Edelbrock carburetor 4x4 offroad modifications

[blubuckaroo]

If 2psi is adequate to maintain the fuel level in the float bowls while off road, why increase the pressure to 5 psi to drive on the roads? I know the roads here in Tucson aren't much better than unpaved Forest Service dirt roads.

Bouncing over bumps allows the fuel in the bowls to slosh and the floats to swing. Not much problem when the float is momentarily too high, but when the float drops, 6PSI fuel pressure can overfill the bowl quickly. Edelbrock/Carter carbs have more issues with this than some others because the floats have less leverage on the needle valves. The spring loaded needle valve offered up by Edelbrock don't increase the seat pressure and do little to help. By reducing the fuel pressure to 2PSI during the lower fuel demands of off-roading, there won't be as much overfilling.
There was actually a manufacturer that made a product called a Cagle Regulator in the 80's that would adjust the fuel pressure automatically depending on the engine's vacuum. The patent owner died and the family didn't continue the product. Of course, fuel injection was showing up around that time too, reducing the customer base. If you can find a good one, they work great on a dual purpose 4X4.

 

[Rustytruck]

I use a Cagle pressure regulator myself and have had it over 20 years. Funny you mention the Cagle family as last year the family was clearing out the old mans assets and sold several Cagle regulators NOS on E-bay. I bought one as back-up to the one I am using. The Cagle regulator was originally designed and sold for the offshore boat racing crowd as the pounding of the boats on ocean chop was wreaking havoc on the carburetors. Cagle regulators are vacuum controlled fuel pressure regulators. High engine vacuum lowers the fuel pressure, low engine vacuum from open throttle position raises fuel pressure.

 

[savage]

The Cagle regulator, looks interesting, has any body seen them for sale any ware? Since they were made for boat racing, they should last awhile.

 

[blubuckaroo]

The Cagle regulator, looks interesting, has any body seen them for sale any ware? Since they were made for boat racing, they should last awhile.

Occasionally I've see Cagles on ebay. You need to be careful which model you get. There was one made for the later model Q-Jet with its built in pressure regulator. It delivers a higher pressure that doesn't work as well with other carbs.
Even if you can't be fortunate to find a Cagle, simple and inexpensive pressure regulators are available at most part stores and work very well to make quick adjustments at the trail head.

 

[jckkys]

I have no problem understanding the theory behind the reduced fuel pressure. My point addressed the fact that first hand experience has not demonstrated it, yet.

 

[partsloco]

The cagle regulator looks pretty cool, Never seen anything like that before. This would eliminate the need to manually adjust the regulator. I wonder how the diagrams are after 20-30 years. Can't believe its already 2015.

 

[savage]

Has any other company made a vacuum operated fuel regulator , besides Cagle?