Jon Steiger wrote:
>
> Ok, I've been doing some more research on this tranny thing...
>
> I checked out the Summit and Jegs catalogs. They have a
> Richmond 6-speed tranny, but they don't call it the T-56, so
> I'm guessing its not. ?
>
> Ummmm... Just before I sent this message I went off and did
> some more research... The T-56 appears to be made by Borg-Wagner, NOT
> Richmond. Oops. :-) Unfortunately, that still doesn't clear up much
> of the confusion.) The SR-71 Dakota web site calls their tranny a
> T-56 6-speed on one page, and a Richmond 6-speed on another page.
> So natually, I assumed it was a Richmond T-56. So, either both
> Richmond and Borg Wagner make a tranny called the T-56, or the
> SR-71 page is wrong. Either way, I'm still confused. ;-)
>
> The overdrive gear ratio in 6th is .76 by default. (My NV-3500's
> 5th is .729, so this 6 speed would actually raise my RPMs!) Not
> what I want to do at all! The Jegs catalog says optional overdrive
> ratios are available from .62 to .91. If my calculations are
> right, a .62 6th gear would have me cruising at about 1830RPMs
> at 70mph with my 3.55 rearend. (Currently, I get 2150RPMs at
> 70mph in 5th) [ .729/.62 = 2150/x ]
>
> Here is what I came up with for RPMs resulting from various
> rearends with my NV-3500 and a Richmond with a .62 6th gear;
>
> sorted by rearend ratio:
> --------------------------------------------------
> Trannny Rearend Approx. RPM @70mph
>
> NV3500 3.55 2150
> Richmond 3.55 1830
>
> NV3500 4.56 2760
> Richmond 4.56 2350
>
> NV3500 4.10 2480
> Richmond 4.10 2110
>
> sorted by tranny:
> --------------------------------------------------
> Trannny Rearend Approx. RPM @70mph
>
> NV3500 3.55 2150
> NV3500 4.10 2480
> NV3500 4.56 2760
>
> Richmond 3.55 1830
> Richmond 4.10 2110
> Richmond 4.56 2350
>
> So, it looks like if I had 4.10s and the Richmond, my
> crusing RPMs would be about the same as they are now. (They'd
> drop about 40rpm) But the .62 6th gear ratio isn't enough to
> compensate for a 4.56 rearend; it would raise my cruise rpms
> by a full 200rpm. (Still much better than the 610rpm they'd
> raise with the NV3500 though...)
>
> Another concern I have is that the Summit catalog said its rated
> to take 450lb-ft of torque. What's the deal there?? I'm probably
> not all that far off from 400lb-ft now, and I plan to churn out
> much more than a measly 450lb-ft!!! Does anyone know the torque
> numbers for the Viper? Its gotta be more than 450lb-ft... Isn't
> it? If that's the case, this tranny being sold by Jegs and Summit
> doesn't appear to be the T-56.
>
> Soooo, if its not, where can I buy a T-56, and does anyone know
> anything about how much it might cost, and what the gear ratios
> are?
>
> Thanks very much in advance!
>
> -Jon-
>
> .--- stei0302@cs.fredonia.edu ----------------------------------------.
> | Jon Steiger * AOPA, DoD, EAA, MP Race Team, NMA, SPA, USUA * RP-SEL |
> | '96 Dodge Dakota v8 SLT CC (14.58@93.55), '96 Kolb FireFly 447 |
> `--------------------------- http://www.cs.fredonia.edu/~stei0302/ ---'
Viper makes 490 lb ft of torque. The 6th gear ratio is also .50. Other
than that, I don't know off the top of my head, but look for some info.
Brian
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