A chat on Italians; from a diluted one.

A chat on Italians; from a diluted one.

"In this Special Series, I set out to improve the heavy, restricted and weird sounding E46 M3 stock exhaust with Supersprint's 63.5mm performance exhaust system.

This entry covers the unboxing of my E46 M3 Supersprint complete exhaust - the great, the good, the bad, and in-depth look at what makes this special."
- Matt

Exhaust Royalty. 

I've been adamant about sourcing and fitting the signature exhaust systems for each of BMW Ms: the M3 V8 has the Akrapovic EVO while my M5 V10 has the Infinity V3 headers and Eisenmann oval mufflers. 

Back in 2012, my 1st E92 M3 was fitted with a complete Supersprint exhaust system with HJS cats, resonated X pipes and the F1 Race rear sections. It sounded amazing, provided significant performance gains and the quality was second to none. 

My E46 M3 came fitted with a header-back Magnaflow exhaust. Not a bad kit at all for sound and price - but it isn't the greatest this chassis has available. 

The greatest never rest.

The Italians have been leading E46 M3 exhaust development since the early 2000s, bringing to market numerous variants that consistently improve upon their initial product designs to meet the rigorous requirements of the BMW M community.

They were the first to develop and market the stepped header configuration: a unique design innovation created by Supersprint to enhance power gains across all RPM for naturally aspirated high revving engines. Most importantly, they make no sacrifice to low and mid range torque often associated with oversized headers. 

There is no greater brand that resonates with E46 M3 enthusiasts than Supersprint. In combination with my previous experiences with the brand, it was the only system sought to acquire. 

I have been dealing with Supersprint for over a decade, and the S54 products remain by far the most popular. 

The problem of choice.

Supersprint has developed many variants of each of the E46 M3's exhaust sections, creating over 300 possible combinations to choose from.

  • Section 0: Headers
    • 60mm euro-style headers for OE section 1
    • 60mm stepped headers for OE section 1 
    • 63.5mm stepped headers to be fitted with Supersprint Section 1
      • The RHD variant is a different design. 
  • Section 1: Front Pipes 
    • HJS Catted
    • Catless
    • Catless with Resonators
    • All are available in 60mm and 63.5mm. 
  • Section 2: Center Pipes
    • 63.5mm Twin Tube 
    • 60mm Single Tube 
    • All are available in resonated or non-resonated variants. 
  • Section 3: Rear Mufflers
    • Street / Strada
    • Sport 
    • Lightweight Race

My selection process. 

It's easy to get lost, it's important to center around your needs and thresholds. As a personal exercice, my E46 M3 is a Sunday performance driver: it needs to be fast, and fun to share a drive with friends & family.

I was unwilling to sacrifice in smell and noise for performance, ever more so considering I'm fitting a CSL airbox along with it. I want to experience the S54 induction noise glory for myself. 

Having fitted the S54-EVO high duration camshaft package, it require the enlarged 63.5mm piping diameter to hopefully exceed 400 crank horsepower when all is said and done.

I settled on the kit with all the juice, and none of the sugar: stepped headers, HJS section 1, resonated twin tube section 2 and Strada rear section. I received in July 2022 and documented its unboxing. 

The Strada" / Street rear section is TUV approved. It's the equivalent box with improved, straight through internals. 

This is no Akrapovic titanium exhaust, it's heavy!

The tips are chromed and slanted, the design should suit the E46's rear diffuser curvature. 

The brackets are crude, and MIG welded.

The rear section is designed to fit OEM section 2 or equivalent aftermarket options. They also fix a common issue on these e46: disintegrating muffler flanges. 

Each Supersprint products, except the headers, usually have a plaque indicating it's SKU, production batch and other serial information. 

The Great.

The headers & catalytic converters are the crown jewels of this kit and why we spend the money we do with Italians. They know where quality matters. 

Supersprint famously introduced enlarged, stepped design headers to the S54 engine over a decade ago. There are precise formulas to determine the diameters, and the position at which the increase in primary diameter should be. 

Stepped designs are suited for precise applications such as high compression, high RPM engines, short primary header lengths, long duration cam with lots of overlap and early exhaust valve opening events. 

Sounds familiar? This is where Supersprint spent the R&D and manufacturing budget.

It shows. These are truly works of arts. It brought me back to feelings of unboxing my V10 headers

You can visibly see the step in primary runner diameter. 

Pay attention to the welds: the headers are TIG welded. 

The headers are designed with all 02 bungs in their proper positions. 

The merge collector diameter is enlarged to 63.5mm for optimal performance. As such, this is a slip fit designed specifically for use with Supersprint's selection of section 1 pipes. 

HJS Motorsport Catalytic Converters.

We often hear the 3 lettered company thrown around as gospel by enthusiasts. HJS needs to be properly introduced. 

German developed and made. 

HJS is a German catalytic converter development and manufacturing company. They have been developing their Motorsport products for over 30 years working with various OEM race teams. 

FIA / WRC Homologated.

The HJS Motorsports products themselves are their premium products developed to endure the higher requirements of motorsport applications by meeting FIA homologations standards.  

CUP Lineup. 

From my research, I believe Supersprint uses a variant of the HJS Motorsport CUP lineup. The CUP lineup is their entry level Motorsport grade product. 

High Flow and High Durability. 

They use a stainless steel catalyst with a 100 CPSI for optimized gas flow. They are rated up to 950C and are suited for non-turbocharged production engines. The HJS cats have metal internals for supreme durability at the higher temperature ranges of motorsports.

Heat is expensive to manage, and it gets more expensive to manage reliably. Having an entry level motorsport product is re-assuring for long term reliability and knowing I'm getting the most performance out of my S54 without pushing unfiltered exhaust emissions into the atmosphere

Supersprint positioned the cats much further downstream than BMW which fitted the cats straight on the headers for US cars. This helps reduce operating temperatures of the cats and prolongs their life. 

The HJS Motorsport CUP cats have triple foil winding, and three winding centers. You can read more about it here

If a member can trace the number to confirm the product lineup used - I'm all ears.  

The HJS Motorsport cats come in a few select diameters. You can see Supersprint tapers down the diameter to suit the 63.5mm piping.

The section 1 piping comes fitted with the required pre-cat 02 sensor bungs as well as post cat bungs fitted directly to the HJS units. 

The 63.5mm section 1s, whether they are catted or not, all come with flanges to fit the OEM section 2 or equivalent aftermarket section. 

The Good.

Tuning and power levels achieved by naturally aspirated S54s have drastically increased throughout the years thanks to breakthroughs in engine tuning and high duration cams. This led to new engine performance bottlenecks being found: the middle section's diameter. 

Supersprint initially developed the 63.5mm stepped design headers with section 1s, however it was paired with 60mm single tube mid section developed in the 2000s. As the E46 M3 underbody is a limiting factor in its exhaust development, they couldn't revise the single tube design with a larger diameter. 

The 63.5mm Twin Tube version. 

Supersprint developed a new version with a larger overall piping diameter. The results are a system that can support power levels up to 400whp. 

This version is a twin-tube design to achieve the required diameter targets within the packaging restrictions of the underbody. This section is available in resonated or non-resonated variant. 

Just like Germans, Italians have their own peculiar ways of doing things. The section 2 is where Supersprint starts loosening its welding standards as they prefer to use MIG welding techniques.

This is the resonated version which helps keeps the decibel levels and rasp down. 

The section 2 has flanges to mount to the Supersprint section 1 or the OEM equivalent. 

They also fitted flanges to be bolted to the rear section or OEM equivalent. They provide a loose flange to be slid on the left pipe pictured below. The tapered section on the sliding flange most likely acts as an heat expansion feature. 

It comes fitted with welded studs to properly fit the underbody. 

MIG welding is faster and cheaper - but doesn't look as good as is evident below. 

The section 2 comes with Supersprint specific hardware as it is a twin-tube design that differs from OEM. As a rule of thumb with Supersprint, if it uses the OEM routing, source your own hardware. 

The Bad.

My title was definitely tongue-in-cheek being of Italian descent myself - yet there's some truth to it. Italians are notoriously slow to manufacture goods; quality they'll say, and for the most part they are right. Yet there often remains irrational things about the overall process of Italian manufacturing.

Let's cut to the chase: my rear section's canister came dented like a winter beater parked downtown with no care given - and one of the tip is dented. 

The tip's dent is difficult to catch with so much light, and the polished & chromed metal. It's the inner tip below. 

The packaging. 

All of my packages were inspected by customs. As such, needed to be opened to be inspected. Did this influence the final dents on the rear section? Partly, I'm sure. I can only suspect an Italian business shipping big packages to another Italian is a red flag. 

Supersprint uses thick plastic bags that are shrink wrapped around each component to further protect them. They also add smaller, still paper thin cardboard boxes and a form of stretchable padded cardboard to what they perceived are sensitive areas like tips, flanges etc. 

Lastly, Supersprint doesn't include hardware on most of their kits. On my configuration, only the section 2 came with the extra flange, bolts, washers and nuts to install it. 

The hardware was taped them to the inside of the vacuumed plastic bag. Half of them were flying around inside the package, good thing the bag didn't get cut.

If they'll ever read this, my recommendation to them would be to be Be like Mike, be like Nike: add "Air" cushions, and foam, a lot more foam. 

The bottom line remains: this is the best engineered exhaust system for our cars. 

Up next: I document my replacement experience, and eventually get to fitting the complete system. 

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