Question about racing an automatic car.

[Iron Woode]

Automatics are more consistent than manuals. This is why they are better in Bracket racing classes where consistency is important.

Nothing wrong with torque convertors. Get a higher stall convertor if your auto isn't fast enough in the quarter or if you need a harder launch.

Want a real hard launch? Get a trans-brake instead of a line-lock.

Some cars have a real big variance in performance when going from auto to manual. Like the old 5.0 mustangs. Autos were horribly slow (high 15 - low 16 sec quarters) and the manuals would be mid 14 - low 15s in the quarter.

In the old days (the 60s and early 70s) autos ruled because they could launch high powered cars with less traction problems.

2 speed autos are still very common in racing today.

Of course I could care less about any FWD cars.

jjessico: i go to many mopar sites. Mopars rule!

 

[jjessico]

Iron: You're right on in your assement. Mopar or no car(for the most part anyways, heeh). Gotta love the classic Mopar v8s slamming through 727s or 904s into 8.75" or Dana 60. Its amazing they could build drive trains to take the abuse those monster motors put out.

Jason

 

[jteef]

Originally posted by: MajesticMoose

Originally posted by: ndee
why are autos slower then manuals (expect the start that you can't rev it)? Can't they be "programmed" to have the perfect shift-timing? Better then any human can ever do?

They are slow because they use a torque converter instead of clutch. That's why some cars are now using a combination or the two; clutch to minimize power loss and somewhat automatic shifting(you still have to tell it to do it

Who is using this setup now? Just Ferarri & BMW still? The SMG gearboxes are elite. Don't torque converters just simply waste power?

jt

 

[Noriaki]

Don't forget driver skill...

Even if you have a setup where the Manual is Faster than the Auto with a pro driver...most drivers couldn't shift a manual fast enough to come anywhere near their own time in an Auto.

I won't rehash, but Manual is not always faster than an Auto. All generalizations are wrong ( ).

There are some Autos that can perform as well as any pro driver with a manual. But particularly in the hands of an Amatuer driver, he probably can't shift fast enough to make his Manual as fast as an Auto.

 

[Ultima]

Originally posted by: Desslok

Originally posted by: Techie333
Well....when ur racing an automatic car....is it better to just floor it and let the engine do the shifting or when say u get around 4000 rpms.....should u release the pedal so it changes the gears real quick?

If it is unmodded that sound you will be hearing is your tranny gernading itself if you just drop it in at 4k.

Naa.. my friend did that many times with his tempo and while the tranny got sort of fvcked it still worked..

if you want you can do a brake stand launch. Have it in drive, then step on the gas and brake at the same time. When you're at 3rpm or so let go of the brake.

 

[MiataGirl]

Originally posted by: ndee
why are autos slower then manuals (expect the start that you can't rev it)? Can't they be "programmed" to have the perfect shift-timing? Better then any human can ever do?

As people have mentioned..the torque converter attributes to this..but also gear ratios. A manual typically has 5 speeds while the auto equivalent has 4. The manual can afford to have wider gear ratios as a result, making it faster.

 

[Mill]

Originally posted by: MiataGirl
the best way would be to replace it with a manual gearbox

but really, if you want the best start possible, hold down your brake, rev up your engine, and release the brake. and if you car has a good amount of power (i.e. you get lots of wheel spin if you floor it), give it just enough gas so that you get traction then floor it.

Wrong. I need some evidence to back up why you would recommend to change to a manual when we are talking about DRAG RACING!

 

[jjessico]

Keep in mind that the gears inside the 4 or 5 speed manual are different than those inside a 3 speed auto. This means that to attain a similar launch with similar power a 4 or 5 speed manual will need higher(numericaly speaking) gears than the automatic transmissions(in most cases). This means a 3spd auto vs a 5spd manual, each car having 3.55(arbitrary) in the rear, the 3spd will be quicker of the line. However you are right in that the manual with more gears will have a higher top end. Of course top end doesn't win races.

Jason

 

[jjessico]

Agreed. Automatics are the way to go for drag racing. Most stock muscle car trannies w/shift kit can compare to manuals. Built up autos are even better, consistent and wicked fast.

Jason

 

[Mill]

Originally posted by: MiataGirl

Originally posted by: ndee
why are autos slower then manuals (expect the start that you can't rev it)? Can't they be "programmed" to have the perfect shift-timing? Better then any human can ever do?

As people have mentioned..the torque converter attributes to this..but also gear ratios. A manual typically has 5 speeds while the auto equivalent has 4. The manual can afford to have wider gear ratios as a result, making it faster.

Wider gear ratios would give it a higher top speed but not a quicker 1/4 mile time. You statement is inaccurate. Torque convertor is not a negative aspect to an automatic transmission and I don't know what asshat told you that. Typically a good torque convertor can help you make much more torque, shift better, allow you to "stall", and other various goodies.

What is with idiots who come out of the woodwork in automatic/manual transmission threads. I forgot that only a select group of us are mechanics or have ever raced at a track.

Sorry but you idiots spouting the superiority of manuals in DRAG RACING is downright idiotic.

 

[jjessico]

Holy crud, someone else is informed and on my side. Thanks for hanging around this thread. I can see by your sig that you're into the whole rwd thing too. Wow is that refreshing.

Jason

 

[Zenmervolt]

Originally posted by: MiataGirl

Originally posted by: ndee
why are autos slower then manuals (expect the start that you can't rev it)? Can't they be "programmed" to have the perfect shift-timing? Better then any human can ever do?

As people have mentioned..the torque converter attributes to this..but also gear ratios. A manual typically has 5 speeds while the auto equivalent has 4. The manual can afford to have wider gear ratios as a result, making it faster.

You mean that the manual has narrower ratios. Wider ratios mean that there is a bigger "jump" between each gear. For acceleration you want a close-ratio transmission.

In drag racing, automatics are very competitive with manuals because they tend to shift a bit faster, plus the damping effect when shifting which helps reduce wheelspin when going into higher gears. Automatics especially help in turbocharged applications because you don't have to take your foot off the throttle to shift, so the engine stays at high RPM and the turbo stays spooled up and delivering boost.

Circuit racing is a whole other story though, and unless the automatic in question is of the SMG variety, a manual will almost always be superior on a road course given that all other factors are equal.

ZV

EDIT: Just to defend some of the people who are anti-automatic, it's quite possible that they are circuit racers who don't spend time researching drag racing. Also, the thread title simply said "racing" drag racing wasn't specified until much, much later in the thread. I wouldn't give you a dime for a car with an automatic tranny if I were going to circuit race with it, there's nothing like braking hard into a slow corner and stepping on the gas only to have the sluchbox take a second and a half to figure out that it needs to be in first instead of 4th. (Or worse, when it chooses 2nd instead of first and you end up pulling out of the corner from 1,500 rpm in 2nd gear.) Of course, if I were drag racing I'd definitely want a built-up Torque-Flight, but drag and circuit racing are two entirely different animals.

 

[flot]

For those that aren't following, brake-torquing (while bad for the tranny) can really be pretty spectacular.

If you have a powerful RWD car and you're feeling lucky, try it. Hold down on the brakes with a reasonable amount of pressure. Now give it some gas. Somewhere between 2000-4000 rpm, your engine will overpower the rear brakes. The fronts will still be holding the car still, but your rear tires will break loose of the pavement and in short order will begin to melt and screech from the friction.

This is the kind of tire-smoking violent burnout that you rarely see in person but somehow always see on TV. Most people think you need a manual to do something like that, but that's not true at all. It would be considerably more difficult to pull that off with a manual.

 

[Heisenberg]

Originally posted by: flot
For those that aren't following, brake-torquing (while bad for the tranny) can really be pretty spectacular.

If you have a powerful RWD car and you're feeling lucky, try it. Hold down on the brakes with a reasonable amount of pressure. Now give it some gas. Somewhere between 2000-4000 rpm, your engine will overpower the rear brakes. The fronts will still be holding the car still, but your rear tires will break loose of the pavement and in short order will begin to melt and screech from the friction.

This is the kind of tire-smoking violent burnout that you rarely see in person but somehow always see on TV. Most people think you need a manual to do something like that, but that's not true at all. It would be considerably more difficult to pull that off with a manual.

If you have a properly set up tranny I don't think it's really that hard on it. As Garfang said before, it can cause heat to build up but you should have a cooler installed if you're doing that kind of thing anyway.

 

[jjessico]

Try it with a line-lock so you don't have to beat up on your rear brakes. You cut them loose asap after hitting the gas and if your rear end sports a good posi unit, a locker, or a spool you will heat up both rear tires nicely. On a side note, smoking the hell out of your tires while you launch is not good for ETs. Warming up the tires before launch to get them hot and sticky is, however; good for ETs. Also street radials do not respond, increased traction-wise, as well as drag radials, or slicks.

Jason

 

[Zenmervolt]

you should have a cooler installed if you're doing that kind of thing anyway.

Cooler's only going to help once the car is moving unless you fit it with a fan of some sort.

ZV

 

[Heisenberg]

Originally posted by: Zenmervolt

you should have a cooler installed if you're doing that kind of thing anyway.

Cooler's only going to help once the car is moving unless you fit it with a fan of some sort.

ZV

True, but once you start moving they will dissipate the heat more rapidly than if there wasn't one there. And they do provide some cooling even if there's no airflow simply from radiant-loss type effects.

 

[Zenmervolt]

True, but once you start moving they will dissipate the heat more rapidly than if there wasn't one there. And they do provide some cooling even if there's no airflow simply from radiant-loss type effects.

Good points. I hadn't thought about the radiant-loss effect.

ZV

 

[thomsbrain]

Originally posted by: gplanet
Of course I know it's bad for the transmission. That's why I haven't done it for 2 years and only did it once or twice before that. But, it IS slightly faster.

In any case, I have timed it to be faster to shift the gears yourself than to put it in drive and let the transmission figure it out. About 1 second faster in 0-60 by my timing.

LOL. you're not "shifting" when you do that. you're merely allowing the transmission the choice of shifting. it's still going to wait until it's ready to shift. and if you have it floored, that's going to be the redline in most cars. so unless you're magically surpassing your redline, it's impossible to improve times this way. the reason those things are there are for engine braking options, if you use them while accelerating you're either doing nothing, or decreasing your gas milage.

 

[Ultima]

Well, I like to leave my dodge shadow in "2" in low-speed situations so it doesn't have to kick down when I want to accelerate. In normal driving though I usually leave it in D.

 

[LAUST]

Anyone who can't see there are pro's and cons to both a manual or an auto should just file out the door now, you don't have a good opinion to begin with, you should just log off and watch what the guys who have a clue have to say, you can ask questions, but statements like Manuals rule every auto, you will find yourself so quickly proven wrong.

Auto's plain and simply have far superior stregnth, making them better towers and better for drag racing. Not only that but resale value is higher cause after people get out of kiddie stage they don't like clutches while in traffic for an hour a day, 5 days a week.

Manuals have many benefits also, they are smaller and easier to work on, they have less rotating mass so while an Auto will have a faster E.T. in a drag race a manual will usually have a better MPH in many cases. They are also more economical for low torque band cars.

In a car like Milleniums an Auto is the only way to go, his car is setup for the drag strip, all your champions in the faster drag classes all run Auto's... Poerglide, C4 C6 727 those are history making names in the tranny world especially in drag racing... The T-5 and the ZF-6 are becoming popular in road racing, but even at that they don't even have near the light the previous Auto's mentioned have.

As far as slamming on TC's thats plain fvckin stupid, a triplelok TC has 3 TCC's which means 3 X the holding power of a manual's clutch. Not only that but stock TC's have been improved so much over the years it's amazing, my truck came with a 12" TC from the factory, it's very powerful and it's never had slip even holding up to almost 600lbs of torque, I could rip any of your manuals to shreads in 1 run.

 

[Thegonagle]

Originally posted by: Zenmervolt I wouldn't give you a dime for a car with an automatic tranny if I were going to circuit race with it, there's nothing like braking hard into a slow corner and stepping on the gas only to have the sluchbox take a second and a half to figure out that it needs to be in first instead of 4th. (Or worse, when it chooses 2nd instead of first and you end up pulling out of the corner from 1,500 rpm in 2nd gear.

WOW! You knew your Accord automatic all too well, kind of like me back when I had mine. Anything over a certain speed, IIRC, about 21 MPH (or was it 25?), you couldn't get it to give you first gear, despite the fact that first was good until about 33 MPH! I hated that when I was trying to have fun driving the stupid thing!

Yo,, Zen, PM me, tell me what happened to the old '88.

 

[Thegonagle]

Originally posted by: Zenmervolt

True, but once you start moving they will dissipate the heat more rapidly than if there wasn't one there. And they do provide some cooling even if there's no airflow simply from radiant-loss type effects.

Good points. I hadn't thought about the radiant-loss effect.

ZV

Not to mention, the larger fluid capacity. Even if it's not much, every bit helps when it comes to heat dissipation.

 

[Thegonagle]

Originally posted by: LAUST
Anyone who can't see there are pro's and cons to both a manual or an auto should just file out the door now, you don't have a good opinion to begin with. . .

YOU DAMN RIGHT!

 

[MiataGirl]

Originally posted by: Millenium

Originally posted by: MiataGirl
the best way would be to replace it with a manual gearbox

but really, if you want the best start possible, hold down your brake, rev up your engine, and release the brake. and if you car has a good amount of power (i.e. you get lots of wheel spin if you floor it), give it just enough gas so that you get traction then floor it.

Wrong. I need some evidence to back up why you would recommend to change to a manual when we are talking about DRAG RACING!

umm..okay..i'm wrong? where's your evidence?

i just know that with 95% of the production cars out there that are offered with both manual and auto form, the manual is often a good deal faster than the auto.

and if someone wants to find gear ratio numbers from both an auto and manual car, for example a 4sp auto and a 5 sp manual, you'll find the manual is definitely better equipped for acceleration.

i wouldn't know where to find numbers..but for example it'd go something like this:

Car 1 - 4 sp auto (1st, 2nd, 3rd, 4th gears): 3.0, 2.2, 1.2, .8
Car 2 - 5 sp manual (1st, 2nd, 3rd, 4th, 5th gears): 3.3, 2.5, 1.7, 1.2, .8

now those numbers are obviously entirely made up..but generally you'll find the overdrive gear to be the same, the 2nd to last gear to be pretty similar too, but it's the first few gears that make the difference.