Let's talk about boost on the 2-step...

Didn't want to hijack anyone, so I started a fresh thread.

I've heard some of you knowledgeable guys say that reducing fuel or timing on the two step reduces boost. I guess I don't get it. I thought the blower made boost as a function of RPM, so if you are on the step at 4000, the blower is spinning 'X' RPM regardless of timing or fuel delivery. How does boost get reduced?

Thanks,

-Brian

 

I thought that you took out fuel or timing while on the two step as the engine isn't loaded and therefore can't use the extra fuel.

 

I havent seen many changes in boost while on the two step by timiming changes however I have seen small changes 1-3pds while changing the amount of fuel , I just dont know why but I belief it maybe in the quantity of fuel being added to the roots blower and the way it tends to seal ....

 

Here is a question for you guys in the know...

We just put our car on a two step and it is beating the hell out of things. I really think I am going back to the OLD way and just hold the throttle steady with the foot.

Is their such a thing as a SOFT two step. We ordered ours from MSD and asked for the SOFT two step but I can tell you it sounds like it is going to blow the blower off the manifold. We are pulling fuel from it at stage but not timing. Timing is being pulled when the clutch is out.

Suggestions ....

 

I don't know about the timing that much, other than your trying to burn the filed evenly, maybe less fuel would cause little sticks of dynamite in the field with the same timing, and beat up the motor. I would check for detonation, in regrades to blower loss of boost when taking out fuel. maybe it has to do with the fuel displacing the air in the manifold which may create less pressure with less fuel. but I may be so far out of the box on my theory. I may be totality wrong.

 

Althought we never had "issues' while on the two step, when I started using it , I wouldnt have the car more that 1-2 sec on the limiter . The engine seemed unstable , ready to explode!!!
As the car started to "dialed in" ( we started to take fuel out with a selenoid) the engine was more stable , finally we changed to the msd digital controller and the engine became very easy on the two step to the point that I can just get it to the limiter and leave it there.
Also all my crew guys would tell me that before the car was just trewing out great quantity of alcohol out the pipes and now it is just spray on a couple of cylinders...

So at the end you maybe you are almost at "hydraulic" your motor on the two step.

jp

 

I dont run a blower ,so i am just asking but cant you use a pnuematic throtle control or are they ilegal ?








Johnny Barb

 

Pnuematic control if done by part trottle only will not get you the same boost as full open trottle on the limiter.