Re: Your experience foot brake vs. 2 step regarding ET
 

Here's my take. If you floor the pedal on a two step set at 3000 or so, the butterflies go wide open and the pump shot from a double pumper is expended with the car on the line. If you rev until you just hear the stutter kick in you still have throttle travel in reserve and get the pump shot when the engine goes under load at launch. I haven't raced enough to tell the difference but I feel more like a racer when I mash the pedal on the last yellow...I mean green light...

Dale

Re: Your experience foot brake vs. 2 step regarding ET
 

Kind of how I used to think about it as well Dale, but according to those in the know the engine does not care about that pump shot because of the airflow with all the butterflies WOT. I see them leave fine so it must have merit. http://i434.photobucket.com/albums/q...ps4a010362.mp4 - http://i434.photobucket.com/albums/q...psc5c634d7.mp4

Re: Your experience foot brake vs. 2 step regarding ET
 

On a two barrel beast like the Gremlin, there is a noticeable difference. With two step the extra accelerator pump shot, can help with reaction time, and car launches tamer, a tick quicker .01 for same launch RPM 60 foot. 1/4 mile no real difference. However the car launches much harder off footbrake and mashing it, and you can adjust your RPM up and down as needed for reaction time.

My fuel injected cars/trucks seem to really like 2 step. Test with dakota a couple of years ago was .02 quicker in 60 foot and .03-.04 quicker in 1/4 mile.

For real accurate data, you would want to datalog the throttle position just to make sure you are at 100 WOT especially if you have wheelstand or hard landings going on also.

Re: Your experience foot brake vs. 2 step regarding ET
 

I find this a interesting subject as I have never raced a "real automatic race car" I learned to race with my 68 Impala stocker with the Jerico 4 speed which I just floored the pedal to the desired RPM set on the 2 step (usually 5500 - 6500) So in building my 65 Impala I wired 2 step through a Brake pressure switch with a on/off toggle to activate the system. I assume with a 2000-3500 rpm range I will mash pedal on 2 step.

I will also be running the Holley version 396/325

Building motor now, can't wait to race. This "bench racing" gets played.

Will Lamprecht
1965 Impala I/SA almost finished.

Re: Your experience foot brake vs. 2 step regarding ET
 

[QUOTE=HandOverFist;511057]Not by intent, but rather by design Rusty. As you can see in the image the activation button is in the brake pedal itself...I know some use a micro-switch.

http://i434.photobucket.com/albums/q...psv7wv6wdw.jpg[/QUOTe

you almost answered my question.....why aren't you putting the gas pedal on the WOT on the floor instead of stopping when you hear it break up ???? Is it any faster not to mat it ???

Re: Your experience foot brake vs. 2 step regarding ET
 

[quote=Rusty Davenport;511598]The correct procedure would be to mat the throttle and come off the brake pedal to launch...just the opposite of what I normally do. I have never taken the time to adjust to this method so I can't answer which is better. Some TNT time would answer this I'm sure...just have to make myself re-learn lol. In simple terms I would be controlling events with my left leg instead of my right leg if that makes any sense.

Re: Your experience foot brake vs. 2 step regarding ET
 

[quote=HandOverFist;511600]So if I am getting this correct......you are actually foot braking and using the 2 step to tell you where you are on RPMs and hold at that point ???

Re: Your experience foot brake vs. 2 step regarding ET
 

[quote=Rusty Davenport;511603]Not intentionally Rusty. I would run across this more often with the Stocker engine combined with the 200 metric trans and 8" ATI converter...with the four wheel discs on the car I could hold it on the line easily upwards of 4000 rpm. The two-step has always had a 3000 rpm chip in it. I normally try to stage just below 3000 rpm.

I see this less often now with the current 383 engine/PG combo as the converter installed is not really optimal for this set-up.

Re: Your experience foot brake vs. 2 step regarding ET
 

I don't know how much about two-steps on a carb motor but an EFI motor must be tuned to do both. Footbraking launch RPM puts you in a lower load cell section on the fuel map and the transition to the high load launch must be smooth and have that accel enrichment stuff all tuned properly. The two step puts you in a high load cell as soon as you drop the pedal to the floor so all accel enrich stuff is finished before actual launch so you are transitioning between high load cells.

Re: Your experience foot brake vs. 2 step regarding ET
 

Rusty-
My experience has been .008-.012 quicker in 60ft ET with a two step switch (same launch RPM) This equates to .016-.024 improvement in 1/4 ETs. It should be noted that to leave matted off of a 2-Step, the carb requires a different set up (think secondaries). My experience with fuel injection stockers mirror Eric and Bobby ( you stand to pick up a little more ET). I suspect this has to do with the amazing starting line efficiencies with FI (compared to the "quadra-bogs")

Feel free to call with questions buddy!

PS- I surround myself with much smarter people than myself! 😁