>Date: Tue, 23 Jun 1998 10:11:28 -0600
>From: Larry Hoy <larryhoy@mcione.com>
>Subject: RE: Differential Calc Update
>To: Michael Graziano <mgrazian@ltcm.com>, MGList <mgs@autox.team.net>
>Reply-To: Larry Hoy <larryhoy@mcione.com>
>
>Your math looks right, have you checked your speedometer?
>
Good point! - I think you may have a spedometer for overdrive
transmission... I just put an O/D in my B and it now shows that I'm
driving 15-20% faster than I really am. (O/D and non-O/D transmissions
have different speedo drive ratio's) Since your speedo is indicating
about 20% slow I'd say you have the O/D speedo.
Wanna trade? then we'll both have the correct speed...
Kurt
>Larry Hoy; Denver, CO. USA
>1969 MGB Roadster
>1987 Jaguar XJ6 VDP
>"It's not how fast you go, it's how fast you go fast"
>=========================================================
>
>> -----Original Message-----
>> From: owner-mgs@autox.team.net [mailto:owner-mgs@autox.team.net]On
>> Behalf Of Michael Graziano
>> Sent: Tuesday, June 23, 1998 8:39 AM
>> To: MGList
>> Subject: Differential Calc Update
>>
>>
>> OK. I sat at home with my manuals, and my MS Excel and did
>> the math.
>>
>> My tires are P155/70R13's. The wheel radius is 11.050
>> inches (and therefore, the wheel circumference is 5.79
>> feet. So at 4000 rpm, the car should run the following
>> speeds:
>>
>> 3.72 differential: 70.70 mph
>> 3.90 differential: 67.43 mph
>> 4.22 differential: 62.32 mph
>>
>> So, I'd have to have a 5x to 1 gearing in my differential
>> to explain 50mph at 4K rpm. Definately not the case. Where
>> to next?
>>
>> BTW - when doing the calc, using the 3rd gear ratio of
>> 1.433:1, I'd be doing 50 mph @ 4K rpm. BUT I KNOW I'M IN
>> 4TH.
>>
>> Can it possibly be a tranny problem?
>>
>> Mike
>>
>
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