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
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