ThaBeaSSt

How is it any different? How come autos. are pulling better 60ft.? I mean...in a manual, your reving the engine up, loading up the clutch, tranny, and rear end with the line lock holding the front tires...how is that any different than holding the brake in an auto. while giving it gas? (brake stall) Also, how do rear ends in autos. hold up longer than ones in a manual if you use a line lock? If youre preloading everything with a line lock, how does it hurt it (tranny, rear end, etc.) any more than brake stalling and hitting it? I figure if youre doing basically the same thing only a bit differently due to the type of tranny, how can it be different with durability, and faster times? I understand the trap times because an auto. is more consistent, but Im having trouble understanding the 60 ft. part. What are your thoughts or what is the reason behind this? Thanks

gator's 99TA

iTrader: (2)

tq multiplication and smooth hard hitting convertors. manuals shock the driveline and are harder to get a good hook off the line. also line locks play virtually no role in a manual launching off the line. also autos have a gearing advantage within the tranny.

CAT3

iTrader: (9)

I cant launch of a line lock in my A4, the rear cuts loose, and M6 guys I know dont use it either, too many switches, too slow.

but yep, the A4s will hit softer saving the rear end, but still build up the power to keep the wheels loaded, so it cut a decent 60'.

ThaBeaSSt

Besides using a line lock for a burnout, I thought manual guys use it to hold the car in place while they rev up the engine and let the clutch out till it starts to grab. Then when its time to go, release the pressure, hit the gas, and let out on the clutch all at the same time. I know that seems like a lot, but isnt that how its done on a manual? Maybe someone was just filling my head up with bull.

Pete2k_Z28

Auto's launch better because of two reasons.

1: torque multiplication in the torque converter. The actual science behind it is a bit long for this thread, but basicly there are two fans and a stator in the TC that act as fluid "gears", the converter slips to a higher RPM than the transmission and in the process acts as a sort of gear reduction. Not the super technical response but good enough for this thread.

2: (and related to one)... The fact that torque converters actually do something with excess engine RPM (multiply torque) means that the engine can remain in the power band while transmitting lower speeds into the transmission. A stick will partly bog, and partly slip the clutch. Neither deliver power to the transmission, and the slipping clutch wastes excess energy (caused by speed difference between the engine and transmission input shaft) by turning that energy into heat. A torque converter, on the other hand, converts most of that excess horsepower into torque, wich moves the car.

The smoother launch of an automatic, compared to the violent snap of a clutch, helps a car stick better as well.

gator's 99TA

iTrader: (2)

i used to launch at 6500 rpms on my mn6 car on slicks all the time. never used the line lock other than for a burnout to make it easy (i was lazy). no you dont use a line lock to launch. launch pads are flat and smooth. also we would never want to add more variables when trying to cut a light. line lock talk is mainly old school. auto cars dont need them either. hell most of us cut great 60' times just hitting it off of idle!

Fast SS on TNT

iTrader: (1)

I used the line lock when I had my M6 to preload the tranny. It was a juggling act to launch the car, and release the brakes at the same time. I'm still scratching my head when I see guys not preload thier rearend before launching with an M6....your just begging to frag the rearend.

I ran slicks for two years on a stock 10 bolt. I attribute the rearend living to always preloading the rearend. However, since adding a transbrake, my line lock is only for burnouts.

Jorday

I always use the brakes to stall the converter as much as possible. Then full throttle and release brakes immediately on 3rd yellow.

PunkNPonys

iTrader: (2)

Do you run better times doing that rather then flashing the converter? I am not sure which one would be better. What do you guys think? What about on the street with street tires?

CamaroSS_2002

iTrader: (4)

It's call Torque Multiplication or STR -- that multiply's torque at input shaft by X.X, which in turn transfers more torque to the tires. off the line is where this happens, More torque equals a better 60ft.

Manuals don't have this.

My converter has a STR of 2.6 that means when converter flashes it multiplies torque at input shaft 2.6 times at the input shaft of the trans. To give you an idea of what your car puts down when the converter flashes run it up to 70mph on the dyno and punch the gas and start the dyno, the car will downshift to second, then hit third real fast and if you look at the dyno graph you will see a HUGE torque spike. On my old converter with a 2.3 STR we did this and we saw 477RWTQ on the dyno graph.

So basically if I flashed the converter off the line that's how much torque engages the tires.

Even though my dyno numbers were 395rwhp/394rwtq

Jorday

My 60 ft times are better when I stall the converter up before the launch instead of launching from idle and letting it flash.

CamaroSS_2002

iTrader: (4)

That's cause you apply less torque that way and you have better traction, if you didn't have traction issues your 60ft would be best flashing the converter.

ducati916

does brake stall do any damage to transmission, engine, converter.

CamaroSS_2002

iTrader: (4)

It's harder on the front pump of the transmission, but not any better or worse on any other components

It might be a little better on the rearend to brake stall

GueSS Who

1.47 60ft with my 6-speed with no line lock. I would rev it up and let out on one of the down revs. Fun, Fun.
1.41 60ft with my 4L60E. Brake stall it up to about 2500 and leave. Really fun.