Shan2nu wrote:
You haven't understood the concept of downshifting.
Synchros cannot match the revs between the engine and the trans, they only help match the revs within the gearbox.
Quote
Unsynchronized transmission
The earliest form of a manual transmission is thought to have been invented by Louis-René Panhard and Emile Levassor in the late 19th century. This type of transmission offered multiple gear ratios and, in most cases, reverse. The gears were typically engaged by sliding them on their shafts—hence the term "shifting gears," which required a lot of careful timing and throttle manipulation when shifting, so that the gears would be spinning at roughly the same speed when engaged; otherwise, the teeth would refuse to mesh. These transmissions are called "sliding mesh" transmissions and sometimes called a crash box. Most newer transmissions instead have all gears mesh at all times but allow some gears to rotate freely on their shafts; gears are engaged using sliding-collar dog clutches; these are referred to as "constant-mesh" transmissions.
In both types, a particular gear combination can only be engaged when the two parts to engage (either gears or dog clutches) are at the same speed. To shift to a higher gear, the transmission is put in neutral and the engine allowed to slow down until the transmission parts for the next gear are at a proper speed to engage. The vehicle also slows while in neutral and that slows other transmission parts, so the time in neutral depends on the grade, wind, and other such factors. To shift to a lower gear, the transmission is put in neutral and the throttle is used to speed up the engine and thus the relevant transmission parts, to match speeds for engaging the next lower gear. For both upshifts and downshifts, the clutch is released (engaged) while in neutral. Some drivers use the clutch only for starting from a stop, and shifts are done without the clutch. Other drivers will depress (disengage) the clutch, shift to neutral, then engage the clutch momentarily to force transmission parts to match the engine speed, then depress the clutch again to shift to the next gear, a process called double clutching. Double clutching is easier to get smooth, as speeds that are close but not quite matched need to speed up or slow down only transmission parts, whereas with the clutch engaged to the engine, mismatched speeds are fighting the rotational inertia and power of the engine.
Manual transmission - Wikipedia, the free encyclopedia
Would you agree the only time the engine speed and the speed of the connected gear box part is not the same is when the clutch is depressed?
Shan2nu wrote:
The engine rpm in a lower gear is always greater than that of a higher gear no matter what speed you downshift at. So shifting from 5th to 3rd even at 30kmph requires the revs to be matched.
That’s where the synchro kicks in.
Shan2nu wrote:
Quote:Agree about the heat problem affecting pad effectiveness though.
Thats what i meant. Our Innova is well known for showing brake fade pretty early. A tad of engine braking solves the whole problem.
But the Innova's brake performance is an exception. Would you agree that a well designed braking system delivers adequate braking without fade?
Shan2nu wrote:
Quote:Safe driving means simple driving, which Heel and Toe is not, though I luv to do it!
Safe driving is safe driving. Simple and Complex depends on how an individual perceives these things.
For a person driving a car for the first time, even something as simple as shifting gears can feel like a highly complex maneuver.
Perceptions change as you learn new things.
Always design for monkey business, I was told. Safe driving is driving designed for the novice driver. The strange thing is that safe vehicles are the ones with the most technology built in. Heel and toe and double declutch are vestiges of the dinosaur boxes.
The more things you have to do, the less time you have for the road. Synchros save you from H&T, ABS saves you from pumping and EPS saves you from steering into the slide.
Heel and toe today is for the performance driver, and performance and safety are a bit antithetical, wouldn’t you say?
Shan2nu wrote:
All i did was provide a solution to the downshift/jerking problem (Which even i used to face before i started rev matching). People who find the technique useful will use it.
And all I did was try to promote safe driving!
Consider, isn’t it funny how the problem of jerking crops up with downshifting for braking?
Simple solution: use brakes for braking!
Proton