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Vafc in a GD3

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Old Oct 19, 2008 | 11:19 AM
  #1  
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Vafc in a GD3

Has anyone tried tuning their Fit with an Apex-i VAFC (I or II)? I've been wanting to tune with it, but I'm not quite sure if it's compatible.
 
Old Oct 20, 2008 | 04:47 PM
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Up!!

I'm interested too!!!

Marko!!
 
Old Oct 21, 2008 | 09:49 PM
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From my understanding, the "vtec" in the L15A isn't 'true' vtec in that there's no actual cam changeover, rather I think some valves close/open in some fashion.

I'm no engineer, so my babblespeak could be completely off......but I don't think a VAFC will do anything.
 
Old Oct 21, 2008 | 09:52 PM
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Originally Posted by chimmike
From my understanding, the "vtec" in the L15A isn't 'true' vtec in that there's no actual cam changeover, rather I think some valves close/open in some fashion.

I'm no engineer, so my babblespeak could be completely off......but I don't think a VAFC will do anything.
VAFC isnt only for controlling VTEC crossover,its a fuel controller.
 
Old Oct 22, 2008 | 10:10 AM
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I know this, but if the vtec function doesn't work, just get an SAFC.

problem is, especially on these newer cars, piggybacks like SAFC's essentially only work in WOT mode, the ecu eventually "learns" the safc tune and overrides it. It's an issue that S2000 owners have been dealing with for a while.
 
Old Oct 22, 2008 | 10:13 AM
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Originally Posted by chimmike
I know this, but if the vtec function doesn't work, just get an SAFC.

problem is, especially on these newer cars, piggybacks like SAFC's essentially only work in WOT mode, the ecu eventually "learns" the safc tune and overrides it. It's an issue that S2000 owners have been dealing with for a while.

very true i had it in my s2k and i hated resetting the ecu every once in a while

but i think same thing.....it won't do shit for a Fit
 
Old Oct 22, 2008 | 10:39 PM
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heres the pic
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it will work on GD3 but cant hook it up to the vtec, if you do the "check engine light" will come out...air/fuel ratio is the only thing u can tune
 
Old Oct 22, 2008 | 10:42 PM
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Did you gain something HP wise?? And what are your mods?

Marko!!
 
Old Oct 22, 2008 | 10:52 PM
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Originally Posted by DOHCtor
Did you gain something HP wise?? And what are your mods?

Marko!!
honestly... i can only feel the car smoother and quicker throttle response, just a little...i have a T-1R intake, axel back, crank pulley, ground kit, voltage stabilizer and spoon ETD
 
Old Oct 23, 2008 | 10:31 AM
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So, good to note for the future fellas:

save your money and don't buy the VAFC. the SAFC is cheaper.

Question though. You did have it professionally tuned via wideband on a dyno, right?
 
Old Oct 23, 2008 | 11:04 AM
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Originally Posted by chimmike
So, good to note for the future fellas:

save your money and don't buy the VAFC. the SAFC is cheaper.

Question though. You did have it professionally tuned via wideband on a dyno, right?
That or a S-AFC Neo that control's all and have more tuning points!!

Marko!!
 
Old Oct 23, 2008 | 11:41 AM
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well, as I said before, the vtec in the L15a isn't a cam changeover style system, so adjusting the point won't do anything.

Anyways, if you really want to tune, don't waste the money on an SAFC of any kind. Emanage Ultimate or full standalone.

but the only way I'd use either of those on a Fit is if I was boosted
 
Old Oct 23, 2008 | 12:55 PM
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VTEC is VTEC, on the L15A it is of the SOHC VTEC variant.

As popularity and marketing value of the VTEC system grew, Honda applied the system to SOHC (Single Over Head Cam) engines, which shares a common camshaft for both intake and exhaust valves. The trade-off was that Honda's SOHC engines only benefitted from the VTEC mechanism on the intake valves. This is because VTEC requires a third center rocker arm and cam lobe (for each intake and exhaust side), and in the SOHC engine, the spark plugs are situated between the two exhaust rocker arms, leaving no room for the VTEC rocker arm. Additionally, the center lobe on the camshaft can only be utilized by either the intake or the exhaust, limiting the VTEC feature to one side.
VTEC - Wikipedia, the free encyclopedia

The SAFC NEO marks the newest edition to the world famous Super AFC line of piggy back fuel controllers. Building upon the powerful SAFC II, the AFC NEO has taken piggy back style fuel control to a new level. The AFC NEO boasts an incredible 16 points of user definable fuel correction. VTEC control has also been incorporated for Honda/Acura applications. A complete monitor mode is also available to keep the driver/tuner informed of critical engine data.
A'PEXi U.S.A. - Products: Electronics

An AFC is a piggy back air/fuel controller. It is used to either add or subtract a percentage of fuel at increments of RPM's set by the user or tuner. As newer models come out they increase the increments available offering more precision and add more features. This device operates at a High throttle and Low throttle points and calculates for in between. The throttle points are set by the user as well. How it works is it intercepts the signal from your MAP in our case or MAFS in other cases, reads RPMs from the ignition circuit, reads throttle position from the TPS circuit, and also has an option for altering VTEC engagement point. This allows for a mild tune or alteration of the fuel output on the car and allows you you to use a different MAFs on certain vehicles. Since it does not dirrectly interact with the ignition or fuel injectors it is only a mild tune.

If you want a complete and thorough tune get an E Manage ultimae, AEM, HKS unit, or ROM tune. Find a good tuner with a good reputation. Not just a shop with a dyno operator.

I hope this helps and also helps clarify any rumors on VTEC.
 

Last edited by Nabisco; Oct 23, 2008 at 01:16 PM.
Old Oct 23, 2008 | 01:33 PM
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no, vtec is not vtec. they're not all the same system on every vtec equipped car.

FYI, Vtec on the fit: The Truly Amazing Honda Fit/Jazz

incredibly good read.

essentially on the L15A VTEC, both exhaust valves are open at all times, but only 1 intake valve before the vtec changeover. At the vtec changeover, the second intake valve opens, it does not switch over to a more aggressive lobe.
 
Old Oct 23, 2008 | 01:39 PM
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Poopy! Thanks for the info. I stand corrected. 12v/16v but not like a D15B or VTEC E.
 

Last edited by Nabisco; Oct 23, 2008 at 01:57 PM.
Old Oct 23, 2008 | 02:48 PM
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What would be interesting to see, though, is how the vtec is actuated on the L15A....because if it's similar to what I think, it might be possible to develop a cam that has a more aggressive vtec lobe. But again, it all depends on how it's actuated.
 
Old Oct 23, 2008 | 02:53 PM
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I believe it only activates the 2nd intake valve therefore enabling all 16 valves and nothing more.
 
Old Oct 23, 2008 | 03:08 PM
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what I'm curious about though, is if the actual cam slides so that the "whole" intake cam lobe activates the second intake valve?
 
Old Oct 23, 2008 | 03:12 PM
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Good question. I doubt the camshaft itself would move. I think it is something with the rocker. I would like to see a diagram or pictures of the real thing to thoroughly understand.
 
Old Mar 5, 2022 | 09:44 PM
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If you could send me a link of where are you installed it on your ECu

Originally Posted by feifei
honestly... i can only feel the car smoother and quicker throttle response, just a little...i have a T-1R intake, axel back, crank pulley, ground kit, voltage stabilizer and spoon ETD
could you send a link to how you installed it to your EC you
 
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