Posted on 06/06/2022 12:22:32 PM PDT by SunkenCiv
Very Expensive Fails Compilation | FailArmy
June 1, 2022
FailArmy
https://www.youtube.com/watch?v=WWxLjAqSM18
Metuchen, New Jersey
https://www.youtube.com/watch?v=HWCQVKa_yLE
Needs more trees.
Maybe something like a cowcatcher.
Extra excrement too.
True, but that requires double-clutching.
I drove an MG Midget which has no syncro on 1st. (straight-cut gear)
I also drove a `68 Bug that had worn syncros on 2nd. I had to rev-match when downshifting to keep from grinding the gear while going around a corner.
You don’t need to double-clutch to do a rev-matched downshift.
All you need to do is step on the clutch, rev the engine up, shift into the lower gear, release the clutch.
For the purposes of reducing clutch wear that will do the job.
Actually, you do.
The whole point of rev-matching is to match in input shaft speed to the output shaft speed.
Depressing the clutch disconnects the engine from the input shaft.
All you're doing when you rev the engine with the clutch depressed is revving the clutch disc, not the input shaft.
The only way to change the input shaft speed is to engage the clutch so the engine is connected directly to the input shaft.
As I wrote, the 2nd gear syncros were gone on my Bug. Simply revving the engine with the clutch pedal depressed did not allow me to downshift without grinding the gears.
I should have written that all you're doing when you rev the engine with the clutch pedal depressed is revving the pressure plate, not the input shaft.
The clutch disc is connected directly to the input shaft. By disengaging the clutch, you're disconnecting the engine from the input shaft.
So, revving the engine with the clutch disengaged cannot alter the speed of the input shaft.
Maybe a matter of semantics, but in a vehicle with synchromesh manual transmission, you don’t need to double-clutch to do a rev-matched downshift.
The syncros take care of speeding up the input shaft as you select the lower gear.
All you need to do is give the engine a little gas to speed it up, and then when you release the clutch pedal there is no driveline shock or jerking, and very little clutch wear.
I believe you're correct. We're both describing different effects.
If the idea is to match the input and output shaft speeds are the same so the gears mesh smoothly, you need to double-clutch. This is what I needed to do with my Bug because the 2nd gear syncros were worn out.
If the idea is to simply match the engine speed to that of the output shaft so that you don't upset the car's handling, then double-clutching is not needed.
Of course, this means that because of a disparity between the speeds of the input and output shafts, the syncros are going to wear faster.
If I'm approaching a stop while driving a manual, I usually just put the transmission in neutral, let out the clutch pedal, then use the brakes to come to a stop. This saves both the clutch and the syncros.
I’ve never worn out the syncros in any vehicle I’ve owned. I know of cases where synchros got damaged by someone trying to shift into 1st at 25MPH and stupid things like that..
On most vehicles I can easily shift into neutral while coming to a stop without pushing the clutch in, at around 1000RPM or so, just before the engine computer turns the fuel back on and tries to maintain idle speed.
This also gives a bit of engine braking while I’m decelerating in gear.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.