18 replies to this topic

[fikasteve]

Would close ratio gears, like the mini spares clubman straight cut ones, with a 3.44 final drive be a pain if used for normal road use? It wouldn't be a lairy 1275 engine at all. Just think pulling away in traffic could become hard?

[Cooperman]

There really is no point in close ratio gears for a road car. Look at the reason for fitting closer ratio gears. It is to keep a higher-revving engine with a smaller power band 'on the cam' so that when you change up at just over peak revs, say 6000+, the revs in the new gear are still within the power band.#]The best gear ratios for road use are those of the original Cooper 'S'/Mini Clubman GT which may well still be available from Mini Spares.

[bmcecosse]

Close ratio gears are a delight to run with - but you do need a decent engine to get the best from them.

[86mayfair]

3.44 isn't that long a diff is it? I thought it was standard for most Minis?

[bmcecosse]

3.44 is a good compromise for a road car.

[fikasteve]

I'll fully admit i don't need them, and the reason for having them i'd admit is silly. Its the noise im after as its my one guilty pleasure im going to allow myself. However the drops will be too much so thought these would be a good middle ground. Plus when im on the motorway in fourth gear then it would be quiet which would be good.

I know its a little bit of a stupid reason to get them but i do fancy the noise, just not too much of it. If it will be pain to drive though then i'll leave them.

[86mayfair]

Trouble is, on the motorway it wouldn't be quiet because the engine would be reving higher because of the shorter gears! They're not really necessary on road cars most of the time

[fikasteve]

Yeah the engine would be loud but at least some straight cut drops wouldn't be screaming at me lol

[bmcecosse]

Top gear in all the (4 speed) sets is 1:1............ so 'noise on motorway' is not affected one way or the other.

[fikasteve]

Thats why i thought it would be perfect, as no gear noise when your in 4th driving distances, but it'll be there in 1st, 2nd and 3rd when you'd might want it and its not quite as harsh. Thought it was a good compromise!

[Cooperman]

In traffic 1st gear would be rather high unless you fitted a lower final drive ratio (FDR). But doing that puts up the cruising revs in top gear for a given road speed. Leaving a high FDR in just really increases clutch wear due to the need to slip it a lot when starting, especially up steep hills. I once tried SC CR gears on an 'S' with a 3.44 FDR and 1st seemed to go on forever. A 3.76:1 FDR might work so long as the cam is not too hot, like up to say a 276. That would give about 4600 rpm in top at 70 mph.

Edited by Cooperman, 29 June 2012 - 06:09 PM.

[fikasteve]

Hmm I dont think there is a compromise that works for me then unless anybody else has any ideas? I'm going to keep the original mg metro cam if its in good condition, if its not probably a Sw5 or 266! All seems a bit much just for a noise for guilty pleasure haha. I'm not really prepared to put drops in as the noise is too much and will drive me mad in no time. Shame there isn't straight cut gears with normal mini ratio's for the gearbox that i could use

[Cooperman]

Normal ratio gears are fine with the helical cut as they cater for flexible engines and such engines don't have a narrow power band so don't need the close ratios to keep them 'on the cam' in competition, which is what the close ratio straight cuts are really for. I've used helical gears at standard ratio in rally cars with up to around 95+ bhp with no problems, although I normally use quite a low FDR like 3.44:1.

[racingbob]

Would close ratio gears, like the mini spares clubman straight cut ones, with a 3.44 final drive be a pain if used for normal road use? It wouldn't be a lairy 1275 engine at all. Just think pulling away in traffic could become hard?

why would a 3.44 dif be hard pulling away from lights, mines fine

[Cooperman]

I have used a 3.44 with SCCR gears and whilst 1st is very high, so long as a 'hot' cam is not fitted it's not a problem. However, having to slip the clutch a bit more does slightly increase the 0 - 60 time compared to using standard helical gears. I used a 510 'S' cam and on the road in the UK it was fine. When I drove it up the Alps I found the gearing to be far too high low down. Then I fitted a 544 cam and a 3.9:1 FDR and that is what I now always use - but that's for competition really.
For road use there is little, if anything, to be gained by using SCCR gears and a bit to be lost in overall capability terms.
In my opinion SCCR gears are really great in 'hot' engines for competition - in fact they are essential - but not really any advantage for road use.