01-01-2009, 02:34 AM
Join Date: Apr 2006
Location: VIRGINIA BEACH, VA
Total Cats: 145
You need AT A MINIMUM, a fuel pressure gauge and the ability to get 100psi of fuel pressure in the rail to push 10psi. That means a Walbro 190lphHP. You can go to the RC website and do the math to see how much fuel pressure you need with those injectors, but since I ran the exact same setup, it's about 90psi. The stock fuel pump on-a-good-day will push 80psi. The Walbro190lphHP will do over 130psi which is good enough for 15psi+. Don't worry, you run out of timing control well before you need that much fuel. There are dozens of thread on how to install a fuel pressure gauge on the rail or on the fuel hose.
Set your BEGi (as per the instructions to 48psi @ ~0", I think) and monitor both the fuel pressure and AFR when you're on the dyno. Adjust the rate-of-rise until your fuel curve is optimized. Due to the unchangable fuel curve of the stock ECU, you will run rich after tip-in (because of the 02clamp) then head for lean-ness in the midrange, and then run pig rich on the top-end. This is safe! Trying to lean yourself out a little on the top-end to maximize power up there means running too lean in the midrange. Adjusting your 02clamp onset can help a little, but after you hit max-boost in the midrange, the stock ECU simply can't keep up no matter how much fuel pressure you run... and when you hit the magic 5500rpm fuel extravaganza, you don't want all that pressure. In any case, bandaids are limited FUEL-WISE to under 15psi with a small'ish turbo.
Bipes: if you're running 93octane and have an intercooler (HINT: put that shiz in your signature), then initial BASE TIMING SHOULD BE 14*. Set the Bipes to pull 10* total starting at 2000rpm, with 1* for every 65*(winter) and 30*(summer). LISTEN FOR KNOCK. Each run you do AFTER YOU GET YOUR FUEL UNDER CONTROL, pull less timing, and start the pull later in the RPM band. THE INSTANT YOU HEAR KNOCK (as long as your fuel curve is still looking good) ADD 1* TIMING BACK IN, AND RUN 1psi LESS BOOST. On a 1.6@12psi with decent bandaid tuning running a small T25, you should see in the 180-190whp range. You can get 200whp with a big exhaust and a few more psi of boost if your fuel curve looks like it can handle it.
With a GT2554, you might get into the 220whp range with a perfectly tuned bandaid setup, but I don't know many bandaid guys running a turbo larger than that. A BEGi "S" kit w/2560 and IC option is still probably limited to no more than 220whp (even on a 1.8) if you had the Walbro and larger injectors +o2clamp... the limitation again being timing.
1.6 SR20 T25 w/Bipes/o2clamp/310's/Walbro190HP/BEGi 2025
I could get 14psi boost with a decent fuel curve at 100-110psi fuel pressure.
Base timing 14* w/Bipes pulling 7* starting at 3000rpm and 1* per 30*F... that got me 200whp with a 2.25" Borla.