Launching!Discuss here=D

[HanJackaL]

Hi to all launching sifus out there, i have a couple of questions that i hope i can get an answer to since i am quite confused.

1)Whats the use of revving the car up to a certain RPM before releasing clutch/handbrake ? What benefit is there to do that?Why cant draggers just balance clutch and gas like normal street driving when moving out of a traffic light ?If just balance like normal driving,there will be totally no wheelspin right ?

2)What is the difference between launching with handbrake and launching with just clutch and gas ?

3)How do i know exactly what RPM to launch my car at?Which RPM is the best?What does maximum torque reading mean?

4)If i choose to rev my car up at the starting grid, is it wise to just totally release my clutch and just control my gas, or should i release my clutch slowly instead ?

5)About shifting patterns,the best way of shifting is just drive your car then shift right before the rev cut right ?That is the fastest way correct ?

Thanks in advance all !

 

[Zeroed]

The above varies with car to car... cars of different power levels and hardware require different techniques.

Suggest you just try it out, think for abit, and decide the best for yourself. :)

 

[jinkl]

press the clutch full in , rev up , then leave clutch , erm ur clutch must be able to catch and clamp the flywheel to go , if slip how hehehehhe , takes time oso

pull handbrake , rev up , bt u cant rev high and hold the car with the handbrake , so u can only rev low , u rev high and let go clutch lil bit still car move redi mar

dunno bout ur launch , mine i usually launch at 4krpm
if i launch lower than tht then i get boost lag , if i rev higher than tht i get only wheel spins and car dont move

u can alwiz look for launching techniques on the net
as for me pull the handbrake , rev till 4krpm , let the clutch go a little where i can still feel the handbrake holding the car , then at green light i let go the handbrake , press oil very little and stable , no hurry in flooring the pedal , u floor , u confirm wheel spin , even with slicks im spinning if i rev too fast

to shift wht gear , erm u dyno then only u know when u should shift, u will know when the powerband ends

 

[zan]

main advantage of doing so is to accelerate faster from standstill. that's all.

and the reason why F1 cars come with launch control. avoid wheelspin and extract most power from max rpm.

 

[jinkl]

if u have a turbo , accelerating from standstill u will kena tapau lolx

 

[HanJackaL]

if u have a turbo , accelerating from standstill u will kena tapau lolx

Why is that bro?Whether you rev up your engine while in stand still, or just balance clutch and move in stand still, you are STILL starting from stand still. How does revving up first (launching) give you an advantage ? Either way you have to start from stand still or wheel spin.

 

[drewn123]

Hi to all launching sifus out there, i have a couple of questions that i hope i can get an answer to since i am quite confused.

1)Whats the use of revving the car up to a certain RPM before releasing clutch/handbrake ? What benefit is there to do that?Why cant draggers just balance clutch and gas like normal street driving when moving out of a traffic light ?If just balance like normal driving,there will be totally no wheelspin right ?

2)What is the difference between launching with handbrake and launching with just clutch and gas ?

3)How do i know exactly what RPM to launch my car at?Which RPM is the best?What does maximum torque reading mean?

4)If i choose to rev my car up at the starting grid, is it wise to just totally release my clutch and just control my gas, or should i release my clutch slowly instead ?

5)About shifting patterns,the best way of shifting is just drive your car then shift right before the rev cut right ?That is the fastest way correct ?

Thanks in advance all !

OKok..... i'm not expert here.. this is my opinion.

1. Every car has a different Maximum Torque at certain RPM, Let's say the car's max torque is at 4800 rpm, to get the best/fastest launch is rev to that number and release your clutch. theoratically, tats the fastest way. Cuz the max spin is done to the wheel..... But if your wheel can't cope with the spin (i.e. spinning of tyres becuz of road condition/tyres condition)..... tats y ferraris/lambo/porsche got anti-slip to prevent spinning of tyres.....

2. Launching wit handbrakes are best if your car is Rear-Drive... for front wheel, use clutch dude...

3. Go get your car a dyno check, they'll tell you... your vehicle's max torque at what rpm. Some mags did publish the max torque at a particular RPM. If the max torque is at lower RPM, tat means the car accelerate faster cuz you achieve the max torq faster.

4. No comment..... u try wat i had recommend then answer this.... hahahahaha

5. nope.... when driving, dun rev until you achieve rev cut... Can't you hear whether ur car's engine are struggling??? Doing so, may/will increase your engine wear and tear. Get the dyno chart, it'll show you the perfect RPM where u should change your gear.....

Lastly, if there's any mistakes, pls comment (cuz i know there is)

 

[theorekz]

Why is that bro?Whether you rev up your engine while in stand still, or just balance clutch and move in stand still, you are STILL starting from stand still. How does revving up first (launching) give you an advantage ? Either way you have to start from stand still or wheel spin.

i'm not expert also.. but i think what mr jinkl is trying to say is.. it is because turbo cars need time to achieve boost... so if u start from stand still... U have to take time to build up the boost.....

correct me if i'm wrong.. i'm not runnig on turbo.. heh heh
:D

 

[alien]

OKok..... i'm not expert here.. this is my opinion.



2. Launching wit handbrakes are best if your car is Rear-Drive... for front wheel, use clutch dude...

why is tat so? for FF, launching wit handbrakes.. wat's wrong with tat..??
please enlighten me oh.. para sifu sekalian.. :tongue:

 

[jinkl]

yeaps thts wht i meant
a race turbo engine equiped with 280 profile high cams , big turbine ,
rev from standstill , maybe even a 500hp evo FF ,
from standstill most probably to kena tapau for first 200meters hehehehehe

u can see the ending and smile

to achieve boost it takes time , stock evo FF for stock turbine around 2.5k onwards only , wht if td06 ? maybe 4krpm only boost builds , from 1kprm to 4krpm aint easy :) cos once high mods are done , its coupled up with low compression pistons and metal gaskets , u can never expect a good response at low rpm , definately have to rev up b4 launching

ok here some techniques from modernracing drag tech article

We will take a look at managing a manual transmission first. With a stick shift, the main aim is to avoid excessive wheelspin by pressing the throttle too much, but also avoid bogging down the motor by pressing the throttle too little. The driver has to get the throttle input just right, like in that Goldilocks fairytale. Each car engine has a different rpm range in which it will produce the most power. The trick is to keep the engine in this sweet spot from the moment you cross the starting line all the way to the finish line, without any of this peak power being wasted. Launching a car hard from a dead stop is accomplished by slipping the clutch and spinning the tires, both within reason. Power is lost here, but most engines have narrow power and torque bands, so the fastest launch will include wheelspin and slipping the clutch. The only way to find out how much slipping would be just right is to experiment at the track, holding the throttle at various rpm levels at launch to see how much juice is needed for the quickest start.

While playing with the clutch and throttle, use the parking brake to keep your car from rolling. This is the only way to keep your car stationary while you work the clutch with the left foot and the throttle with the right. You then release the parking brake as you launch.

Some people may say a manual benefits from powershifting during a race, which is to keep the throttle floored between shifts. It is not a good idea for a beginner, since a ill-timed shift can cause your engine to over-rev and inflict permanent damage.

You get up to the staging lanes and you see that third yellow. You want to make sure that your rpm's are high enough so that you don't bog, but not so high that you'll spin your slicks. So much as chirp can cost you .10 sec in your 60 ft. You release that race clutch ever so slightly (DON'T!!DROP the Hammer!!) while holding your Revs at the set given point. You want the car to feel like it's going to bog for a split sec, then you're outta there. With NOS and turbocharged vehicles the 1st to second shift will come so quick that you probably haven't even released the clutch out fully yet. Stick the clutch back in, go to second, and go on to win your race.

On turbocharged vehicles, keeping you're foot on the gas during the shift ( which must be done quickly) improves you're ET dramatically. It maintains boost pressure in the intake manifold thus giving you more to start with in each higher gear. The difference from "Speed Shifting", what this style of driving has become labeled as, and regular driving can mean as much as half a second and up to 5 MPH in you're trap in mildly turbocharged vehicles.

Use the factory line lock (parking brake) to keep your car from rolling out of the lights once you’re staged. Unless you have an extra leg to operate the brake pedal, this is the only way to keep your car stationary while you work the clutch with one foot and the throttle with the other. That way, you can use your free hand to disengage the parking brake as you launch, and you won’t redlight because your car crept forward after you staged.

Although automatic transmissions have a reputation as being power-robbing slugs, they do have one big advantage for dragracing – the brake-torque launch. Simply put, this launch method involves holding the car in place with the brakes while running the engine up against the torque converter. This effectively preloads the entire drivetrain, and allows the engine to operate closer to its power peak from a stop. In a turbocharger-equipped vehicle, it also allows boost to build before the launch. The only disadvantage is that it puts a lot of stress on the transmission, causing it to heat up pretty quickly. Unless the car is wildly overpowered for the tires it’s on, a brake-torque launch usually won’t spin the wheels because of the shock-absorbing nature of the automatic transmission. Surprisingly, brake-torqued launches are actually easier on the rest of the drivetrain, because instead of a massive shock load, everything from the brake rotors back to the transmission has the torque applied more slowly instead of in one huge jolt. The penalty is that automatic transmissions lose more power later on down the track, and generally don’t shift nearly as aggressively as you can with a stickshift. There are ways to get around this and to tune the performance of an automatic for use on the strip, but that’s beyond the scope of this article.

 

[jinkl]

Why is that bro?Whether you rev up your engine while in stand still, or just balance clutch and move in stand still, you are STILL starting from stand still. How does revving up first (launching) give you an advantage ? Either way you have to start from stand still or wheel spin.

errr to get a sweet spot for torque ?
too much rev will wheel spin
too low rev will be slugish cos less torque

ok laa simple example here ?
u rev and let go the clutch , y does it wheel spin ? cos there is too much of torque and ur tyres cant handle them
try using drag tyres full slick , do the same thing , rev up , let go the clutch :) no wheel spins , bt car just hops and zooms out

if u dont rev up , ur engine powerband at 1krpm is very very low , torque is very very low

u can test em :) bring two cars , identical engine
one rev up to a sweet spot at a range without wheel spins
one more from stand still hehehehe
im sure atleast halfcar difrence for n/a less than 100hp cars , try with 500hp monsta , u might get few seconds diffrence

if revving up b4 launching aint rite , then drag cars wouldnt be doing burn outs and wheel spins at start line

 

[Fluffy]

ahh...so the sweet spot for torque is wat you need to get a good launch rite? :albertein

good info jinkl!

 

[drewn123]

why is tat so? for FF, launching wit handbrakes.. wat's wrong with tat..??
please enlighten me oh.. para sifu sekalian.. :tongue:

FF is Front engine Front drive la
FR is Front engine Rear drive which is quite rare in Malaysia, except old cars or sports car......hehehe

For FR, apply your hand brakes. (you do know the handbrakes ratio are normally 40:60, front:rear) Engage 1st gear wit clutch engaged, Rev till you reached your RPM sweet spot (hehe...no pun intended, jinkl :tongue: ) Let go of your clutch little by little, once you feel the car is gonna move, let go your clutch and step on it..........accel bro

Btw, this is wat i do...... if there's any sifus out there pls comment on my technique... i would love to hear bout other ppls technique.....

 

[alien]

FF is Front engine Front drive la
FR is Front engine Rear drive which is quite rare in Malaysia, except old cars or sports car......hehehe

For FR, apply your hand brakes. (you do know the handbrakes ratio are normally 40:60, front:rear) Engage 1st gear wit clutch engaged, Rev till you reached your RPM sweet spot (hehe...no pun intended, jinkl :tongue: ) Let go of your clutch little by little, once you feel the car is gonna move, let go your clutch and step on it..........accel bro

Btw, this is wat i do...... if there's any sifus out there pls comment on my technique... i would love to hear bout other ppls technique.....

i think u got me wrong..
i was refering to the earlier post..
u said using the handbrake is best for FR.. and use clutch for for FF..
im not talkin bout FR...
wat i wanna noe is.. why isnt the handbrake technique be juz as good when used on FF..?
sorry for the misunderstanding..

and i think u meant let go your 'handbrakes' and step on it on ur last line.. hehe