Air Throttle Problem

We are new to blowers but not to using air throttles. Using Gerodots upright injector. Set the air throttle to partly open the throttle(burnout and/or launch) with the motor off. Start the motor and the air throttle will not open the blades at all. Its like we have too much suction from the blower and the blades are pulled shut. Without the air throttle being activated, the pedal works but is very touchy which supports the the suction theory but I searched this site and could not find anyone with a similar problem. Thoughts?

 

Are there any air bleeds drilled in the butterflies?

Are the butterflies centered?

It all needs to be balanced, or you'll have the sensitivity issues you're describing.

 

Maybe call Don Gerardot , heard he is hard to get in touch with sometimes but he has your answer .

 

I usually don't comment on other folks way of doing things but when it comes to safety I have to.
There is a reason NHRA does not allow air activated throttles on blown cars. It can be very dangerous.

 

www.gerardot.com

 

without the motor running, can you stick a feeler gaugs of any size under the blades of the injector? who ever set up the fuel system should be able to tell you the exact size of the gap, it should be between .008-.012. and make sure BOTH shaft stops are adjusted to the proper gap. if one is loose and one is right, it WILL allow the blades to pull tight at idle.

 

I run the same deal, are the butterflies hard to open when the motor is running, if they aren't you need more air pressure because the vacuam is holding the ram, I run 150 psi and it slams the butterflies open no problem.

 

There are several Gerardot uprights in my area running the air throttle set-up with no issues. I would be glad to send you any pics of my set up if you are interested. The angle of your cable mount to throttle lever is very important. I have seen some set up with the cable pull angle set up almost at 0 deg. This will not work and make it hard to overcome the initial pull. The pedal stop is just as important. You don't want the air cylinder to whack the cast stops on the injector (damage or break the stops). At full throttle you should still have about a 1/32-1/16" of travel left in your linkage. I have set up several of these systems and they work flawlessly. You do not need any bleed holes. I will not hang any of my launch cylinders on the injector. I like my cylinder at the pedal and out of the way of any one walking by with a curios hand. These only work for startingline launch. They do not work down track.

I have run from 90-100 psi at the bottle. I believe my current cylinder is 3/4". You will only putting air on the rod end of the cylinder.

Has anyone had your butterflys out of the shaft. These are all custom fit for each slot in the throttle shaft. They also have a front and a back.

I like my upright. I have been running the current one for 2 seasons. I like the idea of having a crew person being able to squirt in the fuel without having to open the doors. I am in full control of starting the motor except for the fuel being squirted.

PM me for the pics. Gerardot's stuff works good. Here is his email. I am sure that he would be glad to help you. gerardot@dtnspeed.net

Brad Hiatt

 

Brad,

Check your PM.

Frank

 

I run Don Gerardot upright injector on 14-71 HH , and the butterfly are very easy to open , engine running or not .
why don't you go with chip limiter (msd 2 or 3 step) instead of air cylinder ? it simple and works great . Easier to fit your throttle cable right .
Claude