ATX launch RPM

Barry McCockener · Post by **Barry McCockener** » Sun Nov 27, 2011 11:25 pm

I tried searching for launch RPM and all I found was for MTX's which doesn't help me too much since I have a 3 speed auto. Only things I've done to the car are cut off muffler, High flow air filter on the TB and no carpet. I want to keep the rest of the interior but I'll lose the spare and the rest of the BS in the trunk. Any suggestions?

Post by **occasional demons** » Sun Nov 27, 2011 11:32 pm

Your launch rpm is basically what your torque converter stall speed is going to limit it to. Yes, you could neutral drop it, but you may only get 5 feet down the track, and have a nice mess to clean up.

If you are using it for a dedicated drag car, you can get a much higher stall converter. It won't be too streetable tho, fuel mileage will suffer horribly*, and you will want a trans cooler either way.

*You will have no TC lock up either.

Barry McCockener · Post by **Barry McCockener** » Mon Nov 28, 2011 5:38 am

Everything is stock trans wise. Where can I find the info about my stall? I don't do the whole neutral drop thing in this car... Bad joojoo

Post by **occasional demons** » Mon Nov 28, 2011 12:28 pm

Hold the brakes down, and rev the engine in gear. The rpm it stays at is the stall speed. Just don't hold it there for too long, it will overheat the ATX.

Barry McCockener · Post by **Barry McCockener** » Mon Nov 28, 2011 12:40 pm

OK thanks. From the testing I've been able to do to and from work if I manually shift it from 1st at 50 MPH (5700RPM roughly) to second, it only shoots down to about 4k. Should I let it shift itself at 6300 or is 5700 good since that's about the limit for the cam's powerband and it puts me back in? that range I'm 2nd

INVUJerry · Post by **INVUJerry** » Mon Nov 28, 2011 1:07 pm

Let it shift as high as it can.

You can try little "tricks" to launch the car. Regardless of what you do, you'll probably mash the brake pedal to the floor.

One way of launching it is to "flash" the converter. You'll add just a little gas to bring the RPM's up, maybe to 1300 rpm's or so, when the lights drop and go to green, mash the gas pedal. Sometimes this little burst will let your torque converter reach a higher stall point than whatever it is advertised as.

Another way is what Bill said, mash the brake, then stand on the gas pedal, then let the brake go. You'll have to experiment (at the track of course) to see which is better for your setup.

Barry McCockener · Post by **Barry McCockener** » Mon Nov 28, 2011 3:16 pm

I've tried letting it shift on its own and it seems like it bogs more when I do that vs shifting at 5700. I'll have to do a run where I let it shift at 6300 and see where it puts my RPM's after shifting.

INVUJerry · Post by **INVUJerry** » Sun Dec 11, 2011 11:48 am

You'll probably do the best letting it shift as high as possible. The rev limiter on the ecu is 6700. You can upshift the car manually, but if you downshift it manually you could potentially run into issues.

Johny · Post by **Johny** » Sun Dec 11, 2011 1:17 pm

INVUJerry wrote:You'll probably do the best letting it shift as high as possible. The rev limiter on the ecu is 6700. You can upshift the car manually, but if you downshift it manually you could potentially run into issues.

what kind of issues if you downshift? :O

INVUJerry · Post by **INVUJerry** » Sun Dec 11, 2011 1:42 pm

I can't tell you exactly what will break, just that it's not good for the 3-speed. I know the 4 speed ATX is electronically controlled so it can decided when and if to shift.

Barry McCockener · Post by **Barry McCockener** » Sun Dec 11, 2011 6:51 pm

Haven't had anything break with downshifting so far.. That's not saying too much though.

smallblockfreak · Post by **smallblockfreak** » Fri Dec 16, 2011 10:55 pm

psh I manuall upshifted and downshifted my 3spd for 5 years? No issues.

INVUJerry · Post by **INVUJerry** » Fri Dec 16, 2011 11:02 pm

You lucked out. Some other people haven't and had drums, pumps, or bands break. I wouldn't do it myself.

Public Disturbance · Post by **Public Disturbance** » Thu Feb 23, 2012 5:26 am

Personally with me currently having a ATX 4spd there is only 2 settings as far as Im concerned D(Low) for everyday driving, and 1(Low) if I want to "race" let the trans do the work for you, you will be more consistant that way

Forest Green 2k · Post by **Forest Green 2k** » Thu Feb 23, 2012 8:08 am

Public Disturbance wrote:Personally with me currently having a ATX 4spd there is only 2 settings as far as Im concerned D(Low) for everyday driving, and 1(Low) if I want to "race" let the trans do the work for you, you will be more consistant that way

How does it feel "racing" an 18 second car?

Public Disturbance · Post by **Public Disturbance** » Thu Feb 23, 2012 10:26 am

Forest Green 2k wrote:
Public Disturbance wrote:Personally with me currently having a ATX 4spd there is only 2 settings as far as Im concerned D(Low) for everyday driving, and 1(Low) if I want to "race" let the trans do the work for you, you will be more consistant that way
How does it feel "racing" an 18 second car?

Better then being a douche for no reason