I was at the Borders bookstore yesterday reading Car and Driver magazine and came across an article that said that if you skip shift, it will increase gas mileage. So it recommends shifting 1-3-5 and skip 2 and 4. Does anyone here skip shift? Can that be bad for our tranny?

 

might get a better response if posted in cartalk since there is a wider range of cars.

i skip shift in my Mazdaspeed3. I only do it around town since my city mileage is horrendous. its helped a bit.

I only work a mile from my house, but on my MID, my fuel range usually dropped 5-6 miles. now that i skip gears, it only drops two.

 

I've done it in every manual car I've owned. It seems to always help, maybe not much but a little. I do 1-3-6 from a stop and do 2-4-6 on a roll. I don't believe it can't hurt the trans, if anything I would think it would help the clutch since you won't be shifting as many gears.

 

i tend to do this for 2 reasons. 1 i have noticed better fuel economy both with my RSX and TL-S. 2 i am paranoid and i figure the less i shift the less wear i put on the clutch which means it will last longer

 

butt butt what about synchro wear!?

 

I never did. every gear up you go, you increase load, which means more fuel for the same throttle %. I would avg 28 mpg in my city/highway mix and used every gear

 

i have been doing this since 1999 its nothing new to manual trans.

 

i've done this in the mornings because my 2nd gear syncro and fluid usually aren't warmed up, causing a "crunchy" shift. does it like 20% of the time cold, but i've recently stopped skip shifting.

i think as long as you keep it relatively low RPM and wait long enough for the RPM drop you should be fine. I think the trick to getting this to work is to accelerate slowly. going from 1st to 3rd is a pretty large jump since 1st is such a short gear.

 

^ This. I frequently skip shift. I'm lazy and it's easier Plus, the way I see it, you really don't even need those extra gears unless you're accelerating quickly. My first car was a 3-speed '77 Camaro and I did just fine with it. Granted, if I wanted to go quick I had to pretty much redline 1st and 2nd.

And synchro wear is likely very minimal if done at lower RPM's. In fact, I wonder if it's less since you're working less synchros. If I'm correct, downshifting is typically harder on synchros than upshifting, especially if it's done at higher RPM's.

 

I would think there would be slightly more Syncro wear because the car anticipates and holds the rpm for the next sequential gear.

 

i've read in a different thread that this only happens on upshifts above 3.5k RPM.

otherwise, it's just the lag from throttle-by-wire. the RPMs will drop if you wait (as it definitely does with A/C on).

 

I see it on every shift. If i am at around 2500 rpm and shift to second it drops and holds for a second or so around 1500, then it drops down from there. I almost always shift in town between 2500 and 3000 rpm.

 

Now what if you skip shifted 1-3, but in the middle you momentarily put the stick from 1st into 2nd then immediately put it into 3rd.

 

I don't see a point to this. You would only end up burning clutch.

 

I should've added that the clutch remains pressed this entire time

 

Nope

 

I usually go 1-3-6, about 2.5K out of 1st, then 2K out of 4th into 6th. Rev match and double clutch every shift.

The syncros should be fine, most of the time the thing nearly falls into the gear if its done right. Regardless, its too much work to use every gear to go up to 40 and hit another light once you finally get into 6th. When rolling, I usually try to use 4 and 5 to alternate syncro wear.

If you ask me, its WAY less work, just makes for rather slow shifts while you wait for the RPM's to drop. Plus, rev matching is really simple at near idle speeds.

 

^Could you please describe how you rev match and double clutch at lower speeds?

 

How do the speeds make any difference? There is still going to be a differential between gear speeds irrespective of vehicle speed, thats what gears do.

The idea is to minimize the difference between the gear speed and engine speed to limit clutch and syncro wear. Using a more extreme example, I sometimes take the car up to 30 in 1st and go right into 6th. Would it be a good idea to just slam the trans into 6th out of 1st at those RPM's? At lower RPM's it matters less, but it still matters.

 

Okay guys.....It literally says in your owners manual NOT to skip shift. Habitual skip shifting puts accelerated wear on the given gear (and 3rd gear is already glass in this car) and will be visible after a teardown. It's a similar bad habit to someone who always tries to force the shifter into first BEFORE the car has come to a full stop.

It might be fine if your trying to save gas and doing this at low revs, but honestly there are better ways to go about this. The real trouble comes if you attempt this at high rpm (ie: from the top of 2nd to 4th or 5th). In this case you are literally destroying your synchro. Forcing it to drag the mainshaft & clutch disc down from a much higher speed than it's designed for. In fact you may find the selector blows right past the synchro and grinds. You can also try to avoid this accelerated wear if you double-clutch your upshifts. But this is very awkward and no fun to do to save a few cents.


So which is cheaper/easier to fix, clutch disc or synchronizer?

 

I see your point. And you're right about the owners manual. But for me, the proof is in the pudding. I always skip shifted with both of my past accords ('93 and '99) of which I put over 100K miles on each (and already had 90-100K miles on them when I purchased them). Although I never did any sort of tranny tear down, and never even had to replace the clutch on either, they shifted as smoothly and easily as they did when I first purchased them. The skip shifting was almost always done at lower RPM's. Note: I NEVER downshift to slow down unless it's to gain traction in snow or something like that. It's way more work than just hitting the brakes and IMO, puts a lot more wear on the tranny than worth it considering brakes are easy to replace. So maybe my lack of downshifting during slowing countered the wear from skip shifting. Either way, it worked with my last two Hondas so I don't see why it would harm this one.

 

Interesting I'll have to whip out the manual and do some reading.

Any one here "float" gears I don't know any technical term for it, but I know alot of truckers do it to help the clutch. It's where you shift gears and don't use the clutch, except when taking off from a stop. If you know how and do it correctly you can shift into the next gear smoothly without pushing in the clutch. I do this from time to time.

 

It all depends on your driving style. I know some people who act like they are on a track at all times, and jam the shifter into every gear and snap the clutch out as fast as possible. As long as you're double clutching, it shouldn't matter that you're skip shifting, but I wouldn't consider myself an expert.

All I know, is its easy to feel how hard the syncros are working based off the shifter feel. Do things right, and the shifter nearly falls into the appropriate gear. If you're in a hurry and try and jam it into 6th at 5K, and its a struggle to force it in. With the clutch out, trans out of gear, and RPM's down to near idle, I don't see how it matters what you did before that. You can go from redline in 1st into 6th as long as you double clutch and rev match, it just takes a second or two while you wait for the RPM's to drop before you can put it in gear again.

Can anyone prove this wrong? I understand rapid shifting and skipping gears puts more strain on the syncros than they were designed for, but shouldn't double clutching and rev matching negate this entirely? I still think it's much easier than shifting 6 times, and should even save clutch and syncro wear over 'normal' shifting.

 

Clutchless shifting can be sketchy at times. I used to drive my Civic & CRX for full trips around town only using the clutch at a full stop. This was easy on those cars. I thought I was great at it. Then came the day when the wife's Element clutch master cylinder crapped out. I limped the little truck over to the dealer with clutchless shifts and it was nowhere near as easy as my little civics. No matter how well I rev-matched, the damn thing would crunch 3rd EVERY effing time. In the end, it ate up the 3rd gear synchro and it too had to be replaced. Good thing it was covered cause the effing dealer was the one that screwed up the clutch MC replacement in the 1st place.

Yes it does. I mentioned that in my post. But I also mentioned double-clutching an up-shift is retarded awkward because revs are falling. If your letting it hit idle and then blipping it back up to desired rpm, your just being silly.

But it's your car...do what you want.

 

I usually try and shoot for a gear that would match up with near idle speed, so its just a simple matter of waiting for the revs to drop to near idle, and shift. No need to touch the gas until the clutch is back out. Engagement tends to be exceedingly smooth, and this makes getting up to speed quite simple.

I suppose this only really works if you drive slow. I didn't get the manual since I enjoy shifting, I simply hate most every automatic, the manual is simply a better, more efficient choice.

 

I find the car doesn't produce enough torque to cruise at such low rpm. You can hear/feel the motor lugging. If your rpm is low and your throttle is high, the engine runs more rich. It's possible this condition can consume more fuel. I have definitely observed this on my 89CRX. I never put it to the test on the TL though which has much more sophisticated engine management. So it may still work.

I hate autos too, as does my wife. When we decided to have a 3rd kid, the Element had to go. Unfortunately Honda doesn't make anything bigger with a stick, so we ended up with a Pilot automatic. It was like learning how to drive all over again for me. It's a 5AT but only has selections of D321. What the hell happend to 4th? Fortunately our other 3 cars are stick so I rarely have to drive that thing. If that 5AT ever craps out, I'm going straight for a 4G AWD 6-MT trans. I pray it never comes to that. Probably wouldn't work anyways.

COME ON HONDA! BUILD A 5/6MT SUV!

 

Just an update to this, on my drive in to work i checked the RPM's in my car it will hold for the next shift from about 2700 rpm and up. Below that it just drops straight to idle.

 

Is that on upshifts, downshifts or both?

 

I do it on the S2000 and CR-Z. Now granted neither has enough torque that I'm concerned. Plus it's generally at low speeds and slower acceleration.

 

From what i hear, skip-shifting is an even bigger problem in the S2000. This is Honda's official stance on skip-shifting (for those that haven't yet made up their mind).

Good 5th gear synchro


Skip-shift damage on a 5th gear synchro

 

Pics didn't come across. Here is a link to one of the posts floating around: http://forums.s2kca.com/showthread.p...970#post270970

 

I tried doing 1-3-5-6 the other day. I didn't really like it. It felt like one of those old 4 speed autos in pickup trucks with a huge rpm drop off between gear changes. It didn't feel very efficient, as I had to stay in each gear longer than normal, and then lug through the next one.

I think I'll just stick to shifting every gear between 2100-2500rpm. I get 28mpg in mixed driving that way.

 

not doubting improper skipshifting is bad,

but that syncro in the 2nd pic does have points, it's just flipped upside down (which has a blunt end on one side just like the top one)

 

LOL you could be correct. Here is a similar post with another picture to make it even more confusing.

http://forums.s2kca.com/showthread.p...202#post250202

 

Another thing to keep in mind with skip shifting is the transmission itself.

For example, Honda's S2000 6MT inititially carried brass synchronizers which would, if skip shifted constantly, fail regardless of how careful driver's were when skip shifting. Eventually Honda replaced the brass syncros with carbon fiber composite which could withstand the additional pressures caused by skip shifting.

I'm not sure exactly how much stronger the CFC syncros are compared to the brass ones, however if you look around on S2KI you'll find that AP1 owners (brass syncros) experience this far more often than AP2 (CFC syncro) owners.

Of course, this could be offset by the fact AP1s are older and generally have higher mileage than AP2s, but the change of syncro material definitely has at least some effect on the matter.

On clutch-less shifting... The greatest difference (besides physical size) between transmissions found in commercial truck / bus and car transmissions is the lack of synchronizers.

By not using the clutch in a synchronized transmission, you are working against the synchros and defeating the purpose of their existence. I am not saying it is impossible to drive your TL around without using the clutch, but if you miss-shift or do not time your shift correctly, you can kiss a synchro / gear goodbye.

Alright, maybe that's a little harsh, but helical type gears (found in everyday passenger cars / trucks) do not like to be forced together due to their complex design. The helical pattern is composed of "wave-like" or "curved" teeth which are substantionally more quiet when spinning than the "straight-cut" design used in commercial truck transmissions. The flip side of this advantage is that helical gears do not like to be engaged suddenly or quickly due to their pattern.

Synchronizers solve this problem by aiding in their engagement. Additionally, the use of a clutch helps by slowing down the shift, allocating the synchros appropriate time to do their job. If you do not use the clutch in a synchronized transmission, you are forcing the gears to engage at the current input shaft and output shaft speeds of the transmission. If the shaft speeds do not match you'll hear a nasty grinding noise caused by the helical patterns not matching up correctly. Get it right however and the gears will allign without any drama.

Essentially (as I understand it, so beware I might be wrong about this), synchronizers acomplish the same thing as double clutching, without the double clutching. I'm not saying they equalize the input and output shaft speeds of the transmission, but they allow the gears to align despite non-matching shaft speeds.

"Straight cut" gears however naturally "want" to allign due to their more simple design (think of a gear with straight lines instead of curved ones. Now which type will match up more quickly and easily?). These type of gears are more practical for commercial purposes because they can hold more torque and cost less money to produce. Also, they like to be engaged quickly which makes throwing synchronizers on them more of a problem than an aid.

So if you want to drive without a clutch, then go ahead. I just recommend practicing on something that can take some punishment and won't cost a lot of money to fix. A fun thing to practice (which will not destroy your transmission if you mess up) is disengaging the current gear without using the clutch. To do this, accelerate moderately while placing extremely light pressure on the shifter as you prepare to take it out of gear. When at the desired speed, let off the throttle quickly and completely and push (or pull if it is a gear at the top of the "H" pattern) the shifter with a moderate amount of force. If you feel a slight grinding in the shifter, then push the clutch in and shift normally. This means you are not putting enough load on the gear to cause it to push away from its counterpart.

If you did it correctly, the shifter will slide into neutral with ease. This allows you to double clutch without having to clutch to neutral. Now, if you increase the throttle to the desired RPM (higher for downshifting, maybe a tiny blip to recover RPMs for an up shift ) and shift into the next desired gear using the clutch, you will notice the shift feels very smooth. This is because you are simultaneously spinning up both the input shaft of the transmission and the engine as apposed to only reving up the engine when shifting with the clutch.

So why do this? Well there's no reason really other than to better understand how the transmission works. This method is slower than double clutching, requires you to be accelerating, and does not always work in higher gears due to the difference in torque on the gears.

The point of this is to outline (very basically, and uh... Probably not entirely correctly) how a manual transmission works. If you double clutch or half-ass-clutch-less shift like I posted above, you are not putting any load on the synchronizers. If you skip shift without using either one of the previously mentioned methods on the other hand, you are putting at least twice the load on the synchronizer to allign the gears.

Basically, if you want to skip shift, then double clutch. If you want to shift without the clutch, then practice at least getting into neutral without the clutch.

I'm not sure if any of that helps as my post turned more into a ramble than an opinion, but I hope it is at least correct.

 

That's pretty good, BUT....

Our transmissions do not push gear teeth together nor do they move them apart (except reverse). All the gears are continuously meshed together and rotating at various speeds. For each selectable gear, there is one cog locked to a shaft (main or counter), and a meshed cog that is able to spin freely on the adjacent shaft. When you select a gear via the shift lever, that specified collar locks the free-spinning gear to the rotation shaft within. The matching of gear and shaft speed is accomplished by friction between the synchronizer cones (similar to a tiny clutch). So you see synchronization has nothing to do with the gear mesh pattern.