[Diy_efi] Importance of TPS with lightweight cars

[William Shurvinton]

----- Original Message -----
From: "Shannen Durphey" <shannen at grolen.com>
>
> GM did this for several years with light vehicles (pickup trucks did not
> get this type of tuning).  I have done this in my own cars for almost 15
> years.  The trick is to understand when it's possible to operate lean,
> and when to back out.  For anyone who is not mild on the throttle, it
> works out that much less than "most of the range" becomes a lean fuel
> mode.
>
> Look at the hac for the 727/730 calibration.  Read through 'til you find
> the highway fuel mode sections to get a rough idea when one of the big
> three automakers felt it was ok to run lean.

I have looked at this a few times, but seems a bit slow, plus needs VSS,
which I don't yet have. I was approaching from the other direction,
asssuming lean more than normal and correcting with PE. Will re-read the
code again and think some more.
>
> > Seems like the more responsiveness the engine/vehicle
> > combination has (lightweight, easy-revving motor
> > combines with light chassis), the LESS it needs
> > acceleration mapping, because it can accelerate enough
> > to keep intake air velocity up.

Adam: Is some of this related to the fact that goosing the throttle on a
sports bike is a very bad thing to do and the power/weight is such that you
need to feed the throttle in far more carefully? Given how much more
sensitive to bog a low inertia engine is there must be some sort of TPSdot
fitted.

Rgds

Bill


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