BK Racing Ecotec Performance Intake Valves for 2.0L, 2.2L & 2.4L Engines

High-Performance Ecotec Intake Valves for 2.0L, 2.2L & 2.4L Engines

The BK Racing HF35.6 Ecotec Performance Intake Valves were developed specifically for high-performance and racing GM Ecotec engines. Manufactured from 21-4N stainless steel, fully nitrided after final machining, flow-bench tested, and engineered with an airflow-optimized profile, these are not simply replacement Ecotec intake valves.

Our goal was to develop a performance intake valve around airflow, curtain area and valve geometry rather than simply making the valve as large as possible.

That approach produced measurable results.

During development with MWR Technologies, our prototype BK Racing Ecotec intake valve showed an improvement of approximately 10 CFM over the OEM GM Ecotec intake valve at .050" lift on the same cylinder head and flow bench.

The result was the BK Racing HF35.6 — a 35.6 mm performance Ecotec intake valve developed specifically around the airflow characteristics of the Ecotec cylinder head.

Why We Developed Our Own Ecotec Intake Valve

There are already stainless, nitrided and oversized intake valves available for the GM Ecotec.

We weren't interested in simply making another replacement valve.

We wanted to find out how much could be gained by looking at the entire intake valve as part of the airflow path.

Development focused on the relationship between valve diameter, curtain area, backside profile, stem obstruction and the transition between the valve head and stem.

That distinction is important.

A larger intake valve doesn't automatically mean a better-flowing intake valve.

Valve diameter is only one part of the relationship between the valve, seat, throat, combustion chamber and intake port. Increasing diameter can increase potential curtain area, but the valve still has to work efficiently with the rest of the Ecotec cylinder head.

That's why we developed the HF35.6 around a 35.6 mm (+0.5 mm) valve head rather than simply pursuing the largest valve we could fit.

Flow-Tested Against the OEM GM Ecotec Intake Valve

We don't want customers to have to rely solely on claims about what a valve should do.

We tested it.

During prototype development at MWR Technologies, the BK Racing intake valve demonstrated an improvement of approximately:

+10 CFM over the OEM Ecotec intake valve at .050" lift

The largest improvement appeared in the low-lift region, where the relationship between the valve, seat and available curtain area has a significant influence on airflow.

As lift increased, the difference narrowed as other areas of the cylinder head increasingly became part of the airflow limitation.

That's exactly why we believe looking at the complete flow curve matters more than simply advertising valve diameter.

Additional testing against OEM and leading aftermarket Ecotec intake valves is planned, and we will publish those results as testing is completed.

35.6 mm (+0.5 mm) Ecotec Intake Valves

The BK Racing HF35.6 uses a nominal:

35.6 mm intake valve head

This places it approximately 0.5 mm larger than the commonly published 35.1 mm OEM-size Ecotec intake valve.

We chose this size intentionally.

Rather than jumping directly to a substantially oversized valve, the HF35.6 combines the additional curtain area of a modest increase in diameter with an airflow-focused valve profile.

The philosophy behind the design is simple:

Make the entire valve work with the cylinder head.

Airflow-Optimized Intake Valve Profile

An intake valve becomes part of the airflow path every time it lifts away from the seat.

The shape of the backside, the transition into the stem, exposed stem area and valve-head geometry can all influence how efficiently air moves past the valve and into the cylinder.

The BK Racing HF35.6 incorporates an undercut stem, airflow-optimized backside profile and flat chamber-side face developed specifically around the Ecotec cylinder head.

Rather than duplicating the OEM valve shape in a different material, the HF35.6 was developed as a performance valve from the beginning.

21-4N Stainless Steel Ecotec Intake Valves

BK Racing HF35.6 Ecotec intake valves are manufactured from 21-4N stainless steel for strength, wear resistance and durability in demanding performance and racing applications.

Our priorities were:

Strength • fatigue resistance • wear resistance • dimensional stability • sustained-RPM durability

But selecting the material was only part of the process.

Fully Nitrided After Final Machining

Not all nitrided valves are manufactured the same way.

BK Racing Ecotec intake valves are finish-machined first and nitrided afterward.

We specified that manufacturing sequence intentionally.

Nitriding produces a hardened surface layer that can improve wear and surface resistance. Machining or grinding treated areas afterward can remove some of that treated surface.

We didn't want to manufacture them that way.

The required machining and final geometry are completed first. The finished valve then receives its nitriding treatment, allowing the treated surface to remain through important areas of the finished valve.

Finish the valve first. Then nitride the finished component.

Two Ecotec Intake Valve Configurations

Unlike our exhaust valve, the HF35.6 intake valve will be available in two configurations so builders can select the version appropriate for their camshaft.

Standard / Stock Base Circle
Designed for stock camshafts and aftermarket camshafts retaining stock-style base-circle geometry.

Reduced Base Circle / Regrind
Designed for reduced-base-circle and reground camshaft combinations where additional valve-tip height can be used when establishing proper valvetrain geometry.

This gives engine builders the ability to select the correct valve for the camshaft combination rather than forcing one valve configuration to work in every application.

Designed as Part of a Complete BK Racing Ecotec Valvetrain

The intake valve is only one component of the complete Ecotec valvetrain.

As RPM and camshaft demands increase, maintaining valve control becomes increasingly important.

The BK Racing HF35.6 Intake Valves can be combined with our 83 lb Ecotec Valve Springs, Lightweight Titanium Retainers and Solid Lash Adjusters to build a more complete performance Ecotec valvetrain.

Our 83 lb springs provide approximately 83 lb of seat pressure at a 1.325" installed height and approximately 230 lb at .500" lift, and have been tested in Ecotec applications to approximately 9,300 RPM.

For combinations using BK Racing Solid Lash Adjusters, our typical starting lash specifications are:

Intake: .008"
Exhaust: .010"

Final lash should always be established for the specific camshaft and engine combination.

BK Racing HF35.6 Ecotec Intake Valve Specifications

Product: BK Racing HF35.6 Performance Ecotec Intake Valves
Application: GM Ecotec 2.0L / 2.2L / 2.4L
Material: 21-4N stainless steel
Treatment: Full nitriding after final machining
Head Diameter: 35.6 mm nominal (+0.5 mm)
Valve Face: Flat
Backside: BK Racing airflow-optimized profile
Stem Diameter: Approximately 5.97 mm
Stem: Undercut airflow profile
Keeper: OEM-style triple groove
Camshaft Options: Standard / Stock Base Circle or Reduced Base Circle / Regrind
Quantity: Set of 8 intake valves
Quality Control: 100% inspected and supplied in matched production sets
Development: BK Racing Products
Flow Testing: MWR Technologies

GM Ecotec Engine Applications

BK Racing HF35.6 performance intake valves were developed for compatible cylinder heads within the GM Ecotec engine family, including popular 2.0L, 2.2L and 2.4L Ecotec performance applications.

These engines can be found throughout Chevrolet, Pontiac and Saturn platforms including the Chevrolet Cobalt, Cavalier and HHR, Saturn Ion and Sky, and Pontiac Solstice, among other Ecotec-equipped vehicles.

They are particularly suited to:

Circle-track Ecotec engines • high-RPM naturally aspirated builds • performance cylinder heads • modified camshaft combinations • reground camshafts • competition engines • performance 2.2L Ecotec builds • performance 2.4L Ecotec builds

Specific engine and cylinder-head compatibility should always be verified before installation.

Why Choose BK Racing Ecotec Intake Valves?

The BK Racing HF35.6 brings together the features we wanted in a serious performance Ecotec intake valve:

• 21-4N stainless-steel construction
• Full nitriding after final machining
• 35.6 mm (+0.5 mm) valve head
• Airflow-optimized valve geometry
• Undercut stem
• Flat chamber-side face
• Two camshaft/base-circle configurations
• 100% inspected matched sets of eight
• Flow-bench developed against the OEM Ecotec intake valve
• Approximately +10 CFM demonstrated at .050" lift during prototype testing
• Designed to integrate with the complete BK Racing Ecotec valvetrain system

We didn't develop these because the Ecotec market needed another replacement intake valve.

We developed them because we believed the Ecotec intake valve could be better.

Sold as one matched set of 8 BK Racing HF35.6 Performance Ecotec Intake Valves.