How to Launch with a 727

[zerfetzen]

I read an article in Car Craft that said a weakness with 727's/904's has to do with launching in 1st, and when you get traction, it can tear up the tranny.  Most people with 727's launch in 2nd?  Is that really right?  Avoid all burnouts in 1st?  Strange.

Speaking of how to launch, if you have a hot stall (3500 rpm), and assuming you don't have a transbrake, is the best way to launch to hold your foot on the brake, rev it up until just under the break-loose point for the converter, and then simultaneously let off the brake and barely raise the rpm's over the break-loose point?

Put another way...what is your launch technique?

[4Cruizn]

Great thread!!  I'll be watching this one!!   

[Chryco Psycho]

I use first & the clutch !!

[tactransman]

They are referring to the sprag in the back of the case. That is why low band apply valve bodies are recommended by good mopar tranny shops. With the low band on in low it helps the sprag (really it does 95 percent of the work, sprag is only partially holding) When you spin the tires in a burnout in low gear, the momentum of the drive train can be faster than the output shaft is being powered by the engine.That makes the sprag spring and rollers "lay over" ruining the sprag. The low band on makes sure that this "over revving " doesn't occur

All three speed U.S. automatic transmissions (G.M. / Ford / Mopar) have the "sprag" for low take off in the drive position,it is the weak spot in them all, not just a Torqueflite. They just get the most bad mouthing over it.
So the burnout thing goes for all three.

Nobody "launches" in second on purpose ,they do their burnout with second and third only.

As far as loading the converter for launch, most people load it up pretty tight against the brakes. If you leave from an idle , you better have your carb tuned almost to perfection because you will be launching before you get into the "mid range" circuit of the carb.
 

[Carlwalski]

I got told this a while back by the owner at SMR racing transmissions. He said that when you put it in first gear the rear band(s)? touch and can heat up very quick. He swore to always take off in second and when doing a burnout start in 2nd or if you have to 1st for a very short 2-3 second (tops) first few wheel rotations then shift into second.


You got the launch pretty much right. I like to pump the brake hard once (not sure if others do it or I'm just a weirdo lol) but pump it hard just before you're going to take off, like, just before. Kind of like you're pushing the brake when coming to a emergency stop making the car bounce. Make the car bounce and catch it with the gas, it gives it a nice pendulum effect and has worked well for me.

I don't use too much brake in Lucy as soon as I let go she lights up and I just have to pedal it, good for a bit of show boating & getting sideways but nothing else. You'll find plenty of guys out there taking off from idle, so it's not always stall this and stall that, just something to remember. Best way is to go out and try a few different techniques and see what works best for you I guess. Get a mate to sit down beside you with a stop watch and find an open road and see what you can do. You shouldn't have too much trouble trying to find volunteers to jump in your ride I'm sure. lol 

 

[GoodysGotaCuda]

I got told this a while back by the owner at SMR racing transmissions. He said that when you put it in first gear the rear band(s)? touch and can heat up very quick. He swore to always take off in second and when doing a burnout start in 2nd or if you have to 1st for a very short 2-3 second (tops) first few wheel rotations then shift into second.

Yes the low band is applied when you have the shifter in manual low. If you do not have a manual valve body, start in one, get it going a little and shift.

I don't use too much brake in Lucy as soon as I let go she lights up and I just have to pedal it, good for a bit of show boating & getting sideways but nothing else. You'll find plenty of guys out there taking off from idle, so it's not always stall this and stall that, just something to remember. Best way is to go out and try a few different techniques and see what works best for you I guess. Get a mate to sit down beside you with a stop watch and find an open road and see what you can do. You shouldn't have too much trouble trying to find volunteers to jump in your ride I'm sure. lol 

Every combo is different. some can take off from idle, you'll get more torque multiplication..but you better have a dead on tune so there are no hesitations. Some wind it up as hard as their converter will let them before spinning. Just go to the track, try a couple different ways and watch your 60ft. I found the best way for me is about 2,500rpm with my 3,500stall..

Here are a couple goody not so much experience educational experience videos lol. best 60 is a 1.9 when i went 14.0 which ive been told is pretty stellar for that, of course dont forget elevation  These three videos are three different launch rpm, you can see the first was ~2200rpm or so. Ram was about 3500rpm. and the other was another 2500 or so.

[torredcuda]

Those Chevy Craft guys crack me up!  Launching in first is not a problem with any 727 I have heard of.  Doing a burnout in first can cause sprag failure so either start your burnout in second or start in first and quickly shift to second and roll out of it.Launching will vary depending on your combo but you want to get in your powerband as quick as posible for best ET`s.Foot brake and bring up the revs as high as you can without the car creeping forward and launch as hard as you can-if there`s too much wheelspin just back off till you get traction.

 

[zerfetzen]

Hats off to all you guys. Chryco, I'm with you because I've always had manuals, and adjusting to an auto is weird to me.  TacTrans, thanks and I can't afford it now, but someday hope to get a 727 trans shipped to me through you that's all tricked out.  Thanks for the cool vids Goody, I saw exactly how you did it.  NZ, I was always meaning to ask you, how did you name Lucy?  I want to name my car too, and am just waiting until the right one hits me.  Thanks Torred.  My experience has been that Hot Rod is all Ford/Chevy.  Too bad, I loved it when I was a kid.  I signed up for Mopar Muscle lately, and they had a deal to get Car Craft.  This week I resubscribed to Car Craft and they had a deal to get Mopar Muscle.  It seems like there's a good fair share of MOPAR in Car Craft, curious what you think though.  Thanks all.  Before I really go for a launch, I'm going to fry off the BFG's I got on the rear (starting in 2nd, now I know!!!), and get some Hoosier's like my last car.  Cheers.

[Carlwalski]

NZ, I was always meaning to ask you, how did you name Lucy? 

  No worries mate, first girl I ever liked or "loved" even though I didn't know what it was back when I was about 8 or 9? I had a HUGE crush on her. She was blonde, blue eyes etc and she was a year older than me. Lucy was her name and before I could pluck up the courage to say anything to her she moved far North, never saw her again. She was the primary schools "The Girl" you know the ones.....use to smile at me went she went past with her boyfriend or one of the school "jocks". Such a young age though. I've caught up with her, just recently actually, married and has kids, hot RM though! LOL

Anyhow that's how she got her name, short, 2 syllables and IMO is in the era of the car.
Names aren't for everyone but who really gives a shlt.  The 'Cuda is, 'Cuda, no name, Jeep = Jeep or tank.

Cheers and good luck with your launching.....get the trans worked and you'll feel just like a NHRA driver.
They sound bloody mean too blasting past you on the highway with no letting off the go pedal. 

[zerfetzen]

Good stuff, and oh yeah, that trans is going to get worked over.   Thanks all.

[tactransman]

One more thing.......this is what can happen if the sprag fails in a burnout or a drive line failure under full power.

[4Cruizn]

Holy Sh!t!!  That thing definitely exploded!!   Dammn!               

[Rev-It-Up]

    I've never seen anything like that before!   

[GoodysGotaCuda]

  I've never seen anything like that before!   

I have a pic here somewhere where  a part left through the passenger door. luckily not the drivers. 

[4Cruizn]

This one had a piece leave through the roof.  No scatter shield.