Do i have to rev match when down shifting gears?

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Nermin///M3
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Do i have to rev match when down shifting gears?

Post by Nermin///M3 »

Hi guys,

I purchased my first manual transmission car BMW M3. I have been really enjoying the experience teaching myself how to drive manual transmission.

When for example you see traffic slowing down in front of you and you are in 4th. you start pressing break to slow down, when you slow down the car, and simply shift into 3rd and release the clutch the car wants to slow down even more its just doesn't feel right. So i normally give it little blip in gas and then switch into lover gear, then it feels smother.

Is there way to make smooth downshifting without rev matching or should i allways rev match?

Sometimes it tough to do when going from 3rd to 2nd. On M3 the 2nd is a little notchy and if you miss the timing when you rev match you just miss the shift completely car becomes unbalanced.
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Re: Do i have to rev match when down shifting gears?

Post by Rope-Pusher »

Try letting the clutch out between gears during your 3>2 Downshifts -
push in the clutch pedal
slide shifter from 3rd to Neutral
let up on the clutch pedal
tap on the gas pedal
Push the clutch pedal back down
push the shifter into 2rd
let up on the clutch pedal again

Tapping on the throttle with the clutch engaged (pedal released) should help with your efforts shifting down into 2nd gear.
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Re: Do i have to rev match when down shifting gears?

Post by potownrob »

Nermin///M3 wrote:...So i normally give it little blip in gas and then switch into lover gear, then it feels smother.

Is there way to make smooth downshifting without rev matching or should i allways rev match?
you might be the first person i've heard from that actually learned to single-clutch rev-match without being told how to, BRAVO!! :o :)
Sometimes it tough to do when going from 3rd to 2nd. On M3 the 2nd is a little notchy and if you miss the timing when you rev match you just miss the shift completely car becomes unbalanced.
rope-pusher's double-clutch downshift should help you with this. i always found double-clutching to make it easier to get the rev-match right, though it might be harder to learn how to do it. that said, i usually just did single-clutch downshifts. glad you haven't resorted to just slipping the clutch like a lot of people like to do :? . welcome to the forum btw!!
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Re: Do i have to rev match when down shifting gears?

Post by Shadow »

Nermin///M3 wrote:
...Is there way to make smooth downshifting without rev matching....
Well, if you'd rather not do your own rev matching, you could always buy a new 370Z and have the car do it for you.

http://www.streetfire.net/video/nissan- ... 210415.htm
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Re: Do i have to rev match when down shifting gears?

Post by scionkid »

Let out the clutch very slowly. Living in Hong Kong, I frequently ride mini buses with sticks. Unlike the crusty old drivers, them young'uns drove as if they never had been taught to rev match.
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Re: Do i have to rev match when down shifting gears?

Post by Shadow »

scionkid wrote:Let out the clutch very slowly. Living in Hong Kong, I frequently ride mini buses with sticks. Unlike the crusty old drivers, them young'uns drove as if they never had been taught to rev match.

That's not something you'd want to do very often. By doing that, you're basically using your clutch to absorb (for lack of a better word) the engine RPM. A simple throttle blip is a much better idea.
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Re: Do i have to rev match when down shifting gears?

Post by Nermin///M3 »

Thanks guys,

The past week has been definitely a learning experience. Every day i get to drive my car it brings new learning experiences.

I guess the rev matching is the way to go. The car just feels right especially when you get the RPMs right on down shifting the transmission is so smooth. That is what i am aiming for when i down shift. I notice in my car the difference in RPM is about 1000RPM between the gear changes so if i am in 4th going 2000RPM down shifting in third i would need to do it at 3000RPM.

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Re: Do i have to rev match when down shifting gears?

Post by six »

I can't believe no one has mentioned this yet... Welcome to StandardShift! :D Congratulations on your purchase of an awesome car. Please post pictures of your car in the Member's Cars forum! 8)
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Re: Do i have to rev match when down shifting gears?

Post by Nermin///M3 »

Thanks Six,

Its my fault really for not saying anything about myself. I got some pics of my car and will post them shortly. I quick intro, i was born in Bosnia, i left the place when all the craze stuff started happening over there. Long story short, i got to live in few different country in Europe before finally coming to US. :)

My car history, i started driving in High school, and my first car was Nissan Altima 93. Not a sporty car but it had four cylinder engine and i could go for two weeks without refiling the tank, it was nice and reliable. Fast forward today and i finally saved enough and pulled a trigger on 04 BMW M3. I have been wanting one for ever but they very just out of my reach. In recent years the prices have come down a lot on this cars and i decided to finally get one.

About the manual transmission, i have had few friends that had manual transmission cars and they let me try it once or twice, and after that i know i wanted a car where i can change the gears myself just didn't have the funds to get it. After a week of driving M3 i am so happy with the car its a lot of fun to drive. I am starting to get a feel for the car. I am not perfect yet but every time i drive it i gain more confidence.

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Re: Do i have to rev match when down shifting gears?

Post by Shadow »

Nermin///M3 wrote:Thanks guys,

The past week has been definitely a learning experience. Every day i get to drive my car it brings new learning experiences.

I guess the rev matching is the way to go. The car just feels right especially when you get the RPMs right on down shifting the transmission is so smooth. That is what i am aiming for when i down shift. I notice in my car the difference in RPM is about 1000RPM between the gear changes so if i am in 4th going 2000RPM down shifting in third i would need to do it at 3000RPM.

Nermin
Keep practicing...it's just a matter of time before you're automatically blipping the throttle to the perfect RPM without even having to think about it. Like everything else, it comes with practice and soon becomes second nature.
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Re: Do i have to rev match when down shifting gears?

Post by Nermin///M3 »

Hi guys,

Thanks for all the help, i am really getting the hang of rev matching, the easiest down shift for me tend to be from 6-5 and 4-3 the challenging ones are 5-4 and 3-2 ( for now i try not to spend much time in 2nd) i take the corners in 3rd at 1000-1500RPM, i know i don't have the power, but for now and daily driving i don't need it as i am learning and getting used to the feel of the car.

One question i wanted to ask you, this morning as i was driving to work, i was in 5th, car slows down in front of me, and i dont have enough time to rev match on down shifts, so i press the clutch go from 5th to 4th to 3rd slowly release the clutch and accelerating in 3rd. This was very smooth transition in 3rd however i am not sure if i should have blip the gas pedal a little bit while i was holding the clutch in 4th and then put the car in 3rd. The down shift for me was very smooth without rev matching.

The reason i will find my self often in this situation where i have down shift quick from say 6th to 4th and i dont have the speed now to rev match on every shift.

On another note, I will say one thing, i am really loving the perfectly executed rev match, the M3 engine sounds so nice when you rev it up a little bit. I love the sound. :)


Thanks for advice,
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Re: Do i have to rev match when down shifting gears?

Post by theholycow »

With more practice you'll be able to execute a complete rev-matched downshift more quickly. Until then, you can sequentially shift like you did, or you can non-rev-matched downshift, or you can just accept that you'll be a little delayed, or you can try to predict your needs better and shift ahead of time. It's really a matter of personal preference.
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Re: Do i have to rev match when down shifting gears?

Post by Shadow »

Nermin///M3 wrote:
One question i wanted to ask you, this morning as i was driving to work, i was in 5th, car slows down in front of me, and i dont have enough time to rev match on down shifts, so i press the clutch go from 5th to 4th to 3rd slowly release the clutch and accelerating in 3rd. This was very smooth transition in 3rd however i am not sure if i should have blip the gas pedal a little bit while i was holding the clutch in 4th and then put the car in 3rd. The down shift for me was very smooth without rev matching.
Don't overestimate the need to downshift in such a situation. What I mean by that is that you can probably don't have to downshift right away in such a situation. In fact, you might not need to downshift at all unless the car slowing down in front of you ends up slowing down a lot.

For example, if you're in traffic in 5th gear at, say, 45 mph and the car in front of you slows down to 30 mph, you can just brake and stay in 5th gear without having to downshift into a lower gear. You can just use the brakes to slow down and then make the decision whether or not to shift into a different gear.

Also, it is possible to downshift smoothly without blipping the throttle when you're in a situation where your speed is decreasing and it happens to be perfect for the next lower gear.

But either way, don't get too hung up on downshifting because it's really something that we do for fun rather than being absolutely necessary in most circumstances. I know drivers who downshift all the time while coasting to stop at a red light, for example. I'll do that on occasion, but definitely not all the time. Most of the time I'll just coast in whatever gear I happen to be in that the time and just pop the trans into neutral when the rpm is too low to continue moving in that gear. Even if I'm in 6th gear, I still don't have to put it into neutral until I'm under 30 MPH.
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Re: Do i have to rev match when down shifting gears?

Post by Nermin///M3 »

Shadow wrote:
Nermin///M3 wrote:
One question i wanted to ask you, this morning as i was driving to work, i was in 5th, car slows down in front of me, and i dont have enough time to rev match on down shifts, so i press the clutch go from 5th to 4th to 3rd slowly release the clutch and accelerating in 3rd. This was very smooth transition in 3rd however i am not sure if i should have blip the gas pedal a little bit while i was holding the clutch in 4th and then put the car in 3rd. The down shift for me was very smooth without rev matching.
Don't overestimate the need to downshift in such a situation. What I mean by that is that you can probably don't have to downshift right away in such a situation. In fact, you might not need to downshift at all unless the car slowing down in front of you ends up slowing down a lot.

For example, if you're in traffic in 5th gear at, say, 45 mph and the car in front of you slows down to 30 mph, you can just brake and stay in 5th gear without having to downshift into a lower gear. You can just use the brakes to slow down and then make the decision whether or not to shift into a different gear.

Also, it is possible to downshift smoothly without blipping the throttle when you're in a situation where your speed is decreasing and it happens to be perfect for the next lower gear.

But either way, don't get too hung up on downshifting because it's really something that we do for fun rather than being absolutely necessary in most circumstances. I know drivers who downshift all the time while coasting to stop at a red light, for example. I'll do that on occasion, but definitely not all the time. Most of the time I'll just coast in whatever gear I happen to be in that the time and just pop the trans into neutral when the rpm is too low to continue moving in that gear. Even if I'm in 6th gear, I still don't have to put it into neutral until I'm under 30 MPH.
Thanks for explaining this to me. I have this fear leaving the car in high gear while slowing down that i will stall the car. But as i am driving more and more i am finding out that i can stay in gear as long as the car has decent speed without stalling.

And that is good to know that i dont always have to rev match, rather i can slow the car down and then just put it in appropriate gear.

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Re: Do i have to rev match when down shifting gears?

Post by Shadow »

Nermin///M3 wrote: Thanks for explaining this to me. I have this fear leaving the car in high gear while slowing down that i will stall the car. But as i am driving more and more i am finding out that i can stay in gear as long as the car has decent speed without stalling.

And that is good to know that i dont always have to rev match, rather i can slow the car down and then just put it in appropriate gear.

Nermin
No problem, glad I could help. You'd probably be surprised how long you can leave a car in gear without stalling it. If you want to test your own car, try it out on a quiet back road or a large parking lot. Get the car into whatever gear you choose and see how much you can slow down before the engine rpm falls too low. As a general rule, you should be fine until the rpm drops down slightly below 1,000, at which point you should probably step on the clutch pedal in most circumstances.

The only thing to remember is that you might need to downshift if you slow down to the point that the rpm is too low for the car to accelerate at a decent pace. But in most cases, you'll still be able to accelerate slowly even at a very low rpm.

As far as the non-rev-matched downshifts, when you're at the perfect speed, you'll know it because the car will easily shift into gear and you won't get any jolt when you re-engage the clutch. But like I said, you have to be at the perfect speed or very close to it. That comes with experience and you'll have a good idea when you can do that without having to think about it.
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