Question about downshifting with TR-3650

[metroplex]

Does everyone here double clutch to downshift with the TR-3650?

The synchros seem to require a lot of help even for low-speed downshifting (while coming to a stop) to the point where I just want to shift into neutral and then into first gear at the stop rather than try to use the engine braking.

 

[Spdfreak]

That's what I do. Why put the stress on the engine?

 

[welchy]

Why would you use 1st gear for braking? I mean I use 2nd, 3rd and 4th to slow down, but never 1st.

 

[metroplex]

I don't use 1st gear for engine braking but I tend to shift into 1st gear at the stop (getting ready to go) or 2nd gear making a 15+ mph turn. I once grinded gears downshifting from 3rd into 2nd gear while making the turn. Do you double-clutch to downshift at speed? It seems to take forever for the synchros to get going for downshifts. Upshifting is very smooth with this gearbox though. I'm just going to shift into neutral while coming to a stop and double-clutching when downshifting at speed. It seems to be the right thing to do even with these new-fangled synchromesh gearboxes.

 

[JTGrant]

when downshifting please match revs.

 

[66_stang]

I just rev match

 

[metroplex]

Is that double-clutching or do you rev the engine right before shifting into the lower gear?

I thought you had to speed up the intermediate/layshaft in order to properly rev match (via double-clutching)?

 

[Hoboattacker]

Is that double-clutching or do you rev the engine right before shifting into the lower gear?

I thought you had to speed up the intermediate/layshaft in order to properly rev match (via double-clutching)?

Push the clutch in, rev up engine to desired rpm (matching what it should be at when you downshift), downshift into desired gear, enjoy.

 

[CA Lightfoot]

Push the clutch in, rev up engine to desired rpm (matching what it should be at when you downshift), downshift into desired gear, enjoy.

That's rev-matching.

A double-clutch downshift is more. Feels great, lots of fun, and also saves wear on the tranny synchros. But you must actually shift to neutral when you rev up the engine. Hard to explain in words. Have someone show you. Once you get it, you'll wish someone had shown you sooner. But it takes practice to get it right.

Heel-and-toe technique adds braking while downshifting. I never could master that one. More details than you'll need at:

http://www.waycoolinc.com/z3/essentials/fixit/heeltoe/shifting.htm
http://modernracer.com/tips/heelandtoeshifting.html

 

[official_style]

i heel toe downshift all day long. if this is bad for the car who cares its fun as hell and you cant beat the deceleration sound with the LT headers and the flowmasters. i didnt buy a mustang to baby it, i bought it to enjoy it. your either not shifting correctly, or ur trans is screwed. mine shifts perfectly all day, up and down, and i have a tri-ax.

 

[Hoboattacker]

That's rev-matching.

A double-clutch downshift is more. Feels great, lots of fun, and also saves wear on the tranny synchros. But you must actually shift to neutral when you rev up the engine. Hard to explain in words. Have someone show you. Once you get it, you'll wish someone had shown you sooner. But it takes practice to get it right.

Heel-and-toe technique adds braking while downshifting. I never could master that one. More details than you'll need at:

http://www.waycoolinc.com/z3/essentials/fixit/heeltoe/shifting.htm
http://modernracer.com/tips/heelandtoeshifting.html

I know that double-clutching and rev-matching are different. He was asking if rev-matching was the same (I think). Thanks for the info though, I'll have to read up on it when I get the chance

Is that double-clutching or do you rev the engine right before shifting into the lower gear?

I thought you had to speed up the intermediate/layshaft in order to properly rev match (via double-clutching)?

 

[metroplex]

How does rev matching actually work? It would appear the clutch is disengaged from the flywheel, so all you are doing is revving up the engine and not speeding up the intermediate shaft. With double-clutching, it would speed up the intermediate shaft and engine at the same time.

With my gearbox, it feels very stubborn trying to downshift without revmatching or double-clutching even at very low speeds.

BTW I did read most of the guides online and most of them assume the synchros will do the job. I know for a fact that my TR-3650 gives me a hard time occasionally while downshifting. I will try rev-matching and double-clutching in the future.

 

[Hoboattacker]

http://www.wisegeek.com/what-is-double-clutching.htm

Double clutching and rev-matching are very similar. I find it much easier to shift when I rev-match. I haven't really tried double-clutching yet so I can't give you my opinion on that one.

Double Clutch you push the clutch in twice, stopping in neutral to help get everything on the same page so to speak, then shifting into the next gear. I really want to try heel-toe downshifting, should be a lot of fun

 

[metroplex]

I'll try rev-matching first and then double-clutching. I'm assuming these are the techniques necessary to downshift in order to pass slow moving cars or in get-the-fug-outta-there scenarios? E.g. I'm cruising in 5th gear at 40-45 mph and suddenly need to accelerate fast (downshift into 2nd or 3rd gear), I would rev-match or double-clutch?

After reading more about manual transmissions, it seems double-clutching is the better method as the intermediate shaft (or layshaft?) is actually sped up or slowed down whereas rev-matching is basically just speeding up the engine?

 

[Hoboattacker]

I'll try rev-matching first and then double-clutching. I'm assuming these are the techniques necessary to downshift in order to pass slow moving cars or in get-the-fug-outta-there scenarios? E.g. I'm cruising in 5th gear at 40-45 mph and suddenly need to accelerate fast (downshift into 2nd or 3rd gear), I would rev-match or double-clutch?

After reading more about manual transmissions, it seems double-clutching is the better method as the intermediate shaft (or layshaft?) is actually sped up or slowed down whereas rev-matching is basically just speeding up the engine?

Correct. Rev-matching is faster but double-clutching does less wear and tear. Although Rev-matching does less than just clutch in, downshift, clutch out with no other actions.

You will need to know how to rev-match first before you can effectively heel-toe if I am reading the articles correctly (heel-toe is more complicated).

 

[metroplex]

Does rev-matching help make it easier to shift into the lower gears (actual process of downshifting) or does it just reduce/eliminate the lurch after the shift and when the clutch engages the flywheel?

 

[Hoboattacker]

Does rev-matching help make it easier to shift into the lower gears (actual process of downshifting) or does it just reduce/eliminate the lurch after the shift and when the clutch engages the flywheel?

I find that it makes it easier. I don't know if that can be backed by any cold hard facts though. And if you do it right, it will completely rid the lurch.

 

[official_style]

i thought that double clutching had no benefit in modern transmissions? its just fun to do.

 

[Hoboattacker]

i thought that double clutching had no benefit in modern transmissions? its just fun to do.

Pretty much.

But double clutching adds a third step into the mix. The shifter, rather than going straight to the next gear, makes a stop in neutral and then the clutch is released. This is to allow the engine to slow down (or with a tap on the gas, speed up when downshifting) so the transition into the next gear is much more smooth. The driver then depresses the clutch again and completes the shift into the target gear, and finally the clutch is released again, putting the car back into gear. It only takes a split second for the engine speed to match the speed of the gears, so the entire action is done very quickly as a fluid sequence of events.

Most modern cars, however, are equipped with devices called synchronizers that help to synchronize the speed of the gearbox with that of the engine. This effectively eliminates the need for double clutching. Some large trucks on the other hand have so many gears that synchronizers are inefficient, while race cars can squeeze out more power without them, making double clutching a fact of life.

 

[metroplex]

Synchronizers cannot do the job by themselves and can wear out (paper linings, sort of like clutches).