Does revmatching while you downshift wear out the clutch and car more than if you were to downshift regularly??

 

No!!! Rev matching puts a lot less wear and strain on your clutch and tranny as you do not need to ride your clutch to get a smooth downshift. Rev matching should be a habit when downshifting.

 

In a lot of cases it also helps smooth the engagement too. I think I downshift better than I upshift. Pretty sad, eh?

 

I'll put myself out on a limb, and say... "what's revmatching?" I probably do it without realizing it, but...

 

Just after you step on the clutch you blip the throttle to increase your rpms before you downshift. If done right this will cause the engine rpms to match the speed of the drivetrain for that gear.

Rough example: Driving at a constant 35 mph, the rpms in different gears,

5th gear - 1500 rpm
4th gear - 2000 rpm
3rd gear - 3000 rpm
2nd gear - 4500 rpm
1st gear - You probably shouldn't

With this example, while traveling at 35 mph, if I wanted to downshift from 5th gear to 3rd, I would have to blip the throttle to 3000 rpms before letting go of the clutch. If you could do this perfectly, you wouldn't even need the clutch.

So rev matching involves knowing (or having a feel for) approximately what rpm is needed for what gear at any given vehicle speed.

Rev matching also works for up shifting as well, so that you're not riding the clutch into each gear. Most people do this one naturally.

 

Heel and toe more or less.

You'll know how much to rev at whatever speed, whatever gear ur at as u play around and get better at it.

But like evo dan mentions, dont try it if ur thinking of going into first gear, not even if its a normal downshift.

I learnt that the hard way the first time i tried and my first gear usually gets "blocked" or there is this great sounding "GRIIIIIIIIIIIIIIIIIIIIIIIIIIIND" that comes out of the gear box, sumthin about not being synchronized like the other gears.

 

Oh, okay.... I've done this before... kinda like clutchless shifting, yeah? See, I do some of this stuff, just don't know the technical name for it

 

Now, is clutchless shifting bad for the car?!

 

all this shifting talks makes me wanna drive a manual *sniff*
-Bob

 

To get into first if it's unsynchronized you have to double clutch. You have to get the layshaft to match speeds with the gear(it's the shaft that goes between the clutch and the gear). That's normally the job of the synchro's, but since most cars have unsynchronized 1st gears(because you normally start from 0mph) you'd have to manually do the synchro's job. Basically you:
1. press clutch (this disengages engine and layshaft)
2. shift neutral (this disengages layshaft and gear)
3. release clutch (this engages engine and layshaft)
4. rev match to gear (matches layshaft to gear's speed)
5. press clutch (releases layshaft to approx the gears speed)
6. shift gear(if you did step 4 correct, the layshaft will be spinning at approx the speed of the gear you're ****ing to)
7. release clutch (connects engine, layshaft, gear)

If you're really good at it, you can skip the last clutch(step 5 and 7) and just shift gears right when you match the engine and layshaft speed to the gear. It it's not right on though you'll grind, where as if you do steps 5 and 7 you can be a little off because the layshaft is just spinning freely without much momentum. So it'll catch the gear without grinding if it's close.

 

yea, my dad tried to explain this to me too. since we dont have a manual car, i was sooo confused but seeing it in word makes more sense..i need a manual car so my dad can show me his racing skills.
-Bob

 

Clutchless shifting can be bad for the car. The engine and layshaft are still connected. The synchros are there to match the layshaft to the speed of the gear you shift to while in neutral. So if you are not exactly right when you rev the engine to match the gear and clutchless shift, you'll grind and and can wear out the synchro's.

 

You can shift without the clutch if you do it EXACTLY right. And it shouldn't be too hard on the transmission, and it puts zero wear on the clutch. when my jeep was having clutch problems, I pretty much only used the clutch when starting from a dead stop.

 

Just to add to ben's comments, also pulling out of gear without the clutch can also add stress and premature wear to the tranny's gears and synchros if not done correctly. You're just better off not doing it unless your clutch has failed and you really need to go somewhere.

 

Do you have to get off the throttle again before you let out the clutch, or can you just hold it at that RPM as you let out the clutch pedal?