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Old 11-18-2012, 01:44 AM   #1
Subiezilla
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Default How to "launch" car non drag/racing

Fist off I have read ubabombers manifesto in shifting, and the launching section of it seems only apply to racing applications. What I want to know is how to "launch" our wrx's for daily tasks like making a left turn from a yield stop with oncoming traffic, or say merging onto freeway from the traffic control light. Something in which I want to get going relatively fast but not break neck speed of drag racing. I would like not to have the engine bog down when I let out the clutch.

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Old 11-18-2012, 01:51 AM   #2
kh15
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you always let the clutch out the same, that never changes. In certain situations you just get on the gas a bit more.




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Old 11-18-2012, 01:56 AM   #3
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How long have you been driving a manual car? It becomes second nature sooner or later, I honestly don't remember the last time I looked at my RPM's when starting off, but you don't technically launch the car when trying to turn, or get going in everyday driving.
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Old 11-18-2012, 02:05 AM   #4
Subiezilla
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Quote:
Originally Posted by iAmjudge
How long have you been driving a manual car? It becomes second nature sooner or later, I honestly don't remember the last time I looked at my RPM's when starting off, but you don't technically launch the car when trying to turn, or get going in everyday driving.
For 3 years. But I always would just drive normally until my buddy this weekend pointed out that at a ~3,000 rpm rev "launch" at the freeway entrance my car bogged a little bit. I have pretty much never tried lauching or used the lauch control feature on my AP because iv been afraid of what could happen to my tranny. So mainly I always drive normally take off at 1k to 1,500 rpm. This i just something i never masters or attempted to master even over all these years 😓
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Old 11-18-2012, 02:08 AM   #5
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I'm probably at 1500 - 1600 when I need to get going quickly and my car doesn't bog at all...

Maybe your letting the clutch out too quickly?
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Old 11-18-2012, 02:10 AM   #6
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Launch your car, just do it ::nikead::
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Old 11-18-2012, 02:18 AM   #7
Subiezilla
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Quote:
Originally Posted by iAmjudge
I'm probably at 1500 - 1600 when I need to get going quickly and my car doesn't bog at all...

Maybe your letting the clutch out too quickly?
I'm fine with 1500 rpm starts its the 3k one I tried that I failed at. But I will try letting the clutch out slower I guess, but wouldn't letting it out slower also wear out the clutch more?

Edit: I know that it's better to ride the clutch vs grenade your tranny....but again i see this tip for propel that are revving to 5k + rpm's and drag racing. I'm only doing 3k rpm if at that
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Old 11-18-2012, 02:29 AM   #8
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Quote:
Originally Posted by Subiezilla View Post
I'm fine with 1500 rpm starts its the 3k one I tried that I failed at. But I will try letting the clutch out slower I guess, but wouldn't letting it out slower also wear out the clutch more?
Yea it will, but in my experience, it takes just a little more of a pause at the catch point to be able to let the clutch out without bogging. Just a little hesitation and you're good. You just have to get the feel for it so that you don't keep the clutch at the catch point longer than you need to.

There's really no other solution to it; in order to keep the car from bogging down, your speed needs to match the RPMs of the engine when you engage (let off) the clutch, and in order for that to happen, you HAVE to slip the clutch. If you want to start at 3k RPMs, you've got to slip the clutch more than if you want to start at 1500 RPMs.
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Old 11-18-2012, 02:36 AM   #9
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Quote:
Originally Posted by tibug

Yea it will, but in my experience, it takes just a little more of a pause at the catch point to be able to let the clutch out without bogging. Just a little hesitation and you're good. You just have to get the feel for it so that you don't keep the clutch at the catch point longer than you need to.

There's really no other solution to it; in order to keep the car from bogging down, your speed needs to match the RPMs of the engine when you engage (let off) the clutch, and in order for that to happen, you HAVE to slip the clutch. If you want to start at 3k RPMs, you've got to slip the clutch more than if you want to start at 1500 RPMs.
Thanks will try it and report back
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Old 11-18-2012, 02:42 AM   #10
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This is gonna smell real good.

Launching these cars is hard.
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Old 11-18-2012, 04:43 AM   #11
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This is gonna smell real good.

Launching these cars is hard.
^^^^^^ +1
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Old 11-18-2012, 11:15 AM   #12
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Quote:
Originally Posted by ResidentR
This is gonna smell real good.

Launching these cars is hard.
Yeah this is what I'm afraid off
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Old 11-18-2012, 11:23 AM   #13
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have you ever seen that video on youtube of this guy launching his rex at redline to beat a vette? message him on youtube for some mad advice, lol
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Old 11-18-2012, 11:45 AM   #14
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Just slip the clutch to prevent bogging. Also protects your tranny. A clutch is waaaaaaay cheaper than a new transmission.

I've 'launched' once or twice only when it was necessary in traffic. For example, I didn't realize I had to be in the left lane for my exit and traffic was stopped except for the exit lane. Cars in exit lane going ~60-65, my lane going 0 mph. Rev'd to around 4k then let clutch out to engagement point and slipped it until the car was moving. You will smell clutch burning, but that is normal considering what you are doing.

Last edited by mrkyle3; 11-18-2012 at 11:50 AM.
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Old 11-18-2012, 11:54 AM   #15
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These cars, even 300whp ones, will not break tire traction before the engine runs out of power. I'm at 21psi, on winter tires, and I can not spin my tires short of a rain soaked road with a redline launch in my very low 6sp first gear. The 5sp has a much taller 1st, so they are even harder to break traction at the same engine power. Yes, you can spin tires if you shock load the drivetrain. A 2.5L NA will do that too, will also chirp in 2nd gear if you want to. I'm only duscussing actual, smooth delivery of power.

It takes a LOT of torque and gearing to break 4 tires free without shocking the drivetrain.

Because we are engine limited in this equation, we need to slip the clutch to allow the engine to keep up in revs. This also means a strong launch is a high rpm launch. The car makes the most power at or very near redline, so you launch at or near redline. You will not spin tires unless traction is pretty low or you are not smooth with your power delivery. The higher the revs you go, the more power the engine can produce for accelerating the car. Because the engine is limiting, it also means you can use full throttle. The variable will then become only the clutch. You simply slip that as much as needed to keep the revs high and the engine making power. The car will accelerate quite briskly.

Maybe you guys will start a flame war on the wrongs of redline launching and that it's magically bad for the car. Yes, it will wear the clutch more. A clutch is no different than brakes. The flywheels is the same as a brake rotor, and the clutch disk is your brake pad. They aren't really different at all in compound either, often an organic type just like many oem pads. It's also why you can glaze a clutch just like an organic brake pad if you overheat them. The ability to overheat a clutch takes a little bit of effort, more specifically many launches in a short time frame. Longevity depends on how much you do, just like brake pads. It's a wear item.

So how long is longevity with launching? Not bad really. I own a 02 Forester NA that I auto-x and rally-x. It's seen 5 years of use and every run starts with me launching the car at redline. I figured it has somewhere near 250 redline launches on the stock clutch, and this is car with 120k+ daily miles to boot. My bro's FXT had a couple years of auto-x and rally-x use before an engine rebuild. The car was again launched are redline religiously at events. A new clutch went in at 75k miles when the engine was rebuilt after a #4 piston failure. The clutch still had half its life left. The car now runs an Exedgy clutch again, just one step up, and again has years of use added up plus all daily use. Mind you this is with a "fragile" 5sp running 21psi with an 18G. It's been at 21psi most of its ownership. I have a FXT now too, this time with a 6sp, and again I launch at redline at events.

So what's wrong with launching your car? Most often it's only a problem when people shock load their drivetrain or attempt to launch repeatedly with very short intervals of time in between. I personally haven't seem a problem with launches as short as 1.5 minute intervals and repeated a half dozen or more times in a row.

Higher power cars will cause more heat. It's always good to feel for any changes in engagement behavior that may indicate an excess in heat build up. If so, let the car sit a little. Organic material isn't exactly great with heat, although the clutch and flywheel are pretty well sized and can hold and move a good deal of heat around quickly. Still, it's just like your brakes. They can overheat, they will wear, and you can abuse them.
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Old 11-18-2012, 12:16 PM   #16
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My question is, if you didn't notice it before, what's the big deal now? And why are you letting your buddy, who doesn't drive your car every day, get in your head with rediculous sentiment. Obviously nothing is wrong with your car. And the way you get around in traffic.

If you launch your car at higher RPM's it's going to wear stuff out faster. No way gettig around it. Just keep doing what you are doing and you will be fine.

And if you are Coming off at 3k, your revs will drop And you will not be in the boost until it they come back up, your buddy doesn't seam to get what turbo lag is.
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Old 11-18-2012, 12:29 PM   #17
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im confuzed by this thread. launching a car but not for racing? its all about clutch disengagement vs throttle position.
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Old 11-18-2012, 12:35 PM   #18
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Yeah, there's nothing special here, just car nerds discussing car nerd stuff for fun.

I think his concern was trying to accelerate more quickly without bogging the car. People by nature want to use the clutch as little as possible, so they will want to get off of it too quickly and subsequently bog the engine. Unless you have gobs of torque, low grip, or shock load the drivetrain enough to break the tires free, the engine will always bog. The only way around this is to use the clutch more, slip longer, and let the engine hold revs. There's nothing fancy here, but we start doing what people have been taught to fear doing.
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Old 11-18-2012, 12:52 PM   #19
Subiezilla
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Quote:
Originally Posted by Back Road Runner
Yeah, there's nothing special here, just car nerds discussing car nerd stuff for fun.

I think his concern was trying to accelerate more quickly without bogging the car. People by nature want to use the clutch as little as possible, so they will want to get off of it too quickly and subsequently bog the engine. Unless you have gobs of torque, low grip, or shock load the drivetrain enough to break the tires free, the engine will always bog. The only way around this is to use the clutch more, slip longer, and let the engine hold revs. There's nothing fancy here, but we start doing what people have been taught to fear doing.
Yes u are correct, by nature we have been taught not to ride the clutch at least thats how my dad taught me but that was when he taught me in a 92 Nissan Hard Body pick up though. Obviously my subie is a totally different beast with awd. But I guess the other poster is right iv been fine with my car since I bought it back in 09 so I won't try to worry so much and I don't drag race so it's all good.
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Old 11-18-2012, 01:01 PM   #20
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just rev it to 5k and drop the clutch -___-
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Old 11-18-2012, 01:10 PM   #21
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just rev it to 5k and drop the clutch -___-
and BOG, listen to the Guru
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Old 11-18-2012, 01:29 PM   #22
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Quote:
Originally Posted by kj15991
just rev it to 5k and drop the clutch -___-
He asked how to launch not rip the teeth off first.
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Old 11-18-2012, 02:11 PM   #23
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I'm tuned to 20psi with an EWG on my 04 STi and I can spin my tires to redline in 1st gear, especially on snow tires.
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Old 11-18-2012, 02:27 PM   #24
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Quote:
Originally Posted by Heedlessone
I'm tuned to 20psi with an EWG on my 04 STi and I can spin my tires to redline in 1st gear, especially on snow tires.
Vid naow! Or it didn't happen...
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Old 11-18-2012, 02:38 PM   #25
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Like some others said, SLIP THE CLUTCH just a little. Not only will it protect your drivetrain but will load up the turbo and keep the boost up instead of bogging. It also loads the suspension properly for maximum traction.

I like to be on my anti-lag at WOT and let the clutch out about halfway really quickly, and once the car gets moving a little bit (less than 1 sec) just let it out all the way and hang on for dear life!
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