Blow Performance exhaust
Grand HDF Member
Joined: Sep 2022
Posts: 4,100
Likes: 3,523
From: Florida
Rains2much - Nobody in their right mind hammers on a cold engine, riding it, or doing a dyno run! Getting the numbers starting around 1500 rpm is a legitimate question for a low rpm motor like a Harley. It wouldn't make much sense on an engine with a 14,000 rpm redline.
Last edited by Rains2much; Aug 14, 2024 at 06:03 AM.
Grand HDF Member
Joined: Sep 2022
Posts: 4,100
Likes: 3,523
From: Florida
Can’t be any worse than the mentality of one size fits all rototiller metric sounding 2 into 1 pipes that dominate the market because the lazy dyno tuners don’t want to work. It’s easy for them to slap on the darling of the month 2 into 1 and see an increase. They tell you “you never use 4000+ rpm” so they quietly hush what’s left on the table because they bottled the top end with their lazy rototiller pipe.
Custom tune by length, diameter, and step tuning and 2 into 2 can not only match the rototiller pipes in the bottom but far exceed them on the top. Again, never tried these. I know in my experience you generally end up with matching length pipes, and for street performance you usually end up at about 34-40” long pipes.
Custom tune by length, diameter, and step tuning and 2 into 2 can not only match the rototiller pipes in the bottom but far exceed them on the top. Again, never tried these. I know in my experience you generally end up with matching length pipes, and for street performance you usually end up at about 34-40” long pipes.
Last edited by Rains2much; Nov 7, 2024 at 05:44 AM.
Stage II
Joined: Mar 2025
Posts: 2
Likes: 0
From: sanangelo
info
Just wanted to throw in my 2 cents. I just installed a Blow Exhaust system onto my '16 BO. After getting the bike tuned at my local HD dealership, my bike has never sounded better or ran as strong as it does with the Blow exhaust. No loss in power and it sounds just awesome. Couldn't be happier with the results.
Stage II
Joined: Mar 2025
Posts: 2
Likes: 0
From: sanangelo
tuner
Hi, my name is Dom, I have several degrees in Automotive Engineering my background is in race engine building (Top Fueler Drag & Group A Race Cars and commenced my career in 1977 .. before Facebook & Instagram lol. I and am the designer of Blow Performance Exhausts. Thanks for the compliments on the look of the system much appreciated, getting great looking pipes with awesome performance took us 4 years to achieve. Below is a quick run down on the system.
Our designs deliver increased performance and great sound as well as a variation in looks with our bonus 3 heat shield sets with every Killer Kit. We are committed to our customer's satisfaction and stand proud behind our product and service. Since our commencement in 2012 we have been dedicated to what we created for our biker communities worldwide.
Blow Performance Exhausts are Stepped Tuned Headers to enhance HD EVO & Big Twin Cam Engines 80ci - 131ci and Milwaukee Eight Engines 107ci - 117ci.
From the exhaust port, our header pipe merges into a larger diameter pipe and then once more into an even larger diameter pipe thus consisting of multiple step ups along the length of the exhaust system.
The first primary length is close to the exhaust port to prevent reversion, a 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. This creates scavenging, an effect generated by harnessing the inertial energy of a high velocity exhaust gas pulse.
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. Blow Performance 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.
A high velocity exhaust gas pulse 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 and creates a scavenging effect. When the intake valve opens, the air/fuel mixture can cram in, even before the piston begins to travel toward bottom dead centre (BDC) - this generates a very mild forced induction effect. We refer to this as “Induction Boost”
The best performance exhaust systems for 4 stroke performance engines have no back pressure, our system achieves greatest performance without collectors, mufflers, or baffles.
This system is designed to perform using a performance air filter. Tuning is required with installation of Blow Performance Exhausts. This work should always be performed by a qualified technician. For higher performance gains we recommend dynamometer (Dyno) tuning.
Blow Performance Exhaust Systems are all internally coated with ceramic or heat resistant paint to reduce corrosion and overheating, all products come with 12-month warranty and can be purchase individually or in Kits
Blow performance exhausts products are designed and manufactured using the highest quality materials, metals & coatings. We use MetallTech PTY LTD for metallurgical and materials consulting.
Our Killer & Kutbak Kits have been Dyno compared under controlled testing conditions with world recognised tuners, Maztech & ALP Performance Bikes. Using V&H Big Radius 2 into 2 as an example our system delivered an increase of 10 HP using identical controlled environment testing conditions. Without baffles our DB Sound levels were comparative & with our 400 PSI 304 Catalytic Converters our system was considerably less losing only 5 HP and coming in at 103 DB at 2500 rpm. Why? because our Induction boost and 3-step design producers a deep sounding note like a V8 Ski Boat in water.
Dyno sheets can be found on our Facebook Page under pics (Dyno & Performance Results), hope this helps if you want me to email you directly send me a request at enquiries@blowexhausts.com Regards Dom
Our designs deliver increased performance and great sound as well as a variation in looks with our bonus 3 heat shield sets with every Killer Kit. We are committed to our customer's satisfaction and stand proud behind our product and service. Since our commencement in 2012 we have been dedicated to what we created for our biker communities worldwide.
Blow Performance Exhausts are Stepped Tuned Headers to enhance HD EVO & Big Twin Cam Engines 80ci - 131ci and Milwaukee Eight Engines 107ci - 117ci.
From the exhaust port, our header pipe merges into a larger diameter pipe and then once more into an even larger diameter pipe thus consisting of multiple step ups along the length of the exhaust system.
The first primary length is close to the exhaust port to prevent reversion, a 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. This creates scavenging, an effect generated by harnessing the inertial energy of a high velocity exhaust gas pulse.
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. Blow Performance 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.
A high velocity exhaust gas pulse 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 and creates a scavenging effect. When the intake valve opens, the air/fuel mixture can cram in, even before the piston begins to travel toward bottom dead centre (BDC) - this generates a very mild forced induction effect. We refer to this as “Induction Boost”
The best performance exhaust systems for 4 stroke performance engines have no back pressure, our system achieves greatest performance without collectors, mufflers, or baffles.
This system is designed to perform using a performance air filter. Tuning is required with installation of Blow Performance Exhausts. This work should always be performed by a qualified technician. For higher performance gains we recommend dynamometer (Dyno) tuning.
Blow Performance Exhaust Systems are all internally coated with ceramic or heat resistant paint to reduce corrosion and overheating, all products come with 12-month warranty and can be purchase individually or in Kits
Blow performance exhausts products are designed and manufactured using the highest quality materials, metals & coatings. We use MetallTech PTY LTD for metallurgical and materials consulting.
Our Killer & Kutbak Kits have been Dyno compared under controlled testing conditions with world recognised tuners, Maztech & ALP Performance Bikes. Using V&H Big Radius 2 into 2 as an example our system delivered an increase of 10 HP using identical controlled environment testing conditions. Without baffles our DB Sound levels were comparative & with our 400 PSI 304 Catalytic Converters our system was considerably less losing only 5 HP and coming in at 103 DB at 2500 rpm. Why? because our Induction boost and 3-step design producers a deep sounding note like a V8 Ski Boat in water.
Dyno sheets can be found on our Facebook Page under pics (Dyno & Performance Results), hope this helps if you want me to email you directly send me a request at enquiries@blowexhausts.com Regards Dom
Novice
Joined: Oct 2024
Posts: 18
Likes: 3
From: Sydney
Removed due to poor fit on M8 SGS 2019 model
Anyone running the Blow performance exhaust? Thoughts on it?
https://blowexhausts.com/pages/gallery-test
https://blowexhausts.com/pages/gallery-test
My choice, my decision, my life…..
3rd Gear
Joined: Apr 2019
Posts: 7
Likes: 1
From: Sydney
