“The R2C off-road truck filter works great and my crew is very happy about not having to wash those oiled filters! We were able to pull off a 4th place finish in the Governors cup race on Sunday using a R2C filter. Thanks again.”

Steve McCrossan
#33 Pro 4x4

CFD 4150 4 Barrel Air Cleaner Bases

CFD 4150 race air cleaner- 4 hole Direct Flow
Firepower CFD 4150 race air cleaner - 4 hole design

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 And many other quality performance products dealers!




large0 1850C

Use Firepower Base AC10710 for this style and for tall, flat top choke housings.

1.39" Choke Tower Height.

large0 4779C

Use Firepower Base AC10709 for short and flat choke towers. 

1.05" Choke Tower Height.

holley 4150 air cleaner bases

CFD Computer Designed for unmatched power




Unlock the true potential of your street or race carburetor!


Introducing the most powerful and versatile racing air cleaner bases for Holley 4150 4 barrel applications!   Bolt-on double digit power gains.

Smooth radius entry profiles dramatically improve Booster Signal, Increasing horsepower and torque. The result is crisp throttle response,  improved pull out of corners and additional straightaway speed. 

Outperforms poorly designed, faceted and fluted entry profiles that disrupt the boundary layer and increase drag and turbulence.

Allows precision carburetors to perform as designed! 


The best Horsepower gain value available today! 


 easy power and torque gains

   +9 rear wheel horsepower gain on a 604 Crate from many 604 engine  specialists! 

   +16 engine horsepower gain on a Dirt Modified!



*Racer Advisory!

Concerns have been reported from Crate and Late Model racers that are making an attempt to utilize short air filters and steel raised air cleaner bases.
These small filters do not have the capacity to hold dust without raising mid-race restriction to levels that will affect horsepower and response late in races.
An eye-opening example!:  Testing a 3" oiled gauze filter used on a Late Model that competed in a fairly dusty, 50 lap event resulted in a loss of 47 Horsepower!


Don't do this to yourself!

Stop chasing the latest and greatest from people that are not airflow and filtration experts. We have over 70 years of experience designing sophisticated air cleaner systems. 


R2C's patented CFD bases will outperform every air cleaner base made today. They are extremely strong, will not bend and deflect and seal filters even under the most grueling circumstances.  Firepower CFD bases allow the use of large air filters which are vital for maximum, undisturbed air flow throughout the longest and dustiest of races. 

Do not be deceived and cause yourself unnecessary issues!  As racers across the world know, the race proven combination of an R2C Firepower CFD base and Pro Series race filter will serve you extremely well in every condition you will encounter! 





Months of design evaluation using CFD and flow bench testing, followed by extensive dyno and track tests (now well over 1000 independent pulls!) conducted by the most respected names in race engine and carburetor assembly, have resulted in the best flowing, highest power producing air cleaner bases for Holley 4 barrel race applications. Every application from Stock Cars to unlimited Late Models and Big Block Modifieds have achieved significant gains in power and response/driveability.

R2C engineers developed each smooth entry, precision base shape to augment the venturi profile of the popular 4150 series Holley carburetor, resulting in dramatically improved entry profiles, reduced restriction and a much stronger and consistent venturi/booster signal, allowing precision racing carburetors to perform at optimum levels and engines to produce increased power and torque.

When used in conjunction with R2C Late Model/Modified air filter configurations, nothing comes close to the performance advantage R2C CFD 4150 4 barrel bases offer racers in applications from Stock cars to the highest horsepower open engines.

Patented Firepower CFD 4150 4 barrel air cleaner bases are offered in three configurations, allowing racers to select the precision contour that maximizes overall performance based on their individual applications. Strong and durable, R2C CFD bases won't dent or deflect, causing filter sealing issues.

* Patents Pending

  • More Horsepower and Torque than any racing air cleaner base available today! 

  • Patented, smooth radius profile entry design makes more power

  • 3 CFD 4150 shaped flow director configurations to choose from

  • Ultra strong, composite Construction - No bending, dents and it runs cooler.

       Contact your favorite performance parts retailer


 Modified and Late Model Engines


       Dirt Modified dyno testing 

       680 HP Baseline

       696 HP using R2C Firepower  CFD 4150 race air cleaner base - w/2 pulls at +18 HP!

       Excellent power and torque gains throughout the power band.



       Attention 602 and 604 Crate Engine users

      maximum power to keep you in front!


          AC10617 CFD 4150 base and R10523 filter is the best combination.  

           Use lid AC10521 or AC10520  

        9-14 rear wheel horsepower gains!


      * Use AC10617 with HEI Distributors
           Do not use 3" tall air filters on 602 and 604 applications!   
        For maximum performance from the green to the checkered flag, 4-5" filter heights are strongly recommended.

Racer's: Contact R2C with Technical/Application Questions:  racing@r2cperformance.com or 847-970-9566


  •  AC10615 and AC10617 for maximum power between 3500 - 8000 RPM

  •  AC10616 for higher RPM applications 7000 - 9000+ RPM


AC10615  CFD 4150 Firepower Air Cleaner Racing Base - 1" Height Above Flange - Open Flow Director  1 3/8" Drop
AC10616  CFD 4150 firepower Air Cleaner racing Base - 1" Height Above Flange - 4 Hole Design  1 3/8" Drop
AC10617  CFD 4150 Firepower Air Cleaner racing Base - 2" Height Above Flange - Open Flow Director   3/8" Drop


AC10618 CFD 4150 Race System - Includes 3 Shaped Flow Directors, Base and gaskets.            
                                                                         Unassembled components for testing. (No Plungers)


R2C patented Holley 4150 air cleaner bases and Flow Directors are now available for carburetors that are equipped with choke housings such as the Double Pumper series, Street Avenger TM and Ultra models.

Bolt-On Double Digit Horsepower and Torque Gains!


  *Holley Ultra HP - Use Air Cleaner Base AC10617 due to extended bowl length.

    Applications for Braswell 4825 carburetors available soon!


Base Dimensional Drawings


               AC10617 Base


                  AC10615  Base     




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