Gear Ratio's

FPV70 · 13-10-2007, 05:55 PM

I am not too sure if anyone has ever asked the question but, Back in the glory days of the old GT's and maybe Cobra's you used to be able to pick a diff ratio am I correct?

If I am correct, why is it that thesedays we can not choose a ratio that we might like and why are we stuck with a high final drive like 2.92:1?

Yeah great top end but howabout a better sprint??

I believe Holden use a slightly lower Final drive to Ford which would inturn give a good fuel return around town and with the 6 speed auto's and manuals thesedays, I am sure we could do with a slightly lower final drive aswell.

the 290 and 260 would both stand to gain more from it unless the first gear ratio in the gearboxes is too low as they are which would be the only downside I can see.

Anyone else have an opinion?

**Falcon Coupe** · 13-10-2007, 05:58 PM

With the ZF 6speed auto Diff gear changes are a thing of the past.
Great acceleration and economy on highway.

T3man · 13-10-2007, 06:55 PM

There was no choice of ratios on Cobras.

The choice of diff ratios finished with XY. Even then, it was only offered on the GTs, utes and vans, but not mainstream sedan models. From XA through to XF you could option a "lower" diff on commercial vehicles ie. utes, vans, and in some cases wagons (earlier years only).

So few people chose the option that Ford decided it wasn't worth the effort and as far as I know there have been no alternate diff ratios offered ex-factory since the advent of the E-Series.

Anyone interested can choose from several after-market suppliers to do it anyhow.

cowboy · 13-10-2007, 08:53 PM

The BF XR8 ute brochure lists a another diff ratio as a factory option. Can't remember if it's taller or shorter. Taller I think.

Bent8 · 13-10-2007, 10:02 PM

Ford chose the 2.73 ratio for the ZF's because they have a broad spread of gear ratios 1st and 2nd being low ratios. A BF XR8 will do 62kmh in 1st, 111kmh in 2nd and cruise along @ 110kmh in top gear pulling only 1700rpm...

If Ford went with say a 3.23 then you wouldn't even hit 100kmh in 2nd which would seem kind of silly...the 6sp manuals are geared better with a tigher spread of ratios eg the ZF will do 175kmh at the end of 3rd while the 6sp manual will only do 155kmh...

That being said, I think it would be a great idea if Ford still offered different diff ratio options when spec-ing your new car...

FPV70 · 13-10-2007, 10:45 PM

Well thanks for that info guy's. It now makes more sence and also confirms the reasoning for the taller ratios.
Now I can stop those nagging voices in my head as to why/why not

Barry_v · 13-10-2007, 11:11 PM

they offered different rear end gears because they had no overdrive and only 3/4 forward gears.