This is the gearbox that I built for my own car with the intention of competing in Time Attack. I've been offered the opportunity to upgrade to a dog box at the right money so this is now surplus to requirement.

I started the build with a very low mileage gearbox (circa 32,000 from memory) and when stripped, the synchros and ratios were all in excellent condition.

With the intention of using the car on track, the standard top speed was deemed to be too high and after many hours of searching, I found a competition short ratio final drive kit for Mini Cooper S rally cars (using the Getrag MT285 gearbox). This was sourced at enormous expense and fitted alongside a Quaife ATB differential.

Here are some photos from the build:

Standard box opened up:


Ratios and synchros removed for inspection:


Checking clearance on the new crownwheel:


Thoroughly cleaned and inspected prior to reassembly:


Casings cleaned and bearings checked:


Rebuilt:


Straight cut final drive:


Gearbox casing was also painted silver:


The final drive kit reduces all in gear speeds proportionally and it felt much nicer in the limited running in miles I managed in the car before I took it off the road to concentrate on expanding the business.

Standard Ratios vs. Revised Ratios
(converted to a :1 as the 3 shaft setup gets complicated to explain otherwise!)

Gear STD FD Ratio Mod FD Ratio
1 12.8448 15.46282
2 7.8048 9.39557
3 5.6525 6.65
4 4.6325 5.45
5 3.8304 4.61111
6 3.1392 3.77903


Standard ratios on standard ST170 195/45/17 tyres work out to be:

Top Gear gives 23.332 MPH/1000 RPM and a top speed of 167.990 MPH at 7200 RPM

Engine speeds in top gear:-
30 MPH = 1286 RPM 40 MPH = 1714 RPM 50 MPH = 2143 RPM 60 MPH = 2572 RPM
70 MPH = 3000 RPM 80 MPH = 3429 RPM 90 MPH = 3857 RPM 100 MPH = 4286 RPM

Top Speed in 1 gear = 41.197 MPH
And changes into 2 gear at 4388 RPM dropping 2812 RPM
Top Speed in 2 gear = 67.605 MPH
And changes into 3 gear at 5215 RPM dropping 1985 RPM
Top Speed in 3 gear = 93.331 MPH
And changes into 4 gear at 5903 RPM dropping 1297 RPM
Top Speed in 4 gear = 113.843 MPH
And changes into 5 gear at 5953 RPM dropping 1247 RPM
Top Speed in 5 gear = 137.681 MPH
And changes into 6 gear at 5901 RPM dropping 1299 RPM
Top Speed in 6 gear = 167.990 MPH

With the revised ratios:

Top Gear gives 19.380 MPH/1000 RPM and a top speed of 139.539 MPH at 7200 RPM

Engine speeds in top gear:-
30 MPH = 1548 RPM 40 MPH = 2064 RPM 50 MPH = 2580 RPM 60 MPH = 3096 RPM
70 MPH = 3612 RPM 80 MPH = 4128 RPM 90 MPH = 4644 RPM 100 MPH = 5160 RPM

Top Speed in 1 gear = 34.104 MPH
And changes into 2 gear at 4375 RPM dropping 2825 RPM
Top Speed in 2 gear = 56.128 MPH
And changes into 3 gear at 5096 RPM dropping 2104 RPM
Top Speed in 3 gear = 79.296 MPH
And changes into 4 gear at 5901 RPM dropping 1299 RPM
Top Speed in 4 gear = 96.756 MPH
And changes into 5 gear at 6092 RPM dropping 1108 RPM
Top Speed in 5 gear = 114.361 MPH
And changes into 6 gear at 5901 RPM dropping 1299 RPM
Top Speed in 6 gear = 139.539 MPH


Gearbox cost me over £2000 to build and drove faultlessly for the very limited (sub 200 miles) running in I did with the car. Being straight cut on the final drive it does have that 'straight cut whine', be warned

I'm asking £1250 for a quick sale

 

No longer for sale.