Tuning for power

[pickens]

So far, I can tune in my injectors pretty well using just an AFC and pocketlogger. Right now, I tuned it for 17psi on my small 16g and stock smic. I get about 18 degrees at 7k with no dips in the timing curve. I'll probably richen it up a little since I'm at the lean/knock borderline and the summer temperatures are coming. However, as we all know I can't log injector duty cycle on a 2g. I feel the car can make more power if I up the boost because I should have enough fuel for it (RC 550cc). But it is hard to tell if raising the boost will yield more power safely. Sure I can tune for timing, and richen the fuel if it knocks at higher boost. But, I sort of think that may not yield more power simply because I may need to richen it up alot more than optimal A/F ratios to control knock. So how do you street tune to find the max power out of the setup? Maybe only on a dyno w/ a wideband? Anyhow, I'm itching to run 19psi on 91 pump, but if I tune for timing to please my little ecu, this may not make anymore power than 17psi, right? Also, I've heard that 2gs should tune for around 16 degrees at 7k, any opinions on that.

 

[Blk_99gst]

More air will give you more power than timing advance will. I should say more useable air; you're borderline on usable/cold air with the stock sidemount and 19psi, especailly with summer coming up. The best thing to do is get a fmic.

I would say set the boost that you want to run (19psi), and then tune timing and o2's to that. You make only get 16deg of timing instead of 19 at the top, but you will be faster because of the more air.

I recently went to the dyno with some of my friends; had a great time. Saw how invaluable tuning with a wideband is. 2 people picked up 8 and 11 wheel horsepower by tuning for an 11.5:1 air fuel curve, and there was still some more room to tune but we ran out of time. I just sucked it up and bought a wideband, so no more guessing with the pocketlogger. I think my pocketlogger to see timing and a wideband will be a killer combo. For you, I would probably go for a fmic before a wideband; you'd see more benfits from a fmic.

 

[12's]

You will definitly heat soak at 19 psi on a stock 2g ic. They have very small cores to them. I don't think that you will be able to tune 19psi on 91 octane without a FMIC or MKIV ic. I ran 20-21 psi on my stock 1g ic but it was 40* out and I was running 93 octane. You can try it though. 17* of timing would be good enough for me. I wouldn't go messing around with everything to drop 1* of timing off your logger. I would wait and go to the dyno to tune more accurately.

 

[pickens]

Well... I attempted to run 19psi, and the car didn't get any faster. I tried adding fuel, but it still didn't "feel" faster. My timing would be okay on one run, and then all over the place on another. My karman reading went from 1800ish to 1900ish though. So it was definately injesting more air. For the most part I was able to still get decent timing (17* at 7k but only 12* at 5.5k) but like I said the car didn't feel faster, and my track times last night proved that it was running a little slower. So, 17psi it will be until I upgrade the IC.