AFM measurement/backpressure (was Turbo speed sensor)

[clayb]

nacelp wrote:

> Compared to what Mechanical, FI, Carbbies?.

Carbs. And I'm well aware of the fine points of carb and distributor tuning.

>
> Sweeping statements are often wrong.
> AFM are probably the least accurate of the air flow sensors, or at least the
> most restrictive.
> In the archives at the GN Ttype there are statements from actual dyno
> testing where even a MAF sensor cost 30HP.

???

I thought we all knew that throwing something in the airstream was restrictive.
Speed density and turbos are like peanut butter and jelly. I did not mean to
imply it was necessary to measure exhaust backpressure, just that the effects of
good engine management are somewhat more noticeable on a turbo motor.

>
> An SU and electonic ignition control (far a small engine) would be hard to
> beat when set up right.  Webers come close to IR, and a blow thru IR vs
> Weber would be within tenths of a percentage, I'd wager.
> VE, and HP well there is alot for who's doing the tuning.  Just really about
> dry walls vs wet, and reelated issues.
>   Now drivibility, tunability, reliability, emissions are all other matters.
> But, to claim EFI is that "secret to HP + VE" or especially good for turbos,
> is kinda stretching a point, IMHO.
>   I notice noone has mentioned cross over so far.  And that opens the doors
> for all kinds of things.

Compared to old technology, the wider and more varied timing and fuel curve
requirements of a turbo motor are much more effectively addressed with EFI.
Sure, this is true for NA, but not to the same extent.

NA motors generally (here we go...) make similar horsepower carbed or EFI.

Turbo motors can be run closer to that dangerous edge of mixture and timing. The
shape of the timing and fuel curves (especially timing) don't match what old
tech delivers. For NA motors, the approximation is much closer. I never claimed
EFI is the "secret to HP + VE". It is, however, a bigger improvement to a turbo
motor, than an NA motor.

- Clay

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