FASTFATBOY

iTrader: (23)

It AMAZES me still after all this time people just dont understand a drag race.

A drag race is all about the first 330 feet of the track, you want the car working as hard as it can to move as QUICK as it can across the first 330 feet.

A correctly stalled automatic car with traction will loose some RWHP through the converter but will be hugely more efficient in the first 330 feet of the track than a car with the stock or wrong converter.

Lets compare the typical 6 speed vs auto F body. Head cam car. The auto car will typically(when setup right) low 12's/high 11's at 110-112 mph, the stick car is stuck in the mid 12's at 112-115 mph, the reason.....the converter makes the automatic car 60 ft harder, 330 ft harder. The race is over right here.

A car like Gizmo's(NHRA stock eliminator car) is setup with the sole purpose of running the front half of the track(660 feet) as QUICK as it can. These cars have lower HP but ET like crazy. They are basically out of steam by the 1000 ft mark and will run in the 10's at 117-120 mph.

The moral of the story? ET wins races, not MPH at the end of the track.

96capricemgr

iTrader: (1)

A friend has a BBC first gen, just barely shy of the 600hp mark at the flywheel 500tq+ from 3500 till the test was ended somewhere north of 6000, was there for the dynoing, this is not an estimate or a happy dyno. 8" ATI which means it almost has to be north of 4500 stall. Alston rear suspension manual VB TH-400. 3.55s(for the street) 27" Hoosiers, the thing mauls the tires so badly he has to roll/feather into it and still moves the tire on the rim. Think it has gone 11.7 at 117mph, my car same track has done 11.5 at 116 despite more weight and less HP because I can hammer it off the line with my little motor and 3800 stall.

My friend is losing ET and MPH feathering the throttle on launch. If he puts the time in to making it launch it will be brutal and leave me far behind., but without that launch the car just does not ET

nighthawk15

Which is the exact point I tried to make in both of my posts.....and you just used a comparison that is almost identical to the one I used in my first post except I used AWD vs RWD instead of auto vs manual......either I worded my posts in some confusing way or you guys need to read a little closer. I dunno. The post you quoted was me trying to figure out how the hell my statement at the end of my first post didn't make sense to wicked. Maybe I need to not post late at night.....

djm_e22

iTrader: (2)

I wish people would not post unless they read everything. The tranmission guy is assuming he can get traction off the line because he said with the higher stall you want you will be faster off the line, but you will lose at the end of track. So your point is not valid since the transmission guy is expecting him to get traction. Now do you agree that the higher stall will win?

The reason I keep reasking is I am going to have my buddy read all this but alot of you keep saying "well if he can't get traction" but the transmission guy does think he can and he still tells him to get a 2500.

96capricemgr

iTrader: (1)

I do agree given traction more stall is better. My point with the post was that the first 60-330ft are ALL important to ET.

I know even on my car the converter is setup to hit hard, that costs me MPH but 1.53s and 11.5 out of an over 2 ton street car with a little motor says it WORKS.

GIZMO

iTrader: (8)

If you are building a drag car you need to optimize the stall. The peak torque number is a good place to start. Keep in mind that the cars weight and gearing will also change the stall, so that information is important too. A small change in stall can make a difference. That is why good converter companies offer a stall change when they sell you a converter. You need to gear the car to use the HP available at the finish line. Gearing in the transmission can be used to keep the motor in the right place betwean gear changes and to soften the launch. Ever notice how a lot of cars runniing the four speed automatics tend to pop the tires and then bog down a little? That is most likely due to having the wrong converter and way too much first gear (A straight drive is a different story).

GIZMO

iTrader: (8)

Getting traction is the result of having a good car with good tires. To get the best out of the motor you need to optimize the converter (and everything else). If you are going to use the converter to tame down the car you might as well put a smaller motor in it!

GIZMO

iTrader: (8)

You can have too much stall too.

96capricemgr

iTrader: (1)

Agreed but I think it pretty hard to do on the dual use cars most of us have. The fast bolton cars are using 34-3600 stalls.

I don't doubt my car could be quicker yet with 42-4500 stall just not sure about that on the street.

djm_e22

iTrader: (2)

Yes I told him he needs to pick his gear and tire size based on what he should mph through the traps then tell the converter builder to make a 4000 stall(his peak torque is at 4400) by giving the converter builder his gear size, tire size, weight, and etc. I also said the converter guy should give you a restall if needs be. I even told my buddy why don't you ask a converter builder what he thinks instead of his tranmission guy.

Agreed!

I already told him this to. If he went with a 5500 stall he would probably lose all kinds of horsepower through too much heat and too much slip. But I never told him to go that high. So agreed as well!

96capricemgr

iTrader: (1)

My old converter lost 300rpms of stall when I put the bigger heads and cam on probably compromising torque a little around that rpm and gave it 4.10s instead of 3.73s, so yeah make sure to give the converter guys accurate info.

SS MPSTR

iTrader: (1)

This.

Puck

iTrader: (17)

A lot of people assume that a 4K stall that works great in a smallblock that spins to 7K with a 4l60e will still be the best choice for a BBC that only spins to 5.5K with a th400...plus makes a **** ton more tq off idle then the smallblock does peak .

djm_e22

iTrader: (2)

So your telling me even though he makes 75 less lbs of torque at 2500rpms compared to 4400rpms that he will be quicker in the quarter with a 2500 stall compared to a 4000 stall. Please explain.

Puck

iTrader: (17)

Please tell me where I said that.

PS: I was the first in the thread to say that a good place to start to find the proper stall speed, when everything else is accounted for, is around 500rpm below peak tq. There is a lot more to it then that though, but everyone loves to swear by the simplified A+b=c internet formulas(you need xxx rwhp to run xx.x, you need a 2xx duration cam to make xxx hp, you need xxx cubes to make xxx tq, you need xxx gears in xxx style transmission, xxx rear end can only hold xxx hp...etc, etc, etc) that they forget that every car is different, and there is not a magic formula that will make a car faster or quicker - which, as said in this thread, are two different things.

Again, what works in our little 400rwhp smallblocks with their peaky power curves may not be the best bet for a big BBC with broad curves and a lot less rpm to play with.

Not sure what you are asking for in this thread anyway, there are really only two answers:

1. The guy doesnt know wtf he is talking about
2. He knows something about the car or combo that we don't(rpm range, gearing, suspension, weight, etc).

fasteddie94

iTrader: (2)

I't trying to figure out what traction has to do with anything. You can't assume this guy does or doesn't have traction and when choosing a converter this shouldn't even be worried about.

He needs to contact people that build converters and give them his full setup. Weight, TQ, gears, trans, everything. When the proper converter is chosen then he needs to worry about traction.

If you are going to build a car, make it do what you want.

djm_e22

iTrader: (2)

My buddys car has no seats, no steering wheel, no anything. So they have no idea how much it weighs. Matter of fact he hasn't even chose his gears yet. He just has a 460 ready to go in a old 58 truck that has nothing in it. The transmission guy just simply said that a tigher or lower stall will win because a higher stall helps on take off but takes to much horsepower so you will lose at the end of the track.

Besides what does gearing and weight have to do with what stall you choose? You choose your stall according to where your peak torque and of course if it is close to a drag only car you would want it very close to peak torque. Then you give the converter builder your gearing, weight, etc that way he builds it correctly so that it will stall at your requested stall or the recommended stall. Why would the gearing and weight of your car tell you to get a stall that is not close to your peak torque? I feel gearing and tire selection with knowing the weight of the car is chosen based on what you think you can mph through the traps and not what stall you should choose.

RamAir95TA

iTrader: (2)

Sounds like you have it all figured out then.

jaycenk

iTrader: (1)

Horsepower is the measurement of torque over time. To many people base their crap off of hp numbers. You look at the entire torque curve and hp curve to determine the stall speed.
What I haven't seen are the rest of the numbers. So it makes what ever for HP and torque at what ever. None of that **** tells the story. That freakin thing could have a torque curve that falls flat on its face at 4500 for all you have told us. I don't know how ANYONE is having a legitimate argument on this topic at this point. You know nothing of the rest of the story. How in the funkiddydooda do you come up with a suggestion based on a couple tid bits of info for THE BEST RESULTS?
Show a dyno chart for the best stall pick.

Wicked94Z

iTrader: (26)

why does my buddy run a 7200 converter in a bbc with a 6000ish torque peak? Well he runs a glide with a steep gear, and the shift extension was killing him with a 6200 converter. But OMG he's wasting all that peak torque!!!! No he's making a lot more average hp now, and even though he has to spin it another 300 rpm past peak where power was falling off, he still trapped 1 mph more with the converter change, and his 60 improved .08 in worse weather. Trans, tire, gear, weight, powerband, shift rpm all play different roles in converter selection, which is a lot more complicated that most on this site realize. That's why i paid the big bucks for a custom converter and let the pro's do it for me, gotta pay to play.