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Old 01-13-2010, 12:57 AM   #23
Scooby Specialist
Member#: 226535
Join Date: Oct 2009
Chapter/Region: E. Canada
Location: Kingston, Ontario, Canada
1998 Impreza L (RIP)


So an Update...

Since my last instalment, I have swapped out the 1998 legacy 2.5 red top 270cc injectors for stock ej22 220cc grey top injectors modified to flow 390cc. I thought they would flow more than that, more like 440cc +, but in my emanage blue parameters, any more than a 390cc input causes the car to run lean at idle and cruise (Seeing STF's at +10-15 at idle and +20-37 during part throttle). With 390cc entered, I see perfect idling with 0 for the STF's, and part throttle is causing -10 - +10 STF's. For some reason though, 12 psi WOT to redline is making 10:1 and richer AFRs. To combat this excessive richness, I am removing 20-24% from the airflow map (MAF sensor) at 98-100% throttle across the rev range. I see ~11:1 - 11.7:1 AFRs at WOT now, right across the rev range.

I have also swapped out the 2003 WRX exhaust I was using, for a cat back true 3" id ebay exhaust. It is loud, but sounds awesome at WOT. No more bird chirping!!! I saw an excellent reduction in spool up time, and much better boost control. My homemade MBC now controls a perfect boost curve, spiking to as much as 14 psi before settling down to ~11-12psi to redline. I also saw a reduction in fuel consumption (believe it or not) and a much harder charge to redline...I said haul ass before, but it really does!

As far as overall tuning goes, aside from the fuel injection changes I’ve already detailed, data logging with the emanage shows a peak MAF voltage of 4.78v, starting at about 4.6v at ~3800 and reaching the peak just before 6200 RPM (Which is right around fuel cut on the 1998 EJ22). The max voltage the ecu sees from the MAF is about 3.63v, after the emanage has done its trickery. I am pulling 8 degrees of ignition timing at 4.7v MAF voltage; I may increase that, but so far so good.

Remember the idle issue? Its gone now, hasn’t resurfaced since before the injector change... Even with my Atmosphere venting WRX BPV.

Almost all my Subee knowledge came from this forum, COUNTLESS hours of research, and a few well placed PM's not mentioning any names (Thanks REDDEVIL, Kevin Thomas, Abest10, and Philsine!!)... This project is not done yet, always more to optimise, tweak, and upgrade.. I have a set of ej22t pistons in the mail to bring the compression down to around 8:1, then I can really turn up the boost! That will have to wait till spring though...Pics to follow!
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Last edited by cdnsigop; 01-13-2010 at 07:18 AM.
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