Introduction: Nitrous/methanol Injection Wide Open Throttle Switch, Dual Button, Holley Dominator Application.

This instructable will show you how to build a wide open throttle switch that activates 2 separate switches. This unit is mainly focused on race cars or seriously fast street vehicles. It is made to mount on to a carburetor stud of a Holley Dominator style Carb. I use it for nitrous activation and methanol injection activation. The reason for 2 switches is so you can wire the system to activate your alcohol injection when your nitrous is not armed. It also allows for a very robust redundant wiring of your nitrous system just in case 1 of the switches happens to fail, which can and does happen with the violent vibrations of drag car engines.

The custom pieces of this switch are 3d printed and include a base and the arm. The switches can be purchased from race car part retailers or various retailers such as McMaster Carr. The shouldered screw was purchased at a local hardware store.

BOM:

1 x 3d Printed base, I recommend ABS plastic for heat resistance and 100% infill for strength.

1 x 3d Printed arm, also recommend ABS with 100% infill.

1 x 10-24 shoulder screw with 1.5" shoulder length, .247" diameter shoulder for .003 clearance in a .250 hole.

2 x button switchs, I purchased from Tim McAmis race cars part # NEW-A-20GQ-B7K

Step 1: Threading the Base and Assembly.

This is the only fab work to be done on this project, you will need a 10-24 tap and simply tap the hole where the shoulder screw installs. Then take your 2 switches and install them into the 2 large diameter holes and secure with included nuts. Then simply set the arm into place and tighten the shoulder screw, make sure you use a super glue as thread locker so it does not come loose.

Step 2: Watch This Video to See What It Looks Like, and a Tutorial of Features.

This video shows how I mounted the switch, also pay attention to the arm position which should work fine for all dominator carb's but feel free to adjust to your liking.

Enjoy!

Comments

author
scottieK (author)2014-10-28

Added .stl files. Thanks for the heads up peppypickle

author
peppypickle (author)2014-10-28

Nice project, are you able to share the files you used? Nice video explanation, thanks for posting.

author
neo71665 (author)2014-10-28

One sexy engine.

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