Driving Techniques - Manual Driving/Drag Racing

[kennythebomb]

Okay, so something is bothering me.

I have two questions that are closely related, in terms of launching a manual car from a stop.

(1) At a stoplight, just sitting there waiting for the green, is it causing damage to the transmission by holding the clutch down while in neutral? On the same token, is it causing damage if I am still stationary, but holding the clutch down while in first gear? I'm pretty sure holding the clutch down while in neutral isn't going to do anything but holding it while in first, I think it might.

If I want to start as quickly as I can I hold the clutch down while in first gear and keep it at 3 grand, then let out the clutch and maintain pressure on the gas. But I rarely do that because I'm not sure if that is good for my car, so I wait in neutral until it goes green, and then I pop it into first and rev it up to 3, and then let it out.

(2) Assume you are at a stoplight and you are a dangerous streetracer, driving your manual sports car. The fact that streetracing is illegal is irrelevant here. Your reaction time is so good that as the light turns green, you immediately jump off the line.

Now in order to do that, I assume that the driver must not have to try and shift into first, because it seems like that would waste time. So how do you do it? Do you hold the revs while in first for a drag race, or what?

 

[TheCracker]

(2) Assume you are at a stoplight and you are a dangerous streetracer, driving your manual sports car. The fact that streetracing is illegal is irrelevant here. Your reaction time is so good that as the light turns green, you immediately jump off the line.

Now in order to do that, I assume that the driver must not have to try and shift into first, because it seems like that would waste time. So how do you do it? Do you hold the revs while in first for a drag race, or what?

The quickest way to 'launch' in a manual would be to be in first, have the clutch fully depressed and hold your revs at upwards of 4000 (depending on car). When the lights change you side-step the clutch (literally sliding your left foot off the side of the pedal whilst simultaneously burying the throttle pedal with your right foot. It ain't pretty and it doesn't do your drivetrain much good, but i'd say its probably the quickest way.

 

[kennythebomb]

The quickest way to 'launch' in a manual would be to be in first, have the clutch fully depressed and hold your revs at upwards of 4000 (depending on car). When the lights change you side-step the clutch (literally sliding your left foot off the side of the pedal whilst simultaneously burying the throttle pedal with your right foot. It ain't pretty and it doesn't do your drivetrain much good, but i'd say its probably the quickest way.

Well granted letting it out that quickly and at that rpm, it is definitely wearing the drivetrain.

But I'd kind of like to know just in general, does holding a car in first while at a stoplight really hurt the drivetrain? Do most people who launch quickly on the street do that?

 

[Swift]

Okay, so something is bothering me.

I have two questions that are closely related, in terms of launching a manual car from a stop.

(1) At a stoplight, just sitting there waiting for the green, is it causing damage to the transmission by holding the clutch down while in neutral? On the same token, is it causing damage if I am still stationary, but holding the clutch down while in first gear? I'm pretty sure holding the clutch down while in neutral isn't going to do anything but holding it while in first, I think it might.

If I want to start as quickly as I can I hold the clutch down while in first gear and keep it at 3 grand, then let out the clutch and maintain pressure on the gas. But I rarely do that because I'm not sure if that is good for my car, so I wait in neutral until it goes green, and then I pop it into first and rev it up to 3, and then let it out.

That IS bad for your car. There's no reason to bring your revs up that high unless you really are racing. Which of course is stupid unless you're on a dragstrip.

But anytime you have your revs that far above idle and dump the clutch, you really hurting your drivetrain. Specifically the transmission. I would advise against this at all costs.

As far as holding down the clutch. The thing you're wearing out(where you're in gear or not) is the throwout bearing. Basically, you shouldn't hold the clutch down any longer then you really have to. So, if you're at a light and you know it's going to change in the next 30 seconds or so go ahead and get the car in first. But don't come to a red light, knowing it's a good 4 minutes to the green and put the clutch in and weight there.

This is just a nice way to keep the wear on your drivetrain to a minimum.

Oh yeah, drag racing and/or dumping your clutch is really bad for your car. Did I say that already?

 

[Submerged]

When I have wanted to get away quick from the lights on the traffic lights, i do balance the clutch with the accelerator to biting point a few seconds before the lights goes green.

When the lights goes green, I depress the accelerator harder than i release the clutch to prevent stalling. I believe i let the clutch out fairly smoothly for about a second before it becomes fully engaged with the engine, as i don't particularly want the car to suddenly lurch forward and/or burn the tyres.

Therefore you could say that I am balancing the clutch and accelerator. However, in Drag racing, I've no idea what technique they would use.....I wold presume it is fairly similar to what everyone had described?

Submerged.

 

[kennythebomb]

That IS bad for your car. There's no reason to bring your revs up that high unless you really are racing. Which of course is stupid unless you're on a dragstrip.

But anytime you have your revs that far above idle and dump the clutch, you really hurting your drivetrain. Specifically the transmission. I would advise against this at all costs.

As far as holding down the clutch. The thing you're wearing out(where you're in gear or not) is the throwout bearing. Basically, you shouldn't hold the clutch down any longer then you really have to. So, if you're at a light and you know it's going to change in the next 30 seconds or so go ahead and get the car in first. But don't come to a red light, knowing it's a good 4 minutes to the green and put the clutch in and weight there.

This is just a nice way to keep the wear on your drivetrain to a minimum.

Oh yeah, drag racing and/or dumping your clutch is really bad for your car. Did I say that already?

I don't actually drag race my car, and it would lose anyway. I don't have too much low end torque.

That said, I was truly curious as to how people do it.

When I have wanted to get away quick from the lights on the traffic lights, i do balance the clutch with the accelerator to biting point a few seconds before the lights goes green.

When the lights goes green, I depress the accelerator harder than i release the clutch to prevent stalling. I believe i let the clutch out fairly smoothly for about a second before it becomes fully engaged with the engine, as i don't particularly want the car to suddenly lurch forward and/or burn the tyres.

Therefore you could say that I am balancing the clutch and accelerator. However, in Drag racing, I've no idea what technique they would use.....I wold presume it is fairly similar to what everyone had described?

Submerged.

Ah, okay so you're right there at the biting point ready to let loose. Thanks.

 

[Slick Rick]

The quickest way to 'launch' in a manual would be to be in first, have the clutch fully depressed and hold your revs at upwards of 4000 (depending on car). When the lights change you side-step the clutch (literally sliding your left foot off the side of the pedal whilst simultaneously burying the throttle pedal with your right foot. It ain't pretty and it doesn't do your drivetrain much good, but i'd say its probably the quickest way.

If I did that my car would stall probably or the revs would drop really low and id be left with no power.
If I want to get off the line I hold the revs at 3000-4000 and when the lights go green, lift off the clutch till its biting and then floor the accelerator and then lift off the clutch smoothly. It avoids wheelspin in my car but also probably wears the clutch but I dont do it often and the clutch is on its way out anyway so its ok.

 

[Duke]

Be CAREFUL with that "holding the clutch right at the biting point" thing. It's a little hard to judge. At that point you could still be slipping the clutch disks a bit, and it doesn't take much of that to generate some heat and glaze the disks.

If you have the clutch all the way in, the disks are fully separated and are not wearing. If you have the clutch all the way out, the disks are sandwiched against each other and should be turning the same speed without wearing. As Swift mentioned, the only thing you are putting any wear on with the clutch all the way in is the throwout bearing.

The TB is designed to take this and should last at least the life of the clutch under normal conditions. I agree with Swift, though, that there is no sense pressing your luck and no need to sit for several minutes with the clutch in.

And never, EVER should you ride the clutch to hold the car on a hill.

I usually keep an eye on the cross-street's light. When I see them get a yellow, I put the clutch in and put the car in gear. From practice starting on hills, you should be able to instictively let the clutch out right to the biting point very quickly, so the advantage you might gain by pre-releasing the clutch a little is probably not worth the risk of having the clutch slipping without knowing it.

 

[Sage]

I usually keep an eye on the cross-street's light. When I see them get a yellow, I put the clutch in and put the car in gear.

I really wish we had the red-amber sequence (like in the UK) so that we wouldn’t need to do this. It can be really difficult, especially if sunlight is hitting it at the perfect angle to wash out the ambient light from your perspective.

 

[kennythebomb]

Be CAREFUL with that "holding the clutch right at the biting point" thing. It's a little hard to judge. At that point you could still be slipping the clutch disks a bit, and it doesn't take much of that to generate some heat and glaze the disks.

If you have the clutch all the way in, the disks are fully separated and are not wearing. If you have the clutch all the way out, the disks are sandwiched against each other and should be turning the same speed without wearing. As Swift mentioned, the only thing you are putting any wear on with the clutch all the way in is the throwout bearing.

The TB is designed to take this and should last at least the life of the clutch under normal conditions. I agree with Swift, though, that there is no sense pressing your luck and no need to sit for several minutes with the clutch in.

And never, EVER should you ride the clutch to hold the car on a hill.

I usually keep an eye on the cross-street's light. When I see them get a yellow, I put the clutch in and put the car in gear. From practice starting on hills, you should be able to instictively let the clutch out right to the biting point very quickly, so the advantage you might gain by pre-releasing the clutch a little is probably not worth the risk of having the clutch slipping without knowing it.

That was very informative, thank you Duke.

 

[Swift]

I really wish we had the red-amber sequence (like in the UK) so that we wouldn’t need to do this. It can be really difficult, especially if sunlight is hitting it at the perfect angle to wash out the ambient light from your perspective.

I'm not familiar with that.

 

[skip0110]

I slip the clutch like nuts to launch because with AWD and only 165 hp if I dump it the revs just drop.

 

[Sage]

I'm not familiar with that.

In the UK and several other areas, instead of the traffic lights going straight from red to green, there’s an intermediate step where it turns red and amber, which lets manual-tranny drivers shift into first before the light turns green.

 

[kennythebomb]

In the UK and several other areas, instead of the traffic lights going straight from red to green, there’s an intermediate step where it turns red and amber, which lets manual-tranny drivers shift into first before the light turns green.

That's awesome! It would never happen in the states but damn that would be a nice feature (for the 3% of us it seems who drive stick...)

 

[Swift]

In the UK and several other areas, instead of the traffic lights going straight from red to green, there’s an intermediate step where it turns red and amber, which lets manual-tranny drivers shift into first before the light turns green.

That sounds like a very simple thing to introduce. Though I bet a bunch of stupid American drivers would say, "I thought it was yellow!" and run a bunch of lights.

 

[Sureboss]

In the UK and several other areas, instead of the traffic lights going straight from red to green, there’s an intermediate step where it turns red and amber, which lets manual-tranny drivers shift into first before the light turns green.

It'd be really odd going to a country without the red, red-amber then green sequence. I think it works well, doesn't make people have to rush what they're doing. Particularly helpful on hills. Or when you (like me) are learning to drive.

 

[wfooshee]

As has already been answered, holding the car in neutral or in gear with the clutch down does nothing to the tranny, but it's hard on the throwout bearing. That bearing carries the spring pressure of the pressure plate when the pedal is depressed. It's purpose is to transmit the clutch action from the stationary part of the car to the rotating pressure plate. When the pedal is depressed, it's a GINORMOUS load on the throwout bearing. Yes, it's made for the load, but 5 seconds at at time is only 1/6 of 30 seconds at a time. Parts under load are wearing parts. Parts not under load last forever.

As for the holding the clutch at the biting point for a few seconds, that's just as bad, if not worse, than dumping the clutch in a drag-style start. DO NOT DO IT!!!

Wait at the light in neutral with your foot off the clutch, when the side light goes yellow, grab first (unless you know the left turn goes green, not your lane.) Minimize clutch use as much as possible, both the pedal and the slippage.

 

[niky]

I always let it out nearly all the way, and give it a tiny blip to start the car creeping before I let go of the clutch.

Two trackdays and 55k kms of really hard driving have not been kind to my clutch, and it judders if I don't ease into it or rev to 3000 rpms (which I loathe doing, as I don't want to wear it out) before letting off it fully.

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For drag launches, it's highly dependent on the car how many rpms you want to hold before you drop it. For some of those smaller engines, you want to be bombing off (or near) redline before you let go, just to ensure that you're in the powerband when the tires finally stop spinning.

On mine, 4000 rpms seems about fine, simply because my powerband is low and my gearing is short... on the higher strung VTEC-type cars, 5000 rpms +++ gives a lot of wheelspin, but gives better drag times, overall.

 

[TheCracker]

In the UK and several other areas, instead of the traffic lights going straight from red to green, there’s an intermediate step where it turns red and amber, which lets manual-tranny drivers shift into first before the light turns green.

The amber light is there so morons can engage their brains before the light turns green. Other wise they'd still be getting their s*** together when the lights turn back to red

 

[wfooshee]

The amber light is there so morons can engage their brains before the light turns green. Other wise they'd still be getting their s*** together when the lights turn back to red

Like they do here in America. Nothing better than missing 7 seconds of a 12-second green light to the moron at the head of the line.

 

[Kungfujerry]

I always let it out nearly all the way, and give it a tiny blip to start the car creeping before I let go of the clutch.

Two trackdays and 55k kms of really hard driving have not been kind to my clutch, and it judders if I don't ease into it or rev to 3000 rpms (which I loathe doing, as I don't want to wear it out) before letting off it fully.

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For drag launches, it's highly dependent on the car how many rpms you want to hold before you drop it. For some of those smaller engines, you want to be bombing off (or near) redline before you let go, just to ensure that you're in the powerband when the tires finally stop spinning.

On mine, 4000 rpms seems about fine, simply because my powerband is low and my gearing is short... on the higher strung VTEC-type cars, 5000 rpms +++ gives a lot of wheelspin, but gives better drag times, overall.

While it is true that you want the engine in the powerband to accelerate quickly, wheelspin is NOT desireable in drag races. Wheelspin occurs when the tires are pushed to the point where they LOSE traction, and as soon as that happens, you guessed it, you lose traction and lose some ability to put the engine's power into forward motion. Just as in NHRA drag races where grip is imperative and there is minimal wheelspin in the run, the same principle applies to road cars.

 

[Duke]

While it is true that you want the engine in the powerband to accelerate quickly, wheelspin is NOT desireable in drag races. Wheelspin occurs when the tires are pushed to the point where they LOSE traction, and as soon as that happens, you guessed it, you lose traction and lose some ability to put the engine's power into forward motion. Just as in NHRA drag races where grip is imperative and there is minimal wheelspin in the run, the same principle applies to road cars.

Let me further comment on what you're saying here:

You don't want EXCESSIVE wheelspin. However, a very small amount at the launch can be preferable, particularly for a small-bore, peaky engine. Not enough wheelspin at launch will cause the engine to bog, and the loss of power is worse than the loss of a small amount of traction. It's worth allowing some tire slip to keep the revs up.

Watch the Turbo Dodge guys launch, or some of the small-bore touring cars leaving a pit stop. There's a fine line between the sweetspot of the engine and full-melt mode on the tires, and the best acceleration (at least out to the 60-foot mark) is found right on that line.

 

[Slick Rick]

Watch the Turbo Dodge guys launch, or some of the small-bore touring cars leaving a pit stop. There's a fine line between the sweetspot of the engine and full-melt mode on the tires, and the best acceleration (at least out to the 60-foot mark) is found right on that line.

Ive felt that before, it sounds and feels a lot different to normal wheelspin. Ive done it once, Ive tried but havent been able to do it again.
Should be easier to do with a lower powered car with good tyres?

 

[niky]

Let me further comment on what you're saying here:

You don't want EXCESSIVE wheelspin. However, a very small amount at the launch can be preferable, particularly for a small-bore, peaky engine. Not enough wheelspin at launch will cause the engine to bog, and the loss of power is worse than the loss of a small amount of traction. It's worth allowing some tire slip to keep the revs up.

Watch the Turbo Dodge guys launch, or some of the small-bore touring cars leaving a pit stop. There's a fine line between the sweetspot of the engine and full-melt mode on the tires, and the best acceleration (at least out to the 60-foot mark) is found right on that line.

👍 ...which is why I said it's highly dependent on the car.

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Fun to note: Japan likes its Evos with less hardcore rubber than the American market demands simply because it makes for better launches... without bombing the transmission.

Fun to note, 2: Fiat Panda 4x4... awesome 0-30 mph time, simply by revving its nuts off in second gear and dumping the clutch.

 

[GT Pro]

As far as I know, 3/4 total rpm (minus redline to peak) is usually ample for a standard car to launch quickly. However, for more powerful cars, a little less will probably do the same.
For minor to no wheel-spin, slip off the clutch a little earlier in the rev-range and from there on it's your throttle control that will determine the rest. But as Duke said, having it too low can cause havoc to your launch time and can have your car drowning for a little longer than wanted.

 

[Jay]

If making a hard drag launch (not worring too much about some clutch wear) I usually slightly apply the handbrake to hold the car while releasing the clutch just a tad (just before the launch) which takes out all the slack in the drivetrain which intern reduces the possible initial hit on the mechanicals (gears, shafts). Also this slight load increases turbo spool then adjust throttle and clutch slip accordingly to hold around the tyre grip threshold (like niky and duke mentioned).

As expected this type of launch is not easy on the clutch but I rarely do it. This is pretty much how BMI launch there cars in acceleration benchmarks from memory (havent watched them in awhile).

If I can I rather give the car I slight roll and I always like to take up all slack just prior to launching.

 

[niky]

I never thought of it that way. Granted, I have launched off the handbrake at times in time attacks (hey, it won me three cases of beer in the last slalom), but that's only to keep from "breaking out" on timed runs. I guess it does make sense to do it that way to minimize the shock... generally, I only do that with ATs.