6 replies to this topic

[coyttl]

Okay, really basic, "n00b"-type question. However, I've never cared before, so I've never looked into it. Doing a search revealed a LOT OF POSTS, nothing that is pretty simple, tho -

In other words, in basic English (UK or US, I can read either! ), what affect does the Final Drive Ratio have on my Mini?

(by the way, I recently found out mine's 3.105:1 from the factory, and I don't think anything's been changed, so..)

Cheers!
Me.

[Bean]

Can't really tell you the exact science of it, because I don't really know!

But the final drive governs the acceleration and the top speed.


Lowest number: Less acceleration, greater top speed. More suited to cruising.
Highest number: Greater acceleration, less top speed. More suited for power on take-off.


I believe that generally, the standard tends to be a 3.44? The City E has a 2.95 as it was built as the 'Economy' model and therefore needed a better cruising speed and less low-down power.


I hope this makes sense!?



Cue someone who knows what they're talking about, next!

[Scott.Tamson]

3.105 turns of your engine to one complete revolution of your wheel

CLICK ME

Came across this, might be useful ?

Scott

Edited by Scott.Tamson, 09 July 2008 - 01:25 AM.

[coyttl]

3.105 turns of your engine to one complete revolution of your wheel

Lowest number: Less acceleration, greater top speed. More suited to cruising.
Highest number: Greater acceleration, less top speed. More suited for power on take-off.

Very cool. thanks guys. So with 3.105 turns - is that in first, second, third gear?

Scott - thanks for that link! I see now! Each gear has its own ratio! (I guess, actually, I knew this, reading people's comments on trannys and such.) My engine code/# tells me that I have the 3.105:1 ratio - I'm guessing that's more about the tranny than the actual engine.

Thanks guys.
Mike.

[Guess-Works.com]

That's in 4th...

All 4 speed mini gearboxes (transmissions) have a 1:1 ( or direct ) ratio on 4th...

The available FD ratios for the A (and A+) MANUAL gearbox are...

2.7, 2.9, 3.1, 3.2, 3.4, 3.6, 3.7, 3.9, 4.1, 4.2, 4.3

As you can see there are plenty to choose from.

The 3.4 is considered as 'The standard' as this is what the majority of Minis were made with, the higher the number the shorter the FD ( higher revs @ cruising speed - generally used on lower powered road vehicles eg 850 and commercials, or competition vehicles ), the lower the number the longer the diff ( lower revs @ crusing speed - basically used on economy or high torque motors )

My website http://www.guess-works.com would give you more details ( but it's down at the moment )

[coyttl]

That's in 4th...

All 4 speed mini gearboxes (transmissions) have a 1:1 ( or direct ) ratio on 4th...

I know I'm in the US , but is it safe to assume you meant "That's in 1st...", if 4th has 1:1?

My website http://www.guess-works.com would give you more details ( but it's down at the moment )

Actually, your site already helped me with my engine stamping - is how I figured out it was 3.105. Never knew that before!
See, now all the posts about 5-speed gearboxes make sense. (Except the part about trying to speed up and ruining the gearbox. To me it seems like you just wouldn't have enough torque.)

Cheers!
Mike.

[MuppetDonkey]

Another Link Here if this helps...