st185 rc transmission

To use a st185 rc transmission on a usdm standard st185?, do you need the rear differential off a RC too?

thanks
Chris

No.

even if the final drive is not the same?

I don't know much about gearing, but I thought the RC had the same rear diff ratio as the regular alltrac...so it wouldn't matter if you got one off the RC?

Bryan

how is the final drive of a transmission affect the car?

Final drive is before the power split. Rear ratio is the same on all models. I run the RC box myself for a long time with stock alltrac rear dif and then a 205 torsen.

I'm a little ignorant on this whole gearing thing (never got to that point in modding my car yet), but "what" is the final drive? Is it a multiplier or something for the other gears? How does it affect or work with the rear diff ratio (if it does at all)?

Thanks! If there's an article out there that explains this, just link it!

Bryan

Info on our final drive
http://gtfour.supras.org.nz/428ratio.htm

Slight explanation of final drive.
http://newcarbuyingguide.com/index.php/ ... event=view

Think of it as the final gear in a car before the drive wheels. By changing this gear it effects all the other gears since the energy goes through it last. When you hear of a mustang with a gear, it means they have changed their overall ratio for better acceleration. This tends to be a cheaper solution for decent speed gains. The rwd cars have theirs in the rear dif, but the alltrac houses its in the gearbox before the power split. This also makes it a harder item to change in the car.

I have an RC engine/trans in my st185 with the regular alltrac open diff and it's working just fine.

CMS-GT4":17viuf77 said:

Info on our final drive
http://gtfour.supras.org.nz/428ratio.htm

Slight explanation of final drive.
http://newcarbuyingguide.com/index.php/ ... event=view

Think of it as the final gear in a car before the drive wheels. By changing this gear it effects all the other gears since the energy goes through it last. When you hear of a mustang with a gear, it means they have changed their overall ratio for better acceleration. This tends to be a cheaper solution for decent speed gains. The rwd cars have theirs in the rear dif, but the alltrac houses its in the gearbox before the power split. This also makes it a harder item to change in the car.

Click to expand...

Cool, thanks for the help. However, on the second link, it states "taller gears (last sentence or so) give better acceleration...at the expense of acceleration. Typo? What did they mean to type in instead?"

So it all pretty much makes sense except for one thing i need clarification on. Why does shorter/lower gears produce better acceleration? It would seem like a taller gear (such as a pure 1:1) would give better acceleration because..i don't know, it just seems to have more efficient transfer? Like the output shaft spinning at a given rpm would equate to an "equal" transfer of rpm to the axle or whatever...maybe i'm missing something important? With physics in mind, is it just simply just harder/more ineffecient to turn larger/taller gears due to their sheer size?

Thanks for any help...I feel like, i've got all the pieces to understanding this, i'm just missing a key point in all of this lol.

Bryan

NM, i think i found the answer here!

http://www.crankshaftcoalition.com/wiki ... ar_quicker

Bryan