Two-steps Bad/Good

Two Stepping blown alcohol motors is great. There are a heck of a lot of promods that do it. When we first started doing it we didn't bleed off any fuel so we had some problems but that was years ago. If you use a NOS nitro\alky solenoid with a 80-125 jet in it to bypass fuel while on the Two Step then all is well. Some use a throttle limiter also but I think that is not necessary and also stops you from making boost while staging. You want to make boost while staging.

 

I have never run a Two Step with an automatic. Maybe someone else can chime in and tell you. It would seem to me that just a Two Step at the right RPM would keep it off the converter and yes you still need a fuel bypass so you can control the amount of fuel going into the motor. You want those EGTs to be around an average of 600 to 625* when on the Two Step. Too much fuel will cool them down too much and the cylinders will take too long to recover.

 

I would have to agree with Danny if you are a 10.5 tire and can't take all the boost right on the hit

 

automatic

I wouldn't recommend the 2step at wide open throttle with a converter. You have so much torque as it is at 3500 or so with the boost from having the blades just cracked, much less throwing all that extra power/boost/torque with the blades wide open. I'm sure theres people that do it, but it's just that much more power to get rid of.

Like Danny mentioned, the hot set up with auto is to either have a two stage pedal or air throttle to set the blades slightly above the desired rpm, then chip it to the desired launch. This way you always leave on the same throttle/barrel valve position.

I've got a question for those who are two stepping with screws. Have you done a real honest back to back with a two step set up and a set up for swapping feet? I have very little exp with this, but it seems you would definitely have to run more static with the two step to keep the motor from running away from the clutch with the extra boost. Not to mention the motor is going to react quicker by dropping a button versus the motion to go to full throttle from part throttle.

Aren't Scruggs and Hernandez still leaving off the old school foot swap? Wonder what Manzo has the Shiek doing?

If you can get the extra boost to the ground, I can see the advantages.

 

Yes when on a Two Step you need more static in the clutch because youhave the blower making more boost right when the clutch is released. A Two Step allows for a lot of consistancy and not all racers can swap feet with consistency. I can't remember if Hernandez uses a Two Step or not. I believe I have seen Scruggs up on a Two Step

 

air throttle

Jason,

I see your points re: air throttle. What I was talking about is, say your target launch is between 3500-4000. Set the air throttle to go to 4300-4500. Use the chip to keep it down around 3500. That way you always have enough travel to get to your desired launch. You can compensate with BV to get your fuel where you want it.

We used a two stage pedal on the FC I drove and then you have guys like John Anderika with his Lencodrive, he just brings the motor up until he hears it start chipping against the two step.

 

Just as a warning from my own experience. Some air operated throttles are real dangerous because they can go wide open if you let up just a little on the clutch to position the car while staging. Stop and think about that air cylinder on that throttle armed and waiting for the clutch switch release command. We were testing and the car rolled forward so we wanted to back the car up and re-stage. The car would not roll back in reverse so a procedure is to let up on the clutch a little to help it. That is the same as pulling the trigger on a gun. We hold the 60ft record in reverse. I managed to roll off the rear fender and thank god that nobody else or a car was behind us. The other problem with some of the air throttles is you can't snap the blades open to squirt in alcohol to start the car. I think air operated throttles are real dangerous. I have an air operated throttle system complete and nearly brand new. Used just once all for just $100.