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Old 12-26-2008, 08:53 PM   #1
watchunglava
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What's up with trying to launch at like 4k and having no power and a burning clutch. Haha!!! Mechaical or ecu controlled?
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Old 12-27-2008, 02:11 AM   #2
williaty
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That's too high. You're overheating the clutch (which reduces its mu) before you get it to lock up. PEBSAC.








(Problem exists between steeringwheel and clutch)
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Old 12-27-2008, 02:19 AM   #3
watchunglava
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whats pebsac?

i only had to do it due to extreme traffic conditions where this woman allmost plowed into me. burning clutch smells like shoot.

haha thanks for the trouble shooting lol!!!!!!! (Problem exists between steeringwheel and clutch)

ive launched other cars like that but the subaru doesnt like it. would you recogmend a deifferent materal clutch or is it just the nature of the awd like a safe guard so i dont blow my gear boxes out
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Old 12-27-2008, 02:25 AM   #4
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PEBSAC=Problem exists between steeringwheel and clutch

In tech support, I often told people they had a PEBKAC issue, which was Problem Exists Between Keyboard and Chair. In other words, user error. Also often told them they had and "eye-dee-10-tee" problem (id10t).

Anyway, the sweet spot will depend on the exact state of your components, but I find with mine, the best way to launch it is to bring it to about 3k, pick my clutch foot up until the clutch just barely catches, floor the throttle, then pick up my clutch foot as fast as the engine will let me. If you pick your clutch foot up too fast, you'll bog or stall the car. If you pick your clutch foot up too slowly, the clutch will slip, overheat, and you won't launch at all. The advantage of mashing gas all the way to the floor is that it reduces the launch to just one pedal to worry about and ensures the fastest possible launch if you get it right.

If you miss to the high side and get the clutch slipping, you'll need to take your foot out of the gas, put the clutch back in some, and try again with a much more "normal driving" style of start as the clutch will be too hot to grip well enough for a launch.



Now, for REALLY advanced footwork in the "oops, didn't notice I was supposed to be moving already!" arena, You actually can floor it from idle in neutral, and as the revs race up to your launch RPM, start letting the clutch out to "catch" the engine and prevent it from over-revving. It's an amazingly quick way to get moving if you pull it off, but an Epic Fail if you miss even a little bit.
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Old 12-27-2008, 02:29 AM   #5
watchunglava
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yea it was definatly me , trying to just be out , and the clutch not gripping . not that i drive like that but would better clutch plate material like kevlar or ceramic ect. provide the ability drop the clutch it at 4 k and be out?
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Old 12-27-2008, 02:37 AM   #6
williaty
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Basically, you have two choices (and yes, I know I'm generalizing here) in clutches: Clutches that are OK with being slipped a bit so they're easy to drive in the city and don't make women hate you and clutches that grab no matter what and therefore force you to make every start a launch. Yes, some of the materials fall in the middle, but that's the sort of range you're talking about.

So, a more aggressive clutch material will allow the clutch to grab harder even with a larger speed difference between the two sides of the clutch (i.e. your recent experience) at the expense of not really having a "partially engaged" mode that allows for a smooth, slow roll away from a light. Also, those more aggressive clutches make it MUCH harder and possibly impossible to creep up something like a rutted uphill gravel road. Additionally, a OEM-type organic material is going to have the best tolerance for you screwing up and overheating it. Most of the time, once an organic clutch cools back down, it's in ok condition and will keep working. The same isn't true of all composite and ceramic materials. Some of them overheat once and need replacement.

Now, due to how little torque the engine makes, I would be shocked to see you make much of an improvement in your 60ft from a grabbier clutch. The stock clutch, if you use it right, can transfer all the torque the engine has to offer even when still partially slipping (if you don't overheat it on the way). So you'd make the car a little harder to drive without any real performance benefit. You might like the snappier feel, but it also might get old after a month or two.


The one exception I can see to this advice is if you have a boat or something. A clutch with more heat resistance would do much better starting 2klbs worth of boat up a boat ramp every day in the summer.
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Old 12-27-2008, 01:36 PM   #7
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Also keep in mind, since you mentioned it, that AWD provides a LOT of traction, especially on pavement. This means that ANY speed differences between the driveline and engine WILL be made up in the clutch. You don't get the freebie of a slipping wheel to make up for your bad launch. :P
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Old 12-27-2008, 02:40 PM   #8
watchunglava
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i know, i seriously never tried to launch the car at that speed beore last night. ive driven a stick for like 10 years . this is my first awd vehicle.

it was all instinct , like i saw the woman coming through a stop sign and knew she was going too fast. i was at a light and the street she was coming down ended where i was sitting for the light . i watched her and when she slid through , i tried to launch it to just be out. even though the clutch was super hot and burning because i dropped it at 4 k ish , i let out the gas the clutch grabbed, i got back in the gas, and i was able to get out of the way , this all happened in like 4 seconds tops . all though it felt as though i wasnt transfering all the power until the clutch cooled down a few minutes later .

i probably boiled the clutch fluid as well , which probably is the reason my clutch pedal has more resistance.
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