Launching off a converter

[ksurfer2]

My experience at the drag strip is fairly limited, the last car I was racing was a c6 corvette with a 6 speed manual trans. I sold that car to fund my 69 RR. I have the driveline sorted out and am ready to take it to the track to see what it will run in its current configuration. Engine is a 493 stoker still running a 6bbl. Dyno'd at 574hp and 601tq. That was through headers. In the car, it's running through hp manifolds so numbers will be down from there. Trans is a torquflite 727 with a hughes 3000rpm converter. Rear is a dana 60 with 4.11's. stock suspension/tires.

I have never launched off a converter at the track, only a manual. I have done a bit of reading about how converters work and how to properly launch with one. Terminology still has me confused. What is meant by "flashing" a converter? With my set up, should I be launching from Idle or holding break until a higher RPM is achieved.

 

[HEMI-ITIS]

If you are real crisp coming off idle try leaving off idle at the last yellow.Then try powerbraking at 1500 then 2000 and compare the 60 ft.

 

[NOSTRT980]

What is stall speed and how do I determine what stall I have now?

Stall speed is a term used to describe the rpm at which the torque converter transfers the power from the engine to the transmission. There are different ways to test stall speed. "Foot brake stall" is when you press the brake pedal and then press the gas pedal. When the engine rpm doesn't go any higher or the tires start to spin that is "brake stall". (DO NOT TRY THIS! THIS MEASUREMENT IS MEANINGLESS AND POTENTIALLY DANGEROUS TO YOU, THE TRANSMISSION AND THE TORQUE CONVERTER!) "Flash stall" is when you, from a dead stop, press the gas pedal to wide open throttle (wot). Watch your tach needle, you will see the needle jump to a certain rpm, that is "flash stall". A drag racing-style trans brake will give you closer to the true stall speed of a torque converter.

 

[dvw]

It probably isn't going to make a difference with normal street tires. Full throttle will likely result in excessive tire spin. My bet is you're just testing, not racing. You may have to drive it out like leaving a traffic light and ease into it. How quick you can hit full throttle will take experimentation. Don't worry about reaction time at this point. If you want to race it get a pair of sticky tires. Many times if the converter is relativly low stall (3500 or less) it may like to leave close to idle. If the converter is truly loose enough you can vary the starting line rpm to dial in the reaction time.
Doug

 

[HEMI-ITIS]

DVW pointed out you are using stock tires.When I can get to the track I tag onto the back of a group the run factory stock appearing and stock bias tires.
Leaving on those tires is an art!!Get some sticky tires cause traction is a blast!!