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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