Can someone explain in details what exactly is throttle blip and what advantage does it give and in what situations?
As i understand it roughly, the idea is when you downsfift, you blip the throttle(like press the throttle a bit?) before releasing the clutch? so you have higher RPM's when you shift in the lower gear? Is that it?
Anyway, i haven't played LFS with manual clutch yet, so i don't know can this be used with auto clutch and how..?
What are true advantages of throttle blip, and how to do it properly?
I am not too familiar with all of the advanced racing techniques but i want to be..

Blipping the throttle for downshifts makes for a smoother shift. Downshifting without blipping can result in the driven wheels losing traction as the engine and wheels fight against each other.

When you downshift normally, the revs drop and the flywheel spins slower than the clutch, often significantly slower depending upon how long it takes you to shift. Then when you let the clutch out, the flywheel and clutch attempt to match their speeds. The engine resists because the throttle is zero so it just wants to slow down more, and the driven wheels resist because the car has a significant amount of momentum. Most often, you might get a sudden jolt in the car and the revs jump up to the proper level.

However, in racing conditions, it is quite possible that the negative force exerted by the engine upon the wheels is enough to break traction. Depending upon how high the reciprocating mass in the engine is, this could be for a very long time. However, since the engine is always spinning, the wheels never completely lock up. Once the engine reaches the proper revs, the wheels regain traction.

By blipping the throttle on downshift, this can all be avoided. As soon as the clutch is let out, the flywheel and clutch are already spinning at the same speed. Even blipping a little too much is much better than too little, as it's much easier for the engine to slow down than speed up when there is no throttle.

I personally leave all helps off except for autoclutch and also use my right foot for braking. This usually means I have to be very careful about how I time my downshifts so I don't skid too much, but I'm used to it.

Well said. It is more of a problem for rear wheel drive cars where locking the rear wheels on the approach to a corner is the last thing you want to do

Good post. Here's my version:

When you go from a higher gear ratio to a lower gear ratio your engine speed will increase (because ratio=enginespeed/wheelspeed). This change of engine speed can either be done the "easy" way by using the throttle or the "hard" way by making the tyres transfer braking forces all the way through the drivetrain to speed up the engine.

The disadvantage of the second method is of course the unwanted braking effect and the unnecessary load to drivetrain and engine. In LFS many of the fast drivers actually do like to use the engine for braking (machine-gun-downshifting seems to shorten braking distance) but I've never looked at any RAF data to find out why. Wild guess: they are keeping the brake balance setting further forward for trail-braking stability and then making up for the missing rear braking power by using the gearbox.

Damn it.. i still don't get it completely.
So i am going like from 3rd gear, aproaching the corner, and before changing down to 2nd, i first brake, then let go off the brake, press the clutch, tap the throttle a bit, and then release the clutch?? Is that the right order?

Yes, except you shouldn't let go off the brakes. You should be finished with downshifting by the time you come off the brakes.

Quote from Boris Lozac :

Damn it.. i still don't get it completely.
So i am going like from 3rd gear, aproaching the corner, and before changing down to 2nd, i first brake, then let go off the brake, press the clutch, tap the throttle a bit, and then release the clutch?? Is that the right order?

Well, you must brake with your right foot and use clutch at left foot, then you can brake and blip with your right foot heel while you keep pressing brake with toes.

When you lift clutch rpm must be right amount for that gear or you will upset balance of the car and you need to make gear shifting so that you are not wasting time so this is why you need to shift down same time when braking.

This method of blipping throttle that I did describe is called heel&toe. Well, actually it is method of using brake and throttle, but it is used for blipping.

Ok, so basically the point is, not to have too low RPM's when i change to a lower gear, but to have the same amount of RPM's like in the previous gear, so that's why you tap a throttle a bit before releasing the clutch..?

Quote from Boris Lozac :

Ok, so basically the point is, not to have too low RPM's when i change to a lower gear, but to have the same amount of RPM's like in the previous gear, so that's why you tap a throttle a bit before releasing the clutch..?

Basically yes. You maintain the revs by blipping which allows a smoother change. Also handy for shifting down early.

Quote from Boris Lozac :

Ok, so basically the point is, not to have too low RPM's when i change to a lower gear, but to have the same amount of RPM's like in the previous gear, so that's why you tap a throttle a bit before releasing the clutch..?

No. You want a higher rpm than in the previous gear. That's what gears are for, they change the ratio between car speed and engine speed so it can't be the same rpm before and after shifting.

Boris - you can practice in your own car, and at first you don't have to brake. Try this;

Along a nice straight road, perhaps 40mph in 3rd gear. You're going to leave the brake pedal alone for the moment, just practice on the principal.

1) Now, try changing to 2nd as "normal", your right leg doing nothing. You'll notice the car jerking when you release the clutch in 2nd, this is because the gearbox winds the engine up due to the higher ratio between 2nd & 3rd. Try that a few times, listen to the engine note/pitch when you change.

2) Do the same as above, nice and slowly, however this time when you press the clutch in and change to 2nd, squeeze the accelerator pedal gently and bring the engine revs up to match where they would be in 2nd gear. You'll notice now that you're brought the engine revs up to meet 2nd gear instead of the car doing it for you.

This is called a "match rev gear change" and is kinder to the transmission/driveshafts etc.

3) An advanced way of doing this is to be braking with your right foot and using your heel to blip the accelerator. This is called "Heel & Toeing". Don't try this yet, possibly get someone to show you. And never try it on a public road untill you get proficient.

4) Just for completeness, you don't need to read this, and it generally isn't done on a road car, there is also "double de-clutching". Its similar to number 2 above and is intended to change down in vehicles without syncromeshes between the gears. The reason you can actually change gear in a car the 'normal' way is due to a syncromesh. My dad learned to drive army trucks that didn't have these syncro's. So you have to blip the clutch while changing down in order to spin up the shafts in the gearbox so that the gears meshed properly. If you can't do match-rev changes yet don't even consider this one, it isn't really used these days. However I was fortunate to learn this tecnique as I learned to drive and so all the above comes very naturally to me and I use mixtures of all these on the road and track depending on the circumstances.

Dave

Ok, i get it now.. Thanks guys
Until i get the G25... i don't think i would be trying this with my Momo, don't know if i can be bothered setting the clutch on the button... but i will try it in my real car..

Reading all this reminds me of just how badly I want my own car.
Bloody education and the amount of money it costs to study abroad...

Quote from Boris Lozac :

Ok, i get it now.. Thanks guys
Until i get the G25... i don't think i would be trying this with my Momo, don't know if i can be bothered setting the clutch on the button... but i will try it in my real car..

Word of advice, start practising when parked and engine not running, this way you will get feeling to it safely before you actually start driving, when you can do manouver without thinking without too much effort then you are ready to start car and start practising this in low speeds.

It is easier in some cars and more difficult in others, but remember always safety first. I may have some experiences of some things gone bad always better to make it safe way first

Quote from JTbo :

Word of advice, start practising when parked and engine not running, this way you will get feeling to it safely before you actually start driving, when you can do manouver without thinking without too much effort then you are ready to start car and start practising this in low speeds.

It is easier in some cars and more difficult in others, but remember always safety first. I may have some experiences of some things gone bad always better to make it safe way first

Sure, i will...
So, this technique, throttle blip/heel and toe is basically practical and good for the car in every day driving, in your basic road car?
I am doing the car and engine a favor with this, right? Matching the revs, not upseting the car when changing gears..
Now that i think of it... heel and toe techique can also be used when starting on a uphill, you know those minor uphills when there's no need for a handbrake start.
You noticed that i am a begginer real life driver, i am about to have mu driving licence in the upcoming days(hopefully) so forgive me for my noobish RL posts..
So, heel and toe... i hold the brake with my toes, and when i about to start from a uphill, i press the throttle with mu heal, while gently releasing the brake my toes.. so this way, i can avoid car going a little downhill??
Am i making any sence here?

Quote from Jertje :

Reading all this reminds me of just how badly I want my own car. Bloody education and the amount of money it costs to study abroad...

Don't be in a rush my friend, there's plenty of time in life

Quote from Boris Lozac :

So, this technique, throttle blip/heel and toe is basically practical and good for the car in every day driving, in your basic road car?

Erm, no. It is difficult this one - officially heel & toe is NOT good practice for the road, but match-rev changes ARE. Nobody on here should tell you to heel & toe on the road it is even if they use it (and I do!), it is track only. Officially (speaking from the UK) the recommended, best and safer way is the "Roadcraft" way (this is the police drivers handbook) - this is tought by the Institute of Motorists and ROSPA etc...

Okay - the reasons. Well, "proper", controlled, safe road driving is keeping the car under control at all times and crossing your foot over the brake and accelerator pedal is not recommended road driving practice. However you can match the revs happily on down change because you don't have to cross your feet, you can 'normally' change gear with this tecnique.

Of course exactly what you do on the road is up to you. This discussion is for track driving I'd recommend getting further driver training after you pass your road test - after all, you're shown "how to pass the test", NOT how to drive a car!! Of course you'll benefit from on-track tuition too, I've given instruction both on the road and on many UK circuits - keep your road and track driving seperated.


Dave

I aways heel and toe on downshifts with my car, it makes driving much smoother and as my car has tuned NA engine it has pretty strong engine braking, so I can't really use that on daily driving, specially when there is bit ice it is very good to use heel&toe.

I don't think it is very useful for uphill starting as you can't control brake and throttle too well for that particular situation.

Quote from horrgakx :

Don't be in a rush my friend, there's plenty of time in life

Oh trust me, I'm not one to rush

Wow, do people actually drive their cars IRL that hard out on public roads to need heel/toe shifting? I've never heel/toe'ed shifted in my life on public roads. Heck, I hardly ever downshift while braking when driving on the road. New front brake pads are much much cheaper than a new clutch to be putting all the wear and tear on it for normal street driving.

$10-15 for a pair of front brake pads or $150-250 for a new clutch. I think I'll just pull it out of gear into neutral and use my brakes on normal every day driving.

Quote from mrodgers :

Wow, do people actually drive their cars IRL that hard out on public roads to need heel/toe shifting? I've never heel/toe'ed shifted in my life on public roads. Heck, I hardly ever downshift while braking when driving on the road. New front brake pads are much much cheaper than a new clutch to be putting all the wear and tear on it for normal street driving.

$10-15 for a pair of front brake pads or $150-250 for a new clutch. I think I'll just pull it out of gear into neutral and use my brakes on normal every day driving.

I have always gear in and engine is always on such rpm range that there is good amount of power available, you never know if some rice rocket tries to overtake or something LOL

But seriously, in my current car it is almost easier to heel&toe than put gear to neutral, heel&toe happens just automatically, typical situation is where I'm closing intersection at city (40kph limit) where I need to turn right, so I just need to slow down a bit and shift from 4th to 2nd, so I brake blip throttle when speed is close to end of braking shift and lift clutch, move right feet off from brake to completely to accelerator, push throttle so that accelerate trough cornering section and put back to 4th, I just cruise around idle rpm with 4th and all acceleration is then done with 2nd gear that is around max torque.
Problem with putting gear to neutral is that I would need to match rpm when I put gear in (1cm of throttle and it is above 3000rpm already) and also there would not be fuel cut either if I put it to neutral.

Depends a lot from car. But sure, I don't drive slow, well I don't drive overspeed either, I like to use brakes so that they won't rust and accelerate with maximum efficiecy.

Quote from Boris Lozac :

.. i don't think i would be trying this with my Momo, don't know if i can be bothered setting the clutch on the button... but i will try it in my real car..

It is even more effective using a button clutch in LFS currently.

Quote from mrodgers :

Heck, I hardly ever downshift while braking when driving on the road

I think I know what you mean, on the road you actually don't come down through the gears, you use foot braking while in the gear you're in until you need to change again. A direct quote from the "Roadcraft Police Drivers Handbook"; "Be in the correct gear for every road speed and traffic situation".

I've got a late-90s copy of the Roadcraft book, has much changed since?

Not sure, I've never seen a list of changes.

Quote from mrodgers :

Wow, do people actually drive their cars IRL that hard out on public roads to need heel/toe shifting? I've never heel/toe'ed shifted in my life on public roads. Heck, I hardly ever downshift while braking when driving on the road. New front brake pads are much much cheaper than a new clutch to be putting all the wear and tear on it for normal street driving.

$10-15 for a pair of front brake pads or $150-250 for a new clutch. I think I'll just pull it out of gear into neutral and use my brakes on normal every day driving.

Cant agree with you there. My last car, 1997 Grand Am with a 2.4 manual, I put 120,000 miles on it before the engine blew, and the clutch was fine, and I do rev matching and heel/toe shifting unconciously.

Am I the exception? I dunno!