Gearbox Ratios

[heliox]

Does anyone know where i'd find info on the gear ratios used in the SDI T77 and the BW T5?

... if you made changes to the diff or gearbox that were non standard and wanted to enter the car for Sprinting or racing, would this be seen as "Modified" ?

cheers..Heliox

[GreenV8S]

quote:
... if you made changes to the diff or gearbox that were non standard and wanted to enter the car for Sprinting or racing, would this be seen as "Modified" ?

cheers..Heliox

Depends on the specific championship you're thinking about, but for example the southern championships allow internal mods (keeping the same type of castings for heads, block, gearbox and diff) in the roadgoing production class. The 'modified' class is for nutters with stripped out cars on slicks!

[scruff400]

Also from my limited experience - The LT77 (SD1) box is far from 'standard'

BW Gear ratios:- 1st 2.95:1, 2nd 1.95:1, 3rd 1.34:1, 4th 1.00:1, 5th 0.8:1.

SD1 Gear ratios (in mine..) 1st 3.32:1, 2nd 2.087:1, 3rd 1.396:1, 4th 1.0:1, 5th 0.83:1

Hope this helps?

[heliox]

many thanks for your help scruff400, I need work out gearing/wheel speeds with those ratios.

I must come and watch those slick tyre nutters in action one of these days, been meaning too for ages but havent got round to it yet,does seem like a lot of fun.
cheers..Heliox

[shpub]

quote:
many thanks for your help scruff400, I need work out gearing/wheel speeds with those ratios.

Just get in the car and drive it!

BTW the mods to change boxes in a Griff are not simple and cost more than getting an SD1 strengthened a la 520. Still puts you into Roadgoing Production.

Steve

Got me a set of slicks for next year. all I need is to learn how to be a nutter...

[kevinday]

quote:
Got me a set of slicks for next year. all I need is to learn how to be a nutter...

[heliox]

quote:

Just get in the car and drive it!

can't, the diff's broken!..
its being looked at by Bernie at Competition Transmitions and i've got the option to reduce the final drive as the newer BTR diffs run 3.45:1, whereas the older GKN run 3.31:1. With the SDI box running on the BTR ratio you loose some top speed (quite noticeable in low gears) and i'd like to get it back closer to the original 3.31:1 ratio.

cheers..Heliox