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Old 04-04-2014, 12:07 PM   #1
07STiSpoolin
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2007 WRX STi
Obsidian Black Pearl

Default Launch Question

Quick launch question.. What would be a good RPM to launch at?

[07 STi with cat-back exhaust, and COBB AP, stage 1. ]

It has the launch control feature, but what is a good RPM to set it to, and how do I go about a proper launch? I know this question is very "noobish" but I'd like to know a little background info before I try and launch an AWD.

I know I shouldn't "dump" the clutch… but can someone give me some pointers on how to properly launch the car? Any help, tips, info, do's/don't are greatly appreciated.

I've read that I should "slip" the clutch, but what does that mean exactly? Also, how bad is launching the car on the clutch/transmission/axles?
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Old 04-04-2014, 12:10 PM   #2
Brent22
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http://forums.nasioc.com/forums/show....php?t=1433166


If this is your track go, go have fun. Assuming you realize a track car could be fine 1 minute and cost $8k the next, you're prepared. If this is your DD, move along, there is no reason you'd ever need to launch it.
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Old 04-04-2014, 12:22 PM   #3
JAMM0N
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i launch at autocross at 5k RPM's you want to set it where the tire can break loose. try at 4k then move up 500RPM's till you get used to it. i only use 2-3 gears, rather you use all your gears on the track and higher RPM's as you shift.

you will burn out your clutch as you get used to it FYI.

we are not solely responsible for what you do to your car as you choose to do it.
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Old 04-04-2014, 11:14 PM   #4
07STiSpoolin
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I'm not holding anyone responsible lol. I just wanted to get some points on a awd launch and so on. I'm planning on going to a drag strip soon so a proper launch would help out.

Also, would you guys say a stock STi can take a few runs down a quarter without any issue? Given a decent launch, fluids checked.
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Old 04-05-2014, 12:01 AM   #5
Mrbojangles019
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lol are you 17, with your first car, mom and dads money? Cause it sounds like that
And no one can say if it can handle it or not. Could handle 100, could take 1 launch and destroy your drive train, transmission, clutch... who knows.
Unless you have the money to replace anything and everything that COULD go wrong. Don't dick around. Drive the car like an adult and enjoy it for what it is.
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Old 04-05-2014, 01:23 AM   #6
Back Road Runner
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Work your way up. Start at 3k rpm. Get a feel for the engine power and clutch slip. Work your way up slowly. In the end you should be launching at redline. The goal is to launch and maintain peak energy output, aka peak hp. You will slip the clutch for a moderate portion of 1st gear. You have to. There is too much grip, and the engine doesn't make enough power. I say this as a person that isn't stock. I'm running an 18G and E85 making a lot of torque and plenty of hp, and I can't spin my winter tires unless it's wet. It takes a LOT of power to overpower an awd platform. A good ballpark is around 150 ft-lbs per driven tire, and you're not putting down 600 ft-lbs. If you shock load the drive train, you can break the tires free. It's not faster though. If you engage the clutch too fast, the rpms will drop, and you'll drop in output. If you bog down too much, you'll drop out of the boost range and be really slow. The clutch is tough, but heat will fade it and limit what you can do. You need cool down time.
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Old 04-05-2014, 06:26 PM   #7
MoreChuChu
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Why do you need to launch your car? If it's for anything other than private, closed course driving, then don't launch it. Period.
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Old 04-05-2014, 09:58 PM   #8
424wrx
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i use 4500 on the launch control at the track. any higher didnt yield better times.
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Old 04-06-2014, 12:19 PM   #9
07STiSpoolin
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Quote:
Originally Posted by Mrbojangles019 View Post
lol are you 17, with your first car, mom and dads money? Cause it sounds like that
And no one can say if it can handle it or not. Could handle 100, could take 1 launch and destroy your drive train, transmission, clutch... who knows.
Unless you have the money to replace anything and everything that COULD go wrong. Don't dick around. Drive the car like an adult and enjoy it for what it is.
No. As much as I want to refrain from a response, I can't help my self. I'm not 17, and this isn't mommy and daddy bought, nor is it my first car. This is one thing about forums I can't stand, even when posting in the "Newbies" section. If you're going to come in here and be sarcastic, why post at all? And I understand that things could break, go wrong, and cost a lot. That's why I'm posting here in the first place to get some background information on how to attempt it in a much more proper way. Ultimately, it's my car and if something happens, it's my headache, not yours. So, thank you for the part of response that was actually relative to my curiosity.

Quote:
Originally Posted by Back Road Runner View Post
Work your way up. Start at 3k rpm. Get a feel for the engine power and clutch slip. Work your way up slowly. In the end you should be launching at redline. The goal is to launch and maintain peak energy output, aka peak hp. You will slip the clutch for a moderate portion of 1st gear. You have to. There is too much grip, and the engine doesn't make enough power. I say this as a person that isn't stock. I'm running an 18G and E85 making a lot of torque and plenty of hp, and I can't spin my winter tires unless it's wet. It takes a LOT of power to overpower an awd platform. A good ballpark is around 150 ft-lbs per driven tire, and you're not putting down 600 ft-lbs. If you shock load the drive train, you can break the tires free. It's not faster though. If you engage the clutch too fast, the rpms will drop, and you'll drop in output. If you bog down too much, you'll drop out of the boost range and be really slow. The clutch is tough, but heat will fade it and limit what you can do. You need cool down time.
Thank you. Given your mods, my scenario is a lot different. I've heard of many people say "slip" the clutch, but what does that exactly mean..?

Quote:
Originally Posted by MoreChuChu View Post
Why do you need to launch your car? If it's for anything other than private, closed course driving, then don't launch it. Period.
Closed course, drag strip to be specific... where a good launch is key.

Quote:
Originally Posted by 424wrx View Post
i use 4500 on the launch control at the track. any higher didnt yield better times.
I've heard in the 4k's range a lot. I'm tempted to start there and work my way down/up.
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Old 04-06-2014, 01:00 PM   #10
HinshawWRX
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Slipping the clutch means exactly that. Don't let the clutch completely grab and let it slip a bit as you launch.

Yes, this will increase wear in your clutch and make it smell badly.
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Old 04-06-2014, 02:56 PM   #11
Back Road Runner
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Do you lock up your tires every time you brake? You modulate your clutch just like you modulate your brakes. Your launch is engine power limited just like your braking is tire limited. With only so much energy available before you overwhelm the engine, you have to limit the transfer of energy to keep output at its peak. You only partially engage the clutch up to the point where you don't bog down the engine.
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