Looking for WRC gear ratio data

[cougarrange]

I am trying to collect any data on the gear ratios used in WRC cars. Any car, any year, any gearbox any event.

I'd really like to know what typical ratios are for the Impreza WRC S7 - S14 speed.

[shaitan]

I am trying to collect any data on the gear ratios used in WRC cars. Any car, any year, any gearbox any event.

I'd really like to know what typical ratios are for the Impreza WRC S7 - S14 speed.
for what?upgrade your car?

[shaitan]

they always change it depending on the road surface
=----------------
Full time four wheel drive. The front, center and center differentials are electronically controlled. 50%-50% F-R torque distribution.

Five speed Peugeot/X-Trac non synchronized, sequential shift gear box longitudinally mounted. Carbon triple plate clutch.
High ratio rack and pinion, power assisted steering.
Final drive ratio: varies depending on the surface

[midgary]

if you buy the homologation books for each car you will get all the ratios and final drives

[OldF]

if you buy the homologation books for each car you will get all the ratios and final drives

Are these books the ”homologation regulations for group xx”. What do they cost and from where can they be bought?

[janvanvurpa]

Are these books the ”homologation regulations for group xx”. What do they cost and from where can they be bought?

No not the regulations but the
Homologation papers that Sub-a-rat, or Ford or Opel or whoever prepares and submits where every specification of the basic car and all the fun bits that make it a rally car are detailed with dimensions, ever weights and the "Variant Options" are supplied in detail.
If they are talking about a final drive they will state the tooth count like 9:42 and the ratio of 4.67 or if its a connecting rod they list the length center center to center, the width, the weight etc., cylinder head port dimesnsions ---plus their tolerance of + and - this many tenths of a mm etc.
It's used in checking compliance---rememeber Tomi and somebody else getting disqualified for flywheels out of spec weight by a few grams or way back when Per Eklund had his excellent 3rd OA taken away on an RAC cause the original untouched as-cast intake manifold was 0,3mm "too large" even tho it is a sand cast part.

Homologation papers usually can be bought---for stupid money, maybe 65-150 dollars----from your National Federation like Svenska Bilsport Förbundet or
or OMK or RACMSA or equivalent.

Not so in USA where the organisers of the rival 'Champignonskit' are both private corporations and homologation is not a concern.

[Mirek]

Ford Escort WRC

1... 15/27
2... 19/24
3... 22/21
4... 23/18
5... 24/16
6... 24/14

Reverse... 14/30

Final... 18/29, alternative 16/27

[janvanvurpa]

]Ford Escort WRC

1... 15/27
2... 19/24
3... 22/21
4... 23/18
5... 24/16
6... 24/14

Reverse... 14/30

Final... 18/29, alternative 16/27

Mirek being a Ford rally guy, and one who builds gearboxes, I think you are just a little mistaken on the final drive numbers 18/29 would be a ratio of 1.6:1 and 16/27 comes out at 1.68:1.
The final drive was very often 4.44:1 (Ford PN 9092448) I don't have the tooth counts,, wait........here it is 9:40

If you do the math none of the gearbox ratios make any sense unless multiplied by the ratios you have as "final drive" as none are more than 1.9:1 and 3rd thru 6th are crazy overdrive.

I believe you have posted a "drop gear" ratio which is the ratio from the inputshaft gear down to the bottom cluster gear.
Then 1st comes out about 2.88:1 and top about 0.94 or 0.96.

[Mirek]

You're right, it's input ratio accoding to Escort WRC manual. Sorry :)

[sollitt]

I have the homologation papers for Corolla WRC here.
They don't list the gear ratios other than the std ratios of the base car.
Lists all of the homologated final drives - 33 different ratios for the front (from 5.1 down to 2.6) yet only 6 for the rear.
Also lists the transfer case ratios.