i recently found that about this so forgive me if this was last week's news... if you go to http://www.apexi-usa.com/tech.asp, it says:

Q. VAFC: Will the VAFC work on 4 cyl. Accords?

A. No. The VAFC will not work correctly on 4 cyl. Accord models. 4 cylinder Accords incorporate a slightly different method of VTEC control causing the engine to hesitate at approx. 5000 RPM when the VTEC engagement point is changed. The VTEC AFC will work correctly on 6 cyl. Accords.

Please double check our Documentation/ VAFC Updates page for the latest VAFC application charts.

i saw the hesitation at around 5000 rpm on my dyno graph so i rewired the vtec solenoid and vtm wire back to stock so that the vafc would run like a safc... but there is still hesitation on wot/full boost... like the car pulls but then it's struggling in the high end like there's a speed governor... more like a boost governor... any ideas..?? some say it could be spark plugs or distributor... i'm getting msd btm installed and car retuned monday-

 

Works on mine.

 

I've never heard that before. On their site, the V-AFC is said to be compatible with Honda VTEC engines.

 

I read that also, though the V-AFC works prefect on my 2000 accord F23.

Though make sure you have the Vtec engagment no higher then 3800 rpm


[Modified by 3700 Vtec, 11:52 PM 2/8/2003]

 

accordexchange: It will work on 5th gen

 

accord94dx have vafc on his 5th gen..perhap im him for more info

 

If there were a problem I would think it would be with the f23 and what not obd II cars.

 

weird-i called a'pexi usa and they've confirmed the problem in detail... when i had the vafc when i was NA (intake and exhaust), everything "felt" okay... but with turbo i can feel the hesitation... niedejb, what is your lo to hi and hi to lo vtec setting..?

 

lo-hi 3100
hi-lo 3200

Setting any higher just lost me power until engagement.

 

I checked my dyno graph, there was a slight dip in power at 4500.

 

It's only really a problem on The F23 which has a variable engagement point vtec x-over. just don't have the vafc control the x-over and you will be fine.

 

Jweller, so the F23's have some type of i-vtec? Mine seems to be running fine.

 

variable vtec...

cool but not kinda.


[Modified by twkdCD595, 12:59 PM 2/9/2003]

 

that doesn't make sense... you mean lo-hi 3200 and hi-lo 3100 right..? or is it lo-hi 3100 and hi-lo 3000..? cause the hi-lo can't be higher than lo-hi... "The Hi to Lo (deceleration) rpm setting cannot be set higher than the Lo to Hi (acceleration) setting and the Lo to Hi (acceleration) rpm setting cannot be set lower than the hi to Lo (deceleration) setting."

 

Yeah.

Got them backward.

The lowest it can go in other words.

 

the adjustment range is between 3000 - 7000 rpm in 100 rpm increments... the lowest it can go is lo-hi 3000 and hi-lo 2900 if i'm not mistaken...

 

not really i-vtec. just a variable engagement point. it will engage as low as 2300 rpm anywhere up to 3500 (or 3700 i forget exactly) x-over point is determined by the ECU based on MAP sensor and throttle position. If your x-over is set at 3000 you are crossing over late some of the time, and early some of the time. F23 vtec is more for lean burn and fuel economy, not so much for power.

I don't doubt it runs fine. most dynos I've seen don't start below 2000 - 2500 so you probably never see it, and if you are just putting around town, it's not really an issue. best way to tell is if when your motor switches to the high cam, you get that "mad crazy Vee-tech power yo". that pretty much means it is starving for air. when you switch to the high cam you suddenly get more air and boom, you make more power. The Accord is supposed to have a smooth x-over and even when it is pretty highly tuned, the stock cam will still be pretty smooth

the bump at 4500 is fuel related. the stock ECU fuel maps get more aggressive around that point.

 

the v-afc never worked right on the F22b1. it bogged down and ran rich. i called apexi about it and they said it's not been tested or approved for our cars, but it can work.

it works great on the h22 though.

 

It works fine on my 97 EX .. F22B1 here is my dyno ...

AccordExhange and I had a conversation the other day, I wonder if it is due to the fact that his car is auto .. hmm.

 

The Apexi VAFC did in fact work fine on my car. A 94 EX automatic. It controlled my vtec crossover point and worked flawlessly AFTER IT WAS HOOKED UP PROPERLY. When I went by Apexis wiring diagrams it did not work. I did some more research and found out the correct wat to wire it. The info is in the archives here on H-T. Just search VAFC in the Accord archives.

 

Good point. Heres what I've posted here before. Its what I used on a OBDII F22b1

Heres an email I sent regarding the F22B SOHC VAFC install:
OK. All of these will be looking at the wires with the connectors in the
> ecu. The top will be the part with the push tab.
>
> The Red and orange both go to the yel/blk wire on the 32 P connector #11 top
> right corner.
>
> The Blk and Brn both go to the Blk wire just to the left of the #11 above.
> Note the Brn wire needs to be closer to the ECU.
>
> The Grn wire goes to the 32P connector Yel/Grn Wire #20. This is down one
> row and left 3 columns. It should be the one with nothing in the row above
> it (an empty spot).
>
> The grey wire goes to the 16P connector (the smallest) Red/Blk wire. In the
> top row all the way to the left.
>
> The Blue wire is not used
>
> The pink wire goes on the car side of the cut 32P connector #8 Grn/Yel wire.
> Its the wire two to the left of the Blk wire for the ground. The Purple
> wire goes on the ecu side of the same wire. Make sure they dont connect
> bypassing the VAFC.
>
> The White wire goes on the car side of the cut MAP sensor wire. This is on
> the 16P connector white/yellow wire two wires to the left of the Throttle
> Positioning Wire. The ecu side of the cut wire should get the yellow wire
> from the VAFC.

 

That's the info that I went by to install mine. The only thing different I did was I had to hook up the blue VTM wire. When it wasn't hooked up, I went into limp mode. Hook that wire up according to Apexi's diagram.

Edit: Thanks niedejb



[Modified by Stew Pidasso, 6:16 PM 2/10/2003]