Would going from a solid lifter cam 268/272 to a 274/280 change converter stall speed? Foot braking off idle car was a tenth slower. Normally 1.44 was 1.54 this time out but air temp was hotter than normal, was 90 degree's air temp. The car did pull a lot harder in 2nd and 3rd gear with a better mph. The converter is a 10" NOS Turbo Action and flashes at 4800rpm on NOS! Thanks Matt

Maybe the new cam is too big and you lost torque? I've seen that happen a lot of times.

It would make a difference on where you put it in
but yes the cam will change the torque.. might just
be where the torque is made(up higher) but if you advance
the cam it will move the curve lower.... I put my 416 cam
in straight up(on the roller) because I didnt want to make
more torque to make it stall higher.. on my FT cam I moved
it 4 degrees advanced for the torque(because its a smaller
cam)

Thanks guys, This cam is 108/104 degreed in at 104 at 2 degree's advanced! The old cam was a 108/105 degreed in at 105 at 2 degree's retarded! Thanks for all your info! Matt

What sort of difference have you seen in the other increments and is your et slower overall ?

On motor ran the exact same et and a little fast mph 10.77@124.96. I have 8 time slips with this 10.77 but the mph ranges 123.00 to 124.96. On nitrous it varies on where my Nitrous controller is set. The only nitrous pass with the new cam was 10.04 at 136.67, last time out with the old cam and a lot cooler air temp was 9.76@134.01 but the Nitrous controller was off so the full 200 shot once the accelerator was at W.O.T. This pass I had it set at 2 seconds at 10% duty cycle. Still has the same 1000 rpm drop between shifts, shift at 6700 falls to 5700 cross at 7400. I do leave off idle no trans brake. Would a higher rpm like leaving on the brake make a difference? Thanks Matt

To get the best 60 ft and 330 ft times you have to test the stall RPM and the shift RPM It wouldn't suprise me at all that you will see a big difference in the 60 ft times just raising the RPM on the footbake up to around 2700 RPM and higher I normally will try 2300, 2500, and 200 to 300 RPM increases each test until the car gets its best 60 ft times and reaction times. One of my old NHRA stockers would get the same results at 1200 RPM and 3500 RPM, every other RPM between would spin the tires

Thanks Cab, I will try that next!

If the converter is correct with the combination, foot brake or trans brake the car should 60 foot pretty close to identical times.
Same with changing starting line rpm's. Should have very little if any effect.
Changing staging rpm will effect your reaction times though.

I believe the stall changes with the square root of available torque. So a small drop in torque from a bigger cam won't drop stall much, but it will drop some. BUT, you now have a double whammy. A bit less stall and a motor that doesn't like it.

greg is right, the converter "K" factor varies with the square root of torque so the change will be small.

Thanks guys!

Make some passes with the same weather you have run your previous times so you can compare apples to apples.

Could someone explain the square root factor ?

THANKS

If a converter will stall 3000 rpm with 200 ft lbs of torque, then doubling the stall to 6000 rpm will take four times the torque, or 800 ft lbs. If you find the square root of 200ft lbs, then divide it into the rpm the converter stalled at, (3000) you get what they call the K factor. Do the same with 800 ft lbs, divide the 6000 rpm by that square root of 800 and you will get the same number, or the same K factor. So the K factor is the constant that will tell you what stall speed you will have once you know how much torque changed. Multiply the square root of the torque by the K factor and you get the stall speed.