Au BTR Transmission gear ratios

Beer Baron · 02-01-2010, 09:06 PM

Hey Hey,

Running some numbers through my head for diff ratios and tyre sizes. I need the ratios for the automatic gearbox in my AUII. I did a search but it didnt come up with what i needed.

Beer Baron.

Mr Hardware · 02-01-2010, 09:37 PM

1st - 2.39:1
2nd - 1.45:1
3rd - 1.00:1
4th - 0.68:1

I believe. And your diff'll be a 3.08:1

The Monty · 02-01-2010, 10:01 PM

Series 2 SR would be 3.23?

T3man · 02-01-2010, 10:10 PM

diff will be 3.23 unless modded - check the tag.

Mr Hardware · 03-01-2010, 12:20 AM

oooh SR rite rite

Beer Baron · 03-01-2010, 05:26 PM

I thought the diff ratios went as follows for non XR's

Series 1 forte = 3.08
Series 1 fairmont ghia = 3.23
Series 2 forte = 3.23
Series 2 fairmont ghia = 3.23.

So forte and fairmont with 16's standard had 3.23 and series 1 with 15's had 3.08 ?

Beer Baron · 03-01-2010, 05:28 PM

Quote:

Originally Posted by Mr Hardware

1st - 2.39:1
2nd - 1.45:1
3rd - 1.00:1
4th - 0.68:1

I believe. And your diff'll be a 3.08:1

I'm thinking of doing a diff ratio change so would i need to take into account the lock up converter or is that in the 0.68:1 ratio.

The Monty · 03-01-2010, 05:33 PM

Lock up is the torque converters job, and is in third and fourth. I have 3.9's and it hasnt affected anything.

KR1STO · 03-01-2010, 06:30 PM

Quote:

Originally Posted by Beer Baron

I thought the diff ratios went as follows for non XR's

Series 1 forte = 3.08
Series 1 fairmont ghia = 3.23
Series 2 forte = 3.23
Series 2 fairmont ghia = 3.23.

So forte and fairmont with 16's standard had 3.23 and series 1 with 15's had 3.08 ?

i thought all the fairmont ghia's had a 3.45:1 same as XR's and Fairlane's..
might be wrong though..?

Mr Hardware · 03-01-2010, 06:48 PM

1.00 is locked up 3rd
0.68 is locked up 4th

and you'll find all fortes/futuras/fairmont non-ghias had 3.08s
fairmont ghia had either 3.23 or 3.45, i'm leaning towards 3.23
SRs? 3.23 these guys reckon. My AU1 classic had a 3.08 by the way

KR1STO · 03-01-2010, 06:51 PM

Quote:

Originally Posted by Mr Hardware

1.00 is locked up 3rd
0.68 is locked up 4th

and you'll find all fortes/futuras/fairmont non-ghias had 3.08s
fairmont ghia had either 3.23 or 3.45, i'm leaning towards 3.23
SRs? 3.23 these guys reckon. My AU1 classic had a 3.08 by the way

question... about the fairmont ghia's, weren't they all VCT...?
if they were, weren't all VCT's equipped with 3.45:1 or was it just the lanes and XR's that got 3.45's..?

sorry to hijack your thread beer baron, it's just that you've raised an interesting topic..
cheers
kris

KR1STO · 03-01-2010, 07:02 PM

did a bit of hunting around..
this may help..

fairmont and fairmont ghia
http://www.fordforums.com.au/photos/...at=2402&page=2

AU2 falcon and others
http://www.fordforums.com.au/photos/...at=2401&page=2

XR series 2
http://www.fordforums.com.au/photos/...cat=598&page=2

Fairlane series 2
http://www.fordforums.com.au/photos/...cat=704&page=2

LTD series 2
http://www.fordforums.com.au/photos/...cat=552&page=2

hope this helps!!

The Monty · 03-01-2010, 07:41 PM

Wow, good info there Kristo, thanks.

GS608 · 03-01-2010, 08:50 PM

So by the looks of it from those links
Forte/Futura had 3.08
Fairmont had 3.23
Ghia with VCT had 3.45

KR1STO · 03-01-2010, 08:58 PM

yeah pretty much..
forte/futura sedan 3.08
forte/futura wagon 3.23
falcon S/SR 3.23
falcon/fairmont/fairmont ghia V8 3.23
anything with HP6 or VCT6 3.45
XR 6/8 3.45:1
Fairlane/LTD V8 3.23

few variants with manual vs auto but it's all there..

looks like yours is a 3.23:1 though beer baron which i think you sorted out anyway..

Beer Baron · 04-01-2010, 01:45 PM

Thanks guys.

If the gearbox ratios are the same from series 1 forte to series 2/3 forte with the same 3.08 diff ratio they should rev different because series 2/3 had 215/60/16 and series 1 had 205/65/15. The 215's have a larger rolling diameter so series 2/3 should rev lower than series 1 at 100kph ?

Mr Hardware · 04-01-2010, 01:54 PM

Negligable
I had an AU1 with 15's and it revved almost exactly the same, ie 1800rpm at a GPS100kmh

Beer Baron · 04-01-2010, 04:55 PM

So an AU with 15's from the factory will have the 3.08 diff gears then to correct the speedo ?

The Monty · 04-01-2010, 05:14 PM

Depending on the model, tyre profile, width etc, yes.

Beer Baron · 04-01-2010, 10:59 PM

And a series 2/3 forte with factory fitted 16's would need 215/60/16 and 3.23 diff ratio to be the same as 205/65/15 and 3.08 diff ratio. So what im saying is that if a forte came from the factory with 15's it will have a 3.08 diff and if it has 16's from the factory it will be 3.23. Not including XR's and VCT fairmonts.

Beer Baron · 04-01-2010, 11:00 PM

I think, Please feel free to correct me.

KR1STO · 04-01-2010, 11:05 PM

hey beer baron.. did you check the links i put up mate...?
i think they'll answer all your questions...

bodes-sh · 04-01-2010, 11:32 PM

Quote:

Originally Posted by Beer Baron

And a series 2/3 forte with factory fitted 16's would need 215/60/16 and 3.23 diff ratio to be the same as 205/65/15 and 3.08 diff ratio. So what im saying is that if a forte came from the factory with 15's it will have a 3.08 diff and if it has 16's from the factory it will be 3.23. Not including XR's and VCT fairmonts.

no. only au1's had 15's from the factory. au2 onwards have all had 16's, and the forte's all had 3.08 rear ends in them...

frd906 · 05-01-2010, 01:04 AM

i had a set of 15s on my series one au, then i bought a set of 18s and kept the same rolling diameter, so my car came with 205, 65, tyers, so i put a set of 235, 40s on my 18 inch mags to keep the same rolling diameter,

but i have had no speedo troubles at all

The Monty · 05-01-2010, 06:35 AM

Actually Matt, the change you have done would indicate that your speedo is now reading 3.3% too slow. This means that when your speedo says its doing 100, your doing around 103.

Beer Baron · 05-01-2010, 12:37 PM

http://www.miata.net/garage/tirecalc.html

The Monty · 05-01-2010, 05:05 PM

Thanks Baron, been using that for years.

frd906 · 05-01-2010, 05:05 PM

Wierd becuase, i have been past speed cameras doing the exzact speed, and havent herd anything,

Thanks josh

Mr Hardware · 05-01-2010, 06:13 PM

Thats because most falcons have about a three percent error anyway, so most likely your car is actually now dead accurate. Also, in QLD you can fly a kite in the safe zone on speed cameras its so large, it's 10%.

Beer Baron · 05-01-2010, 07:14 PM

Quote:

Originally Posted by Mr Hardware

Thats because most falcons have about a three percent error anyway, so most likely your car is actually now dead accurate. Also, in QLD you can fly a kite in the safe zone on speed cameras its so large, it's 10%.

That's changing mid this year, Going digital. My AUII's speedo needle is 3km out at all speeds.