3 ms·

It's funny, I just got a new car (manual, of course) and it has "rev-matching" so when you shift down a gear it automatically heel-toes (basically a throttle bl

by ollie87 10y ago

It's funny, I just got a new car (manual, of course) and it has "rev-matching" so when you shift down a gear it automatically heel-toes (basically a throttle blip) which means there's not much engine braking going on during downshifts. Granted when driving quickly and dropping a cog or two to overtake a slow moving vehicle it's great. Slowing down for traffic? Not so good. Took some getting used to changing down gear and not feeling the car slow. EDIT: To clarify the folks downvoting me here's and example of how it works: 1) You're in 6th gear doing 60mph. 2) You come up to a tractor doing 25mph. 3) You brake and slow, as you do you compound change from 6th gear down to 3rd. 4) As you place the car into 3rd the ECU gives the engine some extra throttle and match the speed of the gearbox. You can physically see the revs rise BEFORE you release the clutch. 5) You release the clutch and don't feel any transmission shunt or immediate engine braking. This reduces wear and makes it smoother. For more detail watch this YouTube video: https://www.youtube.com/watch?v=FnXLZg_O1rk https://www.youtube.com/watch?v=FnXLZg_O1rk

exDM69 10y ago
Are you sure it actually blips the throttle and it's not just the synchromesh gear in the gearbox? There's no need to blip with a synchronized gearbox, which has been the standard in road vehicles since the 1930s or so. Even if it does blip, you can still utilize engine breaking but you have to shift early and sometimes skip gears.
- ollie87 10y ago
  Not sure why I got downvoted here. It actually blips the throttle. It's not the syncho, trust me. http://www.minif56.com/forum/353-mini-cooper-f56-forum/7010-rev-match-function.html http://www.minif56.com/forum/353-mini-cooper-f56-forum/7010-... It's not the first car to have it either, and there is actually PLENTY of reasons why you'd need to blip or heel-toe when driving even in a car with a synco'd gearbox. https://www.youtube.com/watch?v=FnXLZg_O1rk https://www.youtube.com/watch?v=FnXLZg_O1rk https://www.youtube.com/watch?v=p4n9tMdISBg https://www.youtube.com/watch?v=p4n9tMdISBg
  - exDM69 10y ago
    Yeah, it's not completely out of question that it would blip the throttle, but it's not a very common feature either. I drive an old piece of shit car with a very worn out synchromesh gear (it's a conical brass ring with grooves for friction - that wear out) so it's a bit smoother to blip the throttle a little when downshifting to the smallest gears. I don't heel-toe or left foot brake on the road (I'm proficient in both from simulator and performance driving), I just use my right foot to give a little gas. I rarely need to brake and downshift at the same time unless I'm in heavy traffic, I mostly rely on engine braking controlling speed. Outside of performance driving or old worn out cars like mine, there's no real need to rev match on normal road cars. How does the clutch in your car work? In an unsynchronized gearbox, you'd double declutch and blip when the clutch is up and gear is neutral (to rev match gears inside the gearbox). Is this thing just to match the engine and gearbox input shaft speed? Not gears inside the box? Or does it do something similar to double declutch w/ heel-toe?
    - ollie87 10y ago
      I know how car without a synchro works, the first car I ever drove was a 1950's Land Rover. Watch the video, it works exactly how Engineering Explained describes, he even explains the benefits.
mywittyname 10y ago
What you're describing is not engine braking, it's really clutch braking. Engine braking is what happens when the clutch is fully engaged and the compression of the engine slows the vehicle down. Downshifting to second so the engine is at 5000rpms and letting it gradually slow the car down is engine braking, and this is good. Putting the gear selector in second and slowly releasing the clutch (with no throttle/rev-matching) to slow down the car is clutch braking and its bad (which is why cars automatically rev-match now).

by ollie87 10y ago

exDM69 10y ago

Are you sure it actually blips the throttle and it's not just the synchromesh gear in the gearbox? There's no need to blip with a synchronized gearbox, which has been the standard in road vehicles since the 1930s or so. Even if it does blip, you can still utilize engine breaking but you have to shift early and sometimes skip gears.

ollie87 10y ago
Not sure why I got downvoted here. It actually blips the throttle. It's not the syncho, trust me. http://www.minif56.com/forum/353-mini-cooper-f56-forum/7010-rev-match-function.html http://www.minif56.com/forum/353-mini-cooper-f56-forum/7010-... It's not the first car to have it either, and there is actually PLENTY of reasons why you'd need to blip or heel-toe when driving even in a car with a synco'd gearbox. https://www.youtube.com/watch?v=FnXLZg_O1rk https://www.youtube.com/watch?v=FnXLZg_O1rk https://www.youtube.com/watch?v=p4n9tMdISBg https://www.youtube.com/watch?v=p4n9tMdISBg
- exDM69 10y ago
  Yeah, it's not completely out of question that it would blip the throttle, but it's not a very common feature either. I drive an old piece of shit car with a very worn out synchromesh gear (it's a conical brass ring with grooves for friction - that wear out) so it's a bit smoother to blip the throttle a little when downshifting to the smallest gears. I don't heel-toe or left foot brake on the road (I'm proficient in both from simulator and performance driving), I just use my right foot to give a little gas. I rarely need to brake and downshift at the same time unless I'm in heavy traffic, I mostly rely on engine braking controlling speed. Outside of performance driving or old worn out cars like mine, there's no real need to rev match on normal road cars. How does the clutch in your car work? In an unsynchronized gearbox, you'd double declutch and blip when the clutch is up and gear is neutral (to rev match gears inside the gearbox). Is this thing just to match the engine and gearbox input shaft speed? Not gears inside the box? Or does it do something similar to double declutch w/ heel-toe?
  - ollie87 10y ago
    I know how car without a synchro works, the first car I ever drove was a 1950's Land Rover. Watch the video, it works exactly how Engineering Explained describes, he even explains the benefits.

mywittyname 10y ago

What you're describing is not engine braking, it's really clutch braking. Engine braking is what happens when the clutch is fully engaged and the compression of the engine slows the vehicle down. Downshifting to second so the engine is at 5000rpms and letting it gradually slow the car down is engine braking, and this is good. Putting the gear selector in second and slowly releasing the clutch (with no throttle/rev-matching) to slow down the car is clutch braking and its bad (which is why cars automatically rev-match now).