I take a large exit ramp everyday from work. I come off the freeway in 5th gear, and I need to slow down about 10-20 mph. I tried to go into 4th to accompany the speed I should have been at after taking the exit (approx 50pmh). My car ended up redline, bucking, and I panicked. There were people behind me too, and I had to turn on my hazard lights.

I then tried to shift back into higher gears, but my car just kept bucking and redlining. I eventually slowed down enough and shifted into second gear.

So my question is what is a good way to slow down when you're not coming to a stop? Say, if I want to go from 60-70 mph, to 50-40? I want to use the method that is easiest on my clutch. If I'm coming off the freeway at 80 mph or so, and I will eventually need to be down to 40 or 30 mph, should I not be downshifting?

Also, I haven't a clue as to what rev matching is and when I should do it at which gears/speed.

 

Since you don't seem to understand down shifting and per you statement "I haven't a clue as to what rev matching is and when I should do it at which gears/speed", may I recommend you use your brakes to slow down and than shift into the gear that is appropriate to your speed?

Then you can ask a friend who does know how to down shift to show you the proper way to do it.

 

Sounds to me like you got second instead of fourth. Just try downshifting ONE gear at a time while using the brake too. Do it while driving normally and you will find the downshift points after a little while. Get that down and then you'll be ready to learn more.

 

50mph is less than redline in 2nd, because 2nd does exactly 60mph at 6500rpm in the R56 MCS. Sounds like you were going faster than 50mph if it redlined. Nevertheless, that's not good for the engine at all; over-reving is probably one of the easiest ways to break valvetrain. Before you start learning about downshifting, graph out the speeds the engine is capable in each gear, and then memorize that so you know how many gears you can downshift and still end up at the RPM you want.

 

sounds like you accidently may have thrown it into 2nd when you thought it was going into 4th. I did that the first day we got the car and didn't quite grasp how close the gears were together.
4th gear and even 3rd gear should have been able to handle those revs and speed. 2nd wouldn't...
you def need to learn the basics of rev matching. Go to wikipedia, read up and try it around some safe streets in an industrial area with no one around.

 

Yeah you definitely got 2nd cause you can go like 110mph in 4th gear.

 

In prehistoric times, when I was young and learning to drive standard transmission vehicles, this newfangled thing called "syncromesh" was not available for first gear, and didn't work very well in the other gears. I was taught a technique called "double clutching" to manually sync things. To this day, eons later, I cannot move a gearshift in a stopped standard transmission vehicle from 2nd to 1st without initially dropping into neutral and releasing the clutch, the depressing the clutch and moving the shifter to first. Old habits don't die hard, they live forever.

The least expensive way to reduce the speed of your vehicle is to use your brakes.

The purpose of downshifting during deceleration is to keep RPMs up, for later rapid accelleration. Typically, this is useful in racing, rather than street driving, but it can still be fun. Unfortunately, as you have discovered, doing this improperly risks engine and trasmission damage, rather than just wear on brake parts. In some situations, the clutch mechanism can even disintegrate, which is why most race-prepared vehicles with transmissions located near the driver have protective plating installed over the transmission.

If you would like to learn to drive your vehicle on the street in both a safe and spirited manner, I recommend a performance driving school. At such a school, you will discover the joys of performance driving, and learn many things.... not only how to downshift, but how to evaluate a corner, choose an apex, etc. After graduation, you might find yourself interested in racing your vehicle. SCCA Solo is a great way to get started, and you will also discover that sideways at 50mph is far more exciting than forward at 100mph..

 

Stricting speaking brakes are used for slowing down not the engine. Brake pads and rotors are consumable items, engines are not.

This is the rule of thumb on the racetrack but also applicable to the street - at least sprited street driving.

I tend to agree with others that have posted here that you probably caught 2nd gear instead of 4th and the danger of this is an over-rev damaging your engine. Engines are designed to rev to a certain point after which all kinds of damage can be done. On acceleration the revs are limited (by the "Rev Limiter which is electronic) so there is no damage but what you are describing (catching a lower gear then expected) is a fairly common way of damaging the engine in a race car. Can happen on the street as well. Sometimes the damage will be limited to the clutch (depending upon the rev)sometime more can be done.

Rev matching on downshifts or what is more commonly called heel/toe downshifts are described on the Mini site and plenty of other sites (Google it) as well as in many racing books is a good thing to master. Not only will it make driving more enjoyable but it is better for your engine/drivetrain. It's not easy to learn and much depends upon the pedal placement (which is good in the Mini) but it is worth learning. I can tell you from personal experience that there was a time that I thought I would never master it - now on the race track I mess up maybe 1 of of 50 downshifts. It just takes time to train your muscles and brain to where it becomes automatic.

In a nutshell what happens by not heel/toeing is when you push in the clutch the engine revs drop (because your foot is no longer on the throttle) but the drive wheels (and dif) are still moving at a high rpm. When you let out the clutch the engine rpms have to go up - if the right gear they will go up a good amount but it is hard on all the components involved.

One thing - since the method requires the two pedals (brake and throttle) to fairly close to the same plane (height wise) it generally is not possible to do unless you are braking HARD! For everyday driving when you don't want your laptop and groceries to end up under the dash just doing most of your slowing gently with the brakes only downshifting as necessary.

 

I believe this was very close to what is called "the money shift..."
As in, its gonna cost you a lot of it...

 

Thanks, everyone. It sounds like I have a bit of my own research to do on downshifting/rev matching. And ya'll are right, I threw it into 2nd.

I guess also my question is that shouldn't I be downshifting when decelerating? Or could I have been driving 30-40 mph while still in 5th gear?

 

If all you are doing is slowing down from 70 to 50 on a large offramp, simply take your foot off the gas and let the car slow itself. I see no reason to downshift. In general, excess downshifting causes unneeded wear on the clutch throwout bearing and synchros. Better and cheaper to use the brake in daily use.

 

As a youngster learning to drive, my father made a very firm point: when you are going to slow down "USE YOUR BRAKES! They are cheaper and easier to replace than clutches. Brakes are for stopping, clutches are for shifting."
That said, I dearly love hitting the mark on a good downshift going into a corner and coming out in the gear I need to pull the car around.

 

And that is exactly the key on the racetrack.... also fun on a great road.

BTW - most racers agree, corner EXIT speed is way more important then corner entry speed.

 

Just use the brakes! A lot of times when I see a light up ahead change to red I put the car in neutral and just coast up to the traffic light and use the brakes as needed. Like someone said, the brakes are much cheaper to replace than the clutch or engine. That's what the brakes are for!

 

What people are saying is that you shouldn't be downshifting in order to decelerate the car (use the brake). When you get to the lower speed then downshift in order to get going again. That will eliminate the potential damage that missing the shift could cause to the engine. 2500-3000 rpm is a good place to accelerate from. In my car these are the speeds at about 3000 rpm:
1st gear: 20mph
2nd gear: 30mph
3rd gear: 40mph
4th gear: 55mph
5th gear: 65mph
6th gear: 72mph
So you get on the exit, brake and slow to 30-40 and shift into 3rd and go.

 

And with this being said go out one night and find the absolute limit of each gear ( i am sure it is some where on nam if you search but what fun is that, sometimes ifs more fun doing ) Take first up to 6000, check the speed, and then do the same for each other gear. This will make you personally aware what the threshold of each top gear speed is. Worked for me.

 

YouTube has a lot of good video clips about heel/toe, you should check it out.

And, while you're at it, check out crazy heel/toe work by Walther Rohl.

 

^

GREAT video

 

You are much safer to stay in gear tho...you dont have to downshift or put it in neutral, simply let go of the gas and apply brake as needed...you can ride the current gear out to 1000 rpm (which is usually around 20mph) and then put it in neutral...this is much safer incase you need to go in some emergency situation, causes no strain on the engine/transmission, and actually is better on fuel economy because the fuel supply is shut off when you let go of the gas

 

Now there's a great example of "Happy Feet"! I swear the dude had the left foot on the brake and the right on the gas most of the time. Who was working the clutch anyway? Tinkerbell?

 

Walther Rohl is a god.

 

Blows everything I was ever taught about not breaking with your left foot.

It was a crazy video...unreal that they'd let people line the road like that.

 

AWESOME! I was thinking the same thing about the people. Surely there must've been quite a few fan fatalities back in the day.

 

Walter Rohl not only is a god but those Group B cars were not for human drivers. In their day (the 80's) they out accelerated F1 cars!

BTW - Left foot braking is a pretty acceptable standard now.

 

I find myself using quite a bit of 5th to 3rd for the majority of my driving, 4 ends up too low in the revs, 3rd gives that punch out of the corner. Of course, you brake and shift as the curve requires and how fast you want to take it. I'm not ***** out looking to be the next Alonso or Hamilton, crap I'm too old for that !

Cheers,

Mike