Double Clutching

Does anyone really double clutch?
does it really help??
I always thought it was just a way to unbind shifter cables...
I thought with new cars and new trannys, it wasnt nessesary...

Sometimes i do it for fun, but not sure if it does anything. I was wondering the same thing.

i'm not sure if it actually works either, but u feel a lil boost when u do it tho, but it wears out ur clutch really fast

is it really a boost, or is it just your car jerking after sitting in neutral for soo long?

that's wut i meant, but i see people double clutch really fast and does give a lil boost, but it won't make them .1 faster, maybe not even half that

double clutching is for busses and really old cars. you don't need to do it to new cars. in fact its probably bad for the car. just my .02.

I have a buddy that also has a spec-v. we decided to test the theory... it works, assuming you know what you are doing. how we tested... he double clutched first run, i granny shifted, switched the second run, did this back and forth. each time our start was almost prefectly in sync, a few that weren't so perfect. Whom ever double cluthed won, usually by more than a car length. We were also testing cold car vs. warm car, big difference there too, warm is way better. We tried two different methods. You can double clutch between gears and also in a single gear. what i mean is, push the clutch in, pull out of gear, push it again and put it in the next gear. also (not including first) as you climb through your rpms you can push in the clutch again (while staying in the same gear), climb to 6200 and let out again. each gear you do this in will give you alot of boost. when you are talking 1/4 mile times you will see the difference. When you are using the two in combination it gets a little tricky, but the second method helps to get the most out of each gear. WATCH OUT, these cars have a hydraulic clutch, this type of thing can wear on a clutch of this type, more than normal. what i suggest is practice one run at a time and give it time to cool the clutch in between runs.

Haze,

That's awesome that you and your bud spent some Quality Time testing out the theory. Can you take a minute or two to explain this a little better to me? I am really confused about double clutching.

To everyone else, please read and critique my driving style... I know it is hard to just read something, but I will do my best to explain.

I have been driving a standard transmisison for about 7 years now. Unfortunately I didn't get any real lessons, I just figured it out myself. I considered myself to be a pretty decent driver, but these discussions about double clutching, granny shifting, etc... have me questioning my manhood.... well no.. my driving ability anyhow.

Here is how I drive... my style... In normal acceleration, I shift normal (clutch in, slip out of gear, slip into next gear, back on gas as I am releasing the clutch). If I am trying to race or something, I just do the same thing, only as fast as I can. Sometimes I do it fast enough so that I don't really even let off the gas. I will admit that I haven't gotten used to my Spec V tranny yet, so I haven't done much testing with it.

In deceleration, I put in clutch, slip out of gear, slip into lower gear, and ease out the clutch, letting the engine match to the spead of the wheels. I guess this is called engine breaking, and I have heard that this isn't the best thing? Is that true? It seems real natural to me. But, I guess your better off replacing brake pads than a clutch or tranny.

In a turn.. such as a race course when you brake going in, and accelerate out.... I take my best guess on which gear I will need coming out, then as I am braking with my right foot on the brake, I put in the clutch, and slip to the gear that I want to come out of the turn in... then I very slowly ease out the clutch letting the engine match to the wheels and assist in the braking... at the same time I may lighten up on the brakes a bit just to make sure i don't loose it... then when I reach the point where I can accelerate again, I will have the clutch most of the way out, and I can get back on the gas and let out the rest of the clutch carefully. It turns into a balancing act between two sources of braking, then brakes, and then engine... I think I have gotten pretty good at it.

SO... back to the original question... can you explain double clutching a bit more in detail. My understanding is.... Put in clutch, slip out of gear, let out clutch, put clutch back in, rev the engine up, slip into next gear, and let out clutch... the idea being that your engine should match the speed of your wheels identically making more seemless acceleration possible.. ... Is this right? I just can't seem to make this happen very well. It doesn't feel as though I will ever be able to do this faster than I currently shift... It seems like added and unnecessary steps.

Haze.. you said... "You can double clutch between gears and also in a single gear." I don't get the part about also in a single gear? It sounds like you want me to put in the clutch while accelerating through a gear... that would do the opposite of making me go faster?

Can you explain "Granny Shifting" and "Power Shifting"... are they different from my explaination of when I currently do?

Thanks Haze, and everybody!

Is this seriously a thread on double clutching up shifts?


Double clutching should only be used on down shifts, to enable better matching of engine speed with gear box shaft speeds. On trucks and vechiles with large or no synchros it allows more seemless changes to be made. and on race cars it allows you to change into a lower gear at very high rpm and avoid transmission lock.

When up shift it will do nothing at all, to make you go faster. Infact if you really think about it it will slow you down.
It means more time when the engine isnt driving the wheels, and so acclerating the car.

yeah, moppie got it, double clutching is waste of time unless your driving a semi. as for the other's "granny shifting" is a term that you will only hear on a movie that is a tad bit off:rolleyes: it's just regular shifting, and yeah, the way you said you drive and race (shift regular, but as fast as possible) is the right way to do it. power shifting is something you really shouldn't try for a while, it's shifting without the clutch, it's mainly only useful in a 1/4 mile run and it's very risky, even if you know how to do it. In a turn.. such as a race course when you brake going in, and accelerate out.... I take my best guess on which gear I will need coming out, then as I am braking with my right foot on the brake, I put in the clutch, and slip to the gear that I want to come out of the turn in... then I very slowly ease out the clutch letting the engine match to the wheels and assist in the braking... at the same time I may lighten up on the brakes a bit just to make sure i don't loose it... then when I reach the point where I can accelerate again, I will have the clutch most of the way out, and I can get back on the gas and let out the rest of the clutch carefully. It turns into a balancing act between two sources of braking, then brakes, and then engine...

sounds like you have come close to perfecting a fantastic skill, and i'm frankly impressed that you achieved this without instruction, you could honestly out-drive me any day, congrats:smoker2:

Originally posted by GB Phoenix77

In deceleration, I put in clutch, slip out of gear, slip into lower gear, and ease out the clutch, letting the engine match to the spead of the wheels. I guess this is called engine breaking, and I have heard that this isn't the best thing? Is that true? It seems real natural to me. But, I guess your better off replacing brake pads than a clutch or tranny.

In a turn.. such as a race course when you brake going in, and accelerate out.... I take my best guess on which gear I will need coming out, then as I am braking with my right foot on the brake, I put in the clutch, and slip to the gear that I want to come out of the turn in... then I very slowly ease out the clutch letting the engine match to the wheels and assist in the braking... at the same time I may lighten up on the brakes a bit just to make sure i don't loose it... then when I reach the point where I can accelerate again, I will have the clutch most of the way out, and I can get back on the gas and let out the rest of the clutch carefully. It turns into a balancing act between two sources of braking, then brakes, and then engine... I think I have gotten pretty good at it.



Your upshift is pretty much the same as I do, so no comments. On engine braking, I don't think it is bad for an engine. The main thing is to match engine and wheel speeds to avoid 'wumping' the transmission. The main thing about engine braking is that you are saving your brakes, preventing them from overheating. When your brakes overheat they will not stop you effectively.

On you technique in corners, I'm not sure if you are doing this or not. There is a technique called heel toe downshift. This technique is used by pro racers. The idea it to prevent 'wump'. Basically you right foot will depress the brake and at the same time blip the gas so that engine speed and wheel speed match. You should avoid depressing the clutch in a turn. You will trail brake, shift to neutral, with the outside of your right foot blip the gas so that the engine rpm will match the wheel speed, then downshift and apply power to exit the turn. Essentially I think it is double clutching. The downshift also puts the car on a high torque gear to regain speed as quickly as possible.

To get some really insane exit speed, do all that and add yanking quickly and releasing the e-brake, slide your rear wheels out, counter steer your front wheels, and apply power just past the apex (This is a FF car) to induce a drift. Upon reaching the exit point , let up on the throttle and the car should hopefully return to its normal straightline operation. You may succeed in minimizing the loss of entry speed and your car will be at the ideal angle to exit the turn if you pull it off.

Originally posted by narcted


To get some really insane exit speed, do all that and add yanking quickly and releasing the e-brake, slide your rear wheels out, counter steer your front wheels, and apply power just past the apex (This is a FF car) to induce a drift. Upon reaching the exit point , let up on the throttle and the car should hopefully return to its normal straightline operation. You may succeed in minimizing the loss of entry speed and your car will be at the ideal angle to exit the turn if you pull it off.



Short of spinning out this is the slowest possible way to go round a corner. Drifting looks good, and thats it.

Go watch a F1 or indy car Circut race, and see how often any of them use the handbrake. :)

Originally posted by Moppie




Short of spinning out this is the slowest possible way to go round a corner. Drifting looks good, and thats it.

Go watch a F1 or indy car Circut race, and see how often any of them use the handbrake. :)


I don't know dude... If you want to get a good time in "Ridge Racer", or other games, you gotta slide that tail...

Seriously though... great advice you guys. I appreciate it a lot!

I think drifting is going to be out of my league for a long time. I guess if it were a rear wheel drive, I would work on it, but it just doesn't seem right in a FF car. Again, I'm no expert. It's true.. they never do it in F1 or Indy racing, or Cart, or anything like that, but they definitely do it in Rally racing... seems to work pretty well for them... but then, maybe with very little traction, they have no choice?

I will definitly work on the heel-toe thing. I have heard of that before, but have never been able to find the advantage in it. I guess, I don't do it right, cause I must not be able to match the revs very well. Any advice on how high to rev it?... seems like a lower gear is usually 1000 rpm's or more higher... maybe 1200.. Does that sound right?

Thanks again for the tips guys.... anybody else got input?

GB

Heel toe is a great skill to master, but it does require the right pedal set up.
If the brake and acclerator are to far apart then no amount of skill will allow you to do it.
This is a problem with most family cars, (like the sentra) but a set of bolt on pedal covers may help.



As forRally drving, the are not actualy drifting. They are simply getting the car as straight as possible to get the most accleration they can out of the corner. They are actualy sacrificing mid corner speed to make the most of the 4WD's traction advantage, and in the case of the WRC cars, 600lb/ft of Torque.

But if you ever watch a FWD rally car, then tend to run a very straight line, and slide around as little as possible.
While a RWD car will try and do the same thing, but as you said, there is a lot less traction on gravel than there is on seal. :D

Originally posted by Moppie




Short of spinning out this is the slowest possible way to go round a corner. Drifting looks good, and thats it.

Go watch a F1 or indy car Circut race, and see how often any of them use the handbrake. :)

F1 and Indy cars are cars with excess amounts of horsepower that they can use to quickly rebuild their speed once they exit a turn. Also their high grip tires and extra large brakes can handle the stresses of holding the line in a turn.

Drifting is a technique that can be used by underpowered cars to maintain entry speed without having to rebuild it exiting the corner. It also places them on an ideal angle to exit the turn. There are basically three things to do to increase speed in a turn. 1. Increase entry speed, often by delaying braking until the last possible tenth of a second to apply the brake. 2. follow the ideal line, aka: shortest distance around the turn. 3. Increase your exit speed by applying the gas at the exit point. Following the ideal line is a must. Increasing your entry v. your exit speed can be traded off. Exit speed is more important since most time is lost in those 3-4 seconds it takes to get back up to race speed than in the tenths of a second entering the turn. Underpowered cars lack the horsepower to really be able to build back the exit speed so they save time by delaying and preventing the loss of entry speed and therefore increasing their beginning exit speed.

Driving technique will change when the car has a certain amount of power. Once a car has a certain amont of hp and acceleration (I'd say 200+) the driving style changes. At that point slowing down, following the line, and accelerating out are the fastest way around, and honestly will always be the fastest way in a high powered car. But then you really wouldn't expect, for example, a 130 hp AE86 to beat a 280 hp R34 Skyline in a race. The AE86 will have faster track time if the driver can successfully drift than if the car is driven the same way as the Skyline would.

I suppose drifting a FWD is a misuse of the term. FWD are not capable of actually drifting. They slide. True drifting is being able to take back to back turns. FWD can not change the direction of their slide. Only RWD can do it. But I maintain that it is possible to slide and control a FWD car through such a turn. It just requires heavy use of the e-brake. Hey, I looked hard for a RWD car, but considering my budget, all the RWD cars I wanted stopped production in 95, and the need for some practicality I went with the new SE-R. If it was a RWD, it's the perfect car.

I would disagree and say that rally cars are drifting. An AWD drift is different than both the FWD and RWD drift in that the car pretty much follows a fixed radius as opposed the the skewed lines a FWD and RWD follow. If the tires are skidding, the car is sideways, and turns are taken back to back, then the car is drifting.

try looking at this way.

By drifting you are wasting energy and time going sideways that could be put into going fowards. Which is the ideal way you want to travel around a race track.

Drifting is not the fastest way around a corner.

I second the comments about "drifting" being the fastest way around a course.

First of all, what most people call "drifting" is merely invoking oversteer by artificially breaking the traction of the rear wheels. Drifting in its true form is the perfectly controlled four-wheel slide that a very well sorted car will do when taking a turn. This can be a fast way around a track, but it requires careful control.

Oversteer-drifting can be used to your benefit in select circumstances. A car which would normally understeer in a very tight turn can be made to handle it faster, for example, by pulling a handbrake turn. However, these advantages are usually only seen in very slow turns where your speed would have to be mostly scrubbed off anyway.

Drifting in about any other circusmtance is harmful, especially in a lower-powered car. In a slow car, the fast way around the track is to maintain your momentum at all costs. This is best done by choosing a very smooth line, and making all your inputs as fluid as possible, avoiding sudden changes in direction or throttle inputs. Oversteer induced by artificially increasing the slip-angle of the rear tires will hinder this process by scrubbing off speed. If you're having problems getting set up for a corner, try entering a little more slowly and accelerating out of it -- slow in fast out cures alot of understeer problems when properly done. For more advanced cornering, especially in a FWD car, left foot braking is very useful.

Of course, these are all general rules, and can and will vary. But, for the most part, "drifting" is not the fastest way through a turn.