MustangWorks.com : Ford Forums - View Single Post

LX4Play · 06-29-2002, 02:19 PM

Skyman,

I think that you may be running lean if you are untuned since the intake swap. The Holley has a very big cross sectional area (3.1" sq) compared to the Edelbrock (2.4" sq) per runner. Although, the Holley lower is close to a Felpro 1250 at the opening, unported, which helps to increase velocity when matching up to aftermarket heads (unported)....just at the intake port opening, mind you. This additional airflow volume has definitely changed your fuel requirement, if you haven't already adjusted.
As for the RPM intake, I have run a best of 11.30 @ 122, naturally aspirated, at Carlsbad (with RPM intake). I have since made the switch to the Holley, with no other changes and gained only 3 rwhp, but running way lean. I aslo gained 500 usable rpm from the Holley, for a new peak @ 6,200-6,300 rpm. This was my most beneficial attribute to the Holley. I still need to re-dynotune my combo to get the correct a/f ratio (12.8-13.0:1) I did have to portmatch the lower to a 1262 gasket for a better match to my heads.
The key ingredient to a successful combination is 'consistent cross sectional area' btween the intake runners of the intake and the heads. If your heads do not flow enough air to support the airflow of this intake, then it will not beneficial, as in most out of box heads, unported. The Holley intake was designed to maintain tq production (long runner), while improving peak HP with it's massive runner cross section to meet big airflow demends. I bet if you retune for optimal air/fuel ratio, you will see results!

06-29-2002, 02:19 PM	#14
LX4Play Registered Member Join Date: Jul 2000 Location: San Diego, Ca Posts: 7	Skyman, I think that you may be running lean if you are untuned since the intake swap. The Holley has a very big cross sectional area (3.1" sq) compared to the Edelbrock (2.4" sq) per runner. Although, the Holley lower is close to a Felpro 1250 at the opening, unported, which helps to increase velocity when matching up to aftermarket heads (unported)....just at the intake port opening, mind you. This additional airflow volume has definitely changed your fuel requirement, if you haven't already adjusted. As for the RPM intake, I have run a best of 11.30 @ 122, naturally aspirated, at Carlsbad (with RPM intake). I have since made the switch to the Holley, with no other changes and gained only 3 rwhp, but running way lean. I aslo gained 500 usable rpm from the Holley, for a new peak @ 6,200-6,300 rpm. This was my most beneficial attribute to the Holley. I still need to re-dynotune my combo to get the correct a/f ratio (12.8-13.0:1) I did have to portmatch the lower to a 1262 gasket for a better match to my heads. The key ingredient to a successful combination is 'consistent cross sectional area' btween the intake runners of the intake and the heads. If your heads do not flow enough air to support the airflow of this intake, then it will not beneficial, as in most out of box heads, unported. The Holley intake was designed to maintain tq production (long runner), while improving peak HP with it's massive runner cross section to meet big airflow demends. I bet if you retune for optimal air/fuel ratio, you will see results!