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ok, so in a different thread i was reading about syncrhos and if you skip shift it can strain them. so, when do you shift normally and what rpms do you downshift at? does it waste gas? do you prefer to downshift with brakes, brake only with clutch down, or downshift and let the gear slow you down? and does skip downshifting put the same stress on the synchros as skip shifting up?

 
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i shift from 4th to second or in other words misshift but i do it right. I dont go 100 on 4th then down shift to 2nd, if im going like 30 i wont downshift to 3rd, but instead go to 2nd.

 
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I'm no mechanic and there's folks on this forum who know a heck more than me but here's what I know about this

upshift at 3000 for fuel economy (it's in the owner's manual)
downshift to keep it above 2000 at all times
- upshifting : don't think so.
- downshifting at each stop means you have to blip the throttle uselessly so yeah it's a waste.
- normal downshifting is not considered a 'waste' to me.

When nearing a boring stop I just put it in neutral, get my foot off the cluch and just use right foot to stop the car progressively. Brakes are meant for stopping, gears for going

No clue, but skipping gears all the time soudns like bad driving skills to me since you're not keeping your car in its factory-recommended best performance per mileage sweet-spot.

 
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Wait a second....Im confused here. Why would u stress the syncros if u don't rev match? I thought syncros are suppose to help sycronise gear changes, making the next gear begin to spin so the change isn't so harsh and helps protect the tranny. But if your rev matching shouldn't u be ok?

 
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Because of synchros you don't need to double declutch but you still need to rev match. If you don't, you'll strees the synchros and the whole tranny uselessly. If the shift isn't smooth (if it jolts) you're doing it wrong.

Perhaps our Auto-X junkies could explain this more..

The synchros do a fair job but aren't as good as one expects... not in our econoboxes anyways..

 
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Not revmatching eats your clutch, not your synchros. The synchro's job is to spin up the next gear so they're matched when you shift into it... it saves the gears from grinding and it saves you from having to double clutch between shifts.
What eats your synchros is slamshifting. They need time to spool up, so if you work faster than they do, they don't like it. When the car drops right into gear, then the synchros are getting their job done. When you find yourself pushing it hard into gear, you're working faster than they can and you're unnecessarily heating them up, which makes them less effective and also causes more wear than you need to impart on them. There's also nothing wrong with a 5-2 downshift as long as its not instant. If you pull it in neutral and then into 2nd, no harm no foul. If you dump it in, you cause issues.
You can shift up whenever you want, ideally you want the revs above 1800 or so at all times (unless idling). If you get real sticky on wasting gas, I guess the blip wastes gas, but what's a split second when this thing just sips gas. You shouldn't just brake with the clutch in, it leaves you defenseless, just using the engine like a brake isn't necessarily the greatest thing for the drive train, it won't hurt it, its just that brakes are cheaper to replace. Ideally you use the brakes and downshift to keep the revs somewhere desirable. In city traffic where you have no place to go, the brakes/clutch in is ok, you're not going fast enough that you'll be unable to react.

 
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^yeah what he said.

 
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I like downshifting because it kind of puts you in the correct gear to accelerate again. For example...say you're slowing to a light and you keep downshifting/rev matching and the light turns green all of a sudden, now you're in the correct gear to just accelerate again. If you didnt downshift and just popped into neutral to slow yourself down and the light turned green, then you're fumbling around to put your car into the correct gear while it's in a neutral roll. Most ppl will shove it in gear and feel a jerk. The point is smoothness. If you're not smooth, then you're doing something wrong. Also on downshifts, always rev match by bliping the gas and then letting the clutch out fully. The gear will go in smoothly and no crazy jerking. After practice, you'll be able to do this so quickly and in one swift motion.

On downshifting two gears I wouldnt reccommend just popping from 5th to 3rd and etc. If it were me, I would rev match to 4th and then rev match to 3rd. Once you got downshifting down pretty good, you'll be able to do this so fast that it may even be faster than popping from 5th to neutral then to 3rd and trying to rev match the bigger change in rpm.

Now if you're autocrossing downshift with rev matching is a must, but then other factors come into play like heel-toe action. If you downshift and dont rev match, your car will jerk and it throws the balance of your car off. This is a no no in autoX becuase downshifting is usually associated with taking a turn and throwing the balance off means you = spin out. Hope this info helps.

 
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daily driving:

skip shifting while upshifting can put more wear and tear on the synchros and cause premature failure of the synchros. this is more so on the 6 speed honda tranny than the 5 speed, but the 5 speed isn't exempt from this. (by the way, this information comes from an American Honda Engineer who is the head of a design/engineering team) There is a tech explination for this, but I dont feel like typing it out at the moment.

As for rev matching, the only thing rev matching does is make the shift a bit smoother. (unless of course you are double clutching to bring the layshaft up to speed on the downshift.)

And downshifting. Downshifting and skip-downshifting does not really put excess strain on your synchros. Although clutch wear is minimized if you rev match, synchromesh wear still remains minimal. This is because the synchromesh only needs to match the speed of the drive shaft (lots of momentum) to the speed of the layshaft without the engine engaged. The layshaft has a relatively low mass, therefore it is easy to match its speed to that of the driveshaft.

as for slowing down, it's always wise to keep dropping the gear selector to the next lowest gear as you slow down, however, keep the clutch in and use the brake while doing this. engine braking while daily driving puts more wear and tear on the transmission, clutch, and other such components than need be. Which would you rather replace... your brakes? or your clutch or tranny?


cliff notes:
rev matching on downshift is good.
double clutching is not needed due to synchros.
skip shifting while downshifting is ok. rev match for smoothness.
skip shifting while UPshifting is bad. don't do.

 
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i was waiting for you to pipe in all night lol^^^

 
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i once read (on this forum)- that if youre going downhill, you save more gas if you are in gear, letting the car coast (no gas applied)- than if you were to pop it into neutral and coast.

why? because your car needs to provide gas to the engine to keep it at idle rpm.. whereas when ur in gear- the cars momentum is keeping the engine alive. does that make sense tho? doesnt the engine need gas to stay alive no matter what?

 
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someone answer this guys question! I need to know! ^

 
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AFAIK it most definetly needs gas whenever it's spinning. And I'm pretty sure it eats up more gas if you engine break at 3000rpm than if you let it idle.

What I would like to know is how come even breaking, yes _Breaking_! uses up gas?

 
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I have shifted from 3rd ro 5th a couple times and it hasnt done any harm to me. I do it when I want to merge onto the freeway and gun it in 3rd to get up to speed quick and then just shift to 5th since I really have no need to be in 4th at that point.

 
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incorrect. if the rpms are higher than idle, the car is still being given fuel. it can't just cut the fuel. it would run so lean it'd detonate to all hell. even when coasting downhill, the higher the rpms the more fuel you use.

 
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?? you mean engine braking or braking with the brakes?

 
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this is EXACTLY the type of thing you should try to avoid. it puts heavy load on your 5th gear synchro and *can* cause premature failure.

 
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The easier way is to hit 4th on the way down but not let the clutch out. Its also a more natural motion to just downshift and go through fourth on the way to third... or put it in neural for an extended time (over a second).

 
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Braking with the brakes. Does it make sense? (Not to me)

 
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yeah you should brake with the brakes. lol.

 
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ok, here is something else, what rpms do you guys downshift at? for example, if im in 4th and i want to downshift to 3rd, im going 40 in 4th, so if i downshift i will rev up to 3k to match so there is no jerk. do you guys downshift to 3k or higher? like 4 or 5k? just wondering, and also thinking what is safe rpm to downshift into.