Is it possible to lauch an AT?
Is it possible to lauch an AT?
03-06-2005, 12:16 PM
#4
Registered User
Thread Starter
Join Date: Nov 2004
Location: Chicago, IL
Posts: 332
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Ryan13b
You want to find the point where the car is just about to be moving. Full throttle and just enough brake to keep the car still.
03-06-2005, 12:30 PM
#6
Registered User
Thread Starter
Join Date: Nov 2004
Location: Chicago, IL
Posts: 332
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Ryan13b
It's real bad for the brakes.
The brakes convert kinnetic energy into heat via friction. They work well, but they're not designed to hold back a force. They're designed knowing that the energy of the car will lessen as they work.
So if you're going 100mph the brakes have a lot of energy to dump, but that energy goes away as they slow you down.
When you're not moving and you're trying to accelerate the brakes have to convert all the energy that the engine is making, which they're capable of doing up to a point. Now, since the car isn't moving or slowing down and the engine just keeps making power the brakes have to get rid of the energy at a constent level, it doesn't drop off until you let go of the gas.
I'm not going to bother with the formulas, but I would guess the brakes are stopping the equivalent to about 70mph, except you're holding that energy level. Instead of them getting that energy for just a split second and then it begins to lessen, they're seeing it until you let up.
The brakes convert kinnetic energy into heat via friction. They work well, but they're not designed to hold back a force. They're designed knowing that the energy of the car will lessen as they work.
So if you're going 100mph the brakes have a lot of energy to dump, but that energy goes away as they slow you down.
When you're not moving and you're trying to accelerate the brakes have to convert all the energy that the engine is making, which they're capable of doing up to a point. Now, since the car isn't moving or slowing down and the engine just keeps making power the brakes have to get rid of the energy at a constent level, it doesn't drop off until you let go of the gas.
I'm not going to bother with the formulas, but I would guess the brakes are stopping the equivalent to about 70mph, except you're holding that energy level. Instead of them getting that energy for just a split second and then it begins to lessen, they're seeing it until you let up.
03-06-2005, 01:24 PM
#8
I understand the way they dissapate energy when they are moving, but you mentioned they convert the energy when the car is not in motion, i.e doing a power brake. This is why I reasoned that the torque converter would be the weakest link in the chain while doing this, because I could not see the brakes dissapainting any energy.
03-06-2005, 02:50 PM
#10
Registered User
Thread Starter
Join Date: Nov 2004
Location: Chicago, IL
Posts: 332
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by therm8
And the lack of wheelspin is due to low torque. Power brake an AT F-body or Mustang and you get crazy wheelspin.
03-06-2005, 04:25 PM
#12
Doing this is rather hell on an automatic transmission. I don't know how strong the 8's 4 spd is, but I'd seriously invest in an automatic transmission cooler (like a B&M) to run in line with the car's stock cooler if I was going to consider doing a powerbrake more then once. Technically you should put in a cooler anyway, but since most people think its unnecessary till their ATX explodes out of warranty, I'll just try to stick in a recommendation in a transmission abuse thread.
03-06-2005, 04:40 PM
#13
Stuck in a love triangle
Even ifyou ignored all the potential problems youwere causing by doing this type of launch w/the automatic - the rewards are pathetic anyway. What doyou gain by this? Ill tellyou - you get to 60 by as low as 7.8 seconds instead of the typical 8.1 - 8.2 seconds. Is thatreally worth it to you? Bythe way I havespun out the tires once before by usingthis method butthat was back when my replaced transmission was slipping. Ifyou really want to maximize thelaunch from an automatic you do a neutral slam.
03-06-2005, 04:41 PM
#14
Registered User
Join Date: Sep 2004
Posts: 258
Likes: 0
Received 0 Likes
on
0 Posts
Brakes convvert the friction of the rotors into heat. Power braking will do nothing to the brakes unless you are letting them slip a bit. It will tear up your tranmission in a heart beat. Brakes, nothing at all. No friction involved.
03-06-2005, 05:15 PM
#15
Registered User
Join Date: Oct 2004
Posts: 166
Likes: 0
Received 0 Likes
on
0 Posts
What I did with my 2000 celica gt-s is put it in reverse...reverse back about 5 mph...then drop it in neutral and rev it up...and then drop it into drive and bingo...fwd burnout in a celica :-D good times on the day before i gave her away...
03-06-2005, 07:38 PM
#16
Lawyer in training :)
Join Date: Aug 2004
Location: Atlanta, GA
Posts: 913
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by JeRKy 8 Owner
Even ifyou ignored all the potential problems youwere causing by doing this type of launch w/the automatic - the rewards are pathetic anyway. What doyou gain by this? Ill tellyou - you get to 60 by as low as 7.8 seconds instead of the typical 8.1 - 8.2 seconds. Is thatreally worth it to you? Bythe way I havespun out the tires once before by usingthis method butthat was back when my replaced transmission was slipping. Ifyou really want to maximize thelaunch from an automatic you do a neutral slam.
Can you tell I don't street race often?
03-06-2005, 07:46 PM
#18
I kinda agree with Jerky here. I mean, although I don't own an 8 I have driven both the mt and at offerings now. I thought the mt was a little on the slowish side when I first drove it, but still a wee bit faster than my current car. The at felt a lot slower than the mt, slower than my car I think. On the otherhand, both were a lot more fun to drive than my solara. It's just not worth the damage to the drivtrain to try to make the car a little less slow.
03-06-2005, 10:56 PM
#19
Stuck in a love triangle
The onlyway to make the 6spd manual reach 60 in the low 6s is by launching from high up in the5000+ RPM range. For a regular street start (like from 5mph - 60mph) forgetabout it - not enough torque. Thats theproblem w/the automatic. You cant get away w/that typeof abuse on the transmission theway you can w/a clutch. Imsure that ifwe could safely rev the automatic Rx8s to 5000 RPM andnot worry about destroying the tranny youcould probably makeit to 60 down in the mid to slightly low 7s. Im surethats about the time the low power 5spd manual Rx8s make in Europe
03-07-2005, 01:14 PM
#20
Registered User
Join Date: Jan 2005
Posts: 416
Likes: 0
Received 0 Likes
on
0 Posts
If you are asking how to launch an RX-8 you bought the wrong car. What are you going to race? Civic? Mini Van? F150 would most likely take you out. The car is just not going to cut it drag racing....it's for the curves. Enjoy what it is.
:p
Thread
Thread Starter
Forum
Replies
Last Post