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#31 Ivor Badger

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Posted 11 March 2016 - 09:04 PM

MRA. you are the person who brought up the financial aspect of parts. As for SCs on the road, well the're ok till the novelty wears off, which will probably be around 5 miles.



#32 Cooperman

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Posted 11 March 2016 - 09:28 PM

There often seems to be a lot of confusion about the advantages of SC CR gears.

If a cam which gives a narrow power & torque band is fitted, such as a 286, 296, 649 or similar full-on competition cam is fitted, then a SC CR 'box is needed, but combined with a much lower final drive ratio (FDR). The SC CR gear ratios have a very high first gear, so to enable the car to pull away with good acceleration a much lower FDR is essential. This, in turn, means a lower speed per 1000 rpm in top gear, but with a narrower-band cam the revs used will be higher and the car might be expected to spend a lot of time at well over 5000 rpm, with peak revs at probably just over 7000 rpm. The advantage of the SC CR 'box is that at the point of up-change the revs will only drop back to a level where good torque/power is being developed. In the case of, say, a 649 cam that might mean changing up at 6800 rpm and being right 'on the money' at about 5200 rpm in the next gear. So for a competition engine it is what is needed.

 

For a road engine the disadvantages of a SC CR 'box are that 1st gear is high, so there is a lot of clutch-slipping and poor acceleration unless again a low FDR is fitted, in which case cruising speed will be low and revs at cruise will be high.

 

You don't fit a SC CR 'box for 'bar room bragging', you fit it for serious competition.

 

SC drop gears are quite simply to enable the overall gear ratios to be altered slightly for different circuits or hills, so that max revs can still be used on the longest straight, without having to remove the engine to fit a different ratio diff. There is no other real reason except to reduce the end loading on the transfer gear bushes.

 

When used as intended it would be supposed that a crash helmet would be being worn or, on road sections of rallies, ear plugs.



#33 MRA

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Posted 11 March 2016 - 11:08 PM

The real point is that straight cut gears, LSDs and all these supposedly nice things to impress people with your mini and cash flow are in effect competition parts for competition use. The noise and other disadvantages are not a problem in competition use, you can't hear the box anyway over the other noises. There are obvious performance advantages, but not on the road as the mental degradation in a short period will soon reduce your speed. If you could find a measurable advantage on the road, you probably require your head looked and a bus travel card shortly.

 

To some, but not all, some people like the SC noise, and the rorty exhausts etc....  Unless you drive a bicycle the chances are you drive what you drive for a few reasons,

1) it was available and at the price you wanted to pay...

2) because you like it,

3) to impress your mates.

 

Now whilst you can do a lot with a Mini, 80% of them would not impress your mates other than because of the fun value.

 

Most people I know that want to impress their mates with cars, buy subura's, bmw's, mercedes, ford ST's etc etc....  The people I know with fast Mini's or special Mini's tend to just keep quiet and watch & listen whilst others talk about their fast cars..... 



#34 MRA

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Posted 11 March 2016 - 11:12 PM

MRA. you are the person who brought up the financial aspect of parts. As for SCs on the road, well the're ok till the novelty wears off, which will probably be around 5 miles.

Financial aspects ???  not sure I follow.

 

But I will tell you this, your opinion means nothing to me, simply because I have had SC gearboxes in all my Minis since the 80's  I have used them for daily drives and play things, I have driven hundreds of miles in one stint, stopping for fuel and other breaks I used to drive 89 miles each way every day for to and from work and I did this for about 2.5 years, no issues at all, I think SC gears are like marmite you either love them or hate them it is a choice thing..... but 5 miles ?  lol



#35 MRA

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Posted 11 March 2016 - 11:29 PM

There often seems to be a lot of confusion about the advantages of SC CR gears.

If a cam which gives a narrow power & torque band is fitted, such as a 286, 296, 649 or similar full-on competition cam is fitted, then a SC CR 'box is needed, but combined with a much lower final drive ratio (FDR). The SC CR gear ratios have a very high first gear, so to enable the car to pull away with good acceleration a much lower FDR is essential. This, in turn, means a lower speed per 1000 rpm in top gear, but with a narrower-band cam the revs used will be higher and the car might be expected to spend a lot of time at well over 5000 rpm, with peak revs at probably just over 7000 rpm. The advantage of the SC CR 'box is that at the point of up-change the revs will only drop back to a level where good torque/power is being developed. In the case of, say, a 649 cam that might mean changing up at 6800 rpm and being right 'on the money' at about 5200 rpm in the next gear. So for a competition engine it is what is needed.

 

For a road engine the disadvantages of a SC CR 'box are that 1st gear is high, so there is a lot of clutch-slipping and poor acceleration unless again a low FDR is fitted, in which case cruising speed will be low and revs at cruise will be high.

 

You don't fit a SC CR 'box for 'bar room bragging', you fit it for serious competition.

 

SC drop gears are quite simply to enable the overall gear ratios to be altered slightly for different circuits or hills, so that max revs can still be used on the longest straight, without having to remove the engine to fit a different ratio diff. There is no other real reason except to reduce the end loading on the transfer gear bushes.

 

When used as intended it would be supposed that a crash helmet would be being worn or, on road sections of rallies, ear plugs.

Peter I cannot agree with you on some of your points, for starters I will often change up at 2500 to 3000 rpm which means I can go through the gears and not thrash the engine but still keep up or out accelerate others.   As for lack of acceleration I have a SC in my cooper SPi which is about 80 to 85bhp with a 2.95:1 FDR on 12" tyres I can use the torque that  a race engine lacks to pull away cleanly in first with little more than normal clutch slip but still get to 52mph in first gear so one less gear change which would normally cost you 1 to 2 seconds in fact in my turbo I get to 62mph in first and can still if I want to wheel spin it off the line and get in to second before I start to move I did it in the carpark at Bingley hall some years ago to prove the point (empty bit)

 

I think you should fit one to a fairly average road Mini and see the effects, of course the noise is not for everyone, but personally I like it, and I know others that also like the noise it makes, I did draw the line at SC FD as they are considerably noisier, but again there are still those who will put up with it just the same as those that will fit a 18k rev bike engine on the back seat.... 

 

A race engine needs a closer ratio gear kit, a none race engine can use either and still be effective.

 

And for anyone's information the last time I was in a bar was Christmas.

 

For years you could only get 1:1 drop gears the other ratios came out in the early 90's I believe.

 

Come on Peter surely you don't believe that ?  a crash helmet or earplugs ?  SC gears where fitted as standard years ago you must remember that ?  and racing was going oon well before crash helmets and earplugs !


Edited by MRA, 11 March 2016 - 11:35 PM.


#36 Cooperman

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Posted 12 March 2016 - 09:15 AM

If you suffered from tinnitus as badly as I do, no doubt caused by exposure to workshop and motor sport noise over many years you would wear and advise others to wear ear plugs when driving with straight cut gear sets.
Tinnitus is really unpleasant and impacts on quality of life.
I started in motor sport in 1959 and crash helmets were required back then.

But back to SC boxes, the reason for them is to keep narrow power band engines 'on the cam' and for broad power band units they are not an advantage and are usually a disadvantage. The standard ratios are excellent for all road driving.

#37 MRA

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Posted 12 March 2016 - 09:34 AM

If you suffered from tinnitus as badly as I do, no doubt caused by exposure to workshop and motor sport noise over many years you would wear and advise others to wear ear plugs when driving with straight cut gear sets.
Tinnitus is really unpleasant and impacts on quality of life.
I started in motor sport in 1959 and crash helmets were required back then.

But back to SC boxes, the reason for them is to keep narrow power band engines 'on the cam' and for broad power band units they are not an advantage and are usually a disadvantage. The standard ratios are excellent for all road driving.

If close ratio boxes are not an advantage why have some new cars started using them with 7, 8 and 9 gears ?  when just a few years ago 5 would do ?

 

I will not agree with you Peter, I have done too much research over the years to be drawn in to the thinking that close ratio gearboxes are not an advantage on the road, especially in light of the facts, one of which is "Engineering is a compromise"

 

Every time you have wanted to drop down a gear on the road but couldn't because it would mean the engine is over revving .....  a close ratio gearbox would no doubt have been a benefit !


Edited by MRA, 12 March 2016 - 09:38 AM.


#38 Cooperman

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Posted 12 March 2016 - 11:10 AM

We shall just have to disagree then.
The reason 6, 7, & 8 speed boxes have been introduced is to enable diesel engines with their narrow torque bands to be sold for modern cars.
On an old 4 cylinder petrol engine a close ratio box is quite simply to keep within the optimum power band. With, say, a 6 speed box there will be enough gears to cover a full speed range including the ability to start off on a steep hill and when heavily loaded or towing.
A 4 speed CR box on a broad power/torque engine is a mis-match. Gearing is chosen to suit the engine performance which is why 40 tonne trucks with high-power narrow band diesel engines need loads of gears.

#39 MRA

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Posted 12 March 2016 - 11:18 AM

We shall just have to disagree then.

A 4 speed CR box on a broad power/torque engine is a mis-match. Gearing is chosen to suit the engine performance

 

Yep we will just have to agree to disagree



#40 Ivor Badger

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Posted 12 March 2016 - 11:49 AM

 

MRA. you are the person who brought up the financial aspect of parts. As for SCs on the road, well the're ok till the novelty wears off, which will probably be around 5 miles.

Financial aspects ???  not sure I follow.

 

But I will tell you this, your opinion means nothing to me, simply because I have had SC gearboxes in all my Minis since the 80's  I have used them for daily drives and play things, I have driven hundreds of miles in one stint, stopping for fuel and other breaks I used to drive 89 miles each way every day for to and from work and I did this for about 2.5 years, no issues at all, I think SC gears are like marmite you either love them or hate them it is a choice thing..... but 5 miles ?  lol

 

 

You are assuming that you are the only person on here that has used a SC box. some of us have and a considerable time before yourself. My first S had the close ratio helical box and would always get beaten off the line at traffic lights etc. Worst was getting stopped in Appelby on a hill with a trailer, luckily it was wet and we used  wheelspin to get moving. Doubt it did much for the diff cross pin.



#41 MRA

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Posted 12 March 2016 - 12:13 PM

 

 

MRA. you are the person who brought up the financial aspect of parts. As for SCs on the road, well the're ok till the novelty wears off, which will probably be around 5 miles.

Financial aspects ???  not sure I follow.

 

But I will tell you this, your opinion means nothing to me, simply because I have had SC gearboxes in all my Minis since the 80's  I have used them for daily drives and play things, I have driven hundreds of miles in one stint, stopping for fuel and other breaks I used to drive 89 miles each way every day for to and from work and I did this for about 2.5 years, no issues at all, I think SC gears are like marmite you either love them or hate them it is a choice thing..... but 5 miles ?  lol

 

 

You are assuming that you are the only person on here that has used a SC box. some of us have and a considerable time before yourself. My first S had the close ratio helical box and would always get beaten off the line at traffic lights etc. Worst was getting stopped in Appelby on a hill with a trailer, luckily it was wet and we used  wheelspin to get moving. Doubt it did much for the diff cross pin.

 

No I am not assuming that others have never had SC gearboxes, but people are making sweeping statements and trying toi make them sound like facts without backing it up, just because you don't like SC gearboxes (and by the way the 3 synchro was a lot loader than the later type) I have moved with the times in that I have used 3 synchro, 4 synchro, dog engagement, 4 speed, 5 speed and six speed boxes, I would always try to opt for a direct top gearbox if it was SC as that quiets them down a fair bit making road driving less noisy..... I pulled a trailer with a friends mini on it !  yes dangerous on the road but I was on a private road it pulled it no problem, a little more revs and away it went, ok that was 1380 turbo power not standard 850 by any stretch of the imagination...

 

What I am trying to say Mr Badger is that we are all different, when giving advice it should be down the lines of advice and not like some "preaching"  my personal stance is that some will and some will not like a SC gearbox, I have already advised that the OP should get a ride with somebody who has one before spending the money, they should also make adjustments as to the FD ratio the type of engine etc as to make a better informed judgement, "just saying SC are no good on the road helps nobody"  how can anyone make a judgement based on that ?  if it where a voting system then of course but it isn't !, I was never told when I went to fit my very first SC gearbox that I wouldn't like it, the guy just said "it isn't for everyone, and personally I love them, you can almost change down at any time to get the acceleration you want, the screaming banshee is a joy to hear, but like I said above and in other similar posts, SC gears are like Marmite, you either love them or hate them.

 

PS are you sure about my age ?  You appear to be assuming my age ?? may be not but the point still remains a fact SCCR gear boxes do have benefits on the road, but if you want Rolls Royce comfort...... go get a Rolls Royce.



#42 Ivor Badger

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Posted 12 March 2016 - 12:28 PM

MRA< on your 89 mile journey, how much time did you save with your SC box? You are also assuming my age.



#43 midridge2

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Posted 12 March 2016 - 12:54 PM

Why oh why do we have this continuing attitude from MRA, why be rude to people. 



#44 MRA

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Posted 12 March 2016 - 01:24 PM

Why oh why do we have this continuing attitude from MRA, why be rude to people. 

I was just giving you the opportunity to jump in yet again ..... why else.



#45 MRA

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Posted 12 March 2016 - 01:27 PM

MRA< on your 89 mile journey, how much time did you save with your SC box? You are also assuming my age.

not at all Mr Badger, you mentioned your age I was just pointing out that fact, about 10 minutes.....  I didn't fit it to save time, I fitted it for fun, to enjoy, the same reason you took yours out, because you wanted to enjoy your Mini, like I keep saying I have no issue with those who don't want them it is a personal thing, but you cannot talk for everyone.







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