olij Posted January 14, 2003 Share Posted January 14, 2003 hello, my 7 is a 1400 supersport with a standard 5 speed gearbox and 3.92 LSDiff. What I'd like to know is will a 6 speed gearbox actually make the car noticeabley more accelerative and faster from A to B? I am assuming that it would do, but thought I'd get some opinions before I decide what to do. I guess there won't be much difference between 0-60 times but above that the extra gear would come into play and improve the 0-100 time? anybody quantified this? Also what, besides the gearbox, will I need to buy to do the conversion (I would do it myself) - a clutch for example? Is it just a case of basically lifting out the old one and dropping in the new? Opinions and experiences very welcome thanks Oli Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted January 14, 2003 Share Posted January 14, 2003 Six speed box was basically designed for the 1400 (SS) cars to get 'em to go properly. The first to second change is dreadful on the five as unless you really take the revs well up the scale it drops off the power band upon the change to second. A real nuisance in slow/town driving. Six speed cures that one. Smart changes can be had to keep it all in the power band. But, sixth (top) gear is the equivalent of fourth on the five speed. Try driving it like that and don't change it to fifth on a long haul. Can be a bit wearysome on a 3.92 diff. at motorway cruising speed but great for 'blatting'. Worth the change I think. Speak to Phil at Road & Race Transmissions as he can normally source good 'pre-owned' ones. Clutch etc all the same. Change it and the release bearing (and cover plate too) while the g/box is out though to save hassle/time/money later! Clamshell Club Founder Member. Link to comment Share on other sites More sharing options...
alicat Posted January 14, 2003 Share Posted January 14, 2003 Chris Have a 1.4ss with 6 speed - drove 5's and 6's before buying. 6 speed is well worth it, great fun 😬 😬 😬 😬 Link to comment Share on other sites More sharing options...
scooby dooby doo Posted January 14, 2003 Share Posted January 14, 2003 i'd say fun will be MASSIVELY improved and it will be a bit quicker. the 5 speed is effectively a 3 speed as 1st and 5th aren't much good for accelerating. 6 speed has 6 ratio all of which are useful. Although a 1.4 KSS won't do much in 6th, even with 150 bhp (although on larger 205 tyres) it doesn't really pull. HOOPY 500 kg R706KGU Link to comment Share on other sites More sharing options...
Allen Payne Posted January 15, 2003 Share Posted January 15, 2003 I'll let you know in a couple of weeks Link to comment Share on other sites More sharing options...
Super_Rich_Bernie Posted January 15, 2003 Share Posted January 15, 2003 I changed from a 5 speed 1600 Vauxhall car to a K series with 6 speed. I'm sure that the 6 speed will give some acceleration advantage over the 5speed if you are in a hurry. You could probably get that for less money with a set of close ratios in the 5 speed. However its worth pointing out that the 6 speed has a much more pleasant change, short throws and it moves between gears like a hot knife through butter. Couple it with a revvy engine and light flywheel and you will find yourself changing gear for the hell of it. Childish pleasures maybe but not to be underestimated. Its OK with the 3.92 diff too - 4000 revs at 70 with 205 rear tyres. Jonathan Link to comment Share on other sites More sharing options...
olij Posted January 15, 2003 Author Share Posted January 15, 2003 Thanks a lot for the opinions guys, much appreciated. Allen - could you let me know how you get on with your conversion please? My email is oli_jarratt@yahoo.co.uk - I'd be really interested in hearing what you reckon. thanks again Oli Link to comment Share on other sites More sharing options...
Bob Corb Posted January 15, 2003 Share Posted January 15, 2003 There is a small acceleration advantage with the 6 speed gearbox. In a straight line a 1.8SS (140BHP) with a 6 spd box will accelerate at the same rate as a 1.8VVC(150+BHP with a 5spd) up to around 115mph. Then the more powerful car will crawl ahead. On paper a well spaced 5 spd box such as the SPC/quaife unit will give a better spread of tractive effort than a normal 5spd and given that you wouldn't have to change gear so often it may be the quickest option of all for the road (in a straight line)? The 6 spd gives you more gears so that you can optimise the maximum torque/accel more easily for a wide variety of corners. My calcs were all based on the VVC engine (which I'm about to chuck out so I'll stop singing its praises) so the wide torque spread made the 6 spd a bit superfluous(compared to quiaife 5spd). A 1.4 SS with a more peaky delivery will utilise the 6 spd well, hence I've just (sortof) undermined my own argument.... At the end of the day the slight increase in A to B speed will be irelevant compared to the joy of a tall/useful first gear and then the quickfire change up through the rest of the box. As the man from Evo said: "It's got six gears.. and there all the same!!!" Low Flying Custard Edited by - bob corb on 15 Jan 2003 22:44:43 Link to comment Share on other sites More sharing options...
EFA Posted January 15, 2003 Share Posted January 15, 2003 Nobody mentioned the 6spd is more reliable than the 5 - particularly synchros. Arnie Webb The Fat Bloke back @ 512k Link to comment Share on other sites More sharing options...
Richard J Darnell Posted January 16, 2003 Share Posted January 16, 2003 I upgraded my 1.6k SS from 5 speed to 6 speed and found it to be a very good (albeit expensive)upgrade - the car feels much faster. I kept the 3.92 diff but have 205 rear tyres which helps with the gearing. I was less impressed with the shift quality when the box was new but this has now loosened up nicely. If you have to buy a new 6 speed box it's worth checking out the price of getting Caterham to fit it - this is very little more money as you exchange your 5 speed and saves hassle of storing/selling 5 speed afterwards Link to comment Share on other sites More sharing options...
Alias Posted January 16, 2003 Share Posted January 16, 2003 Would agree with all of the above, but bear in especially bear in mind. 80Mph on a 6 speeder is 4500 revs. Motorways are not fun and to honest, a 1400SS will run out of puff at max revs in fifth. The box really is worth having - most agree that it transforms the car. One car - 1400 Supersport with 6 gears and clamshell wings. Link to comment Share on other sites More sharing options...
Alias Posted January 16, 2003 Share Posted January 16, 2003 In light of the "shortness" of 6th gear, does anyone know how feasible it would be to put a longer 6th gear in to act as a sort of overdrive gear? One car - 1400 Supersport with 6 gears and clamshell wings. Link to comment Share on other sites More sharing options...
Anthony Posted January 16, 2003 Share Posted January 16, 2003 Hi, I have a 6 speed with 3.62 diff, which makes life a bit easier at high speed. With all steel x-flow pulls c. 7400/7500 on back straight at goodwood! It does make first quite a tall gear - and a bore in traffic. One way of having close ratio box but with a bit better motorway/high speed gearing ? Stu's (nee Pinky ) 6 speed tweeked 1600 ( TB's ) with 160 BHP flys with a 3.92 diff in it, v.quick off the mark and perhaps more fun. Link to comment Share on other sites More sharing options...
scooby dooby doo Posted January 16, 2003 Share Posted January 16, 2003 the gearing depends on tyre size and speedo accuracy. woth 205/60R13 rears and a GPS calibrated speedo i get 81 mph at 5000. Also bear in mind that the 6 speed box was designed specifically for the 1.4 K SS. And on the motorway I claim that wind and tye noise etc dominate engine noise... HOOPY 500 kg R706KGU Link to comment Share on other sites More sharing options...
olij Posted January 16, 2003 Author Share Posted January 16, 2003 hmmmm not too worried about motorway type of driving and as you say I could just buy some bigger wheels or tyres. more interested in the b roads and race tracks! Hoopy, do you run a 3.92 diff then? how do I work out the diameter of a 205/60r13 wheel (never really worked that one out) so I can have a play in a gearing calculator? cheers Oli Edited by - oli j on 16 Jan 2003 22:46:10 Link to comment Share on other sites More sharing options...
scooby dooby doo Posted January 16, 2003 Share Posted January 16, 2003 i have a 3.92 - sorry - forgot to mention it. the diameter is worked out from the 205/60R13 numbers, these are various measurements but may not be very accurate. eg a 175/55R13 CR500 os actually 184mm wide. also the tyre distorts and slips when rolling so its not quite the same either. Anyway... using 205/60R13 and calculating diamter the wheel is 13" across which is 13 x 25.4 = 330 mm the side wall is 60% x 205 mm = 123 mm so total diameter is 330 + 123 + 123 = 576 mm circumference = diameter x PI = 576 x 3.14 = 1808 mm HOOPY 500 kg R706KGU Link to comment Share on other sites More sharing options...
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