Quick ? about VAF

[hotfordcat]

On both of my engine swaps from a B3 to a B6 I never changed the VAF. Is there any advantage to using the B6 VAF over the B3? Both cars run very well the way they are. Thanks in advance!!!

[bhearts]

In theory, if you keep injectors paired with the maf, the fueling should stay correct at open loop fueling. And closed loop should pull or add fuel based on o2 feedback

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[sketchman]

Mine works OK like that too. B3 ECU too.

It's got this delay and softness in it when you pin it in low RPMs that I can't figure out though. Even when you're in a low enough gear. Still soft up to 2k and kind of delays coming on at all. I tried swapping VAFs, and playing with fuel pressure. Didn't fix it.

[Movin]

Cam and or disty timing ?

[sketchman]

Yeah, I'll have to put a light on it when I get a chance.

[Dragonhealer]

On both of my engine swaps from a B3 to a B6 I never changed the VAF. Is there any advantage to using the B6 VAF over the B3? Both cars run very well the way they are. Thanks in advance!!!

Regardless of injectors, the code T (1.3 Festiva) and code S (1.6 Miata and some others) VAFs are not perfectly identical, but are so close that they are interchangeable for all practical purposes, having dyno tested dozens back to back on various engines. Biggest difference I can find is about 5% variation in open loop idle when cold.

[bhearts]

Regardless of injectors, the code T (1.3 Festiva) and code S (1.6 Miata and some others) VAFs are not perfectly identical, but are so close that they are interchangeable for all practical purposes, having dyno tested dozens back to back on various engines. Biggest difference I can find is about 5% variation in open loop idle when cold.

Such a vast air flow difference for such similar parts


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[Dragonhealer]

Such a vast air flow difference for such similar parts


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But the air flow difference is the size of the "pump" you have it attached to, the VAF simply responding to the
Air moving through it.
I suspect the reason they are electricly so similar, is the VE curves of the B3 and B6 are almost identicle.
As an aside, this size VAF starts to become an air flow restriction at about 165 WHP even though the instrument is not yet maxed out. This is why it can be used at even higher power levels with forced induction.

[hotfordcat]

Thanks for all the "Techno Info" !! All I wanted was a simple "yes" there's a noticeable difference in hp, or "No" there's not!!!

[tooldude]

The extra information is appreciated by others that are also on the site.

[crazyrog17]

Mine works OK like that too. B3 ECU too.

It's got this delay and softness in it when you pin it in low RPMs that I can't figure out though. Even when you're in a low enough gear. Still soft up to 2k and kind of delays coming on at all. I tried swapping VAFs, and playing with fuel pressure. Didn't fix it.

Make sure you don't have an air leak between the VAF and throttle body.

[shadetree]

On both of my engine swaps from a B3 to a B6 I never changed the VAF. Is there any advantage to using the B6 VAF over the B3? Both cars run very well the way they are. Thanks in advance!!!

What ecm are you running ? What inj are you running .
If you stayed with b3 inj and ecm then leave the b3 vaf . I have run them for years like that with no issue but I will say after changing inj and ecm over to b6 stuff( as in a match 3 set ) I have noticed a difference in power and mpg .

[sc72]

Thanks Dragonhealer for your input, well worth the read.

[scitzz]

I got lousy mileage after my second gen B6 swap. I finally got the right ECU, and that made a big difference, then the VAF got me another 4MPG.

[hotfordcat]

What ecm are you running ? What inj are you running .
If you stayed with b3 inj and ecm then leave the b3 vaf . I have run them for years like that with no issue but I will say after changing inj and ecm over to b6 stuff( as in a match 3 set ) I have noticed a difference in power and mpg .

I have the B6 ECU in both swaps, and using the B6 injectors also!!!