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Discussion Starter #1
Anybody here used VTEC AFC or VTEC AFC-2 ?
The official site says that VTEC AFC has not been tested yet for i-VTECs. But couldn't find any argument for VTEC AFC-2, the second version.

Thanks



A'PEX introduces the first digital fuel computer that combines fuel computer functions with a VTEC engagement controller.

The Apexi V-AFC features a user-definable, eight-point, adjustable fuel curve that can be set in 500 RPM increments.

The range of fuel adjustment is +/- 50% at each of the user-defined setting points. The Fuel Adjustment function considers wide/narrow throttle and low/high camshaft settings, from which four different fuel maps are created (widelow, wide-high, narrow-low, narrow-high).

The integrated VTEC Controller adjusts the point at which the engine switches from the Lo to Hi cam during acceleration, as well as when the engine switches from the Hi to Lo cam during deceleration.
 

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The Apexi VAFC 1 is not designed for i-VTEC engines, it's only suitable for non i-VTEC engines. Thus the more advanced VAFC 2 was introduced/released specifically for the second type of distinctive engine type which also happens to be compatible with non i-VTEC engines as well.
 

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oh well .. ~~ even if it's compatible with i-VTEC ~ how do u kno wut kind of setting is good for the car and how to get some performance gain with these kind of products that matches the money u spent ~ .. ~~ i had been thinking of buying such parts and did find one that compatible with i-VTEC ~ but there is no one who can really make a good setting with our K24A2 which most ppl only kno how to play with the K20A2 ~ the only thing u can do is probalby lower the VTEC pnt and gives more oil ~ anyway good luck ~
 

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Nightdriver ... You don't understand my first statement?

VAFC - No i-VTEC compatibility.
VAFC-II - Yes i-VTEC compatibility & DOHC VTEC compatibility.

And this piggybag device requires quite a bit of wiring. A good tuned setting can net between 5 - 15 bhp at the wheels. The optimal settings on changing VTEC engagement point and adjusting fuel settings needs to be done on a dyno for exact tuning specifications by an experienced tuner of this device. However, I like Andynolife see no justification on this product.
 

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Discussion Starter #6
Noel sorry for misunderstanding :)
Actually my Euro Accord has K20A which is same as the ones used in RSX. But you are right that it should be tuned by an experienced tuner. I actually find interesting to set VTEC point. Instead of 4800 rpm, setting 2500 rpm would be better for acceleration in low rev. The thing I'm interested is that it's adjustable, and whenever you want you can choose low fuel-consumption or high performance by using a button.
 

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Noel said:
Nightdriver ... You don't understand my first statement?

VAFC - No i-VTEC compatibility.
VAFC-II - Yes i-VTEC compatibility & DOHC VTEC compatibility.

And this piggybag device requires quite a bit of wiring. A good tuned setting can net between 5 - 15 bhp at the wheels. The optimal settings on changing VTEC engagement point and adjusting fuel settings needs to be done on a dyno for exact tuning specifications by an experienced tuner of this device. However, I like Andynolife see no justification on this product.
haha .. thx for ur common ~ Noel ~ but u r really the technical guy man .. ~~ i didnt get ur first post at first too haha .. ~~ it's good to have u here to clear things up ~ :thumbsup:
 

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Actually, it's not so simple as lowering the VTEC engagement point to whatever you like and it'll activate like it's on boost. Alot of people who have minimal understanding of how VTEC works think it's like running a turbo or supercharger setup where you can simply dial up or down the boost and it's an instant power kick.

In short, the VTEC cross-over engagement point indeed can be lowered by realistically, you'd probably best drop it 500 - 1000 RPMs from factory and matching the required fuel map settings to accomodate the new VTEC cross-over point. Even if you put it down to 1500 RPMs to have VTEC activate, it still won't activate because the required oil pressure hasn't been reached.

Simply lowering the VTEC point won't increase any power, nor lower fuel consumption if you raise the VTEC point. The mechanism that controls the VTEC cross-over point is the VTEC solenoid along with oil pressure found in the engine bay. When it reaches an X amount of RPM controlled by the ECU to activate VTEC, the VTEC solenoid will base on exact required oil pressure and activate VTEC accordingly, not enough oil pressure, no VTEC activation regardless.

Of course, the factory setting has been setup to be immaculate and most ideal for power delivery. Even Mugen or Spoon with their replacement N1 ECUs with slight VTEC engagement point changes require a complete new fuel map redesigned and rewritten just to accomodate that lowered 500 - 1000 RPM change. Only then will you see true power gains because ignition timing, fuel pressure, oil pressure and other variables have been accurately matched to suit the new VTEC cross-over point.
 

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Discussion Starter #10
Noel thanks...
Actually I'm sure it's not that easy to get power just adjusting the VTEC point. But you are saying that it's possible to do so with this gadget right? Of course testing with a qualified tuner...

Do you know any internet site that shows Honda engines, VTEC technology, tests and so on with simple language? I mean not so technical....maybe charts which makes it easy to see the principle...
 

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This gadget will indeed allow VTEC engagement point modification however do note; The VTEC cross-over engagement point indeed can be lowered but realistically, you'd probably best drop it 500 - 1000 RPMs from factory and matching the required fuel map settings to accomodate the new VTEC cross-over point. Indeed, only a qualified tuner with dyno time will see some sort of gains.

As for your second part of the question, No real hard data. Most discussion and knowledged base information is found on Honda related forums from individual tests and results.
 

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So for a 300 dollar mod, plus 100-300 bucks for tuning/ dyno runs (estimate) = 600 bucks, and a gain of somewhere between 5-15 hp, how could this not be a good investment in a mod in comparison to an exhaust?
 

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well ... exhuast adds apperance and sounding ~ ...
where u wont get anything like that with VAFC-II ~
more bling bling fator .. ~ :D not quite the same thing .. ~
 

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15bhp is a bit over realistic, if anything ... More like between 5 - 10 bhp when tuned optimally to suit your current settings. I personally don't like piggybag devices much like Andy. Electronics control a great deal of the engine management, and it's not something I'm willing to risk especially engine damage if the device is not tuned properly. Not to mention, the settings become almost immediately redundant when you start adding more power modifications.
 
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i have a JDM Fields on my SOHC Vtec Sol, i ahve had noticeable gains in 1/8 mile time with minor mods, "high Flow cat, Cat back, and CAI. i can also tuen it for better Fuel consumtion, and it actually works.. with out detonation. once it detonates it throuse a CEL so you know you have gone too far.. i was able to get my lowerd Sol 38mpg with a CAI, High Flow Cat and Greddy EVO catback system.. a VAFC II is in the works after i get my TSX.. Still waiting.. once i get it, i will post my tuning #'s and what i have installed so you too can have some better settings.. Just my 2 Cents
 

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Making changes based on detonation and CEL indications? Man, that is highly unacceptable to me. Do you know how much wear and tear you'd have done unknowingly?
 
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In theory, since the VAFC is about changing the vtec engagment and air/flow ratio. Can't I use VAFC1 just for the A/F function and not mess with the vtec engagment?
 

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cmf said:
So for a 300 dollar mod, plus 100-300 bucks for tuning/ dyno runs (estimate) = 600 bucks, and a gain of somewhere between 5-15 hp, how could this not be a good investment in a mod in comparison to an exhaust?
If that is the case then hondata is a better mod.
 

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V-AFC 1 is not compatible with i-VTEC engines. Hence V-AFC 2 was introduced shortly after. Of course, the V-AFC 2 can do everything the V-AFC 1 do as well. While comparing Hondata and the V-AFC is very different. One is a flash/reflash while the other is a on-demand/on-board tuning device.
 
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