I finally got my new B&M FPR after the piston snapped from the nut being too tight on the old one.
I'm looking for a bit of guidance as to my fuel pressure and my tune. How dependent is my AFR tune on my FPR? (as compared to injector pulse and duration).
My plan is to hopefully keep everything exactly the same as it is now and then maybe up the pressure. My tune is now a little off because of the Comptech Icebox addition. I have perfect AFRs at 3/4 to 7/8 throttle...but I'm too lean at sudden WOT.....I'm fine if I ease into WOT.
So I'm thinking I will get the car up to operating temps...and observe my idle fuel pressure from the gauge (it's around 37psi). Then I'll install the the FPR, and try to screw the piston in to around the same depth as it was before, and then adjust it without the vacuum connected until I reach the same idle fuel pressure.
Next, I want to bump up the fuel pressure to 40psi, and then see if my AFRs come down to 13-13.3 at WOT...Will I mess with my tune if I try to increase my fuel pressure without altering the tune?
Thanks for any input. Once I get my laptop-to-wideband hookup working, I'll post my AFR graphs.
What are you using to fine-tune your AFR? It all depends on that. For example I'm running a whole 47psi on my LS, but my S-AFC leans this out quite a bit at high rpm. But yeah, if you tuned at XXpsi and change it from what was ideal, it's not going to be tuned quite perfectly anymore. An intake shouldn't make a huge difference though, so I'd concentrate on getting a good AFR at WOT and high rpm and make sure you don't run too lean.
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Yea, before the icebox, Uberdata had me pegged at 13.1-13.3 AFR at WOT. After I installed the icebox...I'm hitting mid 14s at WOT. As I let off the gas from WOT...but still accelerating, I hit perfect AFRs. Also, if I ease into WOT, the AFRs are fine. But if I launch it, or just hit it, it's way lean.....but it has been getting better over the past month.
I was just thinking if I up the pressure 3-4 psi, it would for sure be safe at WOT. When I first installed the B&M FPR, I didn't need to match anything as we were at the dyno and we were playing with it anyways. Now, I have to make sure I get it pretty quickly, or the motor is just going to fall flat on its face. When I get my laptop hookup working, I'll have a better idea of what my AFR curves are really like throughout the powerband.
3rd gear high rpm: AFR pegged at 13.1.
2nd gear high rpm: AFR goes from 13.3 to 12.7 at top end.
1st gear: AFR mid-end at 13.9 to 13.6 top end.
Not sure why it's that different in each gear, but at least I can just mash it WOT, and the AFR is the same as when easing into WOT. (Not sure if this matters, but I was using the stock OEM FPR spring before because the one in the kit was bent...and they never sent me a new one after they said they would)
I still have to call tech support for my laptop hookup, and once that's done I'll post graphs of my AFR for 1st, 2nd, 3rd throughout the powerband.
Also...not sure why this is the case, but now, my idle is PERFECT at around 700-800rpm. Before, it had the annoying up and down fluctuation between 1200 and 1450rpm. Could I have had a leak somewhere in the FPR/Vacuum setup before?
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