Your experience foot brake vs. 2 step regarding ET
 

Would anyone care to share your experience with ET gain.....not drivability......which one is faster, slower, how much difference or any other comments. This would pertain to a stock eliminator type car.

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

.02 with two step

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

.05 quicker with a 2 step on my T-Bird.
But then it's not a V-8 nor naturally aspirated.

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

Larry and Alan,
When you use the 2 step is it set for the same RPM that you were footbraking to?

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

I use a 2 step with a button in Pro and footBrake in street when bracket racing and found that the 2 step is about 2 hundredths slower in ET but .02 faster in reaction time. This is at 3000 rpm in my car. I load the converter to 3400 to make up the difference in RT

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

Bob: In my case no, so there really is not a fair comparison I suppose.

It would be an interesting test tho to set the 2 step down lower to the point where I leave on footbraking.

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

Exactly my question------ like at 2000 on the 2 step OR if its a direct linkage quadrajet get on the 2 step before the secondaries are open----------anyone care to comment ???

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

All the Stock racers I have asked leave with the throttle already matted when using the two-step...I have not tried it yet. Mine is chipped at 3000 and I often hear it when staged. I have resisted trying it because it is just the opposite from what I am used to...leaving off the brake pedal instead of pushing the gas pedal.

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

So let me get this straight------you are using the 2 step but no more throttle than it takes to reach the chip ????

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

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

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! 😁

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

We experienced a marginal performance improvement of .01 to 02 with a 2-step on a low hp Fox Body stocker. Would have to make a few more runs to have a better idea with reaction time, but certainly made staging easier/consistent.

To Bobby's point, we did not adjust fuel enrichment to accommodate the change so not sure if it's a true apples-to-apples comparison.

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

my car hates it (as do i) kills me about .05 at least - more in bad air ....
and i cannot stand that sound ...

so im stuck in the 60s footbraking it

captain

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

Dean could you better explain to me about adjusting the secondary for a FB two step? I have a street car that I Foot brake. I leave around 1500 and it flashes to about 3800. I tried a two step one time and while it reacted quicker to stumbled about 10' foot out and then cleared up. You can IM me with any details if you would like. Thanks

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

Maybe someone will see this and reply but has anyone experimented with low rpm 2 step ......will the motor respond ok on the 2 step at 2000 ????

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

Don't know about 2000 but my R/SA Jeep 4.0 leaves fine at 2550 - down from 3000 because the brakes won't keep it from pushing thru the lights!
4.0 is FI so can't say about a carb reacting.

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

I'm finding out little by little with experimentation, and it gets back a little to what some of you hinted around to, the quadrajet does not like "rich" fuel mixture when leaving on the mat with the 2 step activated by the brake. It will sit on the starting line and hold the RPMS but when you let go the "rich" will usually make it leave terribly, even though it will run great with the same carb setup when running with the footbrake only.
MAKING THE 2 STEP WORK WITH THE QJET IS A CHALLENGE in order to get it to perform at its best especially on a stocker that doesn't have a transbrake and has to leave at much lower RPMS......by what I am seeing testing the 2 step requires leaner setup to run at least reasonably well.
Does anyone else have similar findings ????

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

Plug the accelerator well tubes

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

I used to leave at 2200 with my 455 Lemans. I did what Danny said. blocked off the accelerator tubes and it left great. Always to the floor.

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

I`ve been using a 2 Step anywhere between 2000 and 3100 rpm and the 60` times seem to be about the same. All of this with a V6 "Stocker". I`ve also gone back and forth with foot braking as well and prefer the 2 Step for consistency. Low horse, small carbed cars seem to be more consistent leaving at WOT. I also 2 Step my Super Pro car (big block Chevy with a 950 Holley, dual line lock set up) with the 2 Step around 1900 rpm and it leaves just fine.That's my experiences at least.

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

with the 2 step??

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

Hey Danny sounds like what I've been looking for......but please don't leave us hanging.....can you go into a little depth on the "accelerator well tubes" PLEASE SIR or anyone else who has done this.....THANK YOU

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

Is that the same as "SECONDAY ACCELERATOR WELL TUBES"

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

The accelerator well tubes are the outer 1/8 inch diameter brass tubes in the air horn. They need to be plugged or removed for 2-stepping. However it isn't necessary, but will help the rich condition the moment the 2-step is de-activated. I have had racers with O2 sensors tell me their A/F would go as rich as 10.5 the moment the trans brake was released. I was told my someone a lot smarter than me that while on the 2-step puddling occurs in the intake because of the cylinders being canceled and the moment the button is released the excess fuel enters the cylinders causing the over-rich condition. My preferred method was to tap the tubes for a 3-48 stainless steel set screw. This allowed the racer to go back to foot-braking simply by taking off the airhorn and removing the set screws. You can just pull them out and if you decide to install them just flip them around for a press fit as they are swedged from the initial installation. They should be staked in regardless as they have been known to fall out even from the factory. Hope this helps.

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

I run my secondaries on my q-jet as loose as I can when I foot brake, but when I 2 stepped it would stumble. I tightened the secondary spring 1 turn and it was perfect.

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

yes, the only way I could hit the tree in that car