MAFs

[Rodney_L_Wiggins at keybank.com]

Actually there is a fair amount of turbulence ahead of
the turbo on a suck through system. In my application, I
 have seen the signal from the (Ford) MAF rise from 1.2v
 to 2.5 at constant load and constant throttle position
in response to turbo RPM at an 80mph cruize. Makes for
very annoying highway driving (WOT is fine, but the local
 police frown on WOT as highway cruize policy).
Blow-through also allows the blow-off vale to be
vented to atmosphere.  Yesterday, I spoke at length with
the engineer at Pro-Flow pro-M about pros and cons of blow
 through and whether either can give consistent readings
with a ford MAF on a turbo system. (Ford MAFs is a huge
portion of their business) He was very knowlegable but not
 terribly optomistic--even though he could have sold me
some parts by being less honest. He seemed more concerned
 about any bends in the plumbing than the spinning air
from a turbo. But his turbo experience was minimal. They
 are working on some huge, chambered design that is
supposed to be immune to turbulence (not sure at what
cost in terms of flow restriction) but it is still too
 expensive to market $600+.
Perhaps I do need to convert to MAP. Anyone here have
any experience with the Link AFM?

I have also considered a throttle-position based voltage
 clamp to limit the turbulence-induced enrichment at lower
 rpms. Not an elegant solution, but relatively easy.

Rod
86 944 Turbo.




>Hi Bruce,
>I wouldn't think that a turbo would have any extra
>turbulence before the compressor.  Are you saying that
>the problems occur when they are used as blow-through
>or is it also with normal, pull-through operation?
>Regards,
>Matt


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