spec stage 3 launch help
06-20-2016, 07:28 PM
#21
TECH Apprentice
iTrader: (1)
Join Date: Dec 2004
Location: Sarasota, FL.
Posts: 362
Likes: 0
Received 0 Likes
on
0 Posts
If you were looking at tire efficiency to that degree it would be in something more akin to a stock eliminator car in which case you would use a sintered iron disk. As well in these applications a bias tire is near always used exception would be an automatic car of the same class but that would end the discussion right there.
06-20-2016, 07:49 PM
#22
TECH Apprentice
iTrader: (1)
Join Date: Dec 2004
Location: Sarasota, FL.
Posts: 362
Likes: 0
Received 0 Likes
on
0 Posts
Clutch disc materials are used in conjunction with clamp load from the pressure plate to obtain a specific HP rating. A disc materials C of F is measured to give the manufacturer an idea of what (combined with the clamp load) the disc will hold for power. An organic type disc has a lower C of F so it will slip easier (also loose holding power as temp rises). A metallic type disc has a higher C of F and will not slip near what organic will, therefore as you slip the clutch with a stage 3 type you will have to extend the slip time to get the same launch as an organic without the detrimental heat effect it would have on the organic. NOW... a sintered iron disc (very aggressive due a lot to no marcel or sprung hub) is meant to slip initially with no C of F detriment due to heat build up.
06-20-2016, 08:19 PM
#23
What i'm talking about is matching the Stage 3's ability to slip to the engine's output, basically something you can accomplish with either the hydraulic cylinder or your foot given enough practice. Done right, it's easier to run radials with a stick than it is to run them with an automatic.
06-21-2016, 07:47 AM
#24
12 Second Club
iTrader: (3)
Join Date: Apr 2004
Location: Grand Rapids, Michigan
Posts: 1,512
Likes: 0
Received 2 Likes
on
2 Posts
What i'm talking about is matching the Stage 3's ability to slip to the engine's output, basically something you can accomplish with either the hydraulic cylinder or your foot given enough practice. Done right, it's easier to run radials with a stick than it is to run them with an automatic.
06-21-2016, 12:26 PM
#25
06-21-2016, 05:38 PM
#27
No more of a challenge than a stock weight '12 M6 Challenger with twin rear mounts. By the time you install enough clutch to hold the power, it's too aggressive to launch without bogging, breaking, or spinning. Most guys just roll race cars like this, controlling the hit of an aggressive clutch was key to making it all come together from a dig.
Many guys also getting way more power thru awd and fwd applications than they should be by delaying clutch lockup. One is a 1500hp Honda that's running 7.88 @190, another a 1200hp Subaru Time Attack car in the UK that was topping out at 8.20 @ 173 breaking parts. Less than a month after experimenting with a delay cylinder on the clutch, the Subaru was down to 7.74 @ 179.
There's also guys switching from hi-dollar adjustable long style centrifugal assist slipper clutches to diaphragm style non-centrifugal slippers with delayed lockup. Main benefit is less shock to the drivetrain after the shifts without giving up any ET.
Many guys also getting way more power thru awd and fwd applications than they should be by delaying clutch lockup. One is a 1500hp Honda that's running 7.88 @190, another a 1200hp Subaru Time Attack car in the UK that was topping out at 8.20 @ 173 breaking parts. Less than a month after experimenting with a delay cylinder on the clutch, the Subaru was down to 7.74 @ 179.
There's also guys switching from hi-dollar adjustable long style centrifugal assist slipper clutches to diaphragm style non-centrifugal slippers with delayed lockup. Main benefit is less shock to the drivetrain after the shifts without giving up any ET.
06-22-2016, 07:51 AM
#29
TECH Apprentice
iTrader: (1)
Join Date: Dec 2004
Location: Sarasota, FL.
Posts: 362
Likes: 0
Received 0 Likes
on
0 Posts
No more of a challenge than a stock weight '12 M6 Challenger with twin rear mounts. By the time you install enough clutch to hold the power, it's too aggressive to launch without bogging, breaking, or spinning. Most guys just roll race cars like this, controlling the hit of an aggressive clutch was key to making it all come together from a dig.
Many guys also getting way more power thru awd and fwd applications than they should be by delaying clutch lockup. One is a 1500hp Honda that's running 7.88 @190, another a 1200hp Subaru Time Attack car in the UK that was topping out at 8.20 @ 173 breaking parts. Less than a month after experimenting with a delay cylinder on the clutch, the Subaru was down to 7.74 @ 179.
There's also guys switching from hi-dollar adjustable long style centrifugal assist slipper clutches to diaphragm style non-centrifugal slippers with delayed lockup. Main benefit is less shock to the drivetrain after the shifts without giving up any ET.
Many guys also getting way more power thru awd and fwd applications than they should be by delaying clutch lockup. One is a 1500hp Honda that's running 7.88 @190, another a 1200hp Subaru Time Attack car in the UK that was topping out at 8.20 @ 173 breaking parts. Less than a month after experimenting with a delay cylinder on the clutch, the Subaru was down to 7.74 @ 179.
There's also guys switching from hi-dollar adjustable long style centrifugal assist slipper clutches to diaphragm style non-centrifugal slippers with delayed lockup. Main benefit is less shock to the drivetrain after the shifts without giving up any ET.
06-22-2016, 03:19 PM
#30
While the radial tire is more efficient and quicker than a bias, grip drops off pretty quick when you exceed the radial's limit. That dictates that the maximum torque sent to the tire in that first few tenths of a second can't exceed the limit of the tire. The tire, shocks, chassis are all tuned to work in that 1st few tenths of a second when torque is at it's maximum, from that point on the tire size, shock settings, and chassis adjustments are going to be overkill.
With an automatic you have a lot of initial torque multiplication in the converter, which creates a torque spike that diminishes quite a bit after the first few tenths of a second after launch as the slip ratio comes down.
With a manual, you are also creating a torque spike any time you launch WOT and the rotating assy loses rpm. If you launch at 5500 and rpm quickly drops to 3500 a few tenths of a second later as the clutch locks up, that rpm drop created a huge torque spike that can easily knock a set of radials loose. Much like the automatic only worse, the tire, shocks, chassis must all tuned to work in that 1st few tenths of a second, or the radials will spin and won't recover.
If you launch a manual in such a way that you don't lose rpm, there won't be any initial spike to deal with. You will be able to optimize the tire/chassis to work at it's maximum efficiency all the way thru first gear, not just the first few feet. With an automatic, you are always going to have at least some initial torque spike due to the changing slip ratio, so it won't be able to spend as much time operating near the radial's maximum potential.
If you can't grasp it yet, that's fine. Not many do at first. Give it a try though, you might change your mind.
With an automatic you have a lot of initial torque multiplication in the converter, which creates a torque spike that diminishes quite a bit after the first few tenths of a second after launch as the slip ratio comes down.
With a manual, you are also creating a torque spike any time you launch WOT and the rotating assy loses rpm. If you launch at 5500 and rpm quickly drops to 3500 a few tenths of a second later as the clutch locks up, that rpm drop created a huge torque spike that can easily knock a set of radials loose. Much like the automatic only worse, the tire, shocks, chassis must all tuned to work in that 1st few tenths of a second, or the radials will spin and won't recover.
If you launch a manual in such a way that you don't lose rpm, there won't be any initial spike to deal with. You will be able to optimize the tire/chassis to work at it's maximum efficiency all the way thru first gear, not just the first few feet. With an automatic, you are always going to have at least some initial torque spike due to the changing slip ratio, so it won't be able to spend as much time operating near the radial's maximum potential.
This maybe the dumbest crap I have ever heard, trading a pressure plate and disc that will lose no C of F for one that will, and the repeatability of a good pressure plate for a screen door shock is obscene. And LMAO at shock to the driveline at 1200hp like it's not a dogbox. And time attack and drag racing are pretty well at either end of the spectrum.