17 replies to this topic

[THE STIG]

do you use the clutch on up changes ?

[SukiDawg]

Many people who ride bikes will use the clutch on an upchange, but if you know what you're doing its not strictly necessary.

With a BEC, the inertia of the driveline is higher downstream of the clutch, which actually mekes shift without lift (S.W.L.) a little easier to achive with a short lift of the throttle. The straight cut dogs and lack of synchromesh in a motorcycle gearbox lend themselves to a clucthless gear change - and it should be achievable with a throttle lift. As the idea of a clutchless change is to minimise the time spent off the power though, you can improve it further by introducing either a complete or ramped igntiion cut to momentarily reduce the torque produced by the engine, facilitating a gearchange. This can be activated by a sensor in the shift linkage or by a button on the gearstick / paddle.


Most BEC's (non-mini, as thats where my experiance lies) use some from of ignition cut for their upshifts.

[THE STIG]

yep i know all that i ride a bike have done for many years and most time dont use clutch for up shifts as just back of thottle , most bike engined race cars use a trickshift as interrupts the igntion for a split second while changing meaning they can do full power shifts

just wondered if made any diiferance with the extra weight of the car and if anyone did it

Edited by THE STIG, 28 May 2009 - 11:46 AM.

[alexcrosse]

i never used the clutch on upshifts, and didnt have an quickshift system either. Its too clunky and loads up the drivetrain alot if you use a clutch imo.

[THE STIG]

i never used the clutch on upshifts, and didnt have an quickshift system either. Its too clunky and loads up the drivetrain alot if you use a clutch imo.

you dont need a quickshift system unless doing full power shifts ie you foot stay flat to the floor as you shift

[alexcrosse]

i no... i was answering your question, no i didnt use the clutch, and going on the previous post mentioning i didnt have a quickshift...

if you already no all of this why did u ask? urgh, confused

[THE STIG]

i no... i was answering your question, no i didnt use the clutch, and going on the previous post mentioning i didnt have a quickshift...

if you already no all of this why did u ask? urgh, confused

because a bike wieghs a hell of a lot less than a mini with a bike engine in it, and have only driven cars fitted with bike engines that have trick shifters fitted

hence the question asked do people with bike powered mini use the clutch on up shifts

question is really not that hard is it

[alexcrosse]

and i was answering it, having owned a bike engineed mini...

not a complex answer was it?

[roofless]

most of the time unless I'm showing off.

[Mini_the_Minx]

I would usually use it, unless of course like SukiDawg says, you know what your doing. But changing without the use of the clutch does put extra wear on your plates.

The amount of bikes I had in that had mashed their clutch plates/friction plates because the rider tried an up shift not using a clutch and didn't know what s/he was doing. Its pretty much the same principle as a bike and as you ride them Stig you should know what your doing.

[Basky]

yep i know all that i ride a bike have done for many years and most time dont use clutch for up shifts as just back of thottle , most bike engined race cars use a trickshift as interrupts the igntion for a split second while changing meaning they can do full power shifts

just wondered if made any diiferance with the extra weight of the car and if anyone did it

How do you get on in life! a guy kindly replied back to you & this is your statement! Alex replied to you & you argue! i did see this post from the start & owning an R1 mini & driven 99% types of mini out there bla bla i could answer swiftly in detail but due to our past dealings etc i couldn't be bothered as i knew you would argue etc bla bla

[THE STIG]

get on in life very well thanks

the statemnet did not aswer the question i asked

i just pointed out that i knew that maybe i should have put has anyone on e here with a bike powered mini ghanged gears with out the clutch who does not have a quick shifter

if you think stating something is arguing then thats your opion and your intitled to it,

only time have had any dealings with you is you wanted a centreconsloe but did not want to pay the asking price ,even after gave you the dash cheaper than the asking price at the mini show after you pleaded poverty if that a bad thing then sorry i help you out am such a bad person like that

and dont see how your post is relivent the the question asked !!!

Edited by THE STIG, 29 May 2009 - 09:38 AM.

[SukiDawg]

Oh go on then, I'll bite. I really don't want to start a row here, so I'll leave it at this unless there is something else you would like to know which I may be able to help with.

I did answer your question completely in a way. You were not entirely specific, but "do you use the clutch on up changes ?" can easily be interpreted as "can you change up without the clutch?". Also - you made no mention of mini's whatsoever - and as its directed at "bike engine guys" and I have some experience in this area (and also - as it happens - extensive professional experience of shift strategy tuning from a somewhat more serious arena) I felt I could help with an answer, which I gave as comprehensively as I could.



You further clarified it by explaining that you knew it was possible, but were simply enquiring as to the feasibility of it given the extra "weight of the mini".

As it happens, to be pedantic, the "weight" of the mini, i.e. the force exerted on the ground due to the action of gravity on the MASS of the vehicle has no effect on the gearshift feel whatsoever. The ROTATIONAL INERTIA of the driveline downstream of the clutch, in combination with the greater LINEAR INERTIA of the vehicle mass will effect shift feel and ultimately the speed in which you can achieve a gear change. INERTIA and WEIGHT are two physical quantities, which both relate to the mass of something but are not the same thing at all. Ask an astronaut for a further explanation if you need it. Greater mass DOES mean greater inertia though.


My answer references the increase in inertia, and it's effect on the achievable shift time. So - I also kind of answered your question in the sense that you asked it.

The most basic SWL system (or a full power "trickshift" as you refer to it) will achieve a reduction in the torque transmitted across the drive dogs of the gearbox - allowing a shift - by cutting the ignition momentarily. As engine power and rpm increases, this becomes potentially very harmful to the mechanical components of the gearbox as a step change in torque when the ignition comes back in will rip the dogs off the gears.

Partly for this reason a ramped ignition retard is used (the controlling software to govern the shift strategy resides in "proper" racing engine ECU's) to gain some control over the loads induced in the transmission. With a gearbox designed with SWL in mind the dogs have a special shape to them which means the dogs "pull" into one another with this ramped torque reintroduction further reducing the shift time.


If the shortness of your answer was due to my recent rant elsewhere, I suggest you grow up.

[THE STIG]

Oh go on then, I'll bite. I really don't want to start a row here, so I'll leave it at this unless there is something else you would like to know which I may be able to help with.

I did answer your question completely in a way. You were not entirely specific, but "do you use the clutch on up changes ?" can easily be interpreted as "can you change up without the clutch?". Also - you made no mention of mini's whatsoever - and as its directed at "bike engine guys" and I have some experience in this area (and also - as it happens - extensive professional experience of shift strategy tuning from a somewhat more serious arena) I felt I could help with an answer, which I gave as comprehensively as I could.



You further clarified it by explaining that you knew it was possible, but were simply enquiring as to the feasibility of it given the extra "weight of the mini".

As it happens, to be pedantic, the "weight" of the mini, i.e. the force exerted on the ground due to the action of gravity on the MASS of the vehicle has no effect on the gearshift feel whatsoever. The ROTATIONAL INERTIA of the driveline downstream of the clutch, in combination with the greater LINEAR INERTIA of the vehicle mass will effect shift feel and ultimately the speed in which you can achieve a gear change. INERTIA and WEIGHT are two physical quantities, which both relate to the mass of something but are not the same thing at all. Ask an astronaut for a further explanation if you need it. Greater mass DOES mean greater inertia though.


My answer references the increase in inertia, and it's effect on the achievable shift time. So - I also kind of answered your question in the sense that you asked it.

The most basic SWL system (or a full power "trickshift" as you refer to it) will achieve a reduction in the torque transmitted across the drive dogs of the gearbox - allowing a shift - by cutting the ignition momentarily. As engine power and rpm increases, this becomes potentially very harmful to the mechanical components of the gearbox as a step change in torque when the ignition comes back in will rip the dogs off the gears.

Partly for this reason a ramped ignition retard is used (the controlling software to govern the shift strategy resides in "proper" racing engine ECU's) to gain some control over the loads induced in the transmission. With a gearbox designed with SWL in mind the dogs have a special shape to them which means the dogs "pull" into one another with this ramped torque reintroduction further reducing the shift time.


If the shortness of your answer was due to my recent rant elsewhere, I suggest you grow up.

right this is not arguing this is just adressing some pionts made (just in case as some people dont know the differance )

i asked do you use the clutch on up changes and yes you interpreted that as can you , but thats not what i asked as already know you can
and know how engine and quick shifters work

as for no mention of minis asked the question on a mini forum where the people posting have done the convertion not on a bike engined car forum,so would have thought it was pritty obvous

hence me saying i already know that ,and had nothing to do with your other posts ,so think you may be being a bit paranoid ,

and at 40 years old dont think i need to grow up much more!!!!

so wanted a simple anwer to a question do people with bike engines (in mins) use the clutch on up changes

not can you , how do engines work , how to quick shifts work


and got 3 replies to the question a few other posts that did not answer the question asked !!!

Edited by THE STIG, 02 June 2009 - 08:04 AM.

[SukiDawg]

That is all well and good, but did it really require the short, kurt reply when I was just trying to answer your question in good faith? If it so important that people answer correctly first time you should be more specific.

Anyway, I'm glad you found out what you wanted.

Thanks,

Dave.