rickssz

I am trying to understand how say a3800/2.5 stall is any different than dumping the clutch at 3800 rpm in an M6? Is it easier on the rear end or is it worse due to torque multiplication? Does the stall give the same effect as reving to 3800 in neutral and dropping it in gear(I know that would blow the tranny just using it as an example to get a mental picture) My limited experience was mostly M6 and that has always been add a little suspension and keep getting bigger sticker tires until it takes off and with a factory A4 just go easy on the gas trying to keep it from spinning to death. So can anyone explain how a high stall launches and performs at the track and from a roll to if that doesnt complicate things?

XX11SECZXX

iTrader: (1)

an auto normally has a better 60ft. its easier on rear ends because there isnt the shock of dumping the clutch. an auto will come in gradually and also you wont bog with an auto. if you have 3800 stall that means if you are hooked your car will go to 3800rpm when you stand on it and you will be accelerating. unlike a stick where you can dump it at 3800 and fall to 1500 if you dont have enough power or if you dead hook.

BubaGumpShrimp

iTrader: (1)

nice description xx11seczxx, dont think i could have said it any better.

XX11SECZXX

iTrader: (1)

thanx.

rickssz

If there isnt a shock and the take off is gradual then what is meant by a 2.8 etc STR hitting really hard ?

chrs1313

iTrader: (24)

It hits hard, its more of a cousioned hit that allows the tires to hook.The str is the amount of torque multiplication on the initial hit.A4 stalled hits hard,and continues to pull hard, when a stick hits hard then the rpms drop because it is locked up 1-1.This is the best i can decribe it.Kinda like how a snowmoblie takes off.

TORK?

iTrader: (27)

Here's a video I posted with a 3800 converter. You can see when I let off the brake how the rpms went to ~3800 and never went below. That wasn't full throttle off the line either

http://lsx.streetfire.net/video/075e...14001683a4.htm

BubaGumpShrimp

iTrader: (1)

one of the main differences is that in a stick car the drive line is not loaded upon take off, that inital shock is what blows off tires. Automatic drive lines are always loaded when in gear (makes them easier to lauch) and doesnt suffer that inital shock. As far as a converter "hitting hard" is more of a saying than an action. A converter with a higher str simply pulls a whole hell of alot harder from a stand sitll due to the extra inital torque multiplication hence people saying it hits harder.

XX11SECZXX

iTrader: (1)

the higher the st the harder it hits off the line but it is normally less effiecient. mine is around 2.3 4000 stall. im cutting 1.6 60s wheel hoping bad.

radz282003

iTrader: (1)

I think an easy way to picture what STR is, is to imagine you're making 300 ft.lbs. of torque. An OEM converter has an STR of something like 1.9:1 or something. Theoretically, one could multiply 300 times 1.9 and get 570 ft.lbs. of torque with the OEM converter. So if you had a converter with a 2.5:1 STR, you'd (THEORETICALLY) get 750 ft.lbs. of torque. If you use that theory, one could imagine a stalled car with a higher STR would hit (off the line) harder than a manual car because there isn't torque multiplication in a manual. Visualizing those numbers you could see an auto car explode off the line opposed to a manual car (that's not to say there haven't been good times pulled in stick cars .) The STR DOES fall off though after the car comes off the line though. I believe, typically, the higher the STR, most often times, the lower the efficiency of the converter. If you have less efficiency, you'll be wasting power as the car goes down the track, so you'll want to try to find a balance.

I'd suggest getting a look at Yank's website. I've found it to be very informative in the benefits and operation of converters. I have an SS3800 and love it. It is more efficient than the OEM converter, has a 2.55 STR, and murders my street tires. At the time, they weren't advertising a 3800 but they might build you one. I'd go with at least a 3600 stall though, regardless of whom you decide to purchase from.

For the love of God, get some drag radials!!! All that torque mutliplication off the line won't do any good if your tires don't stick, and there isn't going to be a street tire that will stick. Like I mentioned, STR is only really effective while you go WOT from a stop; rolling onto the throttle, or feathering the throttle off the line, will NOT give you the benefits of all that STR.

Good luck.

Ragtop 99

iTrader: (7)

That depends upon how you launch. some do better by being brake stalled, others do better being flashed at launch. Best 60's I ever got were from flashing, but the results were inconsistent, so I normally brake stalled to produce a known reaction time and consistent 60'.

radz282003

iTrader: (1)

+1. I seem to get a bit better 60s brake stalling than flashing. I figure it helps to preload the rear end too. Maybe at the same time it's preloading the suspension and helps to bite better.

Vetal

iTrader: (3)

With the transbrake engaged, do you still have the benefit of pre-loading transmission and suspension? Or does it hit brutally just like dumping clutch, with the exception of not ever bogging?

StreetSilverado

iTrader: (17)

You call that being a benefit? "Converters" will hit hard or soft, the transbrake is just there for more consistency, faster reactions, spooling (for the FI guys), and things of that nature.

The transbrake really doesn't have to do with the "brutal" launch. It's in whatever you have the gears/converter setup to do.

Say a 3:55 gear with a tight converter would leave soft. A car with a 5:13 gear and a loose converter will rip the *** end out.

Vetal

iTrader: (3)

That's what they say in this thread. And that pre-loading transmission and suspension helps launch. I don't know that, that's why I'm asking

01ssreda4

iTrader: (96)

When I preload my rear suspension I cant get the car to sit down in the back when its time to go. If I give it a touch of gas, then roll into it, the rear will squat. With a mostly stock suspension you do not want to UNLOAD the rear suspension by getting up on the converter too much while waiting to go. It will usually yield negative results.

Vetal

iTrader: (3)

Does transbrake preload drivetrain / suspension any different?

SuperSlow02

iTrader: (16)

Its hard to say, I dont think it does as much as foot braking the car will. My Transbrake will "hit" a whole hell of a lot harder then foot braking the car.

chrs1313

iTrader: (24)

once you get the suspension upgraded and everything working right...my car loves to get stalled to the moon...I am even thinking of running dual calipers in the rear so I can cheat the stall some and stall it higher off the line

1.291...is the best so far, I really want a 1.28 haha

Vetal

iTrader: (3)

When autos footbrake I see that the back end "squats" before the launch, that tells me everything is preloaded. Do transbraked cars also squat when revving on the TB? I doubt it, cause driveline is not connected to converter in this case...