elv73

Hi everyone,
I have a completely standard 93 WRX and was considering fitting a dawes device. My question is will this give a noticable improvement in performance without any other mods and what would be a safe pressure to set it at?
I have a boost gauge fitted and it is currently boosting at around 0.75 Bar(11ish p.s.i ?) which from what I can gather is about standard for this model. Could I up the boost to say 1 bar without any other mods or would this be too high?

Also one more question, the boost doesnt seem to come in until 4000 rpm is this normal and is there any way of getting it to boost slightly earlier..say around 3200???
Cheers
Lee

VAL113R

I'm sure someone will be along to answer your question fully

I wouldn't use the dawse device to up your boost. You would be better using a digital item such as the Apexi AVCR

I personally wouldn't up the boost without supporting modifications to compliment it. The timing and fueling should be change too, which would be better done via something like an Apexi Power FC

4000rpm sounds just about right for your turbo. You've got to remember it's nealry 13 years old. I think there are ways to help it boost a little earlier such as lag your down pipe but sure someone will confirm that

cheers

Isoproturon

Mine is a 93WRX with cat-back exhaust and possibly a panel filter. The boost gauge reads 1.0bar on mine when thrashing it... but you seem to suggest 0.75 is about right for a std. engine.

So I am wondering if mine has been modified in some way.

What is the std. boost on a 93WRX ? Any ideas anyone ?

69WRX

Rather than just up the boost, you would be better off getting a Z4 ecu.
Had one on mine and it ran @ 16psi.
This is a safer way to do it as fuel etc will be adjusted accordingly by the ecu.
This ecu can run on optimax without octane booster, and is available for about £150.

elv73

would I need any other mods along with the Z4 ecu or would the standard engine run 16psi boost ok with the ecu taking care of fueling etc?
Also is it just a plug and play swop or would it need setting up?

jonny gav

iTrader: (1)

Hi Lee, a dawes device or gbe boost controler is a good VFM mod.

with your standard ecu you should be able to raise the boost up to around 13psi without hitting fuel cut.

but thats not the best thing about the dawes device or gbe, it helps spool the turbo much quicker (quicker than any electronic controller) and holds the boost solid to the red line.

if you do fit a z4(well worth it) you will be able to set the boost at 15psi as the fuel cut is at around 16psi.

hopes this helps clear up some of your questions

69WRX

No other mods required, just plug & play.
Not sure if all Z4s run @ 16psi, mine certainly did. Think 14psi is more common, but it will be a significant improvement.

elv73

Would running 13psi on a standard engine with no mods (fuelling etc) do any damage to it?
I will seriously consider the Z4 after christmas but as cash is a bit short at the mo the dawes option seems a good value for money stopgap providing its not gonna knacker me engine!!

elv73

What year/model uses the z4 ecu as standard? (just so I can be on the look out for any that are breaking for spares.

vessy

I have been running a Z4 ECU in my UK Series Mcrae, it's a very noticeable improvement, i have boost problems at the moment so i've refitted the standard UK ECU, problem is still there so it's not the ECU. Unfortunately i dont have a boost gauge fitted so can't give you exact figures, well not until the weekend anyway.

I found this little gem of info on the net, this should answer the boost questions.

Boost Targets & Fuel-Cut Limits
WRX/STi Saloon ECU's 2C, U8, W6, W9 - As above, 11.47psi held to redline. Fuel-cut 14.57psi

WRX (1995/96) ECU Z4 - 12.71psi, dropping to 11.78psi @ 6600rpm. Fuel-cut 15.65psi.

UK/Aus/Euro ECU's V7, 7D and 6D - 11.47psi, dropping to 9.47psi at 6600rpm. With Fuel-cut @ 14.87psi

UK Prodive ECU - 13.33psi (peaks to 13.64 @ 5600rpm, drops to 12.71psi @ 6600rpm). Fuel-Cut 15.65psi.

STi RA (1996) ECU 7K - 13.17psi (peaks to 13.64psi @ 5800rpm). Fuel-Cut 15.96psi.

WRX Wagon ECU V9 - 10.55psi dropping to 6.84psi (starts to drop @ 5000rpm). Fuel-Cut 13.79psi

Z4 and UK Prodrive map are near identicle, with the Prodrive Map running slightly more boost.

IMHO the Z4 ECU is the best stock WRX ECU you can get, as it has much tidier fuel and igntion maps. Comparing it to the earlier ECU's I'm suprised the earlier cars run at all.....

A Z4 ECU will also run fine in a UK and give near UK PPP performance.

jonny gav

iTrader: (1)

the z4 was on the my95-96 wrx.

to be on the safe side always run a high quality fuel like shell optimax or bp ultimate, this will be fine with your setup.

elv73

Thanks for all the info guys, only had the car 4 weeks (was only imported to uk in may)so trying to find out as much info as possible.

Lee

vessy

Just keep looking on Ebay, that's where mine came from, or wait till i convince the missus we really need a UK300, then you can buy mine!!

Might have a long wait though.