RE: 3.55 or 3.90 - This is getting old

From: Bernd D. Ratsch (bernd@texas.net)
Date: Thu Sep 09 1999 - 18:16:33 EDT


Ok...I really hate mathematicians...but explain this a little better..

So you're telling us that if we put 4.56's in the rear (and the engine has a
MAX TQ output of 100, that'll give us 456 FtLbs. of TQ at the rear wheels?
(Regardless of Dyno Runs showing that rear gears don't really matter on the
actual output.)

You can do the math over and over again...the "Real World" results sometimes
are different. Let's take the other side of the coin for a second...(Kind
of extreme comparison...but what the heck)

Offroad "Built" Jeep: 4.56:1 Gears, 350CID V8, 4 Speed Manual.

It climbs and climbs and doesn't skip a beat.

Now install 3.55's with the same combination and all of a sudden it stalls,
burns rubber (slips), and can't make it up the same grades as before.

With numerically higher gears, it's easier to move than with lower
(numerically) gears. That's just a fact.

- Bernd

(Uhhhh...Bob. I can see where this is going and I think we should quit
before it gets any worse.) ;)

---------------------------------------------------------------------------
The torque multiplication provided by your axle gears is torque generated
by the engine times the gear ratio (at any one instant). As an example,
assume that the engine and transmission are delivering 100 lb-ft of torque
to the pinion gear. If the gear ratio is 3.92:1 then the output torque
is 100x3.92= 392. With the 3.55:1, the output torque is 100x3.55= 355.



This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 12:16:40 EDT