is clutching to netural and then cluth off from neutral to whichever gear "SAME" as clutching and then gasing and then off clutch? what is the reason for shiting to neutral before gasing then????

 

The reason for double clutching is to bring the rpm's of the engine upward to match next gear so there is no lug. This aids in shifting since there is less wear and tear on the syncros in the transmission. It also allows easier shifting if there ARE no syncros such as vintage cars, trucks, etc.

The thing is, with the quality of modern transmissions, the power and torque in modern cars, and the ability to shift so quickly that rpms do not drop very much at all, that you do not need to double clutch any more at all.

Don't confuse this with heel & toe shifting.
If you are "downshifting", you can heel & toe to bring the rpms up to to match the speed of the transmission so you don't either overspin the engine or lug the car depending on the situation.



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<img src="http://fototime.com/D433293586DC999/standard.jpg" border=0>
Pepper! '04 MCS
Brad's Garage and Cars

 

The reason to put the gear into neutral before blipping the throttle is to match the engine/transmission's speed to that of the prop shaft speed...or have I got that mixed up? Impossible to understand until it's second nature. Braking while down shiftn is whole nother ball game which will complete your heel/toe driving experience.

Might want to do this pedal mod too:



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in a nutshell, when you double clutch you relieve the stress on the
target gear's synchronizer. check out www.howstuffworks. to learn
fundamentals of a sychro-meshed transmission. Until you understand
the basic mechanics, it probably won't shed much light why we do this on a
synchro-meshed gear box.

 

but there is no difference whether i simply clutch and then rev VS clutch and then physically shift the lever to neutral and then rev right?

as i clutch down (i am already in neutral) so i can rev with the gas pedal....

don't understand the need to shift the stick to neutral before shifting??

many thx!!!!!!!!!

 

yeh me neither

 

When you clutch-in, you are not in neutral..you are still in gear.
since you disconnected the input shaft from the motor you feel like you are in
neutral, but you're not until you physically move the lever into neutral.

The reason for double clutching (especially good when you're skipping
a gear or two) on a down shift is so that you can speed up (blip) the
engine while in neutral to enable proper speed with the layshaft and
your target gear so that the collar's dog teeth off your fork can smoothly
engage into the target gear without hesitation. It helps assist the syncro's as
the target gear is rotating much faster while skipping a gear on a down
shift. Sometimes synrchro's can not speed up the collar enough to
match the target gear's rotation and cause a lock-out state.

again, check out howstuffworks.com if this doesn't make any sense.
someone correct me if my interpretation is incorrect.

sames goes for double clutch shift up as well, just the otherway around.

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03MCS IB/Blk: 123, Aerokit, R90 17x7, Anthr + Leather, TK5 16x7, 6CDMP3, etc.

 

>>but there is no difference whether i simply clutch and then rev VS clutch and then physically shift the lever to neutral and then rev right?
>>
>>as i clutch down (i am already in neutral) so i can rev with the gas pedal....
>>
>>don't understand the need to shift the stick to neutral before shifting??
>>

There is no difference; yes, you can rev the the engine since it is disengaged from the gearbox.

 

 

Just to prevent this from going totally off track, would you mind starting another thread in off topic and telling us a little more about driving a semi. Things of interest off the top of my head are gearing, manuverablity, blind spots, handling in bad weather? Which are the drive axles?

Thanks,
Dave

 

MSFITOY has a great "heel and toe" explanation! Think of the clutch as being one point of transmission disengagement, and neutral on the gearshift being the other. Following his explanation, you are simply trying to get the part of the transmission between the clutch and the output shaft spinning at the same speed as the gear ratio you are preparing to select.

When you do it right, it's the same kind of feeling as hitting the golf ball at the "sweet spot" on the club. If you're on the track, and have the skill to pull off a double clutch, it will not upset the balance of the car since there will be no addiditional weight transfer due to shifting.

DesignIt

 

>> :smile:

 

>>>> :smile:
Let me try then.
It is almost the same....
if you do not let the the clutch out as you pass through N and you blip the gas you rase the RPMs of the motor and you can match the engine speed with the wheel speed. But this does nothing to help the gears in the trans.

When you Double clutch in addition to bringing the engine and wheels into the same ball park for relitive speed - the insides of the Trans are all in motion and the shift can be made more smoothly.

As alread stated the MC & MCS have sencro 1 through what ever. Blipping the gas between gears on a down shift of one gear will most often do the job. However, If you drop more than one gear (my MC going 50 getting ready to pass 5th to 3rd) sometimes a double clutching will make the shift quicker and smoother as the gears inside the trans are all in motion.

I learned to down shift into 1 on my AH3000. Very useful in stop and go traffic and when 2 just was not low enough.

 

>>is clutching to netural and then cluth off from neutral to whichever gear "SAME" as clutching and then gasing and then off clutch? what is the reason for shiting to neutral before gasing then????


I heel toe and double clutch when I drive on the street. I road race cars, so I learned to do both as a result of racing. In my opionion, I think it's easier to heel toe if you double clutch. With a newer car, it's not neccessary to double clutch (though I prefer to) but I think everyone who drives a manual transmission should learn to heel toe. Once you learn how, you'll be so gald you did and wonder why you didn't learn it that way in the first place.

Good Luck!!!

RaceCarDriver

 

I first downshifted into first in my MCS - in stock form. Heck I did it quite often. You had to if you were cruising around in 2nd and needed to take off quickly. I still did it somewhat frequently with the 15% pulley but I can't say I've done it yet in 2+ weeks with the 19% pulley.

 

>>>>
>>Just to prevent this from going totally off track, would you mind starting another thread in off topic and telling us a little more about driving a semi. Things of interest off the top of my head are gearing, manuverablity, blind spots, handling in bad weather? Which are the drive axles?
>>
>>Thanks,
>>Dave

Soyintly

It was a long time ago and very scary memories Will post later.

Sid

 

Here you go DiD:

https://www.northamericanmotoring.co...ic=21269&1

I missed some of your points of interest. I'll add more detail if there's interest.
It's not showing up on the 5 recent topics however.

Sid

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