upped substantially above standard (providing fuelling is adequate).

Leeroy (a tad confused)

IainCam

Don't know that much more than you guys do about it but the TD05 turbo is what's fitted to MY94 and at least up to MY96 (possibly 97 too?). Both myself and Sasim have these turbos and at a recent RR day both got over 270bhp running at about 1bar, can't mind Sasim's figures but I got 287bhp but this was at 7030rpm (just inside the redline) proving that the TD05 just keeps pulling to the redline while it's still running under the standard fuel cut limit.

Downside of the TD05 is that nothing happens till about 2300rpm+ and even then it's not much. My graph shows that it takes to about 3700rpm to get to 100bhp but then it just starts climbing fairly straight all the way to the redline.

With the colder weather I've actually been hitting the fuel cut around 15.5psi a couple of times so I'd doubt very much if 16psi would do much damage, esp if you are running an AFR and knocklink (I plan on getting these fitted before getting the fuel cut lifter).

I'd planned on running around the 17-17.5psi mark as and when (if the afr/knocklink allows) as I'd heard that the earlier ones could take that amount without any problems? Maybe not after all then if MRT are saying 16.5?

Guess at the end of the day if you are running higher boost without using a different fuel map then you are taking a chance with it and it's up to yourself as to how far you push it. Like I said, I'd planned about the 17psi mark and then maybe later on get the ECU remapped/link to see what else could be done.

Katana

Beg to differ Tone, I managed to get mine running at 23 psi. A lot of people with MY93s have been using 20 ish psi too. I think its the engine that would go first before the turbo IMHO.

IainCam

That's a point, what's John Banks running his at? he's a TD05 now hasn't he?

Katana

Don't think so. I heard weeks ago that he was doing research on this board to find a replacement turbo as his TD-04 (I think, can't remember) couldn't hack it. When he says something like this, his car normally ends up with some kind of transformation.

IainCam

I thought that he'd changed the TD04 for a TD05?, maybe I just remember him talking about doing it that's all?

Katana

I honestly don't know mate as I've had a break from the Internet for ages. I'm sorta out of the loop of who's got what at the moment. Hell I still think that POC is still driving his P1...

JamieMacdonald

I'm sure my MY97 has a baby TD04, I run it at 15psi with an AFR but no Knocklink (yet) - call me 'crazy' but hey, that's just me....

PS I think John Banks has a hybrid VF series turbo or something along those lines.

J

Pavlo

td05 can run over 18psi, on david's car we saw 24psi at about 4500 on one occasion. However, holding it is not so good in terms of intake temps. But David's car has an FMIC the size of a bus, and water injection, which helps keep things under control. As mentioned, 550cc injectors were used, along with bigger, parallel fuel rails.

We also checked the fuelling on a wide-band lambda sensor throughout tuning. Runs about 11.5 on WOT once on boost, further refinement pending but time was not available.

Running high boost in the midrange is less of a problem, because the engine consumes less air, so the turbo doesn't have to work as hard (ie spin as fast).

To get back the original question, I would be a bit hesitant to run 16psi on a MY95 car, although the standard UK map is quite conservative. Fuelling will be very rich I would think.
Running a knocklink and gradually increasing boost in 0.5psi increments would be a good idea.

Paul