I been doing a lot of research on the VAFC because i was thinking about buying one and getting it dyno tuned. But the more i do research the more i find out that the VAFC is useless because it can control the air control but can not control timing. I also forgot where i read this info at but i read that even if you richen or lean out your fuel, there will be something to correct it anyways so you only get gains for a couple seconds.
can someone verify this?
i dont want to buy the VAFC, install it and drop 100-200 to get it dyno tune and in the end, i just have a really cool a/f gauge.
Last edited by nartnailuj; 01-26-2010 at 08:13 PM.
The VAFC is not useless. It's a permanent hack. The ECU does not re-learn the original settings. You can read more about how they work here:
Quote:
Originally Posted by Honda-Tech.com
A note on Piggyback controllers (like the Apexi SAFC and VAFC) versus Hondata: A piggyback fuel controller alters the MAP signal in order to fool the stock ECU into thinking the motor is under more or less load than it really is. This in turn will alter the area of the ECU maps the computer is using to choose how much fuel and timing to supply.
Preludes run rich using stock settings, so it's not a bad idea to lean it out some. Doing this will increase power and gas mileage. However, if you have a base model Prelude, I recommend just getting an OBDI ECU and a real tune. I only have a VAFC-II because I have an SH model (as the name suggests).
__________________
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
Hey kronn, i agree with you and that is why i was going to buy one but after i read this article, i was a little skeptical. I just want to make sure im not wasting any money on this device.
Hey kronn, i agree with you and that is why i was going to buy one but after i read this article, i was a little skeptical. I just want to make sure im not wasting any money on this device.
The reason people tend to accuse piggy back systems as "bad" is because they are essentially tricking the ECU and not actually a stand alone tune device. Tuned or connected incorrectly it could ruin an engine. But if everything is installed and tuned by a qualified individual/shop its fine.
For those of us with an SH, VAFC or Greddy Emanage piggy back tune devices are our only option if we intend on keeping atts. As atts requires the stock ECU for operation.
__________________
I design the world you live in.... Cheers for Industrial Designers!!
95 Integra LS <<<>>> 99 CBM Prelude SH
The reason people tend to accuse piggy back systems as "bad" is because they are essentially tricking the ECU and not actually a stand alone tune device. Tuned or connected incorrectly it could ruin an engine. But if everything is installed and tuned by a qualified individual/shop its fine.
For those of us with an SH, VAFC or Greddy Emanage piggy back tune devices are our only option if we intend on keeping atts. As atts requires the stock ECU for operation.
Good post. I too have an SH and honestly I prefer having the motor run as fine as possible much more than atts.
For those of us with an SH, VAFC or Greddy Emanage piggy back tune devices are our only option if we intend on keeping atts. As atts requires the stock ECU for operation.
Don't forget AEM F/IC.
__________________
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
We have smog laws that make it illegal and harder to use these ecu piggybacks. Then you have the more expensive and much more effective ECU's that are "stand alone".....having one of those in most other states is no big deal since there are no inspections.
However, part of the CA smog test is testing your ecu. These modifiable ecu's would not pass, so you must get someone to illegally pass you instead, which can be a big hassle and cost big bucks(depending on who you know).
That is why. I'd love to pay $500+ for a stand alone and get my car tuned to the way it should run....but I don't want to go through hell to get my car legalized.
oh damn. I was wondering if my car would pass smog if i got something for the ecu last night. haha
can't i just unplug whatever i have connected my ECU with before the smog check?
Can you hook up a "stand-alone" tyoe ecu, have full professional tune done. Then simply unplug it and put in a stock OBDII, get smogged, then plug in the stand alone and have everything back to the way it was(before removing the ecu)?
can't i just unplug whatever i have connected my ECU with before the smog check?
Quote:
Originally Posted by pIERCE
Can you hook up a "stand-alone" tyoe ecu, have full professional tune done. Then simply unplug it and put in a stock OBDII, get smogged, then plug in the stand alone and have everything back to the way it was(before removing the ecu)?
Yes
__________________
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
I ended up buying a vafc because im not planning on doing any major mods to my car, just bolts ons i/h/e. Nothing more. so i figure my best bet is getting a vafc. I could go the hondata route but it'll be more money dropped on something i cant use to the full potential because i got a stock engine, and no plans on going turbo.
So im guessing i could unplug the vafc before smog? im not going to splice my wires but use a tap in instead.
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.
Linear Mode
