what does a V-AFC do? - Honda Prelude Forum

C.U.Lata 2 · 02-01-2002, 12:45 PM

I have heard of it but in an SS prelude what is its purpose?
Thanks

payyourtoll · 02-01-2002, 12:50 PM

5 spd or SS....works the same. Basically, V-AFC allows you to change your vtec engagement point and to adjust the air/fuel mixture introduced to your engine.

C.U.Lata 2 · 02-01-2002, 12:52 PM

And is that good to have???

Greek Lude · 02-01-2002, 12:53 PM

YES

C.U.Lata 2 · 02-01-2002, 12:58 PM

What are the benefits for it?
I just have no clue about it.

payyourtoll · 02-01-2002, 01:01 PM

Quote:

Originally posted by PreludeGurl
What are the benefits for it?
I just have no clue about it.

Stock vtec engagement point is high. By lowering it, you not only gain power quicker, but you have a smoother power curve throughout the entire band.

Preludes also run very rich (high ratio of fuel to air). With the vafc, you can lean it out (add more air) for better balance.

C.U.Lata 2 · 02-01-2002, 01:06 PM

Do you normally run into problems with having it?

payyourtoll · 02-01-2002, 01:10 PM

Quote:

Originally posted by PreludeGurl
Do you normally run into problems with having it?

I have heard of people having trouble with the Fields vafc. Ive had mine installed since I bought the car and no problems. Usually any issues with the controllers are related to incorrect wiring or dip switch settings.

Greek Lude · 02-01-2002, 01:17 PM

Get the APEXi VAFC. I'm very pleased with it.

C.U.Lata 2 · 02-01-2002, 02:08 PM

So it will be much faster with this thing?
Cool
I'm gonna look into it.
What do they sell for?

payyourtoll · 02-01-2002, 02:10 PM

Quote:

Originally posted by PreludeGurl
So it will be much faster with this thing?
Cool
I'm gonna look into it.
What do they sell for?

Yes, your car will be faster. You can find the Apexi for 300 and the Fields for 225.

ElectronBlueSH · 02-01-2002, 02:17 PM

Do you need to tuned you v-afc when you get it, and how much does it usually cost to tune? Thanks

Keith · 02-01-2002, 02:20 PM

People who have VAFC in their Ludes have seen anywhere from 8-10whpr gains.. depending on what mods you have already...

payyourtoll · 02-01-2002, 02:20 PM

Quote:

Originally posted by ElectronBlueSH
Do you need to tuned you v-afc when you get it, and how much does it usually cost to tune? Thanks

You should tune it to get the most gains from it, but you dont have to. I personally have never tuned my car. Usually people wait until they have added to their stock engine (cam gears) to tune along with the controller.

Dyno tuning costs differ depending on where you live. Around here, it generally runs 125/hr.

97blacklude · 02-01-2002, 03:11 PM

Quote:

Originally posted by PreludeGurl
Do you normally run into problems with having it?

If problems do occur it will void your warranty

I don't suggest u buying it right away anyways. The purpose of this mod is too get the crossover for vtec adjusted to make the most out of the mods THAT U ALREADY HAVE

I don't c if this is the only mod other then just lowering the vtec but don't expect any gains just b.c u lower your vtec crossover.

The mods i suggest u do r the following: This is just my pref.

AEM CAI
AEM pullies- A MUST FOR SS's
DC CC Header
Any exhaust- Thermal

Then Apexi VAFC

ThePreludeKilla · 02-01-2002, 03:16 PM

I think its a very good investment but i would get CAI first.

Turbo Lude SH · 02-01-2002, 05:21 PM

It's a very useful tool for fuel tuning. It allows you to adjust injector duration/pulsewidth throughout the fuel curve. It's got settings for Hi and Lo throttle as well as off VTEC and on. It lets you change your VTEC engagement point as well and fuel correction points for your VTEC crossover point, something the Field's controller doesn't have and is VERY important.

By just intalling it you'll see no gains. You've got to tune it. Running 7-10% leaner is about where I came out to before going turbo. Oddly enough, I'm running -38% now. Damn 440's are too big.

briton2k · 02-01-2002, 09:27 PM

Turbo Lude SH, If you dont mind me asking I am curious on your VAFC settings. I just got mine dynoed yesterday and and way a little sketched out with how much we leaned it out. According to the wideband air fuel meter we had hooked up to it we had the air fuel just about perfect. I was putting down 171 whp and 138 ft lb torque. Not bad with only having I/H/E & P. I also have an 2001 Prelude so I want to compare mods and vafc settings. If you want to share them but dont want to post them you can e mail me @ cpcalkins@sc.rr.com.

Thanks,

Craig

97blacklude · 02-01-2002, 10:05 PM

Quote:

Originally posted by briton2k
Turbo Lude SH, If you dont mind me asking I am curious on your VAFC settings. I just got mine dynoed yesterday and and way a little sketched out with how much we leaned it out. According to the wideband air fuel meter we had hooked up to it we had the air fuel just about perfect. I was putting down 171 whp and 138 ft lb torque. Not bad with only having I/H/E & P. I also have an 2001 Prelude so I want to compare mods and vafc settings. If you want to share them but dont want to post them you can e mail me @ cpcalkins@sc.rr.com.

Thanks,

Craig

If u want i can email u mine

CornerFreak · 02-02-2002, 06:01 AM

Quote:

Originally posted by Turbo Lude SH
It's a very useful tool for fuel tuning. It allows you to adjust injector duration/pulsewidth throughout the fuel curve. It's got settings for Hi and Lo throttle as well as off VTEC and on. It lets you change your VTEC engagement point as well and fuel correction points for your VTEC crossover point, something the Field's controller doesn't have and is VERY important.

By just intalling it you'll see no gains. You've got to tune it. Running 7-10% leaner is about where I came out to before going turbo. Oddly enough, I'm running -38% now. Damn 440's are too big.

i thought the ATTS couldnt handle the turbo...so everyone says...how are you doing this...what are you boosting? did you disable your ATTS? hopefully you can add some insite...im going to PM you too...thanks in advance