I am sure some on this group will know me, Andrew Goater, regarding PG1 gearbox building. Over the last 10 or more years, I have supplied numerous B4BP close ratio gearboxes for Lotus cars on this group.
For racing the B4BP is too long gears. In a similar way that Lotus have their own UCR gear in the 340R cars, I have had custom made a 3 gear (6 sprocket) kit which uses the original C ratio gears 1 and 2 but a very close ratio 3, 4 and 5. The intention is you only use 1st gear off the line and 2 to 5 are very close. It fits a C6BP 3.9 final drive box and on 16″ wheels gives a top speed of 125mph. If you use bigger wheels or your engine revs more than 7500rpm a 4.2 final drive can be used.
The gears are helical and are the same tooth design as the original gears. So, unlike using straight cut, these are quiet.
3rd, 1.47. 4th, 1.222, 5th, 1.034.
At 70mph (113kph) the rpm’s are at 4500 in top gear. This does mean it’s very fast to accelerate at this speed though!
Happy to take any questions on these gear kits which can be sent worldwide as required using UPS courier.
The UCR gear kit can be supplied and built into a reconditioned gearbox for £1600.
There are gear calculations done at the end of the photos. I can sort another chart to suit your exact car if it’s different from the photo’s shown.
I actually have this gear set fitted in my road car (not a Lotus) just as a test. I can confirm with a video this really does work.
Listing ID: 342686bd12f64077
Comments