Here is a snippet from the Yank Converters FAQ,

What will a higher stall torque converter do for my car?

A higher stall torque converter will multiply the torque of your engine to put more power and torque to the tires! The high stall torque converter will "slip" the engine into a higher rpm range where there is more torque and horsepower. This will make your car haul ***!

What kind of performance gains will I see with a high stall torque converter?

Our customers typically see a .5 reduction in quarter mile times, traction permitting. Highly modified cars with ported heads and bigger cams have seen gains of over 1 second!

 

you missed somthing on #2.


a high stall allows the motor to stay at its peak HP for a longer peroid of time... meaning that if you were to graph the power going to the ground, the auto car would have more area under the curve then the manual car.


THATS technical.
what you said is a basic assumpsion without considering both sides.



it comes down to this: the manual never changes, and the auto can be optimized for drag racing.

i think me and zepher are in the same boat.... we love our manuals, but we're also being realistic and not taking sides...

so if any of you want to jump your respective ship (auto or manual) then we'll be more then happy to pull you aboard... we're sailing to reality.

 

Whats your local track? Cecil, Atco, Englishtown?

I'm asking because I've been to all. Only the slower street cars run manuals - and on test and tune nights. Go to the track some other time like during a heads up race. Where consistency goes out the window and its the quickest car that wins. Report back how many manuals you find... Also, ask around why no one runs a manual transmission because they're quicker, and you'll get a bunch of weird looks, a few laughs, and a couple guys who will just ignore you completely.

Anyone who claims a manual trans is quicker in a drag race doesn't have a clue what a high stall torque converter does. STOP REFERRING TO STOCK LOW STALL CONVERTERS!

 

Cecil is my local track.

There's a guy there with a white 5.0 that runs a Tremec and consistenly runs mid 10s. Another guy runs a red Nova with a T-10 and runs mid 11s. Yet another guy runs a '95 Cobra and clips high 12s a lot. Those are just the guys I know personally. Lots of domestic cars run autos, but the vast majority of the import guys run manuals. Since they make up about half to a third of the crowd you can't just laugh that off anymore, especially since plenty of them are running some quick times now.

Observations are sort of like opinions and @$$holes. Everyone has them and they all stink. You can look around and see exactly what you want to see, and I can do the same. None of that proves anything, so I chose not to accept my assignment Mr. Phelps, since graduating from college a half decade ago I don't plan on doing any more homework for anyone other than myself.

I'm not referring to stock low stall converters. Please read the information in the posts that I took the time to write instead of just trying to assert your opinions in an attempt to achieve alpha dog status.

BTW, a bone stock WRX STi consistently cuts 1.65 60fts on stock street tires, and runs 12.96 @ 106. The car isn't even avialble with an auto.

What Mr. Dude said about area under the curve with the auto is 100% true. That's where you see the torque multiplication (fatter torque curve), but even given that fact the auto eats up more power parasitically, so in the end the cars come out about equal. The stick car still weighs less statically though, which should translate into quicker ETs given the ability to hook the car up.

FYI, I'm not saying that people need to take sides, or that autos are junk and manuals rule. I like my manuals, as do a lot of other people. I also like an auto under certain circumstances (mud bog racing and rockcrawling come to mind, as well as more mundane tasks like towing). I do know this though, this thread has done the typical downward spiral that is inevitable with any question like this one. It's only a matter of time before we all start resorting to name calling and start saying stuff like my dad can beat up your dad.

 

manuals shift more consistantly ( takes same ammount of time to shift, every time since its computer controlled )

manuals way less, one extra gear , allows higher rear end gears.

 

o_O for "consistantly" im sure you MENT to put Autos right?


they can WEIGH less. but like you said, they need a higher rear end ratio to make up for the smaller TQ curve, and you have to shift one more time.


meaning if you take a pig heavy manual (like a T56) and assuming that you have superhuman powers to shift perfectly everytime, you still have to shift one more time, and even then your total power going to the ground is less then a auto.



this is why they came up with a way to attach a torque converter to a lenco. best of both worlds...... athough you kinda have to wonder how manual it really is when it has a converter and a air shifter starts moving the levers too....

 

A trip to ELD or Heffners Performance (local Mustang specialty shops) would make the Mustang owner think twice about the manual. After he talked to dozens of others who have "been there done that" and went nearly a full second quicker with the auto he would switch over. Regardless of the combo, a mid 10 second manual Fox is a high 9 second auto car.

If you want I'll send up a coworkers son who owns a 91 Mustang with a H/C/I/E with a 9psi intercooled Vortech 302. He HAD a Tremec TKO in it with 3.73 gears. Car was good for mid 11s on slicks, professionally driven. After the pro driver (owns a high 7 second Outlaw Mustang) convinced him to switch to an auto with a matching ATI converter, the car went low 10s.

Everytime a built Mustang rolls into our shop, the owner of the afore mentioned Outlaw car rolls his eyes and states:

"It makes good power, but its got a trans problem"
"What? There's nothing wrong with the trans, its a Tremec"
"Exactly. Its a manual. You'd be a TON quicker with an auto"

Thats when they begin to argue and in the end, the owner will switch to the auto 9 times out of 10. The 1 owner who doesn't still can't figure out why all these slushboxes are spanking him at the track. Some people just never learn.

And don't you dare defend the use of a manual by saying the imports use manual transmissions. THEY HAVE TO! No one makes quality high stall converters for the auto cars...

The REALLY fast imports all use autos.

 

on the flip side, in a DIFFRENT SPORT, most of the other forms of racing, from club racing, to openwheel, to ORR, to (ugh) NASCAR, use manuals.

so you dont discount them completely.... but from a drag racing point of view, a auto is a more efficent way to get down the track.

 

Actually, the really Fast Imports, like the Supra, switch to a GM TH350 or 400 with a nice stall.

 

on a TOTALLY un dragracing related note..


i know one with a T56..





but yea, you are correct, the drag racing supra crown do put autos in. :lala:

 

You know, something occurred to me. The whole this car did that and that car did this stuff is a waste of time. I'm sure that every guy can can find a guy that switched from a stick to an auto and went faster, and on the flip side find a guy that went from an auto to a stick and went faster. None of that proves anything. Each car needs to be evaluated on a case by case bassis, and that would take up a libray worth of technical reports. I don't have that kind of time, and frankly I don't care.

When I'm running at the track I'll be driving a stick, and I don't care what anyone thinks of that. I do it because I love it, and ultimately that's all that matters.

 

I will conceede that point about the super fast imports running autos. The worlds fastest WRX runs an auto, as does the world's fastest RX-7, and a lot of others, but again I think this is due to two reasons.

One these cars are race cars, so consistency is of paramount importance. These guys are out to win.

Two, a lot of these cars are making upwards of 1,200 HP, which is about the limit of even the toughest manual trans. After that you need the strength that can only be found in planetary gearsets, which are brutally strong when properly built. All those monster trucks run planetary axels for the same reason. Durability also wins races.

Side note, my buddy now wants to swap a T56 into his '95 Lightening. That new Ram SRT-10 has one, so he figures why can't he. There's already a Ford Aftermarket T56, and you could get a stick in a '95 F150, so it shouldn't be too tough of a swap. It will definately be cool though. Sticks in stuff that never came with them are really cool. I saw a Lincoln with a Tremec once, course it also had an ATI blower!

 

It's not consitentcy they want, it's pure speed since pro drag racing is heads up, ie. first one to the finish line wins.

 

Yes, I too gained two tenths in the quarter mile by going to a T-5, but I lost .1-.2 tenths on my 60 foot. I also gained 6.5 mph. Same tuning on motor, same everything, tires etc. I only have a 12 sec car though, and I do miss shifts from time to time and my 700 was rock solid consistant with a KILLER launch, 2.0 on 235 streets!! I used to beat people with DR's all the time off the launch, now I just spin all crazy.

If the 700 had the same ratios as a T-5 (T56)
2.95
1.95
1.34
1.00

then I say my auto would kill my T-5 in a race, I just switched cause my auto was dying and 1st to 2nd gear is a HUGE drop in the auto(3.06 to 1.64!!) that's almost like going from 1st to 3rd in the T-5/56.

If two street cars raced with the same tires and motors and suspension, AND the same launch points(IE one guy has a stall that grabs at 2500 and the other guy in the T-56 launches at 2500) the T-56 will win in the quarter assuming the guy shifts decent.

True the auto shifts faster, but while the 700 1-2 shift drops the revs from say 6000 redline to 3500, the T-56 guy's revs only drop to 4500 and he reaches his redline in second and possibly third by the time the 700 redlines second.

 

No it won't, the auto will win.

 

At this point Zepher, it's pointless to argue any longer. It's obvious that no matter what facts and tech info are stated certain people will never believe an auto is faster no matter what. Hopefully this thread has been helpful to others in finding out the truth about how autos are better in just about every category for drag racing. For those with too much pride to admit it, just sit back and smirk, because we all know who wins at the track.

 

Well, im definatley not saying an auto will make the car faster, but im pretty sure its a fact that a shift kit auto vehicle will always shift faster and I believe its just humanly impossible to shift faster than a raced out auto. Im a stick guy and never owned an auto vehicle my whole life, however, i'll see you later around those turns .

 

It's not about how fast the tranny shifts, but how the converter multiplies the torque and keeps the engine in the peak powerband through the entire run.

 

a good driver who can keep a manual near redline shifts, will put a hurting on any auto

If i was going to race road coarse. i want a manual, down shift drift through your turns , you rpm is still high , shift up and be gone

if i was to drag , air shifter, 1 bam 2 bam, race over you win

 

by the way anyone seen the new twin clucth trannys about to hit all the car makers, audi allready has one in there new cars

its basically the same setup as a indy car, fun of a manual, speed of a auto shifting

frist clucth ingauges 1,3,5 gear while the other clucth does 2,4,6 gear

so there is seemless shifting but still gives you the powerband controll on shifts. its a pretty sweet tranny.

 

Once again, I go back to the origional post-what are his plans for the car. If it is purely for drag racing, then by all means, go auto with a very high stall. He will stay at peak power and make more consistent, and better times with the perfectly matched converter.

BUT, considering he origionally mentioned being traffic friendly-thus allowing me to assume it will be more than a drag only car, a high stall is out of the question. 25THRSS may have a very 'streetable combo', but chances are the average person with a 4,000 stall will not. High stalls w/ lockup don't exactly have the best reputation for surviving-shoot, my buddy's '91 z is proof of that.

Appearently, technical is too complicated to understand. So I will try to re-explain the whole extra gear is good thing.

Even if you have the perfect torque converter, transmission gearing will still hurt you. For example, you accel better in 2nd gear than you do in 3rd, correct? Even if you are at your peak power in 3rd the entire time, you will go faster in 2nd at peak power because of gearing. Well the same is true for a manual!!!! Except you have one more gear to go through, thus giving an edge. I would hope you would agree with me that you would make better times with a beefed up 700r than a 2speed power glide in a 350hp car. And why would you agree? because the 700r has 3 gears as opposed to 2, thus making for smoother transitions and better accel because it has a "middle" gear. So now do the math and see where I am going with this in reference to the 6 speed manual.....

Another example would be as simple as a bicycle. Assume you put max effort into both tries. First you put it in 18th speed and race it. Next race however, you start in 9th speed, then shift into 18th. Which will out accelerate? The ladder one. Why? Because of the extra gear used.

Ideally, a 5 speed auto would put this whole issue to rest, as given the right torque converter, would tear the average driver apart in an equal stick car, because each has 4 racing gears, but the auto has precise shifts, and perfect control over the power band. But that is not a very realistic option for us.

Once again, in response to the origional topic, a t-56 would be better and yield quicker times for his combo, and retain complete streetablity.

BTW, you guys that only see autos at the track need to venture out a little......I have seen many 5 speed GTs run consistent 11's cutting 1.5 60's. My friend's '93 GT cut's 1.4's, given many suspention mods, but it's still with a 5-speed and spec clutch. Sure, 3rd gen f-bodies may have auto as a more popular option at the track, but you have to realize something like 80% of all 3rd gens came auto from the factory

 

We aren't saying that manuals are slow, what we are saying is that putting an auto with high stall into your manual car will make your car faster than it was in a straight line.

 

Somehow they all got stuck on this stock converter and consistency thing. I've been pounding the heads-up thing. They still don't get it

BTW - the EVEN FASTER Supras use the GM based Powerglide. To all the auto haters that a "horribly geared" 2 speed auto.

 

if we raced bikes, id win..

while you're shifting thru all of your 18 gears, i'll be starting out in a harder to push, but lower gear, and use toe clips so i can pull and push.

thereby multiplying my TQ, and starting out just as fast.... without shifting.

i will then continue with my extra TQ by pushing AND pulling, and winning the race.

even though i have the extra weight of the toe clips.

 

Actually a CV transmission would be the best option (constantly variable) because the motor stays rigth in the powerband all the time. There are no shifts. A belt slides up and down two sets of bevel plates. Snowmobiles run these systems. Honda experimented with one in a car years ago, but could never seem to get it worked out.

In truth in high powered cars a powerglide is often the best choice because it only has to shift once. You lose time during every shift regardless of whether it's an auto or a manual. You need to gear the car steeper to run the glide because the 1st gear isn't very tall. A 'glide is also very light and mechanically simple (fewer parts to break).

I've got a buddy that has a '92 Firebird that runs consistent 8.90s with a glide. I can't see it going faster with anything else. We are talking about a totally unstreetable, dedicated race car though.

 

Thus why I said I would only shift through two gears....not 18 I was trying to relate to the one extra gear in a manual. Simple as that. And yes, in a 9 second car, that extra shift can mean a lot, but in a 12-13 second street car it will be minimal (mostly having to do with traction and launch). I don't know how long it takes you guys to shift a stick, but my nose never lowers when I race. Short throw shifters do wonders.

Also, you are insanely wrong by saying you would start out just as fast starting in 18th speed.......simple physics can tell you just how incorrect that is.
But just to put it in a car related thought, you have basically just said that starting in 3rd gear would yield the same accel as starting in 1st.

I think you mis understand "multiplying" torque. A 400 lbs/tq motor will only put out that much torque. Period. Just because you have a high stall, you do not get "toe clip" effects. In relation to the bike, torque equals the push you can put on the pedals-which would translate to a flat torque curve. So in other words, torque is consistent through the pedal rpms in both situations. Back to a car, you get is a constant 400lbs/tq from 0 mph to whatever the stall rpm will bring you to mph wise in first, assuming the converter is perfectly matched. And don't get me wrong, that is awesome, and excellent. But 400lbs/tq in a 1:1 ratio will not out accel a 380lbs/tq average in a 3:1 ratio. Now take that to a larger level and put it into relation to the tranny, and you will realize why the extra gear is beneficial.

Like TKO mentioned, a cv tranny would work the best because you stay at max power WHILE having optimal "gear" ratio. With that idea in mind, try to see why a close gear ratio is beneficial. Also keep in mind, I am only talking 1 extra shift, not 18. And say what you want about the time it takes to shift a manual. If you want to go there, then just use a short throw and powershift if you must, and if that still doesn't work for ya, well............

 

you have it backwards.
on a slower car, more gears are important... as your power increases to insane levels, you dont need the as many gears..
thats why most ultra fast cars run 'glides... because if you geared them for more power out of the hole, theyd just roast teh slicks.





im damn quick with it if i do say so myself. but that has zero to do with the concept im trying to show you.

forget shifting for a min... think ONLY about the power in the way it hits the ground.



now as you already probly know, the amount of TQ the engine makes has nothing to do with the TQ that the tires see on the pavement. theres the gearing in the trans and rear end that can change that. so in a low gear, your car may be putting, say 400ftlbs to the ground, but in a high gear, only 200..

right now, we're thinking mechanical... one turn of the motor, makes one turn of the trans input shaft.
this in turn goes thru the gearbox, out to the rear, then thru the axles and tires... right?

now what if we spun the engine 2 times for every one turn of the trans input shaft? this would be like a gear set between the trans and motor. you would be making more torque go into the trans, and that higher TQ gets multiplied by the gearset in the trans... then thru the axle... with me?

this is the magic of TQ converters... you see the constant volicity trans (aka constantly variable) that TKOPerformance mentioned above? its kinda like that.


a nice loose racing converter will let the engine spin at 5000+rpm just after launch... but the car will sound like you're slipping the clutch... because the motors engine speed is almost constant.... its staying right in its powerband and making peak power.... the trans is trying to catch up...

for as long as there is a diff between the two, the TQ converter is like a extra gearset thats not only multiplying the power, but changing its ratio constantly to keep the motor in its peak power.. even if the car isnt going fast enough yet to keep up with the motor.

example... pretend this motors peak power is at 5500.

in a manual you launch at 3500, and pull the car thru 4000, 4500,5000,5500,6000 (shift), 5000, 5500,6000, (shift).. ect...

in a performance auto, you launch at 4000 (or however high you can stall it) lets say 4000... instantly the second you launch, the motor shoots to.. 5350, then 5400.. then 5450 then 5450..... 5450...5500..... it just kinda hangs right there at the peak.







physics can be deciving.
i'll give you a 4x4 with a ultra granny gear and 4.50 diffs.
first thing you'll have to do, is shift at 15mph.

this is my point.. (granted, i didnt make it too clear).

if you have the TQ to pull a higher gear and accelerate just as fast, then do so, and you will go faster. my fat *** on one bike pedal will shove it down in the highest speed that bike has... im just putting that much weight on it.

so while you're at high RPM (think pedaling as fast as your legs will move) i just stood on the pedal, it went down, and im already going pretty quick (for a bicycle)

example of this would also be a standard normal 4cyl car vs a standard normal v8 car.

the gearing is totally diffrent... my moms toyota corolla has somthing like a 4.59(i think) diff gear in it... yet, it accelerates normal... i just have to do the 1-2 shift at around 35... meanwhile the V8 can probly get up to 60 in first without issue.. its geared much taller, but it will accelerate faster.... if you put the same gears as the 4cyl in... 1st would be almost useless... (much like 15 of the 18 gears on a 18 speed bike on level ground.)


i think i covered this above.

engine TQ doesnt change.. but tire to the road TQ changes.


being that i have to make everythign into a big dick contest, im jsut going to say, "i can probly shift it quicker then you... i can probly match downshifts better too.... "
im not knocking manuals... i love them. heck, i just swapped my auto car to one. just saying theres a place for everything.. and on the strip, the auto is better suited then the manual.
i didnt say more fun.
i didnt say it will always be faster in every case no matter what.
i said it was better suited.
it can be made to work better then the manual.

 

just happen to be reading this ENTIRE post and was wondering if anyone can tell me the different types of shifting when it comes to a standard..power, speed, granny?

 

umm, i THINK this is what your asking..


what is powershifting, speed shifting and granny shifting?



powershifting is when you just keep the gas pedal to the floor, you dont lift between shifts... usually you clutch JUST enough to pull it from a gear and shove it in the next.... done right its rough but not abusive...and the car just keeps accelerating... done wrong, it can frag a trans..

speed shifting... sometimes its use interchangably with powershifting.. athough othertimes, it can mean you're just shifting really fast... when i say it, im usually refering to lifting only partway and fully clutching, but doing it really fuggin fast..


granny shifting means you shift sloooow.... like my grandma.
same with granny gears... they're gears that are so low, you can walk faster.

 

oh ok thanks

 

I think that its possible that too many egos were hurt in this argument for us to ever come to a definitive conclusion. However, in my opinion, the manual is the faster transmission. I think too many people confuse fast with quick. Tearing through the 1/4 with a 140mph pass is FAST. Doing the quarter in 11 seconds is quick. Definately a difference. Anyway, the Manual will be FASTER, the auto will be QUICKER. I dont understand the argument here. No one can bang gears faster than an auto with a bitchin' shift kit. There are disadvantages too. An auto cant adjust itself for track conditions. This is just my opinion. I know, I know, opinions are like *******s.

 

Mr. Dude,

It is obvious we will not budge in our beliefs. You have explained your side well, but have you have also explained mine in a sense.

I say this because, as I have referenced in every post to this thread, the question is what will help his combo go the fastest. We don't know all that much, but what we do know is that he has a ZZ4 equivelant engine, so I assume around 350hp and 400lbs/tq, and a 3.23 rear end. The rear end is less of a factor because it can (and probably needs to) be changed. The engine however, is good for roughly a 13 second quarter at around 106-110mph.
Based on these numbers, most can consider them "slow" by drag terms, and thus making more gears important for his application. I think you may start to benefit from a 700r auto and high stall when in the mid 11s or so, and a power glide when you are running 10's or lower.
So hopefully that covers why I say a t-56 would be better in his application

Now, I am not going to argue with you as to why autos are better for sub 12 sec quarter miles, because you are right. Driver's skill cannot match the precision of an auto, not only in terms of shift speed, but the ability to hold peak torque on launches as you said. However at this point is where I will throw in an argument.

On a launch, autos with the proper stall are better. Simply because of this: say you have a 4,000 stall in an engine that makes 400lbs/tq at 4,000rpm, and 4,000 rpm takes you to 30mph. So this basically means that from 0-30mph, you have a consistent 400lbs/tq, and then after that you will make whatever power is in your torque curve past 4,000rpm. Simply put, even slipping the clutch will not allow that, thus making manuals "lesser" than autos while launching.

However, I still disagree with you on multiplyng torque. Reuse this example:

The T-56 has a 2.66/1.78/1.30/1.00/.74/.50 gear spread
The 700r on the other hand has 3.06/1.63/1.00/.7.

we'll assume the redline/pk hp is 5,500rpm (close to zz4 specs), and tire size is 12.5" radius. So this is how the shifts look:

700r4: 1st=41.4mph->shift into 2nd brings the rpms to 2,930. Pulling to 5,500rpm again=77.7mph-> shift into 3rd brings the rpms to 3,370. So basically, you are looking at dropping well over 2,000rpms with the auto

T-56: 1st=47.6mph-> shift into 2nd brings rpms to 3,680. Pulling to 5,500rpm=71.1mph-> shift into 3rd brings rpms to 4,020. Pulling to 5,500rpm=97.5 mph-> shift into 4th brings rpms to 4,230. So basically, you are much closer to your peak hp with the t-56, thus making your average hp throughout the quarter higher than that of the 700r4.

For the purpose of the next example, I use engine rpm lower than the stall is only to reference the time it will take the auto tranny to spin the same speed as the tq converter/engine. I understand that with a 4kstall, the engine will not see less than that while racing.

Ok so now we both go to shift into 2nd, the auto drops down to under 3,000 rpm. That will mean 400lbs of tq from 3,000 to 4,000 rpm, and then hp will take over until 5.5k. However when I shift the t-56, I am only 300rpm from my peak tq, which means that it would be around 390 or so. not bad. Then hp takes over until 5.5k
So looking at it closer, you are making 400lbs of tq in a 1.63 ratio, where as I am making 390 in a 1.78 ratio. Consider we can assume more drivetrain loss with the auto (to equal the torque outputs for example), the 1.78 ratio WILL accel faster.
So now I have out accelled you in second, I shift into third, and it puts me right at 4,000rpm and I am able to accel perfectly through my desired powerband (pk tq to peak hp) in a 1.3 ratio.

Mean while you shift into 3rd bringing rpms to 3,370. Thats still 600 rpm from pk tq. So for 600 rpm, you are at peak torque, until you xross over the 4k mark and let hp take over.
During this time, I shift into 4th at 4,200rpm, still very close to pk tq and in my power band and finish the race.

The point I am trying to make is that it is more than just pk tq you want when you race. As I have always been told and have followed is the strongest part of your powerband is peak torque to peak horse power. And the t-56 fits the example well, and I would say the example yields a pretty realistic setup. You shift into peak tq and go to pk hp and do it all over again in the next gear, where as with the 700r4 you shift into peak torque, but are "stuck" at it until your tranny gear catches up and the stall locks up, all while in a lesser gearing, thus, as you put, making for less torque to the wheels because of the gearing

Hopefully all of that makes sense, in that other than the launch side of the house, the t-56 WILL allow you to shift into peak torque, be in a better gear ratio, and thus, allow more torque to the ground as you put it. No need to multiply anything because you are already there.

Considering launching is what makes or breaks your times, it all comes down to how well you can launch a stick. In a 10 sec car, it would be very hard, but in a 13 sec car it only takes a little practice. So what I am saying here is that you have to weigh which will be more beneficial for your application-better gearing for better accel after launch, or a better launch, but loss of gearing advantage.


Oh yeah, btw MR Dude, it's not a bigger d!(k contest. I could care less if you are Dirk Diggler, have 20 ladies, are a millionaire, and must be right all the time. But what I do care about is intellegent conversation-as I am pretty sure that's what these boards are intended for. And trying to tell me you can out accelorate me in a 1:1 ratio, while I'm in a 2:1 ratio with the same engine out put is just insane to me, especially with the facts and numbers I have laid out. I may or may not be right. No big deal. We may both be right and wrong on different points. That is fine. But keep your temper down man, I'm not trying to get under your skin or make you defensive, just talking cars is all.

 

r90camarors-

I have to agree with you on the gearing part of the equation. The only problem is you forgot about the torque converter part of it. When the 700r4 shifts into 2nd with a 3,000+ stall converter the engine will still be turning 4,000+ rpm same as with the T-56. Basically with an auto the more stall speed you have the more the converter will multiply the torque not to mention at the higher rpm the engine will make more power. Another thing that wasn't mentioned is that if you have a large, flat torque curve you don't have to worry about keeping the rpm as close as possible during shifts. In other words you can accelerate the car in a taller gear with less shifts which will make your car quicker. The stick shift will run to a higher speed in the traps though. But what does that really matter if the auto beats you to the traps. For a street car use your preference. I will tell you that in the dallas area it is just a pain in the neck to drive a stick car daily. Stop and go traffic is terrible especially with a performance clutch. Everytime you get rolling you have to stop again which causes clutches to have a fairly short life (around he 50,000 mile mark), where an auto (if kept cool) will easily last 200,000 miles without being touched even then they usually only need a $100.00-$200.00 dollar rebuild kit versus a clutch every 50,000 miles. By the way I am not here to tell anybody what to do, but just inform you of my opinons. For a daily driver and a strip only car I would use an auto, but for a weekend cruiser and for fun car I would certainly have a stick.

 

im in a dilema now....
end of this week i was planning on buying a T56 conversion for my 91 Z. this car is a never ending project and as we speak a custom 383 stroker is being built that will support 900 HP (wont put that out N/A but with the blower....) anyways, i def love the 6 spd and with my 4.10 gears it would be nasty but i want a qrtr mile car that can also be driven on the highway...and i plan to keep my gear ratio. the only possible aut tranny i can get to take this abuse is a TH350 or 400 but they are only 3 speeds so wouldnt that kill me on the highway?

the other thing is i consider myself and so do my friends that im a pretty damn good driver when it comes to shifting. one day after driving my friends BMW M3 i memorized the sound of the engines RPM for the perfect shift at WOT, it is prob a few milla seconds before the rev limiter kicks in so i would call that pretty damn good as i want to get all the speed out of every gear i can. considering my car has all top quality aftermarket suspension work and slicks, is it possible (not saying im the best shifter around) to get running in the 9s with a 6 speed? i just want to know if this is possible or is anyone has ever done it in any type of 6 speed car?

 

The t56 won't handle 900 hp. You're gonna have to go aftermarket for sure.

 

t56 is not stock has twin disk Mcleod clutch...supposed to handle over 1000HP

 

maybe the clutch will, I dunno, but the t56 won't.

 

The richmond 6spd only supports like 450 ft/lbs so basically you need an old 4spd like a muncie or a built up auto. A T-56 can easily be killed by a LT-1 putting out 330 ft/lbs. A viper T-56 can hold about 450 ft/lbs but that is about it.

 

Wrong, the 93 T-56s only could handle 330 lbs, actually think it was 350, the ones beyond that could handle 450lbs stock.

 

That may be so, but he's talking 900-1000 hp here. That's slightly exceeding the t56's rated power, lol. He should prolly look into a built th400 or if he wants overdrive I think the 200r4 can handle more power than the 700r4 when properly built, plus he'll be faster than a manual too.

 

Yea, I think if your going 900+, its time to switch.

 

your talking about how much a STOCK T56 can support because those are the exact numbers. now a built T56 i know can take abuse as theres a Venom around hear that has the old 800 Twin Turbo kit so its laying down like 690HP and 720 RWTQ and it is a 6 speed. THEN, theres is a 99 LS1 with 660RWHP and a T56 but he does want an auto just to be more consistant. and finally there is a
'98 Formula Firebird

120,000 miles (One Hundred and Twenty-Thousand Miles)

Hardtop

6 speed 725RWHP check this baby out www.ls1motorsports.com

so i know that T56 can be made to handle this type of power and i will not be running 900HP thats just what the engine is built to support ill be around 700-750RWHP

anyways i wouldnt mind a auto as long as it wont kill my car on the highway and it can support my type of power without blowing. i know no one makes any 700r4's with this ability so what else are there that wont destroy me on the highway?

 

The strongest T-56 I have found so far is at D&D Performance It is rated at 500 ft/lbs of torque and very reasonably priced. There are probably stronger ones out there though....or maybe it's kinda like this thread has discussed, in that after the 500lbs of tq mark, people are more likely to use an auto for the reasons discussed above.

Fast 305,
I probably should have worded it better, but I explained this:

"For the purpose of the next example, I use engine rpm lower than the stall only to reference the time it will take the auto tranny to spin the same speed as the tq converter/engine. I understand that with a 4kstall, the engine will not see less than that while racing."


You are completely right about the flat torque curve though. But hp does play an important part in it as well, and being in the highest level of torque in a lesser gearing may or may not beat out hp at a higher gearing. At that point, I think it's really dependant on your power band.

 

If you are seriously looking at that much power, then I would have to imagine you're going to need to run a lower (numerically speaking) rear end gear if you ever want traction. In this case an auto would be fine for the highway (given a lockup converter) and probably better all around. What is the engine's redline? Peak tq? What kinda induction?

You may actually hurt your highway goals by going with a t-56, because with a .5 ratio overdrive in 6th, your highway cruising rpms may be to low, given the rear end ratio you need to run if you want to trap near redline in 4th in the quarter.

 

r90camarors,
Your right about the gearing thing, in reference to the input shaft of the transmission. The input shaft of the transmission will drop to that rpm but the engine will stay at or above the stall speed. The difference in the two speeds is what causes the torque multiplication though.


Your also right about the horsepower part. What I meant is you want to get as much power as possible through a large band thoug you still need HP. A diesel has a flat torque curve but isn't going to accelerate very fast because it doesn't have any high speed horsepower. What the diesel will do is get the vehicle off the line and keep it going. The gas engine is better at accelerating a given load. That is what I consider the two extremes of HP and TQ.

 

I agree, and it's true!

Even a Viper T-56 won't handle that! You have to either
get an aftermarket 6 speed ( Richmond ) or somehow
have the F body T-56 totally modified ( BIG bucks either way!)

 

a guy i know was in GM tech 2 months back with a white 2x turbo ls1 z28. hes gone through 3 t-56s so who ever says they are putting down 600+ to the wheels on a t-56 isnt telling the whole truth. sorry but a stock t56 wont handle it for long

 

i know a guy from michigan with a supercharged 5.0, he switched to a done up c4 from a stick, he told me that the year before he would never run an auto, now he tried one in it he loves it, he spit 2 rear ends out launching the thing on slicks at 4500 rpm... with the 5 speed,so here is another factor the autos do not shock the crap out of your crank and driveline as harsh as dumping your clutch, i have a 10 second auto, i ran a guy in a mustang 5 speed this summer that had wheels in the air launch, better 60 foot time and i beat him by over .5 second...so 60 foot time isn't everything..now i am going to turbo 400 cause there isn't much home of a t56 holding up behind a 615 big block is there???

 

i seriously doubt it lol you can ship the t-56 to my house, thanks

 

That is the exact opposite of what has been said the entire thread. The only reason you beat him is because either he didn't know how to shift, you had more power, or he wasn't geared properly. Given all else equal, an auto WITH proper converter/suspension should always have a better 60' time than a manual. And I can't see somebody losing half a second plus in shifting a manual, either.

The reasons for going with an auto for drag isn't because people are worried about shocking the drivetrain. Most people with 10 second power have already upgraded cranks and rearends........The faster you go, there is less room for error, and thats why autos are good for the situation. A converter in your torque range is much easier and precise to launch as opposed to launching a clutch