Quote:
Originally Posted by BlackDeuceCoupe
Er... A final thought...
I don't know about the powerband in a Geo Metro - never drove one - but...
My Honda B16 motor is widely ridiculed as a "torqueless wonder". At 8000+ rpm it will propel my ride like a white hot comet, but "cresting a gentle hill" at even 3000 rpm will cause my engine to labor, and the speed to drop precipitously!
The workaround is to simply drop back into 4th gear and gently build some revs... 
Have you tried this?
It will allow you to maintain your vehicle speed without laboring the motor - shouldn't affect FE too adversely - and retain your vacuum readings, yes? |
Peak torque in the geo is 3300, and it pulls real well from 3k to 4k in any gear. But my understanding was that high revs were the devil with regard to FE. 55 MPH in 5th is about 2800 or so. 60 is around 3k. The only time I have even touched anything above 3 grand is when trying to accelerate quickly in certain situations that require it for safety, and even then I am shifting right on 3300. Mostly I am shifting around 2500 and cruising wherever 10 on the vac leaves me, which has been at pretty low speeds overall. About 45 MPH average in the current weather, I'd say.
Now, when I am going up a hill and the revs are dropping to about 2k in 5th, I'll downshift to 4th, but keeping me vac up still leaves me going between 35 and 40 mph and not gaining any ground until I hit the crest. If I want to maintain speed up a hill I am going to need to give it some gas, one way or the other.
I'll be able to experiment more when I get some of the stuff I ordered yesterday. I just filled up a few minutes ago, 49.6 MPG. Little disappointing, actually, considering how radically conservative I have been driving (I was hoping to be in the low 50's), but given other comments here about the effects of temp and wind, maybe I didn't do too badly.
EDIT: I forgot to calc for a -.83% odometer error! I broke 50! Whoohoo! 50.05 MPG.