Fuel prices / efficiency

[nacelp]

> ON-Topic:  I'm building a gas guzzler just as high octane has gone from
1.22
> to 1.65 in 3 weeks!  I see "economy mode" advertised on some of those
16-way
> selector chips. I know there is stuff in DIY archives on efficiency but
> heres my understanding, please correct / add:
>
> -Go for 15 or even 16:1 AFR at light cruise - just don't abuse the car
with
> this setup and you're ok.

Be hard to actually abuse it, since that means opening the TB, and then your
outta cruise.
Tune for you lowest TPS value per set of cruise conditions.

> -160 degrees Coolant temp is still better than 180 or 200 for economy

I tried this with a SBC every way poosible run 180 or 190.  When fully tuned
correctly will be better/best, at warm/warmer still.

> -higher fuel pressure (for better low load spray pattern) hurts economy at
> idle unless you can tune the idle PW waay down.

Only might work with SEFI, since your randomly sqirtting at closed valves
anyway.  The only advantage with SEFI is PW, and CO, from what I've gotten
from some real detroit guys (ie ones that actually do emission
testing/calibrations).

> -low tire pressure bad bad bad

True True True

> -loose convertors bad for economy  - Lock it up earlier -?

If it's a lock up it doesn't matter, other then for that last .000000011%
increase in mileage, in some cases the engine does better since it will move
with less Throttle.

> -good excuse for installing a supercharger - payback is sooner at those
gas
> prices!

Wrong charger, Turbocharger.  Supercharger is always a drag on the engine,
only at times does it's benefits outweight its drawbacks.
Grumpy

----------------------------------------------------------------------------
To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org