Mike,
the 4th is 1:1, 5th is .82:1
The combination of 5speed and 3.7 works out to 74% the rpm of a ribcase
and 4.22.
Ulix
On Wed, 18 Feb 1998, Mike Gigante wrote:
> Is 5th in the datsun box a 1:1 or an overdrive?
>
> If it is a 1:1, then why not just use a BMC 3.7 diff and leave the
> ribcase box? 1/2 hour for a diff change and that is it!
>
> Mike
>
> -----Original Message-----
> From: Wm. Severin Thompson <wsthompson@thicko.com>
> To: Ulix Goettsch <ulix@u.washington.edu>
> Cc: spridgets@autox.team.net <spridgets@autox.team.net>
> Date: Monday, February 09, 1998 7:41 AM
> Subject: Re: Left Lane Cruiser!
>
>
> >Ulix,
> >
> >I'm trying that combo on a MarkIII Sprite with a 1275 and a Judson
> >supercharger this summer... I'll keep you posted. It should be a
> screamer...
> >
> >WST
> >
> >Ulix Goettsch wrote:
> >
> >> I swapped out the 4.22 for a 3.7 rear end in my car, which is equipped
> >> with the 5-speed. Wow! It has transformed the character of the car on
> >> the highway. WIth the ribcase and 4.22, I felt completely out of place
> on
> >> the highway, the car felt like it was doing something it wasn't designed
> >> to do. I used to drive ~60mph. The combination of 3.7 and 5-speed
> lowers
> >> my rpm to 72% of original. At 4000 rpm, I go the same speed that used to
> >> take 5500rpm, which according to me calculations should be 84mph. 74mph
> >> at 3500rpm. I ride the fast lane unstressed. (All numbers based on
> >> theory, not the inaccurate instruments of my car. rpm to mph conversion
> >> based on Haynes manual that says 17.3 mph/1000rpm in 1500 with 3.7 rear).
> >>
> >> Of course there are tradeoffs. Inclines on the highway will get
> >> me downshifting early, since the motor has less power at 3500 than at
> 4000
> >> which is what I used to see at cruise.
> >> The long rear end makes for a long first gear which makes for harder
> >> takeoff from a stop. First gear on the Datsun trans is shorter than the
> >> one of the ribcase, which helps to offset this some. This shorter first,
> >> coupled with the 4.22 resulted in a very short first gear that is nice on
> >> steep hills, but is also too low to make any significant speed in the
> >> process on accelerating from a stoplight. I didn't notice this until
> now.
> >> Now, after taking off, there is rush of forward motion in 1st, that
> wasn't
> >> there. This is hard to explain, let me try again...if you take off on a
> >> mountain bike in the lowest gear it has, yes - it is very easy to take
> >> off, but this low gear doesn't get you to any useful speed before you
> have
> >> to upshift...
> >>
> >> I have yet to try taking off on an EXTREMELY steep hill in my
> >> neighborhood to test the difference in that respect.
> >>
> >> If you do a lot of highway cruising, I would recommend this combo (maybe
> >> not with a 948).
> >>
> >> Ulix __/__,__
> >> .......................................................... (_o____o_)....
> >> '67 Sprite
> >
> >
> >
> >
>
Ulix __/__,__
.......................................................... (_o____o_)....
'67 Sprite
|