[Diy_efi] Importance of TPS with lightweight cars

[bill.shurvinton at nokia.com]

-----Original Message-----
From: ext Adam Wade [mailto:espresso_doppio at yahoo.com]

>That's a thought.  However, if you tune for best power
>at cruise, you will cruise at a smaller throttle
>opening for a given engine speed, and less fuel.=20

But pumping losses make that less efficient than more throttle and =
leaner. However I have to find the lean limit for my setup first. AS you =
say whether it is worth the effort is another question, but one I want =
to answer.

>Instead of thinking of
>it as enrichening when accelerating, I think if it as
>leaning when at cruise, and returning to "normal" the
>rest of the time. =20

Certainly the GM hacs I have looked at do this, with an added WOT =
enrich, so its known to work. Maybe I should stick with NGW until I have =
a lot more data logged on the car.

>I think I understand what you are getting at here.=20
>However, something to think about...  Is not the
>throttled volume of a 1000cc v-twin the same as that
>of a 1000cc inline four, at the same rpm? =20

Don't think so. Certainly looking at inline 4 bike engines, they are =
direct to head with the throttles only a couple of inches from the =
heads. Doing very rough volume sum would suggest that this is perhaps =
only half the swept volume. Most car installs have >swept volume =
throttled.=20

Bill

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