Street Legal Performance with Screamin Eagle Pro Street Tuner

Answers to your Pro Street Tuner Questions


Answering Your Questions about EPA, ARB, Super Tuner and Pro Street Tuner


What will we do without Super Tuner? And since Pro Street Tuner is EPA-compliant, will it actually make a power difference?


We’ve been getting a lot of questions about this, so I thought I’d answer them for all of you here.


The writing has been on the wall for years. It is not the first time the Environmental Protection Agency (EPA) and/or the Air Resource Board (ARB) (formerly known as CARB) have handed out penalties and fines. Dynojet, Daytona Twin Tech, West Coast Choppers, Volkswagen . . . These are just a few of the companies that have received fines over the past several years.
Power Basics

No tuner really increases the power of a motorcycle. Instead, it allows you to make modifications to the engine that will make power. The only way an internal combustion engine makes more power is by flowing/ combusting more air.

There is nothing in any tuner available for Harley’s Screamin Eagle or aftermarket that can increase airflow.

The only way to make more power is to increase airflow in the RPM range you want to make power in. And the only way to do that is by changing hard parts, cams, heads, exhaust, big bore or stoker kits. Of course, if you increase airflow, you need to increase fuel – or maybe adjust the timing which is where a tuner comes in.

When we use a tuning tool like Super Tuner or Pro Street Tuner, we tell the ECM what the new airflow is from the new hard parts, and maybe the new injector size and/or engine size. It really is a paint-by-number job.
The actual “Black Magic” in making power is in matching the components (heads, cams, exhaust, etc.) to get the optimum airflow for the RPM range you want to ride. You just can’t grab any cam/head/exhaust and get the results you want. The components need to complement each other.

Over all my years of tuning, this is the most common mistake I have seen. People don’t pick a cam to match their heads, and/or and exhaust to match the cam and heads.

Another common mistake is misunderstanding Horsepower and Torque. I did a blog post about it a couple years ago here

The short version is this: Peak horsepower on Harley big twins happens near 6000 RPM. Most people don’t ride there, and those that claim they do must have less traffic and more forgiving police than the rest of us. You want your power to be where you ride. Trying to pass on a two-lane road, pulling into traffic . . . generally the lower and mid RPM ranges.

For me, bottom-end and midrange torque is what I want on my street bike. I have said for years that if I hit 6000 RPM on my Harley, other than on a dyno, I must have missed a shift.

Why not Super Tuner?

Now I can build a calibration with Super Tuner that would meet ARB/EPA standards. However, to be legal for public road use, I would have to pay to have it tested by ARB and receive their stamp of approval, which the EPA recognizes. Then it would have to be locked so no one could make big changes to it. Simple enough, sure. But it takes several months and costs thousands of dollars just to approve the one calibration. Not really practical for every motorcycle you tune.

Can you make EPA/ARB legal power increases?

Harley-Davidson’s Screamin Eagle manufactures performance kits “Matched Hard Parts/Components” to increase power at different RPM ranges. The kits have been tested to be EPA-compliant, and as you probably know, come in different stages for different power increases in different RPM ranges. Something for almost everyone. If you have work at a Harley dealer, you are probably familiar with these kits and know that they really do perform very well.

Just like any engine mods that affect airflow, installing these kits require changes in the fuel, ignition and other areas of the calibration.

This is where the ARB/EPA-compliant Pro Street Tuner comes in. EPA/ARB legal Street Tuner has been around for years. Now we have the new improved Pro Street Tuner to legally dial in calibrations for these Street Legal Performance kits.

Real Power Increases!? Really??

I might be showing my age, but back in the late 60s, early 70s, the U.S. auto industry was putting out some real high-powered cars. When the EPA cracked down on the auto industry, it led to a decade or more of less-than-stellar performing cars. Some people thought it was the death of high performance cars in the U.S.

We now know that is not the case, and in fact it might have been one of the best things to happen to the auto industry. It forced the auto industry to rethink how they did things, think outside of their small boxes, and make more powerful, yet efficient, engines. Look at the New Dodge Challenger, Chevy Camaro, and Ford Mustang.

Don’t believe in ARB/EPA-compliant power? Go drive my current favorite car the 2017 Corvette Grand Sport! 460 Horsepower, 0-60 in 3.6 seconds, that’s faster than most motorcycles 0-60 time, including the Harley Livewire!

You can even buy aftermarket performance products for your cars that are ARB/EPA-approved. The difference here is Harley has been developing and selling ARB/EPA-legal kits for years. So they had a head start and are ready for this.

When used with Pro Street Tuner, the Screamin Eagle kits make great power increases over stock, and HD has spent hundreds of thousands of dollars to make sure they are ARB-compliant.

The key is you have to stick with the kits, including their recommended exhaust. These kits are not just ARB/EPA-compliant. They are components meticulously matched to work to complement each other for the best power increase for their RPM range.

Every motorcycle is just a bit different especially when you start modifying them. Pro Street Tuner has enough adjustable to calibrate it for the exact kit on the bike you have installed it on.

It is still faster and more complete to do this on a dyno. But Pro Street tuner makes it easier than ever for shops that don’t have a dyno to dial as well.

Another thing I have been saying for years. “No company or person has spent as much time and money researching what makes these engines make power as Harley-Davidson Motor Co.”

Simply put HD knows these engines better than anyone.

If you want to learn more about performance tuning and/or dyno operation, please visit our website and sign up for a class.


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