Hi

I'm trying to learn how to improve my down shifts when driving my car. For instance, I might be in forth and try to change to third when going up a hill. If I don't touch the throttle then I get a lurch when the clutch engages.

I've heard that one can blip the throttle just before engaging the clutch to match the engine revs. I'm interested to know when one does this.

At what point do you blip the throttle? While your moving the gear stick to the new gear, or once the new gear is selected?

Thanks,

T

Depends on the throttle response of the engine. A tardier engine means a slower gearshift ultimately, but renders blipping pointless because the engine revs don't drop sharply.

In ordinary driving there's no need to blip the throttle, especially if changing down going up a hill. Maybe let the clutch out slower.

However if cracking on you can use combination of gear chaange, braking and throttle to get into a lower gear at high revs to enter the corner without unbalancing the car.

you remember when you were a kid way back in the olden days and your mother tied your mittens through the sleeves of your jacket on a piece of string. Think of something along those lines. During a gear change – If one pedal is going down the other is coming up and vice versa. Never only one pedal being worked during a gear shift.

Do you mean double de-clutching? Spins the gearbock up to higher RPM ready fpr the lower gear, used to be important before before synchro mesh gearboxes were invented. Even in a modern car it can make a downshift much smoother but you have to do it firmly and quickly otherwise speed and revs drop off anyway.

Racing drivers do it and brake at the same time by heel and toeing on the throttle and brake pedals….

Ah I think I must mean double de-cluching. My Dad makes the engine spin up when shifting which makes things smoother, I'm trying to figure out how its done. All I remember is that the engine would rev up for a little bit.

I can let the clutch out slower, but that just doesn't seem as elegant as how he did it. Also, I tend to slow down too much meaning I have to accelerate in the lower gear which seems like a waste of fuel.

Obi not always the case, as above pressing all 3 pedals at once makes for very smooth changes too.

As Obi says, you feed one onto the other. So as you're letting the clutch out, you bring the gas in. Gently, don't just let the clutch catapult up on the spring.

It sounds like your changing down too early to me! Banging into second from third or any other down shift for that matter will create a lurch if your engine was not struggling in it's existing gear? Is it a low cc smallish car poss 4 speed youre driving. And without being cheeky are you newish to driving?

I was going to say, I'm stunned they don't cover this in driving lessons. But they teach block shifting now, don't they?

You should through the method, be able to learn to change gear without using the clutch, on up and down. It's quite easy really.

The easiest way, as I did on an old Alfa GTV I owned, was to literally, give the gear leaver say, in 4th, a gentle push, and feel how it would seem to almost "slip" out of gear with the gentlist of pushes and a bit of throttle pedal manipulation. Same with then trying to get it into third, you push the gear to the gate, it push it to the point where theres resistance on the stick, and then rev agan. you will just feel a sweet spot when it just wants to slip straight into gear.

Indeed, with a dead clutch, I managed to drive around for a couple of days without a clutch once. Stops were difficult, as to stop you needed to knock it out of gear totally to prevent stalling. Also moving off required turning the engine over on the starter motor until you had enought forward thrust to knock it into 1st or ideally 2nd without stalling.

I do this – mainly to drop into a lower gear approaching a steep downhill corner followed by a long downhill into a 20mph limit. It also works to smooth out the type of "drop a gear and hoof it" applications you describe!

I just blip the throttle by enough to raise the revs to the same level they will be when the lower gears go in. Difficult to describe when to do it as its become subconscious, but generally whilst the clutch is in and the gear lever on its way through the gate, but I guess I overlap with clutch in/out as well.

Done well the engine revs at the top of the blip should perfectly match the new engine speed once you let the clutch back in. This has the potential to reduce clutch wear as well as smooth out your driving.

For more info look up heel & toe gear changing and double-declutching on YouTube. Couple more bits of info – if you read the Police & Advanced driving handbook (Roadcraft) it teaches a system of car control that will reduce the need to change gears under pressure like this. Also worth knowing is that the new Nissan 370Z will do this for you automatically! As well as sounding cool, it also reduces the risk of sudden engine braking locking up the rear wheels!

Hope this helps

I am a new driver, in a 5 speed 1.3 Ford Ka. I've never had a driving lesson as such, was taught by my Dad.

I can downshift without lurching, but I thought it was possible to do this quickly while dumping the clutch. I'm happy to move the clutch out more slowly and apply throttle, but that just seems like the clutch and gearbox are being forced to match the engine revs. I thought there was a way to help the process and reduce wear.

As for block shifting, I rarely do it unless I pull out onto a steep downhill or something.

I'm happy to do everything the normal way, but I'm trying to improve my driving. (Mainly to improve fuel economy)

I think you should buy an automatic 😉

Never! I do enjoy shifting gears – I just want to do it well (i.e almost imperceptible gear shifts)!

I commute to work, so learning to anticipate, minimise braking by throttling off early makes things more interesting.

Block shifting is only really applied for coasting up to give ways etc, fourth whilst braking then into second etc, you need to be scrubbing off speed or your gonna put you nose on the steering wheel. And as I thought low cc and newish driver. No offence meant and you will get the smoothness by applying what the guys have said above rather than trying to blip the throttle.

<Goan to the forum please> 😉

Look up "sustained gearchange" – cop training taught it and it's brilliant once you suss it out.

Very few cars require double de-clutching these days.

Unless you're driving a car from the '40s you don't want to be doing (or need to be doing) double de clutching . . . that is only necessary on gearboxes without synchromesh . . .

Slight throttle blipping on down changes makes for a smoother drive and speeds up the whole gear change process as the clutch can be let out almost instantly because you are pre-matching the driven and non driven parts of the clutch, so there is no clutch slip and no delay while the engine spins up to the speed required for the lower gear . . .

How to learn . . . and please be careful . . .

Find a quiet road . . . drive along at say 30mph in 3rd, look at the revs (and listen to the engine note) . . . now drive at the same speed in 4th . . . again look at the revs . . . what you are trying to do is . . .

in 4th, press clutch, as you start moving the gearbox out of 4th and the clutch disengages and you move towards 3rd blip the throttle so the engine speed is what it WOULD be if the gearbox was in 3rd (just a rapid prod of the throttle will be enough) . . . when it is (or is close) put the gearbox into 3rd and release the clutch . . . if you get it right there will be no feeling whatsoever when you take your foot off the clutch . . . you don't need to be exactly correct matching the revs, but the closer the better . . .

This is one smooth operation where the blip, gearchange and clutch engage/disengage all overlap, so it takes a little practice to get the process correctly synchronised . . .

I haven't mentioned braking because that is more difficult and dangerous to learn, it involves braking and blipping the throttle with your right foot and using the clutch with your left foot, all at the same time . . . its called heel and toe'ing (not that you use heels at all in my experience) and is the best way to brake very hard and do radical gear changes whilst braking without disturbing the braking balance of the car . . . not something you often need to do on a public road . . . and something that really can cause you to crash and is best initially learned somewhere very safe . . .

As an example, the link below is my PB run up the Doune Hillclimb, every down change is done during hard braking and is blip assisted to prevent the rear of the car locking up and spinning the car . . . the big stop at 11:15:30 is from 4th at about 80mph to 2nd at about 30mph very quickly so there is a huge differential in revs when you change gear, hence the huge blip . . .

http://www.youtube.com/watch?v=7jX4TZcS4JQ

Thanks all for the info.

fergusd I'll give it a go, although I'll avoid the braking and blipping thing indefinitely- I was always taught not to brake round corners anyway (I was actually told to slow down before the corner and apply gentle throttle around the corner to prevent the car lo-loping. Does seem to work!).

Btw, nice Caterham! Have you ever driven one with the weather kit? I was wondering how watertight it was.

I never mentioned braking whilst going round corners . . .

All caterhams leak like sieves . . .

Fd

That run looks terrifying! Yeesh.

timothius – do not give any of that a go other than what i said. As a new driver you will not have the observation skills to be able to play with the pedals to see what they do AND keep on top of what is happening outside of the car. You WILL start looking at what your feet are doing.

Go onto http://www.Adiforum.co.uk and get some proper advice from some qualified professionals.

Well that would appear to be my cover well and truly blown. 😉

P.S. FergusD cant drive for toffee. A debate that we have had in depth in the past.

Ok, I'll give it a few months until I try anything complicated. I'd rather not cause any accidents (especially as my insurance in 1.2k+ 🙁 )

Was in an accident as a child, was enough to put me off ever being in one again!

Good sensible man.

As mentioned above it depends on how fast it takes for your engine to respond, so there isn't a hard and fast rule as to when/how much to apply the throttle. As with all things to do with driving, it is a case of practice and getting a feel for it. I do it all of the time, it is now a subconcious (sp?) thing – just like driving becomes after a while when you learn.

What you are essentially trying to do is synchronise the clutch plate and the flywheel to the same speed so that when you let the clutch pedal out, you don't have to accelerate the engine up to the new gearbox input shaft speed. Using the clutch to bring the engine up to the correct speed requires the energy to come from somewhere, and this comes from the kinetic energy of the car, which is why shifts can feel lurchy/jerky as you put a negative torque into the driveline.

Others on here have spoken about double declutching, and heel and toeing. These are both extensions on what you are asking about…. personally I would master the simple 'throttle blip' before moving on. Having said that you may be a fast learner and want to jump in at the deep end – each to their own.
🙂

I havent read any of this thread but I drive the scrappiest old trucks and old tractors etc imaginably so …

Basically you depress the clutch
pull the vehicle out of gear
(whilst keeping the clutch depressed) rev the throttle to a level higher than it will rev when it is in the new gear
keep a gentle pressure on the gear stick and when the engine revs match the axle speed (or something!) the gear will "drop" in nicely

this can be done "clutchless" with the same technique but when you **** it up it griiiiinds!

Nick

ps I am sure that there are plenty of nigel mansels who can pick holes in this but this!

I may be repeating what has already been said but I'm too lazy to read everything. OP is not talking about doube de-clutching he's talking about a boosted gear change. double de-clutching is the same but the clutch is depressed twice with the extra revs being applied whilst the gearbox is in neutral. Boosted gear change is where you match the engine speed to the appropriate gear when changing down. Double de-clutch is only really needed on crappy old gearboxes to slip the gear in as described above by a few people i think. I learnt how to do both on my police driving courses, becomes second nature suprisingly quickly.