air throttle vs 2 step pros and cons

this is for a blown alcohol application. I was thinking that the 2 step might be hard on valve train
but I dont see to many cars with air throttle. leave RPM wont be over3500.

 

On a roots blown pro mod when we switched over from the air throttle to the 2 step we went from running 1.07 60 fts to 1.03 immediately and went from having good to decent lights to -.004 every time....lol

Make a big difference at the hit. I forgot exactly how much but the boost at the hit was like 3 times more or so.

Best wishes,
Trevor Sherwood

 

I agree with with more boost and better lights however when I did that with my Chevy motor it would spit rocker arms out the valve covers. Ever time ! My rocker system was welded together and had extra bolts thru it. PAC springs at 480lbs on seat. Just was random times. On 2 step she was mean. Easier to control and tune. But came with a big price. They were t&d alu rockers. Switched to steel exh rocker and broke an intake rocker tip which turned into a valve spring compressor.... My hemi has been bullet proof on two step. Lol

 

If a person has to run questionable tracks from time to time, would having an airthrottle deal be easier to work with, or is it best to just stick with the 2-step and work with it?

 

M5 20 over 5.8 gallons staged . It hated the 2 step.

 

wot

Very few will agree with me, but i've found the airthrottle used in conjunction with the 2 step to be the best balance of performance and parts destruction. I've tried every variation on roots and screw automatic cars and i've never understood the logic of leaving with near max boost and then trying to kill power with every other tool available.
I set the blades to make 13-22 psi and limit the rpm around 4000 with the 2 step. I've never seen reaction time changes. I used to chase the weather and adjust the blades/boost but with the loose converters we run now it seems to make no difference.
I don't think leaving with lower boost is an advantage on weak tracks as a tuning tool. We have tested back to back and approx the same amount of timing has to be dumped with low or high boost. The converter absorbs so much that the boost evens out quickly.
A lot of people gave up on the air throttle because they couldn't get the mechanical linkage stable enough to open the blades a small amount consistently.
The quickest air throttle car I know of is Mick Snyder. He has a nice system in stock and will provide good setup info.

 

I run a Bac-Man head on an Arias block so that rocker arm issue is troublesome to me. can you take fuel away while on the 2step to fix that rocker issue?
I am looking to leave at about 3500rpm.
This is on a sand drag car if that makes any difference.
I have been running the car for years with a crowerglide and am looking to step up bigtime with the Lencodrive.
I have just been leaving from Idle

 

Trev...you have a Pro Mod??!! Way back in my TD days...ran an Air Controller through a delay Box....DEADLY CONSISTENT! And on Pro Tree "Outlaw" races.....needed "delay" to prevent RED EYES!...Ihave NEVER run a 2-step on a Blower....But I do believe....quicker.....I just hate the SOUND of a 2-step...it HAS to be harder on parts??!!

 

that's what I am trying to figure out AFC357

 

What's your combo? No a hemi it's the only way to go. Never ever had a failure come from 2 step. Keep lash tight , spring psi above 450 , no problems !!!

 

Hi,

The Chevy I tuned on ran 6.20's using the 2 step. We just made sure to use a lean out with a .100 jet on it and it never hurt the valve train. It was a Jesel or T&D system on Dart Pro 1 355 cnc heads. It did have the upgraded bolt package which the driver was told it needed and worked flawlessly for us. Aluminum rocker arms on that deal.

I hate to say it but that sounds like it may have been something either in the tune up or the setup. Its very important to pull fuel out when on the two step or it will cool the cylinders right off but I have never seen one eject the rockers on a shaft mounted rocker deal.

The hemi is worlds stronger though in the valve train...lol

Best wishes,
Trevor Sherwood

 

Uncle Tim

Uncle Tim,

No pro mod...yet....I have everything else here though...lol. That was on Chris's Pro mod and we won the championship with that car (Outlaw pro mod deal) Going to the two step from the air throttle was the first thing Bob Newberry had us change (well that and the coils of wiring just kind of strewn about) when he came on board as our crew chief and it didn't seem to be any harder on parts but we did see a good performance boost on it. The parts cycle didn't seem to change. I do believe its a bit harder on the belt but since I use 1 run 3.5" wide 11mm TF belts I doubt I'll have any problems.

I am putting one on my dragster and sold my air throttle deal after I saw that deal, Bob talked me into it.

Trev

 

So, on a simple system with a points type mag, an 8-71 would an ETC box (used for launch rpm and shift rpm), and a converter helper be the way to go?