A Few Questions About How Tranys Work

[ProfessorBlinks]

1. In a standard, how do you use the clutch petal and Gears in these conditions:
-Shifting Up
-Shifting Down
-Accelerating from a stop to a fast speed
-Slowing Down from a fast speed to a stop
-Starting Up The Car
-Shutting Off the Car

I understand how the principles work(Clutch releases the engine, allows you to shift the gears), but I just dont know how fast you need to release the clutch, when to have it in and when to have it out, where to have the gears, ect.
So to sum that up, the perfect response would have

Clutch=In/Out/How Fast
Gears=Neutral, shifting up/down/not shifting
Gas Pedal=On/Off/Push Slowly

Ive watched a few people drive standards, and Ive noticed weird things like shifting through gears while slowing down, ect. Thats what prompted this question.

2. I understand the principles of how a torque convertor works, but what is the point of it? I know it eliminates the need for a clutch on autos, but all it seems to do is transfer torque to a liquid, then transfer it back to a solid(Like a motor working, except the input is the same form as the output). What part did I miss?

3. Do all newer stock production standard cars(Around 1993-Present) have RPM limiters?

4. Will an automatic tranny let you rev past redline? Like when I am driving my van, if I put the pedal down will the car stay in first and the engine explode? What about in neutral.

5. What will happen if, in an auto, I put the pedal down as fast as I can from a standstill.

6. What is overdrive?

7. On radar detectors, can someone explain the K, Ka, X, and all the other bands and what they signify?

8. Where can I find a place to legally speed, do fun stuff like drifting and spinning out, and just have fun without breaking the law or being in danger?

Thanks to everyone that awnsers the questions, because I poured every question about cars that I can think of here. Thanks

 

[MazKid]

1.Standard, or Manuel transmission, the clutch pedal is used to break the connection from the engine to the drivetrain. This allows you to shift because if you don't use the clutch, you are really trying to force the engine to change speed to a new gear and vice versa. By useing the clutch pedal, the engine speed can be syncronized to the gear speed so that the shift is smooth, unless you are racing in which you usually slam on the gas, puch in he clutch, shift fast, and let off the clutch so that the engine speed is above the gear speed and it give a kick into the gear. Doing th reverse(like going down the road in 2nd at about 20mph, pushing in the clutch, shifting to first, and then letting off the clutch while the engine is at low RPM) creates a backwards force, which is the trans trying to speed up the engine, and it can cause back spin, which is when the wheel litterally skid to a stop or backwards while the car is moving forward.

Damn! I need to read, I just explained what you knew. ahh well.

Anyway, it's hard to explain how to use the clutch effectively, as it changes from car to car, depending on the car, and the wear on the clutch.

Maybe someone else here could do it...

 

[Hooligan]

Originally posted by ProfessorBlinks
I understand how the principles work(Clutch releases the engine, allows you to shift the gears), but I just dont know how fast you need to release the clutch, when to have it in and when to have it out, where to have the gears, ect.

In an ideal transmission, you'd only be on the clutch for 0 seconds. As in no time at all, only fully on or fully off. Any time spent inbetween wears down the clutch, as it is only in partial contact. However, this would break either your gearbox or driveshaft in exactly no time also.

Generally, spend less than one second pushing the clutch down, less than one changing gears, and less than one letting the clutch up. In an average car (<150HP), that's enough to protect both the clutch disc and drivetrain. High-powered and/or modified cars will differ. Start on cheap-a$$ cars first. Makes repairs less painful, too.

As for the gas pedal, feed it in slowly, but don't let the engine speed drop too much. Use your tachometer (RPM gauge) to keep the engine speed from going too high, but certainly too low. What's too low? Depends on the car. If the car jerks or lunges, that's too slow. If it revs then lunges forward, that's too high. If it's smooth as silk....

Ive watched a few people drive standards, and Ive noticed weird things like shifting through gears while slowing down, ect. Thats what prompted this question.

Down-shifting while slowing down helps the car to slow down. It's called engine braking. Let's say a car is in 4th gear at 45MPH, and 2,000RPM. In 3rd gear at the same MPH speed, the engine would be at 3,500RPM. If I were to switch from 4th to 3rd at 45MPH, the engine would be working harder to keep that speed. Easing off the gas would slow the engine down, and thus the car, reducing the engine speed back to 2,000RPM (for example) and now a slower speed of, say, 30MPH.

This technique was used decades ago when brakes were all-drums and really sucked. Engine braking on a big V8 is quite effective, since the engine components are heavier (and there's more of them). The widespread use of good disc brakes and small 4-cylinder engines had made engine braking a thing of real sports cars, auto racing, and dim-witted teenagers who like to over-rev their car.

2. I understand the principles of how a torque convertor works, but what is the point of it? I know it eliminates the need for a clutch on autos, but all it seems to do is transfer torque to a liquid, then transfer it back to a solid(Like a motor working, except the input is the same form as the output). What part did I miss?

Well, you pretty much had it there. It acts like a clutch, easing the changing of gears for an automatic transmission. Since there's no direct user input in an auto transmission (semi-auto's not included), something has to do the easing automatically. As the engine speed changes, the viscous liquid changes properties, from semi-solid to mostly-liquid and back.

3. Do all newer stock production standard cars(Around 1993-Present) have RPM limiters?

As far as I know, yes. They have them to protect the engine from over-revving. Theoretically, you could rev any car to 20,000 RPM. Whether your Toyota's 1.8L would survive past 10,000RPM is up to chance.... There's also a fuel-cutoff, which also considered a limiter of sorts. If the engine can't get enough fuel, it can't make enough power to get to the next cycle, so it automatically slows down. The limit is set differently according to the engine. TVR, for example, likes the limit set quite high.

4. Will an automatic tranny let you rev past redline? Like when I am driving my van, if I put the pedal down will the car stay in first and the engine explode? What about in neutral.

5. What will happen if, in an auto, I put the pedal down as fast as I can from a standstill.

The cars ECU (computer) should keep track of the current RPM, and change to the next gear once it reaches the limit. It will probably allow you to spend more time in first if you have the pedal all the way down (throttle fully open), as opposed to changing earlier if the throttle is half-open. In neutral, the rev limiter and fuel-cutoff should conspire to keep your engine in check. If you keep revving the engine long enough, though, it could die even at 6,000 RPM.

6. What is overdrive?

Where only demons and Ayrton Senna dare to tread. Seriously, it's a marketing term used for the top gear in cars. For example, I had a 1985 Volvo 240 DL, with a 4-speed manual. There was an option, though, for an "Overdrive". This really meant that there was a 5th gear.

It's also used legitimately. The top gear (or top two gears) in a lot of cars are unusually high. This is for cruising on the highway, where 80MPH might equate to 1,500RPM on the tachometer. Awful good for low gas consumption. The gear is said to be "overdriven" because it spins so slowly compared to the output (the wheels). It's still spinning faster than the wheels, but compared to a "normal" top gear, it's a good deal slower. This results in a faster wheel speed, but with less power. Underdriven gears would be spinning faster than normal, with lower wheel speed, and more power.

7. On radar detectors, can someone explain the K, Ka, X, and all the other bands and what they signify?

I hope someone else can, because I sure can't. But this should help somewhat:
http://www.snooper-radar-detectors.com/radar_laser_speedtrap_bands.htm

8. Where can I find a place to legally speed, do fun stuff like drifting and spinning out, and just have fun without breaking the law or being in danger?

First, contact the SCCA [http://www.scca.org]. That should help you find some places to get all that unncessary "I wanna speed" energy out of your system.

Other than that, large country-club parking lots are good this time of year. Your local amusement park should be empty, too. But if there's snow, watch out for parking barriers buried in the snow. But above all, don't go it alone should something happen.


I hope that wasn't too confusing. I know I can ramble on at times....

 

[Cobraboy]

Well done Hooligan! 👍 👍

 

[HRT_Maloo]

Your question about an auto going into the red line...
The 95-2001 Holden Commodore V6s (not sure about the VXs and VYs) will go 500-800 rpm into the redline in second gear with a top speed of 145 kmh (90mph)

 

[ProfessorBlinks]

So, when pushing the clutch in besides making sure you dont press it in too slowly(to avoid burning it), speed doesnt matter?

Down-shifting while slowing down helps the car to slow down. It's called engine braking. Let's say a car is in 4th gear at 45MPH, and 2,000RPM. In 3rd gear at the same MPH speed, the engine would be at 3,500RPM. If I were to switch from 4th to 3rd at 45MPH, the engine would be working harder to keep that speed. Easing off the gas would slow the engine down, and thus the car, reducing the engine speed back to 2,000RPM (for example) and now a slower speed of, say, 30MPH.

My only questions is this: Clutch in or out? I dont know why, but im preety sure my friend was not letting the clutch out as he did this. And I really just should leave it in neutral, I dont need to do this with a small car?

Other than that, large country-club parking lots are good this time of year. Your local amusement park should be empty, too. But if there's snow, watch out for parking barriers buried in the snow. But above all, don't go it alone should something happen.

Is this illegal?

 

[Duke]

Originally posted by Hooligan
What is 'overdrive'?
Seriously, it's a marketing term used for the top gear in cars. For example, I had a 1985 Volvo 240 DL, with a 4-speed manual. There was an option, though, for an "Overdrive". This really meant that there was a 5th gear.
<snip>
The gear is said to be "overdriven" because it spins so slowly compared to the output (the wheels). It's still spinning faster than the wheels, but compared to a "normal" top gear, it's a good deal slower. This results in a faster wheel speed, but with less power. Underdriven gears would be spinning faster than normal, with lower wheel speed, and more power.

Actually, Hooligan gave an otherwise excellent answer but I must take exception to this part of it.

'Overdrive' is not just the term for a the top gear of the car. Overdrive means that the output shaft of the transmission is spinning faster than the input shaft (ie the engine RPM). This is of course before it is subject to the final drive ratio in the differential. Overdrive gears have a ratio of 1.01 or higher (taller), as opposed to underdrive gears which have a ratio of 1.00 and lower (shorter). As Hooligan states, the laws of mechanics mean that you trade off speed to gain acceleration as the gear ratios get to be lower. Making the gear ratio of the top gear taller than 1.00 does allow the engine to turn much lower revs during sustained high-speed cruising, when acceleration demands are minimal.

In further answer to some of the other questions:

3) AFAIK all fuel injected cars from 1990-on or so that are controlled by an engine computer have a rev limiter and most have a speed limiter as well. The rev limiter functions operates at any wheel speed by cutting the gas supply, and it is there to prevent you from overrevving the car during upshifts; HOWEVER, it cannot protect the engine from overrevving if you stuff it into a too-low gear at too-high a speed. The speed limiter operates at a given wheel speed (such as 118 mph) and is usually there to prevent you from exceeding the speed rating of the stock tires.

4) I don't know what kind of van you drive. Normally, the rev limiter will prevent you from overrevving the engine either in neutral or a gear. Most auto transmissions, when put in D, will automatically upshift at or near redline when you hold your foot to the floor. However, if you put the selector in one of the lower numbers, some will hold that gear and let you bounce off the rev limiter; some will upshift anyway. Let me strongly caustion against doing 'neutral drops', where you rev the car in neutral and suddenly shift into gear in order to do a burnout. This places brutal stress on the transmission and the rest of the drivetrain, and will kill it quickly.

5) Flooring the throttle from a standstill in an automatic will make the car try to acclerate as hard as it can right away. If the car is of moderate power it will take off with a little chirp, and upshift at redline as you hold your foot in it. If it has a lot of power, it will smoke the tires and rev highly while the wheels spin to a high speed but the car accelerates slowly.

8) I'll second Hooligan's recommendation of joining the SCCA or a similar sanctioning body. The SCCA has a program called SpeedFreakz, which is spceifically targeted at the younger, street-racing crowd, and getting them involved in high performance driving under safe and controlled conditions.

Hope this helps!

 

[Hooligan]

Originally posted by ProfessorBlinks
So, when pushing the clutch in besides making sure you dont press it in too slowly(to avoid burning it), speed doesnt matter?

Basically, yes. Just make sure to also let up on the gas. If the car is in neutral (clutch fully engaged), the engine will be free to rev itself to bits.

My only questions is this: Clutch in or out? I dont know why, but im preety sure my friend was not letting the clutch out as he did this. And I really just should leave it in neutral, I dont need to do this with a small car?

I'm not 100% sure what you mean by this, but downshifting when slowing down is almost identical to upshifting when accelerating. The only difference is the gas pedal application: very light when downshifting, as heavy as you feel like when upshifting. Clutch motions (both in & out) should be the same: fast in, a bit slower out.

Is this illegal?

Does a bear sh.... Well, of course. But know the neighborhood first. If an abandoned parking lot is well off the beaten path, chances are you'll be okay. However, if we're talking the A&P on Main Street, even at 3am there's the chance of being caught. I think most cops would consider it reckless driving (a points ticket, for sure). Some might be nice about it (if you're nice to them), some might see you as a real hooligan creating a public nuisance. In California, the car-hater state, your chances of getting away with anything are slim. Rural Vermont, for example, is notoriously easy.

 

[Hooligan]

Originally posted by neon_duke
Actually, Hooligan gave an otherwise excellent answer but I must take exception to this part of it.

'Overdrive' is not just the term for a the top gear of the car. Overdrive means that the output shaft of the transmission is spinning faster than the input shaft (ie the engine RPM). This is of course before it is subject to the final drive ratio in the differential. Overdrive gears have a ratio of 1.01 or higher (taller), as opposed to underdrive gears which have a ratio of 1.00 and lower (shorter). As Hooligan states, the laws of mechanics mean that you trade off speed to gain acceleration as the gear ratios get to be lower. Making the gear ratio of the top gear taller than 1.00 does allow the engine to turn much lower revs during sustained high-speed cruising, when acceleration demands are minimal

Oh, I didn't mean overdrive being the top gear was the only answer. It was just one example...one that was used in my beater 240DL. It was a push-button thing, too. When you're in 4th, just push the "OD" button on the top of the gearshift. Some automatic mechanism takes over and shifts you into some...other gear.

 

[Duke]

Well, an 'overdrive' specifically means that the gear ratio in the transmission is greater than 1.0, meaning that the output of the transmission is faster than the input from the engine. I'm not trying to be rude, but that is the only definition.

On your Volvo, like many cars, the pushbutton actually engages a transfer gear, kind of a pre-final-drive. It's still utilizing the main 4 (or 5) gears that it shifts through, but once the acceleration is complete and you're cruising in top gear, it steps up an additional increase in the output shaft to turn the normally-underdrive top gear into an overdrive. This was pretty common in the 80s 4-speed automatics.

Other cars like the Colt/Mirage twins had shiftable final drives, with a shorter 'power' mode and a taller 'economy' mode. The lower range would be all-underdrive for in-town zip, while the top gear or two would be overdrive for economy. Think of a ten-speed bike, with the same 5 gears at the sprocket in back, and a choice of two drive gears at the crank.

 

[Duke]

Originally posted by ProfessorBlinks
So, when pushing the clutch in besides making sure you dont press it in too slowly(to avoid burning it), speed doesnt matter?

Correct, more or less. To upshift smoothly, you should accelerate until your chosen shift point, then ease off the gas slightly before putting the clutch in. This allows the acceleration to taper off rather than nodding your passenger's head forward when the acceleration suddenly ceases. After easing off a little, fully depress the clutch and let all the way off the gas. Make the gear change, and firmly but smoothly release the clutch and get back into the gas at the same time. Half a second in, hold for a second while you shift, and one second out. Take your time and get it smooth - the car will not stop rolling. With practice you will find the point where you can feel the clutch grab as you let it out, and you will learn to let it out quickly to that point and then smoothly the rest of the way.

My only questions is this: Clutch in or out? I dont know why, but im preety sure my friend was not letting the clutch out as he did this. And I really just should leave it in neutral, I dont need to do this with a small car?

Downshifting is your choice. In a lightweight car it is not strictly necessary when rolling up to a stop. You may simply let your foot off the gas with the car in gear and let the engine drag some of your speed down instead of braking lightly. At the point where you would begin to brake firmly in an ATX car, you simply put the clutch in and slip the car into neutral while braking firmly to a stop with your right foot. Brake pads are easier to change than clutches. However, there is no point in rowing down through the gears if you don't let the clutch out between shifts.

Remember, the clutch doesn't really wear when it is in all the way or out all the way. It is half-contact that kills them. If you wish to sit at the stoplight, in first gear and with the clutch all the way in, that's perfectly fine. It may put a tiny amount of additional wear on the throwout bearing, but that's its job. You may also sit in neutral with the clutch out, but then you need to get into gear as soon as the light turns. For beginners it's probably easier to do that while you're waiting.

However, downshifting for a rolling turn is another story. Then your goal is to slow the car, but also to have the engine in the proper gear and revs for accelerating out of the turn. As you approach the turn, release the throttle and apply light brake with the right foot. Almost the same procedure as an upshift: half a second to put the clutch in, hold it in a second while you make the downshift, then let it out smoothly but firmly. Brake a little more firmly while the clutch is in to keep slowing the car. This time, you do not step on the throttle at all, but continue to brake. Let the engine revs come up and the car speed fall more, then repeat the process. Once you've reached the turn-in point, release the brakes, and get back into the throttle smoothly. The clutch should already be out and the car in the lower gear, so you don't need to feather the clutch out like you do on a launch. Just accelerate away smoothly and upshift.


All this is much easier to do in real life than it is to describe on paper. With a couple weeks' practice, you'll have the feel for the steps, and the ear for what the engine wants.

Next month: heel-and-toe!