working out gear ratios

vwtyp2 Son of Jim - Creator of Good

2,504 posts · joined Sep 2003 · 20 Feb 2004, 8:32 am

#142070

what's the secret formula for working out gear ratios?
Looks like I'm gonna be rebuilding a box for my bus, rather than worrying about any further conversions.
this is what i was thinking.....

it needs a taller 1st anyway, as soon as you stand on the gas in 1st, it's straight on the rev limiter.
I was thinking on using a 1st somewhere between the 1st and 2nd I've got now, use my Albins standard 3rd as a 2nd, the Albins 0.70 4th in 3rd, then an even taller 4th. shohld be able to cruise the highway about 140 kph at about 3000 rpm, and around the city 60kph at 2000 rpm in third.
make it kinda like a 3 speed + overdrive.
how do I work out what Ratios I need?😀

Most people seem normal, till you get to know them.

lugnuts Custom Title Time!

1,070 posts · joined Aug 2002 · 20 Feb 2004, 1:22 pm

#142143

Has it got the motor to pull those high ratios your thinkin bout.:o

BiX Veteran Volks Folk

2,499 posts · joined Sep 2002 · 20 Feb 2004, 3:16 pm

#142177

You say u redline in 1st straight away? Is this on the flat what happens when u have to do a steep hill start? etc. I would leave 1st and just adjust 3rd and 4th. Just remember if u have the taller gears is the engine going to be able pull that gear as lugnuts said?

ash logan Commited Dubber

55 posts · joined Aug 2003 · 20 Feb 2004, 3:32 pm

#142181

This is a calculator type contraption that i think you willl find quite handy.

http://www.cvsr.net/php/links.php

It is called Gear Head, look down a bit and it is right there!

[Edited on 20-2-2004 by ash logan]

twoguns simply aircooled

4,275 posts · joined Nov 2002 · 20 Feb 2004, 4:09 pm

#142199

and i might be wrong, but i read somewhere that the rpms the engine run at, also affect the cooling effect. so if you drop the rpm too much would your motor slowly build up heat on a long trip?

Simply Cruzin'...

Baja Wes V6 Baja Pioneer

3,119 posts · joined Aug 2002 · 20 Feb 2004, 4:24 pm

#142207

I believe he has a V6 in the kombi, so no beetle cooling issues to worry about.

If you have access to microsoft Excel 2000 or higher, then my Excel dyno will do exactly what your after and more

http://www.aussieveedubbers.com/forum/viewthread.php?tid=18037

So, do you have Excel?

Wes - www.offroadvw.net - 200HP Quad Cam V6 in a VW Baja - with climate control... 🙂
www.taylorcycles.com.au - My DH MTB racing brothers shop.

wacked1 Custom Title Time!

1,508 posts · joined Jul 2003 · 20 Feb 2004, 8:44 pm

#142286

Yes this has a 3.8L V6 in it!

YOU HAVE JUST BEEN DAKED
don't worry it's a VW thing

vwtyp2 Son of Jim - Creator of Good

2,504 posts · joined Sep 2003 · 20 Feb 2004, 9:23 pm

#142305

yep. no need to worry about horsepower, or air cooling.
it'll beat any normally aspirated 4 or anything up to a vs commodore or ef falcon to 100 kph.
but then I run out of go at about 140 kph. I want to be able to hit at least 100 mph.

Most people seem normal, till you get to know them.

70AutoStik Insano Dub Head

730 posts · joined Aug 2002 · 21 Feb 2004, 1:41 am

#142363

You might actually have trouble finding the taller ratios you're looking for, why not start with a higher final drive?