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    Launching?

    I remember a post not long ago regarding hard launches. It was noted that they were very bad for the mechanics and shouldnt be done.

    Well if I was feeling imature and I was for example at the lights and a hot hatch was wanting a race (the ones with more modifications than a dragracer) then can people here give advice on how is the best and safest way (for the car) to lunch?

    being a sports car it should be up for this type of thing.

    Re: Launching?

    Quote:
    londondude said:
    I remember a post not long ago regarding hard launches. It was noted that they were very bad for the mechanics and shouldnt be done.

    Well if I was feeling imature and I was for example at the lights and a hot hatch was wanting a race (the ones with more modifications than a dragracer) then can people here give advice on how is the best and safest way (for the car) to lunch?

    being a sports car it should be up for this type of thing.



    I agree, just flour it it's under warranty anyway

    ps. btw has anyone noticed how easily this car's clutch burns? I got used to it now, but the first week of ownership took a little getting used to the clutch as I have to pull out of a steep driveway then slowly over a curb, I always smell my clutch afterwards and it was for maybe a couple seconds.

    Re: Launching?

    You shouldn't have to think too much about beating a hot hatch off the lights. Just let the clutch out quickly and floor it.

    Re: Launching?

    No I know its not rocket science and I do it in my boxster now but I did read that it shoudnt be done her ea while back.

    Re: Launching?

    Quote:
    Ed J said:
    You shouldn't have to think too much about beating a hot hatch off the lights. Just let the clutch out quickly and floor it.



    Not always.. Here are some hatches that will even beat a car like a Enzo/CGT over here..

    Re: Launching?

    "Best way" and "Safest way" are polar opposites. Basically, your main concern is that you don't launch hard frequently. But the occassional odd stoplight launch should be no problem for your Porsche. DON'T SLIP THE CLUTCH. Just drop her, and get it engaged so it doesn't go up in a cloud of smoke. I recommend, for a street launch, a 3,000 rpm quick drop. The magazines have been doing 4,000 grand launches, but I worry about the clutch at those revs. Fine for a magazine, they're driving a rental, what do they care? But for your own car, 3,000 should be tops.

    Re: Launching?

    Are the clutches in the various 911s the same? Will the turbo have the same clutch as a 997S? How about the GT3? Just curious.

    Re: Launching?

    The 997S has a self-adjusting clutch, and the standard does not. I would imagine that the clamping power of the clutches differs a bit, and likewise, Porsche will have to install a sturdier clutch in the GT3 and Turbo to withstand far greater loads, and greater abuse especially for the GT3, considering its intended use.

    Re: Launching?

    Really? The C and CS clutches are different? I had no idea. That's interesting. Thanks.

    Re: Launching?

    3000 rpm is a place where u shouldn't worry at all abt the car abuse

    however u probably have to be easy on throttle ( or do an even smaller rpm drop) cause it will not laucnh that well unless u have limited slip diff.

    or u can do it with PSM on which will just smoothen things for ya but thats cheating isn't it?

    Re: Launching?

    Quote:
    londondude said:
    I remember a post not long ago regarding hard launches. It was noted that they were very bad for the mechanics and shouldnt be done.

    Well if I was feeling imature and I was for example at the lights and a hot hatch was wanting a race (the ones with more modifications than a dragracer) then can people here give advice on how is the best and safest way (for the car) to lunch?

    being a sports car it should be up for this type of thing.



    Let the clutch out quickly and floor it as hard as you want. Just don't fry your clutch. That is, don't floor it and let out the clutch at the exact same time and don't rev the engine before letting out your clutch. You could easily destroy your clutch in two seconds and that is NOT covered by your warranty. It's a delicate balance where a fraction of a second can make all the difference between blasting off perfectly and sitting at the light with a burnt out clutch. After a few practice runs you ought to get the hang of it. Remember that you don't even need to give the 997 (or the 996) any gas when letting out the clutch. The car will roll without any gas at all. So start off your practice runs by letting the clutch out and then hitting the gas. Each time you do it try to time the gas closer and closer to the clutch. Eventually you will get to the point where you feel the clutch engage and that's where you want to hit the gas. And you'll also know if you blow it because you'll smell your clutch for hours (maybe days) later.

    Re: Launching?

    Its all very childish behaviour but beautiful at the same time...... Thank you for the info!

    Re: Launching?

    Quote:
    U Boat Commander said:
    Quote:
    londondude said:
    I remember a post not long ago regarding hard launches. It was noted that they were very bad for the mechanics and shouldnt be done.

    Well if I was feeling imature and I was for example at the lights and a hot hatch was wanting a race (the ones with more modifications than a dragracer) then can people here give advice on how is the best and safest way (for the car) to lunch?

    being a sports car it should be up for this type of thing.



    Let the clutch out quickly and floor it as hard as you want. Just don't fry your clutch. That is, don't floor it and let out the clutch at the exact same time and don't rev the engine before letting out your clutch. You could easily destroy your clutch in two seconds and that is NOT covered by your warranty. It's a delicate balance where a fraction of a second can make all the difference between blasting off perfectly and sitting at the light with a burnt out clutch. After a few practice runs you ought to get the hang of it. Remember that you don't even need to give the 997 (or the 996) any gas when letting out the clutch. The car will roll without any gas at all. So start off your practice runs by letting the clutch out and then hitting the gas. Each time you do it try to time the gas closer and closer to the clutch. Eventually you will get to the point where you feel the clutch engage and that's where you want to hit the gas. And you'll also know if you blow it because you'll smell your clutch for hours (maybe days) later.




    Let the clutch out first, and THEN hit the gas?? LOL!!! U boat, have you ever drag raced competitively, at a track? You'd be getting schooled by Camaros my friend, leaping off the line so hard that you'd be 3 car lengths behind them before you clipped the 60-foot lights. If that's how you launch for a street race, I'll run you zero-60 in a Kia Rio towing a U-haul car dolly for pink slips, and I guarantee I'll own your P and be pulling it home on my dolly at the end of the race!!!

    If everybody launches like that, it's no wonder I've never lost a standing-start street race in my life.

    For the record, if you do an off-idle clutch-engage, and then floor it, you're so far down and out of the good torque band, that the race is lost before you get to 20 mph. There's night and day difference, when you put a clock to it, launching aggressively in the power band versus popping the clutch from idle and forcing the car to climb up to it's powerband. It's the reason that automatic trannied drag race cars run stall-speed converters that bring revs to a specified high rpm before converter engagement. It's the reason that you get quicker results in an auto trannied street car at the strip when you spin up against the converter with your foot on the brake to increase launch rpm.

    You're DEAD when you're fully engaged, between 1,000 and 3,000 rpm, in a Porsche flat-6.

    You shouldn't have a problem frying the clutch doing a 3,000 rpm drop, just make sure you DROP the clutch, don't slowly let it out, allowing the pressure plate to slip rather than clamp. If you're too conservative with the revs, then you don't get enough "leap" on clutch engagement to keep the revs up, and you bog, leaving you no better off than you would have been doing an idle-launch like U boat suggested.

    I raced NHRA Sportsman regularly for 10 years between 1988 and 1998. My stock original clutch in my modded 5.0 Mustang finally gave up the goat at 70K (replaced with a Centerforce dual-friction that was an animal of a clutch ). I was young, and abused the daylights out of that car, and that clutch was enduring hard 2,400 rpm launches (more low-end grunt, not as many revs necessary) every weekend, with 80 more horsepower than stock to hold onto. After the Mustang, I bought a new 1993 Corvette LT1 with ZF 6-speed. A few mods later, it was running consistent 12.90's @ 107-108 mph. I launched that car at 2,800-3,000, depending on track conditions. It had 60,000 miles on it when I sold it, and the clutch was still operating great. Those are cars that won Sportsman trophies at divisional meets, ALOT of abuse.

    Doing a properly executed hard launch, every now and then (I mean, honestly, how many times do you really have a "drag race" in your 911? ), isn't going to fry anything, unless you slip the clutch like a dummy, or go too high up the rev-band. The magazines have all been accomplishing their impressive 1/4 mile and 0-60 times with 4,000 grand drops, so I've read, and the clutches have been grabbing hard and not slipping. But even still, I'll reserve such a monumental effort for an icy cold evening when I go up to my old stomping-grounds, Gainesville Raceway, to get some accurate timed runs on my 997S this November (may as well wait for cold weather to get the best times). But a street race isn't worth going 100% out for, so that's why I recommend a more conservative 3,000 rpm.

    Fact of the matter is, that poor technique in everyday normal driving is far more detrimental to a clutch's lifespan, than a rare heavy launch. One gorilla launch is nothing compared to thousands of days of bad throttle matching combined with ham-footed clutch engaging in daily commutes.

    While I got 70K miles, drag racing every weekend, out of my stock Mustang clutch, my buddy's girlfriend had totally worn out her 5.0 Mustang's clutch in 25K miles, bone-stock engine, never raced, just lousy driving technique.

    Re: Launching?

    Good comments 69bossnine. You can learn a lot about launching a car with a few weekends at the dragstrip. Most people are hesitant to treat their cars that way but I'm with you, I've launched using the same high rpm/sidestep the clutch technique many times in many different cars and I have never replaced a clutch before 70k miles.

    Re: Launching?

    The critical thing is the clamping power of the clutch. Is it strong enough to bite at "X,XXX" rpm. If it is not, you'll drop the clutch but you won't leap away abruptly, the clutch will slip, and you'll feel your problem. Sometimes you will mistake clutch slippage for wheelspin, so you've really got to be on your toes. You need to be very alert to this, such that if you launch too aggressively and the clutch is slipping, you quickly pull back on the throttle and abort your run. If you react quickly, you really haven't done any real damage. A clutch is like a brake pad or tire. It's got alot of friction material and is designed to last alot of miles, and you can't wear it to nothing in a single event, unless you just sit there and keep your gas pedal on the floor while it smokes down to the plate. Which would be as stupid as smoking your tires until they popped.

    In fact, using tire spin as an understandable analogy is a good analogy. Ask yourself, if I launch conservatively and don't spin my tires, and if then I launch aggressively and don't spin my tires, are my tires losing rubber on the more aggressive launch? No, not really. Therefore, why not go with the aggressive launch? However, there's always a point where you get TOO aggressive, and the tires break loose, and that smoke you see and smell is rubber burning. Now, you're using up your tires' lifespan. A clutch is not much different. Tires use friction to transfer power from the wheels to the pavement, a clutch uses friction to transfer power from the crankshaft to the pressure plate attached to the transmission. As long as you don't spin your tires, or spin your clutch, all is good.

    Of course repeated aggressive launches will fatigue all driveline components involved, so you don't want to make a habit of it. But here and there, that 2 or 3 times a year you get an opportunity that you can't pass up, man, hammer that baby!!!!

    SVT engineer John Coletti used to have a test for all SVT vehicles, where they had to withstand 100 repeated aggressive dragstrip launches and passes, IN A ROW, as fast as the driver could pull them off, run back to the starting line, and go again. What a torture test!!

    Re: Launching?

    One last post and I'll shut up. The reason I get shaky at launching a 997S at 4,000 rpm or higher, is because my instincts and experience tell me that those HUGE rear tires, combined with the gobs of rear weight transfer pressing down on them inherent in a 911, creates a TON of clamping power between the rear wheels and the pavement. That means, that in a "tug-of-war" between the grip power of the clutch, and grip power of the tires, the tires would likely win, sending the clutch up in smoke. In many cars, the clutch is stronger than the traction-potential of the rear tires, so it is IMPOSSIBLE to smoke the clutch, as the rear tires will spin before the clutch will, allowing the power to release the driveline components from strain. But in a 911, you've got to be careful. The clutch is probably engineered to handle up to 4,000 rpm, standing start, but not much more. It's spinning to quickly, with too much power, after that. Somebody else can try finding the limits with their car!! LOL!!

    Re: Launching?

    U Boat Commander said:
    "Remember that you don't even need to give the 997 (or the 996) any gas when letting out the clutch"

    69bossnine Is this true?

    Re: Launching?

    nice posts 69 i second that or shall i say these

    do u laucnh the 997 with PSM on? cause i wouldn't but found it to require alot of caution with throttle initially otherwise u lose alot of time

    with PSM on ( cheating IMO) u can launch much harder and doesn't kill the power too much

    i was launching my M3 much harder with very little backing off ( wihtout stability on) on the throttle probably becuase of limited slip diff.


    how much did u run for 1/4 mile with your S?

    Re: Launching?

    Quote:
    alin330 said:
    U Boat Commander said:
    "Remember that you don't even need to give the 997 (or the 996) any gas when letting out the clutch"

    69bossnine Is this true?



    It's true if you're pulling away from a stop sign on your way to the store to pick up some milk and eggs.... It's definately NOT true if you're launching for a stoplight or dragstrip race.....unless you feel like getting spanked horribly off the line.

    Re: Launching?

    Quote:
    krC2S said:
    nice posts 69 i second that or shall i say these

    do u laucnh the 997 with PSM on? cause i wouldn't but found it to require alot of caution with throttle initially otherwise u lose alot of time

    with PSM on ( cheating IMO) u can launch much harder and doesn't kill the power too much

    i was launching my M3 much harder with very little backing off ( wihtout stability on) on the throttle probably becuase of limited slip diff.


    how much did u run for 1/4 mile with your S?



    Leave PSM off, as optimal launch will result in a launch more aggressive than PSM will allow. Factories such as Ferrari are starting to allow a bit of wheelspin in their launch-control programs, as this allows the car to get to its powerband quicker, and managed well, can result in a quicker launch. But I find Porsche's PSM to be on the conservative side, plus, you want the shocks to be free to float to allow as much weight transfer to the rear as possible.

    I have yet to run a timed 1/4 mile in this car. As I stated in a previous post, I'm waiting for colder weather for optimal performance. If I'm going to beat on my car a bit, I want the conditions to be as good as they can be, otherwise I'm just wasting time...

    I've played around with street starts though, and find 3,000 rpm to be fairly safe and effective. At the track, the launch pad will be sticky in rubber and traction enhancing goo, so I'll have to lift up the revs and watch out for clutch slippage. I only plan on a few passes, as such launches are fairly abusive on the driveline components.

    Re: Launching?

    69 GREAT let us know when u get some runs

    anything less than 12 flat will not be accepted

    Re: Launching?

    Quote:
    alin330 said:
    U Boat Commander said:
    "Remember that you don't even need to give the 997 (or the 996) any gas when letting out the clutch"

    69bossnine Is this true?



    I can get my 997 to roll from a stop without gas as long as the road is flat or downhill. With my 996 Turbo if I let out the clutch without gas it would stall everytime.

    Re: Launching?

    You can get anything to roll from a stop with nothing but idle-speed-power, it just depends on how patient you are (as well as the poor folks stuck behind you!) LOL!

    Re: Launching?

    My 996 wouldn't do it.

    Re: Launching?

    Anything that spins a crankshaft will do it.... theoretically, it just takes time. It could possibly take 10-20 seconds to engage your clutch in your 996 from idle, feathering the clutch to keep the engine running at 500 rpm... Like I said, it's silly, but anything can go from idle with time, feathering it. I do it all the time with old cars that have less than 100 h.p. pushing 4,000+ pounds, moving stuff around in tight confines. The gas pedal for a 1930 Lincoln is basically a round push-button on the floor, that's impossible to modulate with precision. It's easier just to set the throttle at idle speed on the steering wheel throttle control, and use the clutch all by itself to get it rolling forward or backward into a spot.

    Man, we must be bored debating something this banal.

    Re: Launching?

    I don't think we were debating. Besides it's an auto forum where as can you discuss this junk. It was something that I brought up before too because I really like the way the 997 rolls for me when I often get stuck in traffic. It was always something I didn't like about my 996. In fact I went back and forth in my mind about waiting for a paddle shift Porsche because of the pain 996 clutch. Glad I didn't wait. Leaving my office now anyway so I can't debate anymore till tomorrow.

    ps: Comletely agree about your points on take-off
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    LTR

    Re: Launching?

    I'll jump in and say that Stradale may have a point. Some vehicles have their idle speed set so close to the stall rpm that the energy necessary to move the vehicle from rest just cannot be overcome without a slight amount of throttle. It's just that initial friction of moving all those components from their resting state that has to be overcome and sometimes the power available between the idle rpm and the stall rpm is just not enough. Adjusting the idle up about 50 rpm or so can cure this.

    Re: Launching?

    Quote:
    69bossnine said:
    If everybody launches like that, it's no wonder I've never lost a standing-start street race in my life.




    69Bossline: You misinterpreted my comments. Obviously, you can't let the clutch out and sit there before pouding on the gas. But you also can't reve the car way up and pop the clutch with a car that's intended to be a daily driver. I saw a guy try this with his 996 and he fried his clutch in one go of it. As I wrote in my comment, it's a delicate balance between clutch and gas. If you're a newbie to a 911 (as is the guy I was writing for who is clearly not dragging at a track) you need to learn the right balance or you will find yourself walking out of the Porsche dealer $1500 lighter in the walet after replacing your clutch. Reving up to 4,000 RPM and dropping the clutch is way too much for the 911. IMO, 3,000 is the most you want to do.

    And by the way, I've never lost a street drag race in my 300BHP 996, and even beat a 400BHP Vette until the shift to third.

    Re: Launching?

    Quote:
    STRADALE said:
    Quote:
    alin330 said:
    U Boat Commander said:
    "Remember that you don't even need to give the 997 (or the 996) any gas when letting out the clutch"

    69bossnine Is this true?



    I can get my 997 to roll from a stop without gas as long as the road is flat or downhill. With my 996 Turbo if I let out the clutch without gas it would stall everytime.



    Of course it's true. Go try it. Just let out the clutch and the car will start to roll. I suppose if you're on an incline this will not work. But I do it all the time on flat pavement.

    And one other thing for 69Bossnine, Londondude (the guy who started the thread) was asking what is the "safest way" to launch his car. Not what is the fastest way.

    Re: Launching?

    Quote:
    alin330 said:
    U Boat Commander said:
    "Remember that you don't even need to give the 997 (or the 996) any gas when letting out the clutch"

    69bossnine Is this true?



    It is for a GT. But not a 997S. Try it ! - You'll stall unless you give gas *immediately* after. Or, a better way to think of it is,as in a previous discussion here, what RPM do you engage the clutch at ? Newbies do 1200 or so, more experienced maybe 1000, and experienced at 800-ish. But the car will stall immediately after letting the clutch out unless you hit the gas then.

     
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