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About Blow Performance Exhausts

Blow Performance Exhausts manufacture performance exhaust systems for Harley Davidson, Chopper & Custom Motorcycles Evolution & Twin Cam Engines with 80 ci to 131 ci from 1983 onwards.

And currently Introducing Performance Exhausts for Milwaukee-Eight 107 ci to 117 ci Engines 2017 onwards.

Our designs deliver increased performance and great sound as well as a variation in looks with our bonus 3 heat shield sets included in our Killer Kit Range.

Blow Performance Exhausts are 3-Stepped Tuned Headers. From the exhaust port, our header pipe merges into a larger diameter header pipe and then once more merges into an even larger diameter header pipe thus consisting of multiple step ups along the length of the exhaust pipe.

The first step is placed where the exhaust port ends (44.5 / 1.75) and the exhaust pipe begins. To prevent reversion, this is left as a step rather than making the pipe diameter match the port diameter thus preventing exhaust gases from flowing backwards into the combustion chamber after the piston reaches TDC. The second step diameter (55 / 2.17) is found at a calculated distance and the 3rd and final step diameter (63.5 / 2.50) is found once again at a calculated distance. The steps are placed for the greatest performance level achievable by our Blow Performance Exhaust System.

Blow Performance Exhausts are designed for high RPM's and run at greatest performance without collectors, mufflers, or baffles. The first step helps prevent reversion, thus giving power at low RPM's. Steps placed further down the pipe create pressure drops in the flow of the gases, and increase power at higher RPM's. Our designs work with the exhaust pulse and give a broad power band on 80 ci -131 ci EVO & Twin Cam Engines as well as 107 ci – 117 ci Milwaukee Eight Engines.

Specifically designed and calibrated for piston to valve synchronization, the pressure wave begins to travel down the tube. When it reaches the end of the tube, it reverses as a vacuum wave and comes back towards the cylinder. Our tuned headers time that wave to hit right around the closing of the exhaust port, this boost scavenges residuals out of the cylinder while the intake begins to fill.

Blow Performance Exhausts first primary length is close to the exhaust port. This prevents a sudden drop in velocity due to a volume increase from head port to exhaust tube, from there we start stepping up the diameter.

Scavenging is the effect generated by harnessing the inertial energy of a high velocity exhaust gas pulse. The best performance exhaust system has no back pressure, this is misunderstood and confused with the pressure wave.

A high velocity pulse of exhaust gas carries with it energy; as the pulse moves through space it displaces the following volume behind it. This generates a low-pressure zone like a weak vacuum. Scavenging effect is created, and a low-pressure area is left in the vacated cylinder ready for the incoming intake charge. When the intake valve opens, the air/fuel mixture can cram in even before the piston begins to travel toward bottom dead center (BDC) — this generates a very mild forced induction effect. We refer to this as “Induction Boost”

Our 3 Step Tuned Headers are all ceramic coated internally to reduce corrosion and overheating, All products come with 12 month warranty and you can purchase components individually or in a Kit Combination such as


  • Ceramic Matte Black Long & Short Exhaust Pipe or Chrome Showroom Quality Long & Short Exhaust Pipe
  • Ceramic Matte Black plus Chrome Showroom Quality plus Solid 1.5 mm Polished Copper Long & Short Heat Shield Sets (3 Sets in Total)
  • Heat Shield Clamp No 2 38-57 Stainless Steel (5)
  • Centre Housing Bolt 75 mm Stainless Steel (1)
  • Kong Support Bracket 8mm Stainless Steel (1)
  • Bung Plug 18 mm Stainless Steel (2)
  • Bung Reducer 12 mm Stainless Steel (2)
  • O2 Sensor Crush Washer (2)
  • Flange Stainless Steel Kit (1) (2 Exhaust Port Flange Clamp Stainless Steel, 2 Exhaust Port Flange C-Clip Spring Steel, 4 Exhaust Port Stud Stainless Steel, 4 Exhaust Port Nut Stainless Steel, 4 Exhaust Port Washer Mild Steel, 2 Exhaust Port Flange Standard Gaskets, 2 Exhaust Port Flange Pro Race Gaskets)
  • Catalytic Converter 400 Stainless Steel Kit (1) (2 Catalytic Converter 400 Stainless Steel, 4 Catalytic / Baffle Bolt 18mm Stainless Steel, 4 Catalytic / Baffle Flat Washer Mild Steel, 4 Catalytic / Baffle Spring Washer Mild Steel)
  • All components come individually wrapped and packaged in a styrene box with a graphic retail sleeve and shipped in a strengthened cardboard Shipper.


  • Ceramic Matte Black Long & Short Exhaust Pipe or Chrome Showroom Quality Long & Short Exhaust Pipe.
  • Ceramic Matte Black or Chrome Showroom Quality Long & Short Heat Shield Sets (1 Sets in Total)
  • Heat Shield Clamp No 2 38-57 Stainless Steel (5)
  • Centre Housing Bolt 75mm Stainless Steel (1)
  • Kong Support Bracket 8mm Stainless Steel (1)
  • Bung Plug 18mm Stainless Steel (2)
  • Bung Reducer 12mm Stainless Steel (2)
  • O2 Sensor Crush Washer (2)
  • All components come individually wrapped and packaged in a strengthened cardboard Shipper.

We are committed to our customer's satisfaction and stand proud behind our product and service. We commenced in 2012 with design and testing, we are proud of what we have created for our biker communities’ worldwide.

New development will see the release of products in 304 Stainless Steel, Carbon Fibre as well as exciting new coatings and finishes new to the industry.

Blow Performance Exhausts is an Australian Owned Company with design and manufacturing affiliates in the USA & China.

We currently have distribution warehouses in the USA, UK & Australia. We ship to most countries.

The Introduction of CATs

Blow Performance Exhaust is designed and intended for closed circuit environments, however in some countries EPA regulation allows for noise and emission levels to be much lower than the International regulations standard.

Previously we modified our Blow Performance Exhaust systems to allow fitment of Fiberglass mesh filled baffles to reduce noise levels with countries that our customers were able to use our race systems for street use.

Our latest evolution in environmental contribution will see our Exhaust Baffles faze out and our 400PSI Catalytic Converter 2 in one EPA assist systems fill that space. Our CATs not only provide emissions support but also reduce the sound levels to an acceptable consumer satisfaction without losing the quality deep muscle sound our market has come to love.

Blow Performance Exhaust ships product worldwide, our products are designed and used for race enhancing purposes please check with your governmental regulatory authority that monitor and enforce EPA Emission Regulations in your area.

Blow Performance Exhausts makes no claim that our CATs System meets your local EPA Emissions regulatory Levels. We advise that should you use our system for street use that you test the Emission Levels against your local regulatory standards.

Let’s talk about the introduction of our 400PSI serviceable Catalytic Converters. Serviceable means our CATs are exchangeable within 5 minutes and can be done without the services of a motor mechanic. We designed the system this way so that should we desire we can change models. The would allow us to strengthen or reduce the emissions burn and honeycomb density of the system. Our CATs our backward compatible allowing previous Exhaust System products fitted with Baffles to replace them with our Catalytic Converters.

BLOW CAT KITS BESSPK008 uses catalysts with metal substrates to convert Nitrogen Oxides (NOx),Carbon Monoxide (CO) and Hydrocarbons (HC) into Carbon Dioxide(CO2)water(H2O) and nitrogen(N2).

With Precious Metal coating technologies, Blow Performance Exhausts strives to achieve with optimized precious metals a higher catalytic performance enhances higher oxygen storage capacity(OSC) and stability, by applying Precious Metals-Rare Earth compound catalytic technology.

By obtaining Metal substrate oxidation transitional layer technology, we meet the requirement of uniformity and stability.






Manufactured for closed course competition. Please check your local EPA authorities for street use.

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