Clutch and launching problems - Subaru WRX Forum
 
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#1 Old 03-01-2005, 09:04 PM
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Clutch and launching problems

So ive been practicing my launches alot lately and i keep burning clutch. If i go much above 3500 rpm i burn clutch. So what RPM would you launch at? Also how much damage am i doing when i burn the clutch like that? How many times can i burn the clutch launching before it goes out? Does the clutch burn easier after it heats up from a few launches, or is it always the same? Finally what clutch would you recomend upgrading to to get better launches on a stage 1 wrx and still have normal street use?
Thanks for any thoughts,
Jacob
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#2 Old 03-02-2005, 06:38 AM
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Well, if you are constantly launching your car, one launch after the other, you may be destroying your clutch. With the stock clutch and any aftermarket clutch for that matter, you have to let it cool down between lauches. You can't just abuse it and expect it to perform forever. I launch around 4500 rpms. Clutch grabs, and the car takes off. But if I launch and launch and launch without giving it a chance to rest, then the clutch turns to puddy. Soon, I want to upgrade to a centerforce clutch. I don't know how everyone else feels about this clutch, but I like the idea of having the peddal feel stock, but still be able to take alot more punishment.
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#3 Old 03-02-2005, 07:34 AM
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i sucked at launching. i came across a thread on WRXF and how to launch. i tried it out a few times today and i'm sure it's going to help at the track and get me under 2.0 in the 60ft.

no more bogging on my launch

well here's the post from hotrod:

"Being nice to your tranny and not out to launch

There are two things you need to accomplish to get a good launch in the wrx.
You need to launch under some boost,
and you need to control the load on the engine so it stays near max torque rpm for the first few feet without banging the clutch and shock loading the drive train.

There are several variations on the theme and each person will discribe it slightly differently but you want to engage the clutch quickly and smoothly so it slips just a bit with out just side stepping the clutch, or frying the clutch by holding it at partial engagement. The newer 2003 cars have a flow limit valve in the clutch line so you cannot just let up on the clutch and break things. It slows down the engagement just a bit. On the 2002's you'll have to do that yourself.

One of the top WRX drag racers in the country describes the technique where you stage, and then let the clutch out a bit until you can tell it is just ready to engage (the friction point) is just a fraction of an inch away.

Hold at a moderate fast rpm (everyone picks a slightly different number) I use about 3000 3500 rpm.

Now comes the key to launching under boost.

You can only build boost under no load conditions when the engine is accelerating at WOT .

Just as the second yellow comes on, stomp the throttle to the floor from your stage rpm, the engine will take about a second to rev to red line. There is only .500 seconds between each of the yellow lights.

Watch the tach and as the rpm swings by 5000-5500 rpm let up on the clutch quickly.
(you can't wait for the green light you have to start leaving on the last yellow)

Since you prepositioned the clutch right at the friction point there will be very little clutch motion, or shock, your engine will be very close to 5500 rpm when the clutch engages and under some boost because you floored the throttle a fraction of a second earlier. If you get all that coordinated you should have enough torque and energy stored in the flywheel so the engine does not bog.

Hang on !!! you will be accelerating at over 1 G and hit red line in low in about 1.5 seconds.
Be ready to shift !!!!!
The biggest time loss that keeps folks at 2.x seconds is a slow shift, you have to shift quickly to get back under power in second gear before you complete the first 60'.

Shift quickly and firmly but NOT VIOLENTLY !!! your not trying to break anything just be quick.


I tell folks to hold the shifter in their fingers not to grab it like a club, this gives you more feel and makes you less inclined to try to rip the shift knob off the console.


If you get it right its quite a ride.

Larry"
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#4 Old 03-02-2005, 11:01 AM
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If you are burning the clutch, you are letting it out to slow. On a good launch, you shouldn't smell burning clutch. I launch at 4500-5000rpms and let it out pretty quick.
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#5 Old 03-15-2005, 07:08 PM
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my 05 boggs at 3000 rpm or 4000 rpm, i`m letting it go pretty fast but still boggs down.
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#6 Old 03-15-2005, 08:46 PM
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launch at a higher RPM.
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#7 Old 03-18-2005, 10:30 PM
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i guess i`m a little nervous about breaking the trans (i`ve always heard wrx`s trans were`nt very tough)
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#8 Old 03-19-2005, 12:48 AM
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yea im scared too
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#9 Old 03-19-2005, 08:29 AM
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u'll be ok just as long as your not constitenly launching. a launch every now and then is fine, if your not grinding the gears every shift.
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