danglerb

Greg Brown can make a close ratio box, but I don't recall the details of how its done.

5th gear is 1:1 through the tranny, so that has me wondering what ring and pinion ratio would put top speed at 125 mph?

atb

Please post more pics of this car.
There is a way to combine gear sets from different boxes to give you a tighter ratio, do a search.
What year is your 928? Sounds like an OB box with the 2.75 final drive would be about right.

Cortina

Car is 1981 , although it was built as a rally car during 2008/9.
Final ratio I can easily work out (we have to use a 70 series tyre in historic motorsport here !!) , but ratio will be a lot higher (bigger number) than 2.75 !
Have another photo to interest you .

OJ GTS

Hello mate, not sure what sort of budget you're on, but have you tried ringing Quaife or Hewland or someone like that on the mainland?

Not sure if the 928 box shares any common componentry with any 944 or 911 boxes, but if you get the box apart, measure the gears up and give them a spec, you might find someone already produces something suitable.

jon928se

I don't think any of the stock 928 gearsets will do you much good, Limited to 70 series tyres you'ld probably be best trying to find some 14inch wheels that will fit going as wide as you can find but you'll still end up with a lower effective final drive ratio than you can get by buying gears and just accept that any combination of 928 gears is not going to be ideal . Given you'll be traction limited by the tyres just forget 1st gear - I don't think that gear ratios will be your limiting factor.

SQLGuy

I talked to Quaife a few years ago about 928 R/P and LSD sets... they said something along the lines of, "Sure, we'll make 'em... just find nine friends who also will commit to buying them."

littleball_s4

Great pics!

How is it to use one hand to handbrake and the other to shift gears? Or you happen to have an hydraulic handbrake in the tunnel?

My own experience is yes, 928 gearing doesn't seem to fit rallying and no, you don't make much with perfect gearing if it doesn't include dog box (more average RWTorque but a lot more slow shiftings along the rally).

I think it's just better to use it like an auto, try to make as few shifts as possible and use the extra "brain capacity" to brake later and hammer it down earlier, if you know what I mean.

Good luck in the quest for the perfect rally car!

c_span

Nice car

Right, well assuming there isn't anything off-the-shelf available out there then.. Beyond the Quaifes, Hewlands and Sadevs (who are big enough that they won't get out of bed for a custom project for less than £££££) there are a few other specialists you can try..

When I was looking to get custom gearsets made (for my non-Porsche track car, but equally difficult to find developed parts for) I found Drenth very helpful and a lot less expensive (I won't say cheap!) than the above companies for a custom gearset.

Also worth trying Bacci Romano (Italian but have UK distribution), though I ended up going with Drenth in the end.

As for treating gears, look up "Oeliken Balzers", they do coatings which harden the gears up - providing, of course, that the gears are up to the job in the first place! (but I don't think you're running ridiculous torque in this car, are you?)

brianrheffron

Hi Cortina,
You have got a whole crowd of 928 geeks just desperate to find out more about your car.
Please, please find the time to do a write up on your car plus lots of pics (build and action)
and tell us more about historic road rallying in Ireland. On the UK mainland the law does not allow
rallying on closed public roads hence rally special stages on forestry roads and inside stately
home estates but in Ireland both North and South it is allowed. In Ulster they used to race
cars on closed road circuits such as at Dundron back in the days of DB2s and D types.
I think they still have motor bike road races a la Isle of Man TT races.
About 40 years ago I had a big "moment" playing at being a racer around the circuit at
Dundrod when it was not closed. I was blasting down the long straight at full chat in a
Mk1 AH Sprite which was probably no more than 75 mph and a local farmer drove a tractor
and trailer from field to field right across the road. I did manage to stop but with only feet
to spare. I'm quite sure if I had been two seconds earlier or the tractor two seconds
later I would not be here to write this.

mark kibort

It would be the ratio of 4th gear of a GTS. in a 2.2 box, the 3rd gear is 118mph, and thats about a 4.5:1 total ratio. so, 4.3:1 rear end, might do it.

mk