norvalwilhelm

Thanks Wayne I changed my order this morning and will get the LM-1 Thursday so I can spend the weekend playing.

norvalwilhelm

You only drill the throttle plates if there is a idle screw at that plate. If you have 4 corner idle then drill all 4 plates. Only 2 screws only drill the primary plates.
You hold the car upside down and only drill on the side of the throttle plate that forces you to hold the throttle CLOSED. Do NOT drill on the side of the throttle plate that normally would close tighter if you push the drill. Drill so you need to hold the linkage and keep the throttle closed while drilling.
Drill about a .100 hole, one per throttle plate.
If the throttle plate is say a clock face, drill 1/2 way between the center where the hands pivot and 12 oclock. A single .090-.100 hole 1/2 way between 12 and the shaft where the hands would come through the face.
I always drill these holes and still have to use a .015 wire.

gkull

Wade I tried to find an on line picture for you. I used 1/8th inch drill bit and placed the hole edge about 1/8 inch in. What you are doing is inducing a vacuum leak to lean the A/F ratio at idle. I didn't think that two holes was enough so i did the secondaries also. Then i had so much air that the idle speed was high with the throttle blades exposing .020 of the x-fer slot. I just bought new blades for the rear.

This is someone else write up.

you may have to drill small holes (1 per plate) in the primary throttle plates to allow air in while the plates cover the transfer slots. This is a trial and error procedure, so start small, about 1/16 inch. You should not have to go much larger than 3/16 inch. Drill on the side opposite of the transfer slots, to help keep this added airflow away from the idle ports and transfer slots.

MotorHead

My Race Demon comes from the factory with the holes already drilled in the throttle plates, not sure but I thought the Mighty Demon comes that way too

morganjd

I have an LM1 meter and love it, i would look at the one from f.a.s.t , you only need the single o2 sensor version. The advantage is you can get a playback of a run right on the unit, no need to download the run on a pc.

I have a 750 mighty demon and installed a .020 wire purchased from a hobby store in the IFR and the difference was unbelivable in out of the hole performance. I then had my idle mixture screws turned out only 3/4 of a turn to get the ideal 13.5 af ratio for idle, otherwise use a vacume gauge and adjust for maximum vacum. I found that maximum vacume was still a little bit fat. All 4 idle mixture screw need to be equal, change the power valve to a 4.5 to avoid an overly rich condition once you are off of the idle circuit. This method does nothing permanent to the carb and can be brought back to stock at any time. You could also just buy the replaceable IFR in the smaller size and instal them. THE WIRE COST NOTHING!!Come to Michigan and I can help you out. If any body is in the detroit area and would like to use my LM1 meter, call me, will be willing to help out anybody for no charge. I woul recomend getting the o2 sensor bung installed in your exhaust, as the tailpipe clamp is marginal at best to adjust idle, ok for the rest of the tunning

jmorgan3@twmi.rr.com

ImBatman

Thanks for the write up. I am definately going to do the wire mod first sense it is reversible. Not sure I am comfortable enough with drilling holes in the throttle plate myself.... I am going to check this weekend though and see if MotorHead is right about the Mighty Demons already having the holes drilled. Thanks for the offer to help out but Detroit MI is a bit of a drive from Clover SC.

Does anyone know if Holley parts are a direct fit to Demon carbs? I have a speed shop near me and I know I can pick up a 4.5 PV there.

Thanks
Wade

TJ76

All parts are interchangeable. But be careful of jet sizes. The numbering system is different between Holley and Demon. They fit and work fine, you just have to measure them to match them up. In other words an 80 in a Holley won't be an 80 in Demon. Find the one that measures the same as what's in there and go from there.
TJ

norvalwilhelm

There is no problem fixing the throttle plates if you don't like the holes. I had the holes for years and then decided to see how it would act without them. Remember I have 2 850 double pumpers so that was 8 plates I had to remove. They came out easily and I welded up all 8 plates, ground them so you couldn't tell they were fixed, installed them and drove like that for a few months.
Decided I liked the holes better and redrilled all 8 plates.
Alot of work fiddling with 8 plates but they welded up easily if you don't like the holes.
I would definitely go for the holes.