All other things being equal (which they almost never are, of course), the
lower engine
speed will yield better gas mileage, just based on the fact that you are
filling the
cylinders fewer times per minute. There are a lot of variables involved, but as
a general
rule, one would use an overdrive top gear for cruising at freeway speed because
the lower
engine speed conserves fuel and reduces engine wear. The powerplant has to have
the torque
to pull the taller gearing, of course, but i trust that the Nissan engineers
did their
homework in this regard.
According to the data in the '69 Owner's manual that I have in JPEG images (I
can't
remember who it was that scanned the manual and put it on their website -
thanks whoever
it was), the R16 and SU U20 both develop almost identical torque at 4000 RPM
(130 vs 132,
respectively), so an R16 powered Roadster might be able to handle the 5-speed's
top gear,
but it might not be compatible with the other ratios.
Gary McCormick
San Jose, CA
"Ryan, Richard" wrote:
> With everyone talking about MPG I have a question.
>
> Assume you have a 2000 Roadster and you are driving on a flat freeway at 70
> mph.
>
> Which gets better gas mileage?
>
> A. Fourth gear at 4,000 rpm
>
> B. Fifth gear at 3,200 rpm
>
> (I think these rpm estimates are about right. I haven't driven mine in
> years.)
>
> Why?
>
> Dick Ryan ex. 24022
> (650)312-4022
> Risk Management Dept.
> SM 2000/2
> FAX (650)312-5830
>
> Pat,
>
> You just can't compare an Altima to the roadster. Apples vs. Oranges!
>
> My '66 2000 cruises between 4000 and 4500 rpm at highway speeds, and I'm
> getting about 26 mpg. I've got the 1600 rear end (3.90?). In city driving,
> stop and go, the mileage drops below 20 mpg, where the tach is often at
> 3000 (peppy!). Lower rpms do NOT guarantee consuming less gasoline. And I
> know quite a few of the other BADROC'rs are getting similar mpg, about 24
> to 28 mpg on the highway.
>
> Fred - So.SF
> BADROC
>
> 3800 RPM on the Highway is consuming a lot of Gasoline. My '98 Altima gets
> 27 on the highway and it is turning at 2200 RPM @ 60 mph. You must be at
> about 20 MPG. I know my roadster(67.5 2000 w/Solex) gives me 30 MPG on the
> highway. I don't know the Ratio.
> Pat.
>
>
> >Hello,
> > I have the 4.11 LSD on my Solex U-20, I really don't think it makes
> >that much of a difference in around town gass mileage. On the freeway I am
>
> >turning maybe 3800rpm at the super fast CA freeway cruising speeds.
> > But I do think that it makes a difference in low rpm power. The
> >car really does feel more peppier.
> > Daniel 69 2000
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