White91Prelude

I have an SAFC1 that I am installing on my 1997 Prelude SH.

I have read through pages of searched "SAFC" and also read through the VAFC fact in the FAQ section.

I understand that the SAFC does not have the ability to change when VTEC engages, so I will begin HIGH value changes at the RPM increment that VTEC engages in. I will have a wideband.

Questions:
1. What is the consensus on exactly when VTEC engages? Knowing this will allow me to begin HIGH throttle value changes when I need them to.
2. Can I set my HIGH throttle value to, say, 80%? So that I cross between factory closed loop and adjusted closed loop based on whether I am going for WOT driving or partial?

Thank you!

Kronn 98SH

Concensus: VTEC is designed to engage at ~5250 RPMs. According to my tach, that's pretty much exactly when it did. However, according to the dyno, it was engaging at ~5000 RPMs.

Now, my best advice....put the SAFC on ebay and get a VAFC. The ability to adjust VTEC is huge. Plus, a VAFCII will give you more adjustment points. Also, don't hack your harness. Get a PnP harness.

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1988 Prelude S - victim of an 80mph backflip
1991 Prelude Si - sold
1989 Accord DX - impounded
1998 Prelude SH - totaled on 3/29/12
2006 CRF150F - sold
2006 YZ250F - sold

TypeT

if you had Base, much better way would be obd1 ecu & conversion harness
but since you have SH, is there any other choice than VAFCII

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Honda Prelude 1997 2.2 VTI

White91Prelude

Well crap. I just picked the SAFC1 up today for $100. I guess I can just sell the controller.

Kronn 98SH

I picked up my VAFC-II for $150 + $50 for the PnP harness. And that was like 3 years ago. You should be able to find one even cheaper than that now.

__________________
1988 Prelude S - victim of an 80mph backflip
1991 Prelude Si - sold
1989 Accord DX - impounded
1998 Prelude SH - totaled on 3/29/12
2006 CRF150F - sold
2006 YZ250F - sold

White91Prelude

What I don't understand is that, if I am only interested in tuning AFR for High Cam, why can't I simply begin tuning at 5,000 rpm and go up from there? I could use the factory VTEC engagement point and base the majority of my lean tune towards 5,500 and beyond to fix the rich vtec AFR I have?

indylude18

^You could do that, if you really wanted to. All that moving the vtec engagement point can do is help to even out the powerband a little.

Another thing to consider with the SAFC/VAFC is that they really only work at wide open throttle while the ECU is in a closed loop. You can tune your A/F ratios at partial throttle with them, but your ECU will eventually compensate for any changes you make, which essentially puts you back to a stock tune at partial throttle. Because of this, they both kind of suck, but because you have an SH your only other options for tuning are much more spendy (stand-alones like Greddy eManage or AEM EMS).

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Bluetop H23a Vtec Swapped NHBP '99 Base