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Old 04-12-2009, 12:19 PM   #1
asujosh1
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Default Launching an 08 STi - autoX

I picked up an 08 STi over the winter and now that it has warmed up a bit, I have been trying to work on launching the car, but have yet to get it right with any sort of consistency. I was wondering if some of the people running a new model STi (or any for that matter) could give me some insights in how to properly launch my car without lunching my clutch, tranny, or diffs.

I am running in the stock class, but with street tires, and this is my first AWD car, ever.
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Last edited by asujosh1; 04-12-2009 at 12:51 PM.
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Old 04-12-2009, 01:22 PM   #2
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For autox you should not be launching it very hard - just hard enough not to bog. You should just have to slip the clutch a little. On an STi where you have a lot of lowend torque you can probably launch with a little clutch slip at ~2500-3000 RPM and be okay.
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Old 04-12-2009, 04:20 PM   #3
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With the 2.5 block you'll be fine launching from 3500 to 4200. I'd say work on being smooth with the clutch and then just increase the speed that you let it out. The local guys with 2.5's go at about 4200 to 4500 and it does pretty good.

Just be glad you don't have a 2.0 with a lightened flywheel like me....I'm up at like 6200 for a good awd launch
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Old 04-12-2009, 05:17 PM   #4
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So, are you trying to break the tires loose, or just slipping the clutch for the launch? I have been told anything from slip it to dump it and everything in between.
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Old 04-12-2009, 05:22 PM   #5
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Slip the clutch, don't dump it. Do not break the tires loos on an AWD car.

Auto-x starts should be designed to minimize drag-start launches (unless you're at a ProSolo) so breaking loose, you're losing traction. Just work on getting into 2nd gear smoothly, and quickly.


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Old 04-12-2009, 06:22 PM   #6
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Like KC said, you're not trying to do a burnout. You're trying to get the best start possible. There's usually a little wheelspin if you do it just right. The biggest point is to not bog the car and get into 2nd quickly.

My local region has a good mix of pro starts and regular starts so there are events that play to both types.
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Old 04-12-2009, 07:13 PM   #7
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Ok, thanks for your input. I had previously been told to get it to 5 or 6 and dump it, and I was worried what effect that would have on my driveline.

I'll work on getting away at 35-4500 without bogging it.
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Old 04-12-2009, 07:51 PM   #8
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5000rpm, quick slip and go. That's what we do with our 08 STI. Works well.
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Old 04-12-2009, 07:58 PM   #9
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I have been doing autocrosses for 2-3 years now. I am on my original stock clutch and have 63K on the odo. I got my 60K service and the mechanic was surprised at how well the clutch had held up. I am very easy on the tranny around town. I double clutch and rev match, because Vin Diesel told me so. I don't love drag starts, but if it is required, I don't mind. I am on street tires, not R-comps. That said, here's how I do it.

For my 2.5L WRX. I blip the throttle a few times to get the turbo going and engine moving, up to about 5-6K (I may be a little wrong on the mechanics of it, but it's better than holding the throttle steady). As the revs drop down to 3-4K, I'll let out the clutch to the pressure point, then let it slip a little as I go. Still on the gas. I get a little itty bit of wheelspin (usually b/c there is plenty of grit already at the start). I never feel any shock to the tranny, the clutch does not smell.

It may not be the textbook way to do it, but it has always worked for me and my clutch and tranny are still in pretty good shape. knock on wood.
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Old 04-12-2009, 08:43 PM   #10
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5 - 5.5K - lift left leg like I trod in dog *****
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Old 04-12-2009, 10:02 PM   #11
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Quote:
Originally Posted by asujosh1 View Post
I picked up an 08 STi over the winter and now that it has warmed up a bit, I have been trying to work on launching the car, but have yet to get it right with any sort of consistency. I was wondering if some of the people running a new model STi (or any for that matter) could give me some insights in how to properly launch my car without lunching my clutch, tranny, or diffs.

I am running in the stock class, but with street tires, and this is my first AWD car, ever.
Where is your 1st event?
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Old 04-12-2009, 10:07 PM   #12
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Where is your 1st event?
I am running in the MN Autosports Club events. This is my second season, but first in a car that is actually made to be driven hard. I ran a TL Type S last year (auto-stick) and the only way to launch was to just mash it.

Our first event is May 2 at Valley Fair, just south of the Twin Cities. Event number 2 is the next day !
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Old 04-12-2009, 10:53 PM   #13
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Rev bounce up to 3.5k, catch it on an upswing, slip the clutch out as smoothly and as quickly as possible. You want to catch it on the upswing so as to catch it when the boost is building, not dissipating.

Then for me, cry as I shatter my transmission.
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Old 04-13-2009, 12:28 AM   #14
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No need to launch for auto-x, just be aggressive. About 80% of the courses i've done there has been a turn out of the gate anyways. Be more concerned about your tire pressure and suspension adjustments than launching, you'll make up more time. You are going to love sliding in turns with awd.
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Old 04-13-2009, 09:11 AM   #15
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Quote:
Originally Posted by asujosh1 View Post
I had previously been told to get it to 5 or 6 and dump it, and I was worried what effect that would have on my driveline.
A bad one I'm guessing. Certainly, the 6-speeds don't break as much as the 5-speeds and you're not on overly sticky tires like R-Comps, but it still isn't necessary as others have said, and any driveline will eventually start showing the signs of that kind of abuse.
-N
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Old 04-13-2009, 09:50 AM   #16
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No need to launch for auto-x, just be aggressive. About 80% of the courses i've done there has been a turn out of the gate anyways. Be more concerned about your tire pressure and suspension adjustments than launching, you'll make up more time. You are going to love sliding in turns with awd.
I did my first year last year with a 02 Honda Civic SI so I am wondering on this. What do you meen by sliding in the turns? Just the back end sliding out and the front end pulling you though the corner?

Quote:
Originally Posted by ButtDyno View Post
For autox you should not be launching it very hard - just hard enough not to bog. You should just have to slip the clutch a little. On an STi where you have a lot of lowend torque you can probably launch with a little clutch slip at ~2500-3000 RPM and be okay.
I will have to start doing this this week to get ready for this weekend in WI. I at least having a driving school on Saturday and I hope I get an instructor that drives a Subaru to help me out.
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Old 04-13-2009, 09:58 AM   #17
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it all depends on what youre willing to do. But advice to weather you are dumping at 3k or 6k. is to find the piont in your clutch right befor it graps. If you push the pedal to the floor and dump it from there its very bad *"id compare it to if you were stuck and had slack in the tow strap and someone just hammerd the gas to get you out. NO NO. take as much slack out befor pulling" find the piont in just befor it starts to grab. it will take the quick axle snappng jaring effect out of the launch. Its like getting punched from an inch away opposed to a 2 feet away. also let the tires and clutch take the wear. they are easier to replace than axles, trann, diff.

there are penty ways to take off. you just have to find the fastest, safest way between BOG and SPIN
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Old 04-13-2009, 10:19 AM   #18
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Quote:
Originally Posted by 04trailsti View Post
it all depends on what youre willing to do. But advice to weather you are dumping at 3k or 6k. is to find the piont in your clutch right befor it graps. If you push the pedal to the floor and dump it from there its very bad *"id compare it to if you were stuck and had slack in the tow strap and someone just hammerd the gas to get you out. NO NO. take as much slack out befor pulling" find the piont in just befor it starts to grab. it will take the quick axle snappng jaring effect out of the launch. Its like getting punched from an inch away opposed to a 2 feet away.
Um, what? If you have the pedal prior to gripping the clutch and then sidestep it, you are going to be sending the same jarring effect through the whole driveline as if you dropped it from the floor. Disengaged is disengaged, right? Sidestepping (or dropping) is basically just going from disengaged to engaged really quickly, and that is going to happen if you have an inch of travel, or 3 inches of travel before the clutch picks it up.

It sounds like the best method is to get it just to the point of starting to grip and then release as fast as you can without melting the clutch or smashing the driveline. If the tires spin a little, oh well, they are cheap.
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Old 04-13-2009, 03:37 PM   #19
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Ok well you keep doing your to the floor side steps. Ill stick with what gets me trophies.
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Old 04-13-2009, 09:40 PM   #20
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Quote:
Originally Posted by asujosh1 View Post
I am running in the MN Autosports Club events. This is my second season, but first in a car that is actually made to be driven hard. I ran a TL Type S last year (auto-stick) and the only way to launch was to just mash it.

Our first event is May 2 at Valley Fair, just south of the Twin Cities. Event number 2 is the next day !
Well here is the Milwaukee Region SCCA schedule if you want more competition. Our first event is this Sunday.

http://www.scca-milwaukee.org/Solo/2009/09sched.htm

Bart
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Old 04-14-2009, 11:36 AM   #21
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I did my first year last year with a 02 Honda Civic SI so I am wondering on this. What do you meen by sliding in the turns? Just the back end sliding out and the front end pulling you though the corner?
Maybe my statement was a little misleading. Sliding or drifting is the slowest way around the track. You need to find that point right before the tires will break and start to slide and then tone it down to say 90%. You want to drive to the brink of the tires grip. Sliding is fun though it surely won't win you any trophies.
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Old 04-14-2009, 12:53 PM   #22
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I never under stood why many say the launch doesent matter much for autocross? I can see that being the case if there is a turn directly at the start. However if there is even a little bit of an acceleration zone, it seems to me it makes a difference. Consider a drag start: a poor one in an sti gets you to 60ft in say 2.2 sec a good one is 1.8ish. .4 seconds at 60ft is a huge lead. maybe there isnt 60ft before the first turn but many times there is say 45 ft.

I am not being argumentative here, but I feel like I must be missing something since so many people say it doesent matter. That being said I see some pretty good autocrossers leaving the line agressively.
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Old 04-14-2009, 01:37 PM   #23
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I have run a few events where a turn is right away. It depended on the car how you wanted to leave the line.
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Old 04-14-2009, 02:32 PM   #24
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I never under stood why many say the launch doesent matter much for autocross? I can see that being the case if there is a turn directly at the start. However if there is even a little bit of an acceleration zone, it seems to me it makes a difference. Consider a drag start: a poor one in an sti gets you to 60ft in say 2.2 sec a good one is 1.8ish. .4 seconds at 60ft is a huge lead. maybe there isnt 60ft before the first turn but many times there is say 45 ft.

I am not being argumentative here, but I feel like I must be missing something since so many people say it doesent matter. That being said I see some pretty good autocrossers leaving the line agressively.
Even an autocross course that doesn't have a turn right away will likely have one before the 60ft mark. So consider what you're suggesting: that the perfect launch is going to net you 0.4 seconds. It's going to be less - probably less than half that because that first corner will come faster (ProSolos excepted). It's not that those tenths aren't valuable, but if you're asking how to launch your car in an online forum, that tenth could be made up 30-fold by just driving more and getting better at autocrossing in general.
-N
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Old 04-14-2009, 03:07 PM   #25
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Also greatly depends on where the start lights are.

You can have a slight straight, but the lights are right before the 1st turn. Just getting up to speed spiritedly is just as good as dumping the clutch. No reason to.

If the lights are 5 feet in front of where you stage, and THEN you have a straight, sure... go break things. Your call.

The more you look at things, the more you're going to realize that the distance from the lights to the 1st corner, and more importantly the apex of that conrer to the 2nd corner is really the deciding factor on launching. You can have a 20-30' straight. If the lights are at the end of that straight into a right hander, you can just get up to speed normally, turn the wheel and THEN get on it.

There's no one right way to launch, but there's 1000 ways to screw up that 1st corner.

--kC
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