sti69

iTrader: (1)

Hi guys,

I own a MY94 STi saloon which was running a SA ecu with no mods to the circuit board and that used to boost up to and hold at 1.1bar (15.9psi) fuel cut is about 1.2bar (17.4psi),anyway i bought an Z4 ecu (totally standard) and that boosts to 1bar (14.5psi) fuel cut at 1.1bar (15.9psi).

The mods are STi version 4 i/c, STi panel filter, lightened flywheel, de-cat down pipe and afterburner exhaust.

With using the Z4 the boost drops off to 0.8bar (11.6psi) when high in the rev range (about 6500rpm-7000rpm max) is this right?

Should i stick with the Z4 or go back to my original SA ecu also which is the best ecu to use ie.peformance/reliability/fueling?????

Cheers,

Paul.

sti69

iTrader: (1)

bttt...

rossyboy

iTrader: (8)

IMO there's no point in buying a Z4 for an early STi . Its mapped for a WRX with a lower rev limit and different spec internals. Also, a Z4 isn't expecting a de-cat.

You can either fuel the car with original ECU in place with 97/98 RON plus booster, get hold of a chip that maps for 97/98 and de-cat (eg ScoobyECU if it caters for STis) or replace with mappable ECU.

sti69

iTrader: (1)

Cheers mate,ive just put my SA ecu back in cos im sick of the boost being sooo low.

The car runs on optimax with o/b since i bought it a year ago and its always sat at 1.1bar with no problems .

Scott.T

iTrader: (2)

The SA should have the additional chip fitted to the ECU motherboard, probably with a sticky label on it covering the window.

I expect the map is very similar to the SB ECU from an STi 1 RA. Which does run quite lean at the top.