Perfect Rev Matching for 6MT M3

[col.faith]

Originally Posted by Radiation Joe

I know the transmission is going to do what I want it to do, instead of what some committee in Germany thinks it should do.

If you don't ever misshift with MT that is... which is virtually impossible.

That's why they used the DCT in the GTS, because you misshift from time to time on a racetrack, and it doesn't happen with a sequential semi-auto gear box. Just my opinion though.

[Radiation Joe]

You know folks, I once thought the DCT would be the greatest thing since sliced bread. So I ordered one. Then I drove it for 18 months, tracked it, put 50k miles on it, had BMW refuse to service it even if I paid. Unless you've owned and tracked both the DCT and the manual e9x M3s, I'm not going to put a whole lot of faith in your arguments.

[captainaudio]

I once bought sliced bread thinking it was going to be the greatest thing since the automatic transmission. I found that it was sliced too thin and regardless of how often I took it back to the store they refused to slice it thicker even if I paid. Now I buy unsliced bread. I want to decide myself how thick I want my bread sliced. I don't want some committee at the bakery deciding for me.

CA

[Sedan_Clan]

Originally Posted by Radiation Joe

Maybe I'm some super Stig snuffing, manual transmission shifting savant. But I doubt it. All I know is I can bang off downshifts consistently better than a DCT. I'll be out at NJMP and WGI with my slow shifting manual later this year. All you DCT drivers are welcome to come out and show me the way around the track in those technologically superior DCTs. Chances are you'll won't be significantly slower or faster, but you won't have as much fun while doing it, either.

Ohhhhhhhhhhhhhhhhhhhhhhhh! I love when somebody is offers to put their money where their mouth is. I do the same thing when it comes to racing a bike. I always get the, "Ducati's are over-priced POS!" comments from Big-4 motorcycle riders (..as if I've never owned a Big-4 bike). They start quoting horsepower and torque figures while simultaneously stating, "You could have purchased bike X for the price of that 848." Then they exclaim how much faster they are in a straight line (..usually because they own a Big-4 liter bike). Once I invite them to bring their bike(s) to the track (..usually on my dollar) so that their riding skill can be put to the test, they either ignore the offer or comment that "they don't ride the track". Figures!


[/pot stirring]

Originally Posted by OC3

I think I realize what's going on here. See, some of you MFest guys think that mod'd car = expert driver, and bone stock car = n00b driver. What a hilarious crap that is. lulz

Unfortunately I agree here. There does seem to be a correlation with mods equating to driver skill. I'm not pinpointing the MFest group specifically; I'm speaking in generalities.

Originally Posted by OC3

DCT's obviously not having a driver-kickable clutch, (again, w/ DSC turned off) you just turn and get on the throttle. How much throttle depends on the situation, but when done right, you'll get the tailend coming out just as nicely. This guy is in a DCT M3:

Nice find!

[sameh]

Originally Posted by Radiation Joe

You know folks, I once thought the DCT would be the greatest thing since sliced bread. So I ordered one. Then I drove it for 18 months, tracked it, put 50k miles on it, had BMW refuse to service it even if I paid. Unless you've owned and tracked both the DCT and the manual e9x M3s, I'm not going to put a whole lot of faith in your arguments.

Is there any hope in convincing you that your personal experience with 2008 DCT is understandably negatively biased? Would you accept my offer to drive my 2011 around the track so maybe, maybe you'd come back and say "I still think 6MT is better than DCT but I also think this DCT isn't as bad as I thought".
You cant be the only good driver on this forum, some of us DCT owners must be as good or better than you (fair assumption?) how can those people opinion in the DCT be on the extreme right and yours is on the extreme left..No one is claiming it’s the best thing that happened since sliced bread, all we saying is:
It was in fact invented and improved AFTER sliced bread when the MT you’re currently driving was BEFORE sliced bread..In other words, people went to buy sliced bread for the first time and thought “that must be the best thing happened since MT!!” That’s where we start linking it to F1, essentially saying the world and technology is moving to this improved, faster, safer,

[Radiation Joe]

I'm not the only one commenting on the poor downshift characteristics of the DCT. There have been others. I think people are choosing to ignore that the DCT isn't perfect. It is that imperfection that makes me question it's abilities. Other than the horrible lag, I don't think my DCT behaved differently than anybody else's DCT on the track.

I trust my timing for clutch engagement while downshifting a manual. I don't trust the DCT. I didn't just come up with some irrational fear of DCT one day. I drove the thing for 50k miles. I assure you my 2009 behaved just like the 2011 models. I had the latest software as of June 2010.

[captainaudio]

Bottom line is that given two otherwise identcal M3s, one with a DCT and one with an MT a good driver will have virtually identical lap times with either car.

CA

[SIIK2NR]

Rev matching is all about timing.

Rev match downshifting to accelerate and Rev match downshifting to engine break either to a stop or before entering a turn.

First practice blipping the throttle with clutch. Blip it enough to jump about 3k. If you blip it too soft u may as well not have blipped it at all.

Second practice blipping with clutch and shifting. Timing is critical or else the rpm will drop before u clutch out and it will be as if u didnt blip at all. Essentually all u will be doing is killing your gas mileage. ;-).

Once u can revmatch and apply breaks (decelerate) And rev match and apply throttle (accelerate) The next step is to practice blipping with your heel.

Once u can blip with your heel, it will be much easier to transition to heel/toe.

Practice!

[Sandye90m3]

I mean just knock her into s5 mode and get perfect shifts, it's not that hard

[piloto]

Please buy my upcoming book titled:

6MT vs. DCT: And you thought the Middle East conflict was unresolvable!

[UNNATRAL]

you will never get it perfect everytime..sure itll be perfect a few times, but you wont ace it everytime.

and besides, rev matching isnt something that can be taught fully..it has to be felt and you have to feel as though you are the car, i donno how much sense that makes but yeah. i tried for years until i finally got it down right, and now everytime i do it its a great feeling getting it right. patience bro, youll learn it in no time if u try hard.

[OC3]

Originally Posted by Sandye90m3

I mean just knock her into s5 mode and get perfect shifts, it's not that hard

Indeed. With all due respect to Radiation_Joe, I do believe his opinions/preference are influenced by his not-so-positive experience w/ an early model DCT.

Originally Posted by piloto

Please buy my upcoming book titled:

6MT vs. DCT: And you thought the Middle East conflict was unresolvable!

lulz

[OC3]

Originally Posted by Sedan_Clan

Unfortunately I agree here. There does seem to be a correlation with mods equating to driver skill. I'm not pinpointing the MFest group specifically; I'm speaking in generalities.

Indeed, mod'd car might but doesn't necessarily equate to "mod'd" driving skills.

Anyhow, I should revise my statement re: "MFest" group, as Trung in no way speaks for said group. While my statement still stands for the punk, it does not apply for said group.

[Mr. ///M3 RD]

Originally Posted by sameh

Damn it!! how did I miss that one?
in any case, I'm glad we all agree that DCT is far better than 6MT

I have not driven a manual since my e29 (we still have her it's my daughters daily driver). I hope to match once I get back into it driving my e92 manual 6 like I did my manual e29.

However, I don't think I'll ever be as perfect as the computer shifted my former Z4 35i with DCT or my former 346 M3 both of course had paddles too.

Time will tell, I do love the sound of the exhaust as I up or down shift my e92. Nice to be in control again

This is a great thread

[captainaudio]

"Heel and toe" is a term dating back to the days when the brake and accelerator were much farther apart then they are today. In a modern car it is usually more "left side of the foot, right side of the foot"

Engine braking is also an old concept dating back to an era where race drivers were trying to prevent brake fade which was caused by drum brakes overheating. On modern cars and certainly on a track the brakes are used for slowing the car and the transmission is used to get the car in the proper gear to keep the engine operating in the most efficient RPM range.

CA

[Mr. ///M3 RD]

Originally Posted by elp_jc

Even if you rev match badly, it's A LOT better than taking the lazy approach and getting an automatic . And yes, I said lazy because that's what it is <insert spoiled accent here>: too much traffic and my puny leg will get tired; I can 't text while I'm in traffic; I'd look stupid with my friends that I don't know how to drive a manual well if I don't get a DCT; I like to pretend I can drive like a pro right off the bat... Ha ha. And yes, I understand an automatic for a family car, but on a high-performance car I just don't get it.

It's exactly the same as if you let a porn star bang your SO because he's going to do it better than you. As bad as you do it, it's something you want to do do yourself, and learn how to do better, right? Same thing folks. Get a freaking 6MT while you can and enjoy having full control of your car; who the hell cares how slower than DCT you are. And yes, we all know we'll be slower than DCT, but just as the example above, I rather do the work myself than letting somebody else (or a computer) do the work for me . Now I freaking made it a 6MT vs DCT... to defend our honor . Good day gang.

Well put and right on I say also not to forget we do use less gas and save our breaks if we master the task just right

Cheers

Rolf-Dieter

[captainaudio]

Originally Posted by Rolf-Dieter

Well put and right on I say also not to forget we do use less gas and save our breaks if we master the task just right

Cheers

Rolf-Dieter

They are BRAKES no BREAKS and the only time you should use engine braking is when you are descending a long steep decline and this can be done with an MT, a DCT or a Steptronic.


Engine braking was good back in the days when the brakes were marginal - it has no place in todays car.

The only reason to shift down while braking is so that you are in the corect gear when the time comes to accelerate. Blipping the throttle to match revs is done for one reason only - and that is so that you don't cause the rear tires to break traction when you down shift into the lower gear and let the clutch out....remember the rear tires will be lightly loaded under braking making this a very real possibility.

CA

[Erhan]

Originally Posted by captainaudio

A drift can be initialted by snapping off the accellerator to break the rear tires loose and then applying enough throttle to keep them spinning. By modulating the throttle and the steering a drift can be held throughout the corner. This not really something that is done in track driving as it may look spectacular but is by no means the fastest way to get around a turn.

The best place to practice is on a wet skid pad.

CA

Yesterday, I tried the wet skid pad before the students arrive (I was a volunteer for car control clinic). It was cold (low 30s) and I wasn't able to catch the back. Once it looses traction (which is very very easy to do), it just spins. I have Hankook V12 summer tires.

I had a quick lunch and before we re-arrange the cones for next exercise, I spent some more time on the skid pad, this time temperature was mid 40s. M3 is definetly easier to drift then Z4MC. I was able to kick the back by pushing the throttle and hold it with counter steer and throttle modulation. I need more and more seat time, but I'm happy about the M3s dynamics.

At the end of the day, we have an open session auto-cross. The car worked great in there as well. During the slalom, the weight is there.. Z4MC is just more agile. But on relatively spaced cones (meaning higher speed) M3 is really nice. It is also very easy to drift out from tight hairpins to rotate the car for the next cone.

One "problem" of the M3 is a lot of power Gotta be careful with throttle.

[Prince_of_Persia]

So let's look at engineering / theory wise:

The gear ratios for e92 M3 is

1st Gear Ratio 4.23:1
2nd Gear Ratio 2.53:1
3rd Gear Ratio 1.67:1
4th Gear Ratio 1.23:1
5th Gear Ratio 1.00:1
6th Gear Ratio 0.83:1

so 2nd gear to 1st gear ratio is: 4.23/2.53=1.67
3rd gear to 2nd gear ratio is: 1.51
4th gear to 3rd gear ratio is: 1.36
5th gear to 4th gear ratio is: 1.23
6th gear to 5th gear ratio is: 1.20

So basically if you are for example on 4th gear and your RPM is 2000 and you want to down shift to 3rd gear, for a perfect rev-match your RPM should be: 2000 X 1.36 = 2720

Am I right?

Again, this is just theory, for my understanding.

[captainaudio]

Originally Posted by Prince_of_Persia

So let's look at engineering / theory wise:

The gear ratios for e92 M3 is

1st Gear Ratio 4.23:1
2nd Gear Ratio 2.53:1
3rd Gear Ratio 1.67:1
4th Gear Ratio 1.23:1
5th Gear Ratio 1.00:1
6th Gear Ratio 0.83:1

so 2nd gear to 1st gear ratio is: 4.23/2.53=1.67
3rd gear to 2nd gear ratio is: 1.51
4th gear to 3rd gear ratio is: 1.36
5th gear to 4th gear ratio is: 1.23
6th gear to 5th gear ratio is: 1.20

So basically if you are for example on 4th gear and your RPM is 2000 and you want to down shift to 3rd gear, for a perfect rev-match your RPM should be: 2000 X 1.36 = 2720

Am I right?

Again, this is just theory, for my understanding.

You may be right but I think you are overanalyzing the situation. With a bit of practice it will become second nature and you won't have to think about it or look at the tach.

CA

[Prince_of_Persia]

Originally Posted by captainaudio

You may be right but I think you are overanalyzing the situation. With a bit of practice it will become second nature and you won't have to think about it or look at the tach.

CA

This is for my understanding. I am not gonna take a calculator to my car and calculate the RPM

[JCtx]

Originally Posted by Prince_of_Persia

So basically if you are for example on 4th gear and your RPM is 2000 and you want to down shift to 3rd gear, for a perfect rev-match your RPM should be: 2000 X 1.36 = 2720
Am I right?

First of all, you're assuming that car is not decelerating, which is usually the case. And most importantly, that'd be the rpm at which the clutch should be engaged, meaning engine has to be 'blipped' a bit higher to allow engine rpm to drop to that level while clutch pedal is released . Makes sense? Fun stuff.

By the way, doing this on straight gate downshifts, like 4-3, or 6-5, is easier, but it becomes trickier on cross-gate downshifts, especially on lower gears, like 3-2, where it feels a lot jerkier if not executed properly. This is why driving a manual never becomes boring . And yes, as they say: practice makes perfect . Good day gang.