iv got a 93 wrx import.

thinking about trying to get a bit more power from it in the near future (after iv upped the brakes abit)

looking for about 280hp to start with, only thing its got at the mo is a hks mushroom filter which it had on when i bought it.

iv seen de-cat pipes for sale claiming a 30hp increase...surley that cant be right??

what exhaust would people reccomend? its got to be as quiet as possible as i cant stand a loud daily driver.

 

30bhp from slapping a decat on? No
On my 93 wrx i have a Revolution 2.5" (iirc) system which isn't very loud but does give a nice burble.

Powerwise it all depends on how much you want to spend really.
Upping the boost (manual or electronic controller) along with fitting an uprated fuel pump (and possibly a fuel pressure regulator) would be a start.

If you can afford it a remappable ecu/daughterboard is ,imo, your option as it can be mapped for any more mods you think of but they start off at about £500+

 

Sell the car and buy a STi, that will be the cheapest wayby far, trust me.
Even, or especially, a MY 99 or newer.

Edit: just sum the above suggestions up. (And the STi have parts you'll never get to upgrade on a WRX)

 

sellling it isnt really an option to be honest because i got it cheap and its completly mint condition so wana hold on to it.

wont just upping the boost make it run lean? or will the uprated fuel pump + fuel reg' stop that happening?

what sort of boost is safe to run?
is the OE ECU remappable?

thanks,matt

 

OE ecu isn't remappable but requires a daughterboard (approx £500) Enduring Solutions Limited.

Max boost is 1.1/1.2bar on the standard MAP sensor (most aftermarket chips will run 1.1bar).

Upping the boost should obviously be monitored properly by a quick session on a rolling road,the uprated fuel pump/fpr combo set up should stop any leaning out.
BUT don't forget your car is quite old and some of the sensors may not be working as well as they should.
Get rid of the HKS filter and replace either with a standard airbox or induction kit such as K+N or Apexi (normally people suggest this only when fitting a fmic)

 

The ECU gives fuel (injector duty) according to MAF reading, so upping pressure doesn't make it run lean. But you might hit top of MAP sensor, and very possibly fuelcut (when MAP sensor/ECU sees to high pressure).
If you would fit bigger injectors/fpr it *will* run even richer than original.
Fitting a freer breathing exhaust will make it possible for the turbo to keep boost higher up the rev-band, but more or less requires some boost control, otherwise it might spike to fuelcut.
Good luck!

 

To start with, i fitted a polar performance chip, and decat with stainless exhaust, this gave a noticable increase in power.
But, in the end this will limit what you can do in the future.
I ended up having the esl live ecu chip fitted/mapped with later map sensor and 440cc injectors. (see my profile for full spec), as i had reached the limit of the plug and play chip.
This cost £550 for the ecu, £60 for the map sensor, and £60 for the injectors.(all +vat)
The difference mas well worth every penny! Im running 1.35 bar.
This is also future proof, as you can re-map when required.

Mit

 

i think 280bhp is a good reliable amount to stick at for a 14/15 year old car so i would say cheapest option.
z4 ecu
walbro fuel pump
panel filter
decat exhaust
good service
around 280 bhp. cost around £500 plenty of used parts knocking about.

maybe polar performance chip mine made 292bhp with the above and chip

 

The chips the reason you got the 292bhp, the other mods wouldn't have got there without it!

 

as stated in my post around 280bhp without the chip
z4 about 255bhp
decat about 25bhp

 

no need to sell on mate can get more than enough power reliably with a few mods, ive got the polar performance ecu as mit mentioned very good for the money & a tsl group n back box & decat middle section sounds nice & subtle

 

is the z4 just a later more powerful ecu? would there be any complications using it in my 93 wrx import?

 

yes and no but if you want 280bhp then a remappable solution ,imo, will be your best (but more expensive route) although the polarperformance chips have proved on many cars their worth

 

You could always fit the polar chip, then if you decide you want more in the future, just sell it on. I ran mine for 7 months, and only lost £45 when i sold it on.

 

yeh think polar chip sounds like the best idea for the moment.so if i just got a chip and left everything else as it is what power do you think i would get? how easy are they to fit?

 

Dead easy to fit. Just remove the ecu from under the passangers carpet, pop the cover off, install the chip into the spare socket(most have a chip holder fitted, if not you'll need to solder one in, the chip comes with one just in case), and cut the J1 resistor leg to swop the map over to the new chip, then just put it all back together!
The chip comes with full instructions.
The chip will give 1.1bar boost, and adjust timing and fueling to match. The other benifit is it will de-limit the car from 112mph, and make the car safe to run on UK fuel.

 

ah right, didnt realise it would make it safe to run on uk fuel too.think il have to invest in one after christmas