Angus Posted October 13, 2007 Posted October 13, 2007 Are there alternative ratios for the 6-speed box ? Specifically I am looking for a taller 6th ratio than the standard 1:1 I want a more relaxed top gear for touring. I do not want to change the diff (3.92) as I want to keep the acceleration. Also, can someone point me to a engine speed / gear ratio / mph calculator on the web ? Thanks Angus Angus Denny (ex-Surrey AO and ex-Seven owner who's been away far too long but now seen the light)
MADMALC Posted October 13, 2007 Posted October 13, 2007 I have a spread sheet that I can email you. It is in microsoft works format. Let me know if it is of use. S7MAD
mav Posted October 13, 2007 Posted October 13, 2007 Pretty sure this has been asked before and the answer was no. A search of the archives will reveal the answer...
Alex Wong1697456877 Posted October 13, 2007 Posted October 13, 2007 I run a 3.38 diff with mine. Loads of people said it would be sluggish but it isn't at all. I've toured to the south of france, got a 3rd and 4rh at Curborough against faster cars and has been more than repectable on trackdays. I ran shorter gears with a sequential box but it was slower as the gears were too close and too short.
oilyhands Posted October 13, 2007 Posted October 13, 2007 A taller sixth would be a challenge since it is a direct gear, I.E. 6th is when the first motion shaft and thrid motion shaft are locked together... Oily
Nifty Posted October 13, 2007 Posted October 13, 2007 Phil (Road and Race) told me it is not possible to turn the Caterham 6 speed into an overdrive gearbox. Don't forget road speed will affected by rolling circumference of the tyres as well as gear and diff ratio. Keep off the straight and narrow 😬
Ray Pearce Posted October 13, 2007 Posted October 13, 2007 You can download a nice gear ratio calculator from here
Angus Posted October 13, 2007 Author Posted October 13, 2007 Ray - excellent calculator - thanks for the link Oily - Ah - that would be a fundamental problem I guess, if there are not any actual gears to swap over. Alex - what engine do you run ? Do you still have the Vx ? That should have plenty of torque, well able to take the taller diff. The Duratec also is a torquey engine I believe, so perhaps I could go with a different diff without noticeable loss of acceleration. Rgds Angus
Alaskossie Posted October 13, 2007 Posted October 13, 2007 I am about to try out Alex's advice. I am currently building a 2007 Series 3 Seven and specified the 3.38:1 rear diff ratio from Caterham (at significant extra cost!). I'm trusting that my 2.3 Cosworth Duratec (250 hp spec) will have enough torque to not make the car feel sluggish on acceleration. Highway cruising should be a treat in 6th.... Tom Meacham Alaskossie
Martin Erhard Posted October 14, 2007 Posted October 14, 2007 Didn't Caterham mention a choice of 6 speed boxes in their sales literature a year or two ago?
Area Representative Richard Price Posted October 14, 2007 Area Representative Posted October 14, 2007 Didn't Caterham mention a choice of 6 speed boxes in their sales literature a year or two ago? Yes, but they were refering to different final drive ratios, not gearbox ratio's
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