4 replies to this topic

[Nial81]

I've recently rebuilt my gearbox with this gearset and a 3.1 final drive and really not enjoying it at all.
It's a nightmare to pull away up a hill and even on the flat it's just too long.
I've a 1293 turbo which is putting out decent power which is why I made the change.
Are there any tips for driving with this?
I would rathet not have to take the engine back out just now to change the final drive.

[Gaz66]

Not knowing the engine spec, wheel size or torque output of your engine it's hard to say what ratio would be ideal but I'd say the 3.1 is far too tall as you've found out.
If I was to install an "all rounder" with that gear kit it would be a 3.7
If you are running 13" wheels you'll probably be pulling 50mph at full chat in 1st?
A 3.7 will drop that to around 40mph but of course you will lose top end speed.
There's no driving technique I'm aware of that will help as it is apart from smoking the tyres on set off or slipping the clutch 😬

Edited by Gaz66, 22 May 2025 - 11:58 PM.

[Spider]

From memory it's a closer ratio gear set, so first gear is taller than as found in the standard sets. That coupled with a tall final drive as you have with the 3.1 set there, yes, it'll be quite dreadful to drive unless you can make bags of torque from about 1200 RPM.

Where is the power band on your engine ? Start from there and work down.

 

[Cooperman]

It does sound like you are ‘over geared’ due to the high FDR.
Unless you change to a lower final drive you will be forever slipping the clutch to pull away from rest and have to change the clutch plate more often due to high wear rate. Your acceleration will also suffer.
You could try a 3.44:1 which could work well, or a 3.76:1 for better acceleration.
The wheel diameter makes little difference as the rolling radii with 10”, 12” or 13” wheels is not much different due to the different tyre width to wall ratios.

[KTS]

i'd recommend a visit to the page below to have a play about with the various final drive (..and drop gear ratios if you're inclined..) to find a combination that will suit the engine characteristics and your driving style

 

http://www.guesswork.../Tech/ratio.htm

Edited by KTS, 24 May 2025 - 08:33 AM.