Do Performance Exhaust Valves Increase CFM? Ecotec Flow-Bench Testing
Do Performance Exhaust Valves Increase CFM? Our Ecotec Flow-Bench Testing
Yes, an Ecotec performance exhaust valve can increase CFM—but simply installing a larger valve does not guarantee more airflow.
We learned that firsthand while developing the BK Racing Ecotec Exhaust Valve.
Rather than beginning with an oversized exhaust valve and assuming additional valve size would improve flow, we approached the development differently.
We intentionally tested a smaller-than-stock development valve.
Why?
Because we wanted to determine whether the valve design itself could improve airflow. If we could outperform the stock Ecotec exhaust valve while actually giving up valve diameter, we would have much stronger evidence that we were moving the design in the right direction.
Back-to-back flow bench testing performed with MWR Technologies showed exactly that:
The intentionally undersized BK Racing development valve flowed 3 CFM more than the stock Ecotec exhaust-valve baseline.
During the same development process, an oversized aftermarket exhaust valve was also evaluated. In that particular cylinder head configuration, the larger valve did not outperform the stock baseline.
That doesn't prove smaller valves are better.
And it certainly doesn't mean oversized Ecotec valves don't work.
It demonstrates something much more useful:
Exhaust-valve diameter alone does not determine CFM.
The valve, valve seat, throat, bowl, port and combustion chamber have to work together.
That discovery ultimately influenced our production direction. The finished BK Racing Ecotec Exhaust Valve is 30.1 mm—stock-size architecture rather than an oversized design.
Quick Answer: Do Performance Ecotec Exhaust Valves Increase Airflow?
They can.
But changing to a performance exhaust valve doesn't automatically increase cylinder-head flow.
A performance valve can potentially influence airflow through its overall shape, backside profile, stem design, seat relationship and the amount of obstruction it presents to the exhaust port.
Valve diameter is another variable, but it isn't the only variable.
Our testing provided a particularly clear example:
| Exhaust Valve Tested | Size Strategy | Flow-Bench Result |
|---|---|---|
| Stock Ecotec exhaust valve | Stock baseline | Baseline |
| Oversized aftermarket valve | Larger than stock | Did not outperform stock in our test configuration |
| BK Racing development valve | Intentionally smaller than stock | +3 CFM over stock |
| BK Racing production valve | 30.1 mm stock-size architecture | Final production configuration |
The important part of this table isn't simply the +3 CFM.
It's how that 3 CFM was achieved.
The valve that produced the gain wasn't larger.
It was deliberately smaller.
What Does CFM Mean on a Cylinder-Head Flow Bench?
CFM stands for cubic feet per minute.
A cylinder-head flow bench measures how much air can move through a port under controlled conditions.
For an exhaust-port test, the valve is opened to predetermined lift points while a controlled pressure differential is applied across the cylinder head.
The resulting airflow is measured in CFM.
This allows an engine builder or cylinder-head developer to evaluate how changes to the port, valve seat, valve or other components affect airflow.
The critical word here is controlled.
A useful flow test isn't simply about generating the largest number possible.
It's about comparing changes under consistent conditions.
Why Back-to-Back Testing Is More Important Than Comparing Internet CFM Numbers
This is one of the most important things to understand when comparing cylinder-head flow numbers.
A flow number from one shop isn't necessarily directly comparable with a number from another shop.
Testing procedures can differ.
Bore fixtures can differ.
Exhaust tubes can differ.
Test pressure can differ.
Valve jobs can differ.
Cylinder heads can differ.
Even the way a test is conducted can influence the result.
ZZPerformance provides a good example because it publishes its Ecotec cylinder-head testing conditions. Its LSJ flow data specifies testing at 28 inches of pressure with a 3.5-inch bore plate and a 1⅝-inch exhaust flow tube, using stock 30 mm exhaust valves. ZZPerformance
That information makes the data far more useful.
But it still doesn't mean we should take a CFM number from that test and directly compare it with a number generated on another flow bench under different conditions.
For valve development, the more useful question is:
What happens when we change the valve while keeping the rest of the test as consistent as possible?
That's why our development emphasized back-to-back testing.
Same basic test environment.
Stock valve baseline.
Change the valve.
Measure again.
Now we're learning something about the component we changed.
Why We Started With the Stock Ecotec Exhaust Valve
Every development program needs a baseline.
The stock valve provides one.
GM currently lists OE exhaust valve 12615936 at 29.8 mm head diameter, 5.9525 mm stem diameter and 99.7 mm overall length, with three keeper grooves. GM classifies it as a standard-size steel valve. GM Parts
Those specifications establish the basic dimensions of one widely used OE Ecotec exhaust-valve architecture.
Our objective wasn't simply to prove that an aftermarket part could look different from the GM valve.
We wanted to determine whether changing the valve could produce a measurable airflow improvement.
That's a much higher standard.
Why Valve Diameter Seems Like the Obvious Way to Increase CFM
If you make a valve larger, you potentially create more valve curtain area.
Valve curtain area is the opening created around the circumference of the valve as it lifts away from the seat.
As a simplified geometric concept:
Curtain Area ≈ Valve Circumference × Valve Lift
or:
Curtain Area ≈ π × Valve Diameter × Valve Lift
That means increasing valve diameter increases theoretical curtain area at the same valve lift.
So why wouldn't the biggest valve always flow the most?
Because theoretical opening area and actual port airflow aren't the same thing.
The air still has to get through the rest of the cylinder head.
The Cylinder Head Has to Use the Additional Valve Area
Imagine increasing exhaust-valve diameter while leaving everything else unchanged.
The valve may now provide additional theoretical curtain area.
But what happens immediately behind it?
The airflow still encounters the valve seat.
Then the throat.
Then the bowl.
Then the exhaust port.
The combustion chamber can also affect the way gases approach and move around the valve.
If one of those areas is already controlling the airflow, simply increasing valve diameter may not produce the improvement expected.
This is why oversized valves are normally best viewed as part of a complete cylinder-head development strategy.
The larger valve creates potential.
The rest of the cylinder head has to take advantage of it.
What Happened When We Tested an Oversized Ecotec Exhaust Valve?
During our development work, an oversized aftermarket Ecotec exhaust valve was tested in the same general development program.
We're deliberately not identifying the manufacturer.
The objective was to learn—not to turn the test into an attack on another company's product.
In the cylinder-head configuration being tested, the oversized valve did not outperform the stock exhaust-valve baseline.
That's an important result, but it's equally important not to overstate what it means.
It does not establish that the valve is poorly designed.
It does not establish that oversized Ecotec exhaust valves don't work.
And it doesn't establish that the same valve wouldn't produce an improvement in a cylinder head whose valve seat, throat, bowl and port had been developed specifically around the larger diameter.
What it establishes is this:
Installing a larger Ecotec exhaust valve did not automatically produce additional airflow in the configuration we tested.
That changed how we approached the next part of development.
Our Next Test Was Intentionally Backwards
Most people trying to increase cylinder-head airflow probably wouldn't intentionally make the valve smaller.
We did.
And there was a specific reason.
We wanted to separate diameter from design.
If we made our development valve larger than stock and it gained airflow, we'd immediately have another question:
Was the improvement coming from the valve design?
Or did we simply gain airflow because we increased valve diameter and curtain area?
So instead of giving our development valve an advantage, we deliberately gave it a disadvantage.
We reduced the valve diameter.
Then we put it on the flow bench.
Why Test an Undersized Ecotec Exhaust Valve?
The test was intended to answer one specific engineering question:
Can the direction of our valve design improve airflow even when the valve has less diameter to work with?
If the answer was no, we'd learn something.
If airflow stayed equal to stock, we'd learn something.
And if the smaller valve actually flowed more than the stock valve, we'd have strong evidence that diameter wasn't responsible for the improvement.
That is exactly why the development valve was intentionally produced undersized.
It wasn't a manufacturing mistake.
It was a controlled development decision.
The Undersized Valve Outflowed the Stock Ecotec Valve
The result was encouraging.
In back-to-back testing performed with MWR Technologies, the intentionally undersized BK Racing development exhaust valve produced:
+3 CFM over the stock Ecotec exhaust-valve baseline
Think about what that result does—and doesn't—tell us.
It doesn't tell us that smaller valves inherently flow better.
They don't.
It doesn't tell us that every feature incorporated into our development valve individually increased airflow.
We didn't test every feature independently.
And it doesn't tell us that the final production valve automatically gains the same amount.
The production valve is a different configuration.
What the test does tell us is extremely useful:
The measured airflow improvement could not be explained by increased valve diameter, because the development valve was actually smaller than the stock valve.
That's exactly what the experiment was designed to determine.
Why 3 CFM Is More Interesting Than It Sounds
It's easy to look at “3 CFM” and immediately ask whether that's a large gain.
But context matters.
We weren't comparing a completely stock cylinder head with a heavily ported cylinder head.
We weren't changing the entire exhaust port.
We weren't increasing valve diameter.
We were evaluating the effect of a valve-development direction.
And we intentionally reduced valve diameter while doing it.
So the important result isn't simply:
+3 CFM.
It's:
+3 CFM despite deliberately giving up valve diameter.
That's a very different development result.
Why We Don't Convert 3 CFM Into a Horsepower Claim
There are rules of thumb on the internet attempting to convert cylinder-head CFM directly into horsepower.
We're not going to use them here.
A flow bench is not a running engine.
An engine has moving pistons, changing cylinder pressure, combustion, exhaust-system pressure waves, camshaft timing and a constantly changing pressure differential across the valve.
The airflow requirement also changes throughout the engine cycle.
So claiming:
“3 CFM equals X horsepower”
would imply a precision the test doesn't provide.
The appropriate conclusion is simpler:
The development valve measurably improved static exhaust airflow over the stock-valve baseline under the conditions tested.
That's what we measured.
That's what we'll claim.
Does This Prove the Valve Shape Is Responsible?
It tells us the complete development valve performed better.
That's an important distinction.
A performance valve can include several airflow-related characteristics.
These can include its backside profile, stem design, transitions, margin, seat relationship and other geometric features.
But unless each feature is individually A/B tested while every other dimension remains identical, we can't responsibly assign a specific amount of CFM to one feature.
So we don't say:
“The undercut stem added 3 CFM.”
Or:
“The backside profile added 3 CFM.”
Or:
“The back-cut added 3 CFM.”
We say:
The complete BK Racing development valve produced a 3 CFM improvement over the stock baseline.
That's what the test actually demonstrated.
Can an Undercut Valve Stem Improve Ecotec Exhaust Flow?
An undercut stem can reduce the physical area of the valve stem exposed to the airflow.
The basic principle makes sense: the valve stem is sitting inside the port, so reducing unnecessary obstruction can potentially help airflow.
But that doesn't mean the smallest possible stem is automatically the best design.
An exhaust valve is also a structural and thermal component.
It has to survive high temperatures and repeated mechanical loading while maintaining stability within the guide.
So stem geometry has to balance airflow, strength, heat transfer, durability and mass.
Our production valve incorporates an undercut-stem concept, but we're intentionally keeping the proprietary dimensions and geometric relationships private.
Customers need to know what the design is intended to accomplish.
Competitors don't need our blueprint.
Does Exhaust Valve Shape Affect CFM?
Potentially, yes.
The exhaust gases don't disappear once they reach the valve.
They have to move around it.
That means the backside of the valve is literally part of the airflow path.
The transition from the valve head toward the stem can change the shape presented to the moving gases.
Seat geometry can change how airflow initially leaves the combustion chamber.
Stem geometry can change obstruction farther into the port.
But once again, these areas interact.
That's why there isn't one universally perfect exhaust-valve shape for every cylinder head.
The valve needs to work with the cylinder head around it.
What About the Valve Seat and Throat?
These areas are critical.
The valve seat isn't merely there to seal the combustion chamber.
When the valve opens, the seat becomes part of the airflow transition.
Immediately below that is the throat.
If the throat is poorly matched to the valve diameter, increasing valve size may create theoretical area that the rest of the port can't effectively use.
This is also why an oversized valve often requires additional cylinder-head work.
A valve and cylinder head should be treated as a combination.
Bigger Doesn't Automatically Mean Better—but Bigger Isn't Bad Either
This distinction is worth emphasizing because it's easy to turn the testing into the wrong conclusion.
We are not saying:
Oversized Ecotec valves don't work.
We're saying:
Oversized Ecotec valves need the cylinder head to support them.
There are absolutely combinations where a larger exhaust valve can increase airflow.
If the seat, throat, bowl, port and chamber are developed appropriately, additional valve diameter can be useful.
Our testing simply showed that diameter by itself wasn't enough in the configuration we evaluated.
That's a much more useful lesson for someone building an Ecotec cylinder head.
How Does This Compare With Other Ecotec Performance Valves?
The current aftermarket itself demonstrates that manufacturers take different approaches.
Supertech's current catalog covers the GM Ecotec LSJ 2.0/2.2/2.4 family and offers performance valvetrain components for those applications. supertechperformance.com
ZZPerformance sells stock-size Inconel Ecotec valves for LSJ, LNF, LDK/LHU and LE5 applications and specifically describes those valves as sharing stock dimensions rather than relying on oversizing. ZZPerformance
That illustrates something important:
There isn't one universally accepted rule that a performance Ecotec exhaust valve must be oversized.
Material strategy, intended operating temperature, cylinder-head work and valve geometry all influence the design choice.
Our own development led us toward a stock-size production valve.
Why Is the BK Racing Production Exhaust Valve 30.1 mm?
Our final production exhaust valve is 30.1 mm.
That's an important specification because it establishes that the finished valve remains within the stock-size Ecotec architecture rather than being an oversized-valve conversion.
We didn't arrive at that decision simply because “stock size is good enough.”
We tested alternatives.
We tested an oversized aftermarket valve.
We intentionally tested our own development design undersized.
And the undersized development valve still produced more measured airflow than the stock baseline.
That gave us a strong reason to continue developing the production valve without depending on additional diameter as the primary airflow strategy.
Is 30.1 mm Bigger Than the GM 29.8 mm Valve?
Numerically, yes.
GM currently lists 12615936 at 29.8 mm, while the BK Racing production valve is 30.1 mm. GM Parts
But in aftermarket performance-valve terminology, approximately 30.1 mm is generally treated as the standard/stock-size Ecotec architecture, rather than an oversized conversion.
That distinction is important because a true oversized valve is intended to increase valve diameter enough that corresponding cylinder-head work may become part of the installation.
So throughout our technical content, we'll refer to the BK Racing 30.1 mm valve as stock size, while also publishing the actual 30.1 mm specification so engine builders know exactly what they're working with.
Did the 30.1 mm Production Valve Gain 3 CFM?
We need to be very clear here:
The measured +3 CFM result came from our intentionally undersized development valve—not the final 30.1 mm production valve.
That's not a weakness in the data.
It's what makes the development test interesting.
The experiment was designed to determine whether our development direction could improve airflow while working with less diameter than stock.
It did.
But until the 30.1 mm production valve is tested under the same controlled conditions, we're not going to attach the development valve's CFM result to it.
We won't turn an expectation into a test result.
Will the 30.1 mm Production Valve Flow More?
That's exactly what the next round of testing is intended to determine.
From a development standpoint, restoring the intended valve diameter gives us additional potential curtain area compared with the deliberately undersized test valve.
So there is a logical reason to investigate whether the production configuration can improve further.
But airflow isn't determined by diameter alone—that's the entire lesson of our testing.
Therefore we won't predict a number.
We'll put the production valve on the flow bench and measure it.
If it gains more, we'll publish the result.
If the result teaches us something unexpected, that's useful development information too.
Flow Bench vs Dyno: What's the Difference?
A flow bench answers:
Did this change alter airflow through the cylinder head under controlled conditions?
A dyno answers a much broader question:
How does the complete running engine perform?
Those aren't interchangeable tests.
A flow-bench improvement can help guide development, but the engine's final output also depends on compression ratio, camshaft timing, intake system, exhaust system, combustion efficiency, RPM, tuning and numerous other variables.
Ideally, serious engine development uses both.
Flow testing helps understand the cylinder head.
Dyno testing evaluates the complete engine.
Track testing tells us whether the entire combination actually performs in its intended environment.
For a circle-track program, all three can matter.
Does More Exhaust CFM Always Mean More Horsepower?
No.
Cylinder-head airflow is important, but maximum CFM isn't the sole objective.
The engine has to use the airflow at the valve lifts and RPM where it actually operates.
Camshaft timing and lift determine how the valve moves.
The port's cross-sectional area influences velocity.
The exhaust system influences pressure behavior.
And the intake and exhaust sides have to work with the complete engine combination.
A cylinder head shouldn't be developed simply to win a peak-CFM contest.
The goal is to make the engine perform.
Why Exhaust Flow Matters in a High-RPM Ecotec
As RPM increases, the amount of time available to move gases through the engine decreases dramatically.
At 9,000 RPM, the crankshaft is completing 150 revolutions every second.
Because a four-stroke engine completes one exhaust cycle every two crankshaft revolutions, each exhaust valve can be going through approximately 75 complete events every second.
That's why high-RPM airflow and valvetrain control become so important.
The valve has very little time to perform its job.
For a circle-track engine that remains at elevated RPM for extended periods, this isn't a brief event.
It happens continuously, lap after lap.
That's the environment around which much of our Ecotec development is focused.
Airflow Isn't the Only Job of an Exhaust Valve
This is another reason we don't simply make every feature as aggressive as possible.
An exhaust valve has several jobs simultaneously.
It needs to allow gases to leave the cylinder efficiently.
It needs to seal combustion pressure.
It needs to transfer heat into the valve seat and cylinder head.
It has to survive repeated contact with the seat.
It has to remain stable in the guide.
And the spring has to control its mass at the engine's intended RPM.
A design that creates an impressive flow-bench number but compromises durability isn't necessarily a better racing valve.
The challenge is balancing all of those requirements.
How the Exhaust Valve Fits Into the Complete Ecotec Valvetrain
Once RPM increases, we can't discuss the valve without discussing the rest of the system.
The camshaft determines the motion being commanded.
The rocker transfers that motion.
The lash adjuster establishes the operating relationship.
The valve follows the motion.
The spring controls it.
The retainer moves with the valve and contributes to the mass being controlled.
That's why the BK Racing Ecotec Exhaust Valve, BK Racing 83 lb Valve Springs, BK Racing Lightweight Titanium Retainers and BK Racing Solid Lash Adjusters shouldn't be viewed as unrelated parts.
They're different pieces of the same system.
What Our Ecotec Exhaust-Valve Testing Actually Proved
After all of the discussion about CFM, valve size and geometry, it's worth separating the measured facts from the development conclusions.
What we measured
The stock Ecotec exhaust valve established our baseline.
An oversized aftermarket exhaust valve did not outperform that baseline in the particular test configuration.
An intentionally undersized BK Racing development exhaust valve produced 3 CFM more airflow than the stock baseline in back-to-back testing with MWR Technologies.
What that supports
Valve diameter alone did not determine the airflow result.
A larger valve was not automatically better.
A smaller valve was capable of outperforming the stock baseline when the overall valve design changed.
What we are NOT claiming
We are not claiming every oversized valve flows worse than stock.
We are not claiming smaller valves inherently flow better.
We are not claiming any one BK valve feature was individually responsible for the 3 CFM improvement.
We are not converting the 3 CFM measurement into a guaranteed horsepower number.
And we are not claiming that our final 30.1 mm production valve has produced a particular CFM gain until that exact configuration is tested.
That distinction between what we know, what the testing suggests and what remains to be tested is important to us.
So, Do Performance Ecotec Exhaust Valves Increase CFM?
They can—but the valve has to work with the cylinder head.
Our testing demonstrated that simply increasing valve diameter didn't guarantee additional airflow.
More importantly, it demonstrated the opposite:
An intentionally undersized BK Racing development valve produced 3 CFM more airflow than the stock Ecotec exhaust-valve baseline.
That result gave us evidence that the development direction was doing something beyond simply manipulating valve diameter.
Our final BK Racing production exhaust valve is 30.1 mm, retaining the stock-size Ecotec architecture.
The next step is straightforward.
Put the production valve on the same type of controlled test.
Measure it.
And let the data tell us where we are.
That's how the development started, and that's how it will continue.
Ecotec Exhaust Valve Flow-Bench FAQ
Do performance Ecotec exhaust valves increase CFM?
They can. The amount depends on the valve design and the cylinder head surrounding it. In our testing, an intentionally undersized BK Racing development valve produced a measured 3 CFM improvement over the stock baseline.
Do bigger valves increase horsepower?
Not by themselves. Bigger valves can increase potential airflow, but horsepower depends on the complete engine combination, not valve size alone.
Does an exhaust valve affect performance?
Yes. The exhaust valve influences airflow, sealing, heat transfer and valvetrain control, so its design can affect how the engine performs.
Is a valved exhaust illegal?
That question is about exhaust systems, not cylinder-head valves. This article focuses on Ecotec exhaust valves inside the engine, not exhaust cutouts or valved mufflers.
What size exhaust for 400hp?
That depends on the engine, powerband, camshaft, exhaust system and application. This article does not make a universal exhaust-system sizing recommendation.
Does a bigger Ecotec exhaust valve flow more?
Not necessarily. A larger diameter increases potential curtain area, but the valve seat, throat, bowl, port and combustion chamber need to use that additional area effectively.
What size is the BK Racing production exhaust valve?
The production BK Racing Ecotec exhaust valve is 30.1 mm, which we classify as stock-size architecture.
Was the valve that gained 3 CFM the production valve?
No. The +3 CFM result came from an intentionally undersized development valve. We keep that distinction clear because the final 30.1 mm production valve is a different configuration.
Why intentionally test a smaller valve?
We wanted to determine whether the development direction could improve airflow without gaining an advantage from increased valve diameter. The smaller development valve outperforming the stock baseline provided evidence that diameter wasn't responsible for the measured gain.
Does 3 CFM equal a certain amount of horsepower?
Not reliably. A flow bench measures static airflow under controlled conditions. Actual horsepower depends on the entire engine combination.
Does an undercut valve stem improve airflow?
It can reduce physical obstruction in the port, but its effect depends on the complete valve and cylinder-head combination. We don't attribute our measured 3 CFM gain to the stem alone.
Are oversized Ecotec exhaust valves bad?
No. An oversized valve can be beneficial when the valve seat, throat, bowl, port and combustion chamber are developed to take advantage of the larger diameter.
What engines does this information apply to?
The principles are relevant to the GM Ecotec family, including commonly modified L61, LAP, LE5, LE9, LSJ and LNF engines, although individual cylinder heads, OEM valves and operating environments can differ.
Continue Learning About Ecotec Exhaust Valves
Building the right Ecotec valvetrain involves more than choosing a single valve. Exhaust-valve material, head and stem geometry, valve springs, retainers, lash adjustment and camshaft geometry all work together—especially in sustained high-RPM racing applications. If you're putting together a complete combination, explore the guides below and see how components such as the BK Racing Ecotec Exhaust Valves, BK Racing 83 lb Valve Springs, BK Racing Lightweight Titanium Retainers and BK Racing Solid Lash Adjusters fit into the complete Ecotec valvetrain.
Stock vs Performance Ecotec Exhaust Valves: What Actually Changes?
Learn what really separates an OEM replacement valve from a purpose-built performance exhaust valve, including material, nitriding, backside geometry, stem design, margin and intended operating environment.
Ecotec Exhaust Valve Size Guide: Stock Diameter, Stem Size & Applications
Compare stock and aftermarket Ecotec exhaust-valve head diameters, stem sizes, overall lengths and applications across the L61, LAP, LE5, LE9, LSJ and LNF engines.
21-4N Stainless vs Inconel vs OEM Ecotec Exhaust Valves
Understand the differences between OEM valve materials, 21-4N stainless and Inconel—and why the BK Racing Ecotec Exhaust Valve uses fully nitrided 21-4N stainless for the naturally aspirated, sustained-RPM racing applications it was developed around.
Why Exhaust Valve Shape Matters: Tulip, Back-Cut, Margin & Stem Geometry
Learn how the valve itself becomes part of the airflow path and why tulip shape, back-cut, margin, head thickness and stem geometry can matter just as much as valve-head diameter.
Stock Ecotec Exhaust Valves at High RPM: What Are the Limitations?
See what changes when a production Ecotec valvetrain is subjected to sustained racing RPM and why exhaust valves, BK Racing 83 lb Valve Springs and lightweight retainers should be considered as parts of the same system.
Undercut Valve Stems: Can They Improve Ecotec Exhaust Flow?
Learn how reducing the exposed portion of an exhaust-valve stem can decrease obstruction in the port and why the BK Racing Ecotec Exhaust Valve uses an undercut stem with a smooth transition into the backside of the valve.
Ecotec Valve Springs, Exhaust Valves & RPM: Building the Valvetrain as a System
Go deeper into the relationship between valve mass, spring pressure, installed height, cam profile, retainers and RPM, including how the BK Racing 83 lb Valve Springs, BK Racing Lightweight Titanium Retainers, performance valves and BK Racing Solid Lash Adjusters can be combined into a complete racing valvetrain.
Reground Ecotec Cams & Valve Stem Height: Why Geometry Matters
Learn why reducing a camshaft's base circle changes the relationship between the cam, rocker, lash adjuster and valve—and why the extended-tip geometry of the BK Racing Ecotec Exhaust Valve was developed with reground-cam combinations in mind.
Ecotec Exhaust Valve Comparison: OEM vs Ferrea vs Supertech vs BK Racing
Compare OEM, Ferrea, Supertech and BK Racing Ecotec Exhaust Valves by dimensions, material, geometry and intended application, including where we have actual back-to-back flow-bench data and where we don't.
Are L61, LAP, LE5, LE9, LSJ & LNF Exhaust Valves Interchangeable?
See which Ecotec engines share basic exhaust-valve architecture, where important differences remain and what should be measured before combining valves, cylinder heads and valvetrain components from different Ecotec generations.
Start With the Complete Guide
The Complete Guide to GM Ecotec Exhaust Valves: L61, LAP, LE5, LE9, LSJ & LNF
Our complete Ecotec exhaust-valve resource brings together valve sizing, materials, airflow, geometry, high-RPM operation, camshaft compatibility and valvetrain setup in one place. It's the best starting point if you're planning an Ecotec cylinder-head or valvetrain combination and want to understand how all of these areas work together.