whoa...Danno and Idstang50....you just cleared up A LOT for me....Great explanation! Now just gotta practice..hehe

 

Last, first
I would not downshift when maximum braking in an emergency situation unless I was doing a speed far beyond what the brakes could handle.
The consequences of dropping the clutch or not revving high enough is locked up tires and a harder to handle skid into whatever you were trying to stop before.
During cornering heel toe you are coming off the brake as you slip the clutch, which doesn't carry that risk...

Are you doing this coming into the turn or exiting the turn?

 

You can do it when approaching the cornor depending on your speed. You adjust exceleration and braking by the pressure pressed on each side of your foot.
At high speeds:
- To get closer to the inside you use a bit more brake.
- To get further outside or go faster use more gas.

Note that driving in rainy or snowy conditions takes a different technique as excilirating on water will cause your tires to spin more and increase the understeer drasticlly.

 

firstly, it isn't your clutch you will damage by downshifting it is your bears and synchros. secondly, while you may only use your right foot to do it, the technique you are talking about is left foot braking, where you should not be depressing the clutch, rather you should be near WOT while feathering the brake pedal to keep the front in.

not trying to flame, rather clarify

 

synchros are here...no need

 

rev -matching is what you need to do....does wonders...once u've mastered that like I have you must master heel-toe....thats what I have trouble with....bad feet and pedal setup...

 

either you do the traditional double-clutch or you do the heel and toe or even what i call single clutch method.... as EVOag mentioned, rev-matching is wats important...getting your RPMS up so when you downshift, it smoothly goes into gear and your gear does not lurch forward

 

since we have synchros.... rev matching is to prevent wear but as long as you dont go nuts it wont destroy your tranny.... rev matching is also very important because without it your car will lurch as weight is violently transfered to the front and effect your handling in a very negative way

 

If you dont rev match you can dammage your clutch. If you are going from 3000RPM to 5000RPM (for example) to a lower gear and you just let the clutch out your clutch hits the flywheel harder and over time will dammage it.

I have never heard of left foot braking. Please explane more. I find that in my car (Lancer OZ) that the gas peddle and brake are almost alligned in height and not that far apart in width either. The clutch sits in a completly different postion. The way I look at it you have 3 peddles and 2 feet. You need to double up with one foot and I personally find it easier to use my right one for that.

I hope nobody thinks your flaming. Thats not what this is about. This is about sharing driving techniques and learning new ones. I dont know everything I just know what works really well for me. You introduced me to a new method and I will practice it a bit and see how it works for me. As of now though The method I described seemed to be the best for my driving technique and best ease.

 

left foot braking is a technique used in Circuit Racing it is most helpful for FWD, but it has applications in rwd and awd. for instance if you come in to a corner to hot, you can stay on the throttle but feather the brake with your left foot( this is one of the hardest techniques to learn only because if you drive a manual your left foot is used to slamming the clutch in so you must practice alot i have been doing it for over 3.5 yrs and i still occasionally push the brake to hard) you do it slightly differently but the result is the same... by applying light pressure to your brakes the front end likes to dive to the inside, in an awd this is much more significant... whereas the front wheels are pushing when the rear wheels are pushing... especially if you have negative camber. and in rwd you can easily see what can happen if you depress the brake too much. also there is different points for each drivetrain to use left foot braking. FWD will use it at a corners entrance. AWD will use it at the apex to return the car to its proper line. and RWD will need it at the exit since RWD generally has insane oversteer you use left foot braking to correct the angle you are leaving the corner... hope i didn't confuse anyone

 

Thats what I do but with my right foot. I have big feet and I can acuratly controll brake and gas pressure with the same foot while using the other foot for the clutch.

 

that is the term of the technique you are employing , i have big feet as well, but it seems to me that it would be hard to have the ***** of my feet on the brake and modulating the throttle with you heel

 

It's odd that inn a Lancer/Evolution (assuming they have the same pedal placement), you would have much trouble with that because of their spacing. I too have big feet, and when I first got my Ralliart I accidentally did something like heel and toeing a couple times! I have to rub my right foot up against the right side of the foot well to use the gas safely. I've long since gotten used to it and don't think it about when driving anymore, but it was very noticable at first.

 

Well I drive an OZ not an Evo and like I said before. The peddles in the Lancer are almost perfectly lined up for it. If you have pedel covers it makes it great to do.

 

There's some horrible descriptions of the concepts thrown about in this thread, so maybe this will help. Originally posted for SoCalEvo.net members here

Lifted from a post on DSMTalk that I remember helped me a good bit with the various shifting concepts. The DSMTalk thread is <a href="http://www.dsmtalk.com/forums/showthread.php?s=&threadid=91627">here</a> (has some other interesting comments). On to the content:

(START QUOTE)
This tech tip was found on a BMW site 3+ years ago. The link is now dead. I am posting here so that forum members would benefit. The original link the information was obtained from and the date it was printed is on the bottom of the page.

Shifting Technique

"Heal and toe" refers to the right foot position as it operates both the gas and the brake pedal at the same time. Actually, on most modern cars it's better to use the ball of the foot (under the big toe) on the brake pedal and the edge of the foot (about halfway between the little toe and the heel) on the gas pedal. I think it's better to refer to it as "ball and edge".

There are some individual variations in position based on foot size, type of shoe, seating position, pedal placement, and so on.

It's important to give preference to the brake pedal for safety reasons, and because the brakes require more accurate control feel than the engine speed.

I have size I I shoes. In my ti I position my foot so that my heel is on the floor near the base of the gas pedal. The ball of my foot is centered half way top to bottom on the brake pedal, with the edge of the brake pedal at my middle toe. My foot is in approximately the eleven o'clock position when I am doing this. In this position I can firmly apply the brakes, and the control feel is pretty much the same as if I was operating the brake pedal alone. By rocking my foot, I can apply the gas without varying the pressure on the brake pedal (this is one part in particular that takes practice). When I'm done braking, I slide my foot over so that it's directly on tile gas pedal. My heel has remained on the same place on the floor.

Some people, particularly with smaller feet, don't keep their heel on the floor. There are some other cars that I lift my own heel from the floor. I like to have it on the floor if possible because it makes it easier to consistently control the brake pressure while rocking the foot. It's important not to have the seat too far back because the knee needs to move side to side just a little bit when doing this. Having the leg stretched out too far restricts this motion.

Aftermarket pedal covers can benefit some cars and foot sizes by bringing the edges of the pedals closer together and by changing the height relationship between the pedals. On some cars with hanging gas pedals, the gas pedal can be bent to a more favorable position (this can't be done on the ti because the pedal is hinged from the floor). I don't recommend trying to bend the brake pedal. Also be aware that pedal covers can reduce the space for a larger foot to fit between the brake pedal and the center console.

I have found the stock pedal positions to be quite good for me. Obviously this is a highly individual thing. I would suggest that people spend a significant amount of time experimenting with foot positioning before trying to reposition the pedals or investing in pedal covers.

Why heel and toe (ball and edge)?

One basic situation is starting up hill. Ball and edge allows a smooth transition from brake to gas while operating the clutch with the left foot so that the car doesn't move backwards.

Many people also use the term "heel and toe" to refer to rev matching while shifting and/or double clutching, but it's actually just one component of these processes.

Rev matching refers to matching the engine speed to the transmission input speed before re engaging the clutch. This is particularly desirable when downshifting for a corner. In a hard comer, the suspension needs to be stable and the tires need to be loaded so that all of their traction is being used to generate cornering force. If the engine is at a different speed than the transmission input when the clutch is re engaged, this will generate a force on the driveline that will upset the stability of the suspension and will cause the tires to exceed their traction capability if the corner is being taken near the limit.

It *is* necessary to rev match if a corner is to be taken near the limit. It isn't necessary for slower comers, but it will make them smoother.

Double clutching is a technique for rev matching the transmission's *intermediate shaft* to the output gear that is to be selected. This is a function that is normally handled automatically by the transmission's synchro mesh gears (or synchro's). It is useful to double clutch for extreme gear changes, for older transmissions with worn synchro's, or simply to save wear on the synchro's. It's also an entertaining thing to do.

Before I get into the specifics of rev matching and double clutching, it would probably be good to review the inner workings of the clutch and transmission.

The ti's gasoline engine has a limited output bandwidth of approximately 1000 to 6000 RPM. It can't operate from 0 RPM (like an electric motor can), so it needs a device (the clutch) to disconnect it from the drive train so that it can idle while the car is at a standstill. The power is not constant from

1000 to 6000 RPM, so it is also necessary to have different gear ratios in the transmission to extend the car's useful operation speed range and to maximize available acceleration. The clutch also serves to disconnect power to the transmission when changing gears,

THE CLUTCH:

The clutch is integrated with the engine's flywheel. There is a disk with friction material, similar to a brake pad, that is connected to the transmission input shaft on a sliding spline. This disk is surrounded by the flywheel surface on one side, and the pressure plate surface on the other side. The pressure plate is spring loaded to squeeze the clutch disk against the flywheel, effectively making a solid connection. The pressure plate can be moved by pressing down on the clutch pedal. This releases the coupling pressure between the flywheel and the clutch disk so that they can rotate independently.

There are three states the clutch can be in:

CLUTCH DISENGAGED (pedal pressed down): The engine flywheel and the clutch disk can rotate independently. No power is being transferred.

CLUTCH SLIPPING (pedal brought up just to the point that the clutch starts to grab): The engine flywheel and the clutch disk are still rotating at different speeds, but power is being transferred. If the clutch pedal is continued to be brought up properly, the speed of the engine and the clutch disk will be brought together. This is the state that clutch wear occurs.

CLUTCH ENGAGED (pedal up): The engine flywheel and the clutch disk are locked together. Full power is being transferred, and no clutch wear is Occurring.

THE TRANSMISSION:

The transmission has an input and an output. The ti has five forward gear ratios (fifth gear is a straight 1: 1, not an overdrive) and one reverse gear ratio. The forward gears are all *constant mesh*, that means that the gear teeth for all ratios are always engaged with each other at all times. Instead of sliding a gear out of engagement with another gear, the gear is disengaged by disconnecting it from the *shaft* that it is on. Only one gear ratio pair can be connected to the shaft at one time. The reverse gear is an actual sliding gear whose teeth actually slide out of engagement when it's not being used.

Each forward gear can be coupled to its shaft by a sliding locking coupler. This coupler connects splines on the shaft to splines on the gear. The coupler needs to be at the same speed as the gear splines to avoid grinding. (When people refer to "grinding the gears", it is actually the splines that are grinding, not the gear teeth). To synchronize the coupler with the gear splines, there is an intermediate device called a synchro mesh.

The synchro mesh is a lightweight ring with spline teeth on one side, and a conical friction surface on the other side. It is positioned between the sliding coupler and the gear splines. The gear also has a conical friction surface that mates with the surface of the synchro mesh.

When a gear is to be engaged, the shift linkage selects a sliding coupler to connect to a gear. At this point, the coupler and the gear to be engaged are usually spinning at different speeds. As the coupler starts to slide, it first engages the spline teeth of the synchro mesh ring. Because the synchro mesh is so lightweight, it can virtually instantly change speed to match the sliding coupler that was just forced into engagement with it. It then becomes part of the coupler. As the coupler continues to slide towards the gear splines, the friction surface of the synchro mesh ring is pressed into contact with the ffiction surface of the gear assembly. This friction causes the transmission's input shaft (which at this point is hopefully disconnected from the engine by the clutch) to be accelerated (or decelerated) so that the coupler and the gear are spinning at the same speed when their spline teeth finally engage.

I think it's helpful to find some junk transmission parts to move around by hand to help visualize this process.

A synchro mesh is limited in how much mass it can accelerate and how fast it can do it.

DOUBLE CLUTCHING:

There are *three* separate spinning entities that need to be coordinated when shifting: The engine. The transmission input. (I'm going to refer to this as the intermediate shaft). The transmission output (which is directly related to the vehicle speed).

When the clutch is disengaged (pedal pushed down) and the transmission is in neutral (such as when shifting between two gears), the intermediate shaft is essentially free spinning. In normal shifting, we rely on the synchro's to control the speed of the intermediate shaft as it engages with the gears connecting it to the transmission output.

Decades ago, transmissions didn't have synchro mesh. (Many large trucks still don't). On these transmissions, it is necessary for the driver to manually control the speed of the intermediate shaft so that it matches the speed of the gear to be engaged. This is done by the following process when shifting from one gear to the next:

1) Power is removed and clutch is disengaged (pedal down). 2) Transmission is shifted from original gear to neutral. 3) Clutch is re engaged (pedal up). (Driver now has control of intermediate shaft speed by controlling engine speed). 4) Driver 'blips' throttle to match intermediate shaft speed to speed of new gear. (This takes practice to get the right match). 5) Clutch is disengaged (pedal down). 6) Transmission is shifted from neutral into new gear. 7) Clutch is reengaged (pedal up) and power is applied.

Steps I 3 can be done casually or quickly. Steps 4 6 *must* be done quickly so that the intermediate shaft doesn't slow down again before it's engaged. If step seven is also done quickly, the engine will also be 'rev matched' to the rest of the driveline so that engagement will be smoother.

REV MATCHING:

When taking off from a stop and then going up through the gears, steps 1,2,6,7 above are the normal shifting method for each gear change. The synchro mesh are more than enough to control the intermediate shaft speed. The engine will passively rev match itself because it slows down naturally and this is appropriate when shifting up.

When down shifting, the engine needs to spin faster as it engages the new gear. This can be achieved by 'blipping' the throttle as the transmission passes through neutral. If the engine isn't manually sped up by the driver, it will be sped up by the driveline when the clutch is re engaged. This can be OK for normal street driving, but if the car is cornering near the limit this can upset the suspension and the tire adhesion.

The synchromesh are usually adequate intermediate shaft control when down shifting one or two gears. Aggressive downshifts (like a 5 2 shift from high speed) can benefit by using double clutch shifting to assist the synchro's. Shifting into first gear in a hard corner is nearly impossible without double clutching (this is useful for those really tight hairpins, especially if they exit uphill).

LEARNING TO DOUBLE CLUTCH, REV MATCH, ETC...

I think that the biggest problem people have learning these techniques is that they try to incorporate everything all at once. The following are suggestions that I have for progressively learning things one at a time.

GETTING INTO GEAR AT A STOP:

Because the synchro mesh doesn't operate unless something is turning, it's easiest to get into first gear by shifting from neutral into first just before the car comes to a complete stop. If the car is already stopped, a lot of extra force may sometimes be required if the spline teeth don't match up. (Sometimes it might help to briefly re engage the clutch to spin things around again). If the car is moving too fast, a lot of effort is required to get the lever into first (it might even 'crunch' if the synchro's capabilities are exceeded).

Try this exercise: When slowing to a stop, push in the clutch and *lightly* press the shift lever from neutral towards the first gear slot at around 10 MPH. Don't force it in. As the car slows down, there will be a point that the lever easily slips into gear by itself This will occur just before the car comes to a stop.

What is happening here? The intermediate shaft quickly slows down (due to friction) to near zero speed. This results in a fairly large speed difference between the intermediate shaft and first gear. The first gear synchro *resists* the lever movement. As the car slows down first gear also slows down. When the car is almost to a stop, first gear has slowed down to the point that it nearly matches the intermediate shaft's speed. At this point, the synchro is able to accelerate the intermediate shaft to a matching speed. When the speeds match, the force required to engage the splines is reduced, and the lever slips into place.

This is a rather slow, passive rev matching situation. Using this technique results in a smooth, low effort engagement into first gear when coming to a stop at a light. It reduces the wear on the first gear synchro.

More importantly, this is a good way to learn to recognize the 'feel' of a properly actuated synchro. This light touch engagement is something to strive for when learning to actively match revs with the engine and double clutching. Some people refer to this as treating the shift knob like an eggshell. By *accurately* shifting, shifts can actually be done faster than by forcing the shift lever with muscle. Again, it also has the benefit of reducing transmission and clutch wear.

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