Lack of air

[justushdw]

I recently had some work done tuning my 429 with a Demon Carb. It's in a Shell Valley kit. It seems like it's starving for air when sitting at idle. With the hood closed the idle goes down by about 150 RPM, when I open it up the RPM goes back up. When I'm driving it runs great as long as it's moving. Even the idle is good as long as it is moving. Any thoughts on what could be done to fix this or shouldn't I worry about it.

Joe

[jhv48]

Post a picture of your air cleaner and carb.

[*13*]

Some of he original 427 cars had a single carb with a small air filter in a turkey pan. Always wonder how they can get any air in there. Yes, pictures of your setup might shed some light. What type of filter are you using? Thats about the only blind question comes to mind.

[Grubby]

It seems really unlikely it is starved for air at idle. At wide open throttle it might need 850 cfm at idle it would need only a few hundred.

John

[Grubby]

It seems really unlikely it is starved for air at idle. At wide open throttle it might need 850 cfm at idle it would need only a few hundred.

I am sure closing the hood is a clue.

John

[Gaz64]

Originally Posted by Grubby

It seems really unlikely it is starved for air at idle. At wide open throttle it might need 850 cfm at idle it would need only a few hundred.

I am sure closing the hood is a clue.

John

If the engine is losing this amount of rpm at idle when the hood is shut, then the engine would be starving for air at anytime above idle speed.

I would remove the aircleaner, and see what it does then.

You could also have a hot air issue that makes the carb mixture different at hot idle.

[undy]

Idle mixture or float level would be what I check first.

[Jac Mac]

You mention the idle improves once moving, that could mean the under hood temps rise quickly at a standstill. Seal the carb to hood scoop and look at shielding /wrapping headers etc and work on getting hot air out of the engine bay rather than getting more air in.