Chủ Nhật, 22 tháng 1, 2017

Launch Technique part 1

wildwrxwracer 06-07-2005 11:45 PM

Launch Technique
How does everyone launch? Over the weekend i went to the dragstrip and did horrible because of my launch. I ran 16.6 and 15.6 in my 03 WRX. This was the first time i have ever ran a 1/4 mile and first time with the WRX. ANy tips or pointers so i can hopefully run a 14.9?
McBain_TP 06-08-2005 02:46 AM

Look at the links in the search below, then practice, 'cause it's hard.
[url="http://forums.nasioc.com/forums/search.php?searchid=1956371"]http://forums.nasioc.com/forums/search.php?searchid=1956371[/url]
brickhoss 06-08-2005 10:55 AM

Do you have your timeslip? If so, I'm sure the guys on here could pretty much break down where you are messing up.
BadTrip 06-08-2005 02:18 PM

With times like that we don't really need in-depth analysis of timeslips....the guy just needs some info and some practice.

First, the disclaimer....I'm not a drag-race professional, so after hearing what I say, if you feel it's not worthy, feel free to discard it, there's no charge. :)
Next - always remember that a drag-style launch is one of the (potentially) most stressful and damaging things you can do with your car...so be prepared to pay if you wanna play.

Ok, enough of that crap....and on to the real info:
I'll assume your car is stock since you didn't list any mods

Under a hard launch, one of three things will happen.....
You spin your tires
You slip the clutch (or it slips)
You shear gears off the shaft

Try your best not to achieve the third option. The best way to do that is to spin the tires some and/or slip the clutch some.

I advise starting with pretty hard tires, especially in the front....start with maybe 42-43psi. This should HELP you spin the tires some when you launch hard. Some tire spin, in my opinion, is a good thing.
If you find that you're spinning the fronts hard, then start dropping the air pressure in one-pound increments until you get less tire spin. At the point where you are able to come off the clutch hard and quick (not a side-step or a clutch dump, which is extremely shocking to your tranny) and you get no tire spin, you are now at a point where your traction is overwhelming your clutch's ability to grab. This means that you've now eliminated one of the three options and only clutch slip or tranny break is possible. Again, I think SOME tire spin is a good thing.

Clutch slipping is definately a technique and it requires practice. If you have no idea what "slipping the clutch" means, let us know, because there are many, many other things you should be made aware of. :)
You definately don't want to let the engine bog down and drop out of the power band of both the engine AND the turbo.

Keep in mind that if you're only after ET, it doesn't matter if you win the race.......so concentrate on your launch. Good ETs are usually made or broken with the launch.

Avoid the water box....don't try to do a burn out, .....please.
Get pre-staged......when you're ready pull your rpms up to about 3000rpm and slowly release the clutch until it just grabs enough to start rolling the car forward. Inch forward very slowly until the second stage light is lit.
Do NOT push the clutch all the way back in.....only push it in far enough that it disengages...i.e; about 1/2 an inch prolly.
At the same time you should be blipping your throttle pushing rpms up into the 5500 range or so....falling down to the 4000-4500rpm range.....this is to try to spin the turbo as much as possible even though you can't really build boost pressure until the engine is under load, which means the clutch is engaged.
Anyway, your goal is to be releasing the clutch as the rpms are going UP, ~4500rpm. Slip the clutch to avoid excessive shock on the tranny...smoothly, fairly quickly. Some of the guys around here liken it to the speed you pick your foot up if you stepped on dog crap.....for whatever that's worth. I haven't been able to make the connection between the dog crap and the drag strip yet, but hey, that's just me.
Sorry, back on topic...so:
42psi in the front
Avoid the water box
Stage at your own pace
launch at your own pace if you're after ET as opposed to "the race"
Blip the throttle
launch at about 4500 rpm with some amount of clutch slippage

For shifts.....it's all about the SMOOTH. Smooth and quick usually beat hard and fast all day long.....at least as far as drag racing goes.
Pre-load the shifter......no need to push the clutch all the way to the floor.....just like the launch technique....there's a spot about 1/2 way down where the clutch is disengaged. Any further than that is just wasted time and effort. If you miss a gear/shift.....calm down....it's ok.....relax and put it in the gear you wanted and drive on down the track. Don't keep yanking the bastage until it goes into gear, meanwhile running your rpms through the roof. Miss a gear?....relax and head for the next run. We've all done it, even if Davenow says he hasn't. :devil:

personally, I launch at about 5500rpm....hard on the clutch (stocker), back-pedal it very briefly as the tires are spinning (clutch slippage), then engage fully. ...usually get some tire spin and some burning clutch smell. 30k miles on stock tranny and stock clutch but HIGHER than stock power level....nothing has fallen out yet.

Keep us posted.
wildwrxwracer 06-08-2005 03:53 PM

I have an 03 WRX. FMIC, Turbo XS BOV and HKS exhaust. When i launched, i was revving at around 4-5 and dumped the clutch on green. It bogged like a mofo. Ill show the slips if i could figure out how to post pics...
Zumble 06-08-2005 05:55 PM

Dumping the clutch is your problem. That's a huge shock to your drivetrain.

[QUOTE=wildwrxwracer]I have an 03 WRX. FMIC, Turbo XS BOV and HKS exhaust. When i launched, i was revving at around 4-5 and dumped the clutch on green. It bogged like a mofo. Ill show the slips if i could figure out how to post pics...[/QUOTE]
wrxfactor 06-08-2005 06:11 PM

[QUOTE=ZuMBLe]Dumping the clutch is your problem. That's a huge shock to your drivetrain.[/QUOTE]

He's exactly right. You need to slip the clutch in order to actually get the power to the wheels. Try slipping from about 5k down to about 4200, where you'll be able to let off the clutch and launch pretty hard.
jaxscuby 06-08-2005 07:23 PM

[QUOTE=wildwrxwracer]I have an 03 WRX. FMIC, Turbo XS BOV and HKS exhaust. When i launched, i was revving at around 4-5 and dumped the clutch on green. It bogged like a mofo. Ill show the slips if i could figure out how to post pics...[/QUOTE]

I see a transmission rebuild in your future...
wildwrxwracer 06-08-2005 09:47 PM

I did it like three times this weekend. I dont understand that tho, my buddy in his EVO dumped his clutch and just went... :confused:
attitude 06-08-2005 10:18 PM

i see a clutch in his future
krustywrx 06-08-2005 11:39 PM

Bad trip Thanks a lot for the tips I'll be trying this next time
wildwrxwracer 06-09-2005 12:11 AM

Those tips rule by the way!! He has a 100kwarranty on his Evo so i dont think he really cares...
BadTrip 06-09-2005 09:17 AM

[QUOTE=krustywrx]Bad trip Thanks a lot for the tips I'll be trying this next time[/QUOTE]

You're welcome. Let us know how it works for ya! What are you currently running with what mods?


[QUOTE=wildwrxwracer]I have an 03 WRX. FMIC, Turbo XS BOV and HKS exhaust. When i launched, i was revving at around 4-5 and dumped the clutch on green. It bogged like a mofo. Ill show the slips if i could figure out how to post pics...[/QUOTE]

Don't need to see your slips. If you're bogging down then you're engaging the clutch too quickly based on the rpms you're revving, period. Two options.....more revs to spin the tires, or slip the clutch so it doesn't engage so quickly. If you want to stay with the clutch dump technique, which I highly advise against, then pump up the tires and pull revs up to 5500-6000rpm. Maybe you got a Thursday transmission and it'll hold up to that abuse for a while. FYI, you can plan on a minimum if $2000 if you have to replace/repair the tranny.
Why do you have a FMIC? Other than the BOV and the exhaust, those are the only mods? I'm not arguing or confronting you or anything....just asking.
subieworx 06-09-2005 11:05 AM

Evo's are much different machines. The have what I call binary boost, especially on the stock turbo. This means that boost is basically either on or off; there is not much waiting in between where it is building boost. In an Evo you can rev to 5k or so and mostly dump the clutch. It will buck slightly but will build boost so fast at that point that it will be off and running. Not the ideal way to launch that car, but it will work better than on our cars. Not to emtnion the trans is stronger on the Evo.
offset 06-09-2005 12:21 PM

[QUOTE=wildwrxwracer]Those tips rule by the way!! He has a 100kwarranty on his Evo so i dont think he really cares...[/QUOTE]
LOL, ya Mitsu warranties are awesome. They never claim abuse. And they are sure to be around for the next several years honoring them :lol:

offset
nyngbld 06-09-2005 12:49 PM

[QUOTE=wildwrxwracer]How does everyone launch? Over the weekend i went to the dragstrip and did horrible because of my launch. I ran 16.6 and 15.6 in my 03 WRX. This was the first time i have ever ran a 1/4 mile and first time with the WRX. ANy tips or pointers so i can hopefully run a 14.9?[/QUOTE]

I feel your pain. I am still VERY n00b with drags. At least I get practice, we have them every Tuesday at IRP here. My best run was 15.0 flat. I got a great launch on that one, just little tire chirps. BUT, my question is which gears to run all way to redline, all? Should I just go to about 5k in 1st & 2nd, then run to redline in 3rd and 4th? ty.

Mods: STi short shifter - BORLA 2.5" catback - Samco IC Hoses - AEM shorty intake.

-ny
drees 06-09-2005 01:28 PM

On a mostly stock car, you probably want to run close to redline for 1st gear because the difference between it and second is so big.

Remember, peak HP is between 5500-6000 RPMs so you want to keep RPMs around that point. A decent shift point is 6500 RPMs for 2nd and 3rd.

If you hit redline in 4th, you are really moving!
BadTrip 06-09-2005 02:02 PM

[QUOTE=nyngbld]I feel your pain. I am still VERY n00b with drags. At least I get practice, we have them every Tuesday at IRP here. My best run was 15.0 flat. I got a great launch on that one, just little tire chirps. BUT, my question is which gears to run all way to redline, all? Should I just go to about 5k in 1st & 2nd, then run to redline in 3rd and 4th? ty.

Mods: STi short shifter - BORLA 2.5" catback - Samco IC Hoses - AEM shorty intake.

-ny[/QUOTE]

Personally, when my car was stock, I took 1st to about 6500rpm...or 6750 or so......run 2nd and 3rd to 6500.......that's my opinion. Some of the guys around here feel that short-shifting at about 6250 is the best....maybe that works for them.
Try to be smooth and quick with those shifts. Hard and fast is not what you're after, in my opinion.

For reference purposes....my local track is 1/8th mile only....so that's where I've been getting to know my first awd car.
Personal bests in stock form were a 9.43et 1/8th. most runs were very consistently in the 9.69 - 9.75sec range. Trap sped of 74-76 if I recall correctly. Best stock 60-foot time was a 1.91.
That's in total stock USDM 2.0L form.....AND with pretty gentle shifting. No banging, no differential smacking the bottom of the car, etc.

I think one of the guys around here has a slip for a 8.7xx 1/8th which he claims was from a bone stock 2.0L USDM WRX. ..I'm not sure I necessarily BELIEVE him, but that's the claim anyway. :)
Point being, mid-9 second 1/8th mile times should be achievable without being an expert, and without being dramitcally harsh on the car......as evidenced by me. :p
nyngbld 06-10-2005 02:55 PM

[QUOTE=BadTrip]no need to push the clutch all the way to the floor.....just like the launch technique....there's a spot about 1/2 way down where the clutch is disengaged. Any further than that is just wasted time and effort. [/QUOTE]

OMFG... I should let each member on this forum smack me once. I have always driven cable clutch, slamming it to the floor. I read this and my shifts are 95% smoother now. I can't wait to hit track. I bet I will shave at least .5 sec off my 1/4 mile time. With the ideas on shift points, I REALLY hope I drop my time at least into 14s. I will post after next Tues drags. THANK YOU!!!

-ny
rallytim888 06-10-2005 08:03 PM

thanks for all the great info guys!!! now all i need to do is do 867,254 times b4 i get it down. i hope i dont mess up the tranny too bad, but hey, what are warranty's for LOL.
rallytim888 06-10-2005 08:04 PM

btw, that stuff on not pushing the clutch all the way down is golden!!!!!
wildwrxwracer 06-11-2005 11:29 AM

ill have to try again next time i go. Not sure when that will be but ill keep up to date
BlackedOut REX 06-12-2005 09:20 AM

Over on the clubwrx.net board i was readin how to launch and the guy was saying hold you rpms to around 3k then on the second yellow light floor it and at about 5500 dump the clutch. He was saying that he even had his tranny looked at by a subaru dealer and they said it looked like it had 15k on it. And he said he was launching like that for i think he said 200 1/4 mile passes.

After reading about that i tried it on the street and it worked, no bog or anything, a little bit of wheel spin which is what he said should happen.

What do you guys think? Anyone else on this board launch that way?
Kevin Thomas 06-12-2005 10:14 AM

[QUOTE=wildwrxwracer]How does everyone launch? Over the weekend i went to the dragstrip and did horrible because of my launch. I ran 16.6 and 15.6 in my 03 WRX. This was the first time i have ever ran a 1/4 mile and first time with the WRX. ANy tips or pointers so i can hopefully run a 14.9?[/QUOTE]

Forum: "Proven Power Bragging,
Big power, big egos... Report and discuss your 1/4 mile, Dyno and other [B]achievements here[/B]."

So, you aren't actually bragging about your 1/4 mile time or your launch technique? :confused:

*Moving*
showbo 06-12-2005 10:52 AM

[QUOTE=BlackedOut REX]Over on the clubwrx.net board i was readin how to launch and the guy was saying hold you rpms to around 3k then on the second yellow light floor it and at about 5500 dump the clutch. He was saying that he even had his tranny looked at by a subaru dealer and they said it looked like it had 15k on it. And he said he was launching like that for i think he said 200 1/4 mile passes.

After reading about that i tried it on the street and it worked, no bog or anything, a little bit of wheel spin which is what he said should happen.

What do you guys think? Anyone else on this board launch that way?[/QUOTE]


Thats sorta how i launch, except i slip for a split second..just enough to get my tires rolling then i dump out of it and i get mad tire spin.

BTW i already broke my stock tranny doing that method, with a vf-22. Now i have the STI RA-gearset and im not scared anymore to launch hard. The stock tranny will break like that though, sooner or later.


Oscar
AlboWRX 06-12-2005 11:51 AM

[QUOTE=rallytim888]thanks for all the great info guys!!! now all i need to do is do 867,254 times b4 i get it down. i hope i dont mess up the tranny too bad, but hey, what are warranty's for LOL.[/QUOTE]
Dont get launch-happy or you`ll be in for a surprise when you find out that the dealer wont cover the tranny that has been abused.
BlackedOut REX 06-12-2005 06:58 PM

How much does the STi RA-Gearset cost?
AlboWRX 06-12-2005 07:31 PM

1400-1600 not including labor
rallytim888 06-12-2005 11:53 PM

[QUOTE=AlboWRX]Dont get launch-happy or you`ll be in for a surprise when you find out that the dealer wont cover the tranny that has been abused.[/QUOTE]

Very true. Ill take it easy, and it wasnt as hard as i thought it would be to get down. And i have the half clutching shifting down very well!!! :banana:
BadTrip 06-15-2005 09:29 AM

[QUOTE=nyngbld]OMFG... I should let each member on this forum smack me once. I have always driven cable clutch, slamming it to the floor. I read this and my shifts are 95% smoother now. I can't wait to hit track. I bet I will shave at least .5 sec off my 1/4 mile time. With the ideas on shift points, I REALLY hope I drop my time at least into 14s. I will post after next Tues drags. THANK YOU!!!

-ny[/QUOTE]

[smack] [/smack]
Well, you're quite welcome. I do hope it helps! Keep us posted!
BadTrip 06-15-2005 10:17 AM

[QUOTE=BlackedOut REX]Over on the clubwrx.net board i was readin how to launch and the guy was saying hold you rpms to around 3k then on the second yellow light floor it and at about 5500 dump the clutch. He was saying that he even had his tranny looked at by a subaru dealer and they said it looked like it had 15k on it. And he said he was launching like that for i think he said 200 1/4 mile passes.

After reading about that i tried it on the street and it worked, no bog or anything, a little bit of wheel spin which is what he said should happen.

What do you guys think? Anyone else on this board launch that way?[/QUOTE]


It's that term "dump" that can get you into trouble. In my opinion a true clutch dump is like a sidestep off the pedal....as opposed to quickly and smoothly engaging the clutch. The sidestep method can and will, in my opinion (I'm not a transmission guru) exert extreme shock to the gear teeth.
Those gears might hold xxx lbs of torque with no problem at all IF they are loaded in a progressive manner. But hit the same gears with the same torque in an instant and they are not nearly as tolerant.
That's just my own opinion.....and, admittedly, I'm not an expert.
Migo 06-15-2005 10:27 AM

AWD + dumping the clutch = bad tranny

AWD + slipping the clutch = happy tranny

It's been that way with any AWD sportscars. The Evo, the Porsche Carrera 4S, even the Lambo.
BadTrip 06-15-2005 10:35 AM

[QUOTE=Migo]AWD + dumping the clutch = bad tranny

AWD + slipping the clutch = happy tranny

It's been that way with any AWD sportscars. The Evo, the Porsche Carrera 4S, even the Lambo.[/QUOTE]

Yep....few cars have the ability to find enough traction with two tires/wheels to apply the sort of forces on the tranny that an AWD set up is capable of.....street cars anyway....on street tires...or even R-compounds.

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