The drag race demon comes with 4 .093 holes in the throttle butterflies to provide more air at idle. Well.. I think I have too much idle air. The idle screws are not open enough to allow any transfer slot exposure but the motor will idle at 1000 when fully warm. Actually.. its over 1400 when you first let off the gas and then it settles down.. I think this is an effect of the transfer slot.

I guess I will have to replace the butterflies with ones that have smaller holes.

 

i've never heard of a problem with not enough transfer slot exposed..just too much.

 

Been down this road already with an 850 Holley. Make sure your throttle plates aren't binding. If you have no transfer slot showing then you beyond the designed range. They can stick and will often do just like you are describing. The carb will "settle" back down to an RPM as the springs slowly force the blades back closed the last tiny bit. I found I could manually push on the throttle arm and force it to immediately return to proper idle RPM. You can also have something of a lean out problem without the transfer slow showing. The throttle blades start opening until they hit the slot and then they have to open the slot enough to start fuel through it. If you follow Holley's suggestions for throttle blade position you won't start an appreciable flow through the transistion slot but you will expose it enough that you are close to it. Then it can add fuel to your mixture rather than having the blades open up some leaning it out before they activate. Reducing, if not eliminating, the holes in your throttle blades sounds like a step in the right direction. You need to get the throttle blade positions back in spec before moving on to other things.

 

the main system won't start up at the point b4 the idle tends to sign off.. and with the TS not at the right point.. it makes off idle unsmooth..

I got a 14dollar 4hole spacer from ebay and i think that will pickup low speed velocity. If that helps.. i will slowly work to make it an annular dist version. that should pickup low speed without hurting my top too much.

the demon book says all race versions after spring 2001 had an adjustable air valve that elminates the holes in the throttle plates. Of course.. mine is older than that and they problably want a fortune to change the baseplate to one of those.

 

the BG part numbrs at summit are now GPT prefix.
just fyi

The boosters are going to run about 100 (with the installer tool) and butterflies are about 10 bucks. I already ordered the butterflies.

 

Where is your timing set.

If it is too high the car will not idle at low rpms even with the blades closed.

I have my timing fixed at 36 degrees and the car wont idle at less than 1200.

I fixed the holes in my butterflys by sealing them up with black rtv and wiping it flush with the blades.



How does the car drive?

 

drivability is good except around 1500-1800. Got a little surge up higher but not bad. i might try closing the existing holes somehow.

 

You might be able to seal them using some sort of epoxy..at least temporarily to see if it helps you. Most things, like RTV and JB weld will dissolve in gas pretty quick. gas tank sealer won't stick and will get sucked off.

 

it still will flat not run at anything between 1200-1800. It just bucks. Maybe the cam is just too much down there.

back to the drawing board.

 

What do you mean by bucks?

Does it bog? ie. hesitate?

Does it hesitate under load? Or does it hesitate when out of gear?

What is the engine vacume?

Have you adjusted the idle mixture screws?

If all else is adjusted properly, You may need to increase your shooter size.

The rtv in my throttle blades has been there for six months and has seen 7400 rpms...

It is a good temporary way to fill the holes.

 

It's a surge effectively. The motor will not maintain consistent rpm under load in gear.. if you try to drive at that speed it will just slow down. Once you open the thottle a little more it will gather rpm and get past the dead area. Its not a bog, or a flat spot..

Idle screws and all that has been checked and adjusted. vacuum is 10" max. but thats bc the cam.

 

I have a theory...

Try raising the float level.

I believe that the float is low.

BECAUSE
When you get the motor to a certain RPM 1700 it is the gas from the accererator pump that gets you there. When you maintain that RPM the accererator shot is used up and the carb runs lean hence the surge.

When you raise the RPM, the vacume increases and it is sufficient to pull the fuel into the main metering system and it runs fine.

If You raise the float level... It will be easier for the carb to pull fuel at the lower rpm at low vacume.


This is the only thing that I can think of that may be causing your problem. I had a similar problem and this fixed it. I ran the float level at slightly higher than recommended.

Please give this a try and let me know the results.