Larini E46 M3 Sports/Anti-Rasp Section 1 + 2

Purchase Larini E46 M3 Sports/Anti-Rasp Section 1 + 2

The Euro E46 M3 has 4 separate exhaust components:  the headers, a front section 1 incorporating cats, a center section 2 incorporating a mid-resonator, and a rear muffler.  The Euro spec M3 rasps as stock, albeit not as badly as the US spec M3.  The US E46 M3, bound by higher emission standards, incorporates the following changes:  

• The converters are moved from the Section 1 position into the headers
• An additional resonator and plain pipework make up the Section 1  
• The section 2 and rear muffler remain unchanged. 

This arrangement allows the exhaust to heat up faster to reduce cold start emissions, but unfortunately robs power.  Furthermore, this arrangement massively increases the raspy tone of the M3. 

SECTION 1 AND 2 REPLACEMENT
Changing some or all of the components in the exhaust system will increase performance.  However, the dilemma for US vehicle tuners is a) selecting a performance section 1 and 2 that will give power and torque gains, while complimenting any possible future upgrade to Euro headers b) selecting a performance section 1 and 2 that will not further amplify the M3’s rasp and c) selecting a performance section 1 and 2 that will significantly reduce the M3’s rasp without excessively silencing the car, or causing drone or vibration. 

Finally, the wait is over. Larini Systems has developed the only Section 1 + 2 that will remove the M3’s rasp, improve sound quality, and give noticeable power and torque gains on either a US or Euro exhaust spec M3.   The Larini Sports Sections 1 and 2 have been designed and developed to work as a unit, independently of each other, or to compliment other modifications (such as Euro spec Larini GT Sports Cats).  Furthermore, they perform different tasks depending on the US/Euro header set-up they are mated to.

Please Note: The OE section 1’s, section 2 and rear muffler are all physically interchangeable between Euro and US spec E46 M3’s. The same applies when fitting Larini components, allowing a fully modular exhaust system.

Rasp Removal (US exhaust spec)
Root Cause:  Stock engine tone
Additional Cause:  OE headers-cats & OE front section 1 combination
Amplifier: OE center section 2
Removal: To eliminate the rasp, only the Larini Sports Section 1 needs to be fitted

Rasp Removal (Euro exhaust spec)
Cause: Stock engine tone
Amplifier: OE center section 2
Removal: To eliminate the rasp, only the Larini ‘Sports’ Section 2 needs to be fitted

Larini Sports/Anti-Rasp Section 1 (US Exhaust Spec):
The Larini Sports Section 1 is a direct replacement for the OE US section 1 - the main contributor of the rasp when coupled with US headers.  Using octave band frequency monitoring techniques we have developed a Sports Section 1 that will actually eliminate the excessively raspy and tinny sound now standard on the M3.  Once fitted, the pure note and tone of the engine are significantly tuned and improved, for a much sharper, aggressive sound.

Nevertheless, power and torque gains have not been overlooked.  Enhancing power from within this area involves carefully tuning the Section 1 to work with the headers and catalysts.  When exhaust gas exits the cylinder it produces sound/pressure waves that travel up and down the exhaust system, if these S/P waves can be controlled correctly, they can be harnessed to draw extra gas from the cylinder and so make the engine more efficient.  

Hence, the Larini Sports Section 1 incorporates two super-performance, lightweight caged-pipe components that work with the cats.  As soon as the gas reaches these expanded sections, the S/P wave creates a reverse pressure pulse. As this wave hits the back of the valve it bounces back and causes a suction pulse that helps pull out more gas the next time the valve opens. A higher exhaust suction-pressure allows for more efficient removal of the exhaust gases from the engine.  This results in a cleaner, more efficient burn - leading to enhanced engine performance.  

Accelerated gas-flow also minimizes engine-bay temperatures by dissipating heat more effectively.  This is particularly important for improved performance, as cooler operating temperatures boost engine efficiency further.  Unlike OE, there are no flow stifling crimped or flattened areas.  Increasing the internal flow area with larger diameter pipework allows for a further improvement of the flow-rate and velocity of the exhaust gasses, guaranteeing a more free-revving engine with improved throttle response.

This product delivers a similar power increase as an alternative pipework-only section 1, but offers a noticeable torque gain as backpressure levels are modulated optimally. This arrangement is the performance ideal for vehicles with US spec headers.  Acoustically, there will be no excessive bass, rasp amplification, drone or vibration issues. Once fitted, no modifications will be required to the engine management system. 

Larini Sports Section 1* (Euro Exhaust Spec):
For vehicles equipped with OE Euro or aftermarket performance headers, the mandrel bent Larini Sports Section 1 can be used as an alternative for the massively restrictive OE Euro catalyzed section 1, providing exhaust gases with zero flow restriction.  Lambda Bosses are located in the correct positions for the Euro Lambda probes (US cars required to extend stock sensors or replace with Euro versions).

This product delivers a similar power increase as an alternative pipework-only section 1, while offering a significant torque gain as a vital balance between lower backpressure level and flow rate is ensured for optimal performance.  One can expect much sharper throttle response from a now free-revving engine.  Operating temperatures are reduced too, as accelerated gas-flow minimizes engine-bay temperatures by dissipating heat more effectively, while protecting the manifolds from damage. This is particularly important for improved performance, as cooler temperatures boost engine efficiency. 

Acoustically, the muffling effect provided by the bulky stock Euro cats is eliminated, subtly enhancing volume levels, while the note and tone of the engine are significantly tuned and improved for a much sharper, aggressive sound without any excessive drone or vibration issues.

*Please Note: A Larini Section 1, when coupled with Euro headers, is intended for non-highway use only in America, as US law for many areas requires fully functioning catalysts to be fitted at all times.

Larini Sports/Anti-Rasp Section 2 (US/Euro Exhaust Spec): 
The Larini Sports Section 2 is a direct replacement for the OE US/Euro section 2, which contains an H-pipe plus a mid-resonator – an amplifier of the rasp.  Air flows from an area of high pressure to an area of low pressure.  The bigger the pressure differential the more air will flow (and faster).  This is a physical law.  The OE H-Pipe and mid-resonator are cost effective attempts at merging the gasses between the two parallel exhaust center pipes to create these differences in pressure, which lead to an increase in mid-range torque.

However, enhancing power from within this area involves pressure tuning the section 2 by varying the length and type of the merge junctions.  Hence, the Larini Sports Section 2 utilizes two Y-pipes and a light weight caged-pipe component, connected by two expansion tubes, to create the optimal pressure differentials necessary to speed up the flow of exhaust gasses.  Additionally, increasing the internal flow area with larger diameter pipework allows for a further improvement of the flow-rate and velocity of the exhaust gasses.

This careful tuning of gas-flow velocity rates and backpressure levels, via manipulation of internal diameters, the merge points and expansion points, produces the ultimate effect - expelled exhaust gasses are now rapidly sucked away from the engine, increasing efficiency and boosting performance.  This product offers an Hp and significant torque gain as gas outflow rates are manipulated more effectively. Once fitted you will feel the difference.

Acoustically, there will be no excessive bass, rasp amplification, drone or vibration issues, which may be experienced by alternative pipework-only section 2s (as with lengthy pipe work the amplitude of the lower-frequency sound is typically increased).  Once fitted, a Larini Sports Section 2 lifts the volume, makes it deeper at low rpm, adding a subtle, aggressive tone and then lifts the pitch at high rpm, so when matched with throttle opening it develops a beautiful sound under acceleration. It really is just one of the most satisfying tuned exhaust notes.

Please Note: Unlike alternative aftermarket section 2’s, the Larini unit is supplied with a fitted heat shield, so no broken stud issues will arise.

KEY FEATURES – Larini ‘Sports/Anti-Rasp’ Section 1 + 2

• Delivers an extra 6 Hp combined approximately
• Noticeable torque gain
• Eliminates the E46 M3 rasp
• Vastly freer flowing in comparison to the OE sections 1 and 2
• Lightweight construction parameters throughout
• No excessive drone or vibration issues
• Engineered for optimal flow efficiency, using complex caged-pipe components
• No adverse technical implications, while guaranteeing a more free-revving engine with improved throttle response
• Mandrel bent pipe work allows a constant internal diameter, maintaining a smooth, constant gas flow
• Constructed using aircraft grade T.316 & T.304 Austenitic Stainless Steel
• 100% Tig welding construction
• Correctly positioned, heat-distortion resistant, CNC-machined stainless steel Lambda bosses and heat probe connections
• Precision, laser cut, mounting flanges and brackets, for easy fit and removal

SUPERIOR CONSTRUCTION

• T.304/316 stainless steel's ability to resist corrosion and maintain strength at temperature extremes makes it the only material suitable for a Larini Sports Section 1 + 2
• The laser-cut manufacturing process ensures alpha-quality repeatability and reproducibility - guaranteeing that flange #1000 is as accurate and leak-proof as flange #1
• Euro Lambda probe positions remain unchanged from the original Euro equipment, allowing for the future installation of the Euro OBD II (On Board Diagnostics II) system probes for Euro header conversions – for off-road use only
• Unique thick-walled, stainless steel Lambda bosses can withstand temperatures in excess of 1600°C, and will not distort.  Conversely, regular thin-walled bosses expand and cause the threads to bind, rendering future removal of the Lambda probes near impossible
• Advanced construction techniques, dedicated fixed-jig equipment, and 100% Tig-welding ensures maximum durability and a perfect fit

VISIBLE QUALITY

• Pipework, bosses, Lambda probe connections, flanges and caged-pipe components are all Mirror Finish polished
• The improved quality of a Larini Sports Section 1+ 2 is immediately noticeable as soon as it is removed from its box

EASE OF FIT

• Larini Sports Section 1+ 2 fits perfectly to the US or Euro headers, mounting points, and rear muffler, requiring no special procedures or modifications to fit

CUSTOMER FEEDBACK

From David Andrade of Lorsch, Armed Forces Europe/Middle East/Canada on 8/30/2005: 

I have been searching the chat rooms and listening to many different exhaust clips and I have to say that this exhaust (Larini Club Sport) coupled with the Section 1 and Section 2 is the sweetest sounding exhaust I have heard yet.  Neil and the guys in London have hit their signature note right target.  I wanted a sporty alternative to the crappy stock exhaust.  I can say that the car even feels like it has a bit more torque.  I would recommend this to anyone thinking of doing this upgrade.

Please note: While the Larini Sports/Anti-Rasp Sections 1 and 2 are dedicated sports components, maximum rasp removal capability may be compromised when fitted individually to vehicles equipped with aftermarket superchargers and pipework-only exhaust sections as these products may further exaggerate the M3’s raspy tone.

FAQ (US Exhaust Spec):

Q. Why is the US spec OE section 1 the main contributor to the rasp?
A. The Euro section 1 incorporates 2 catalysts.  The US spec section 1 doesn’t (as the cats are fitted into the headers).  In their place the factory installed a resonator on one side and a straight pipe on the other side.  With now lengthy pipe work, the amplitude of the lower-frequency sound is increased.  As the M3 engine has a naturally raspy tone anyway, this arrangement serves to create even more rasp.  Where the Euro M3 has a mild raspy tone, the US spec M3 rasps aggressively throughout the rev range.

Q. What happens if I fit a Larini Section 1 only to a stock US exhaust spec M3, in terms of the rasp?
A. It will eliminate the rasp.

Q. What happens if I fit a Larini Section 2 only to a stock US exhaust spec M3, in terms of the rasp?
A. It will cease amplification of the rasp, unlike the OE section 2, but a raspy tone will still remain.  Because, the main contributor to the rasp, the OE section 1, is still fitted.  Swap out the OE section 1 only with the Larini Section 1 to eliminate the source of the rasp.

Q. Will an aftermarket pipework-only Section 1 eliminate all the rasp?
A. Lengthy straight pipework by the factory helped increase the rasp in the first place.  So, fitting a pipework-only section 1, with double the length of straight pipe compared to the OE US section 1, naturally will not help matters.  Aftermarket pipework-only section 1’s were actually originally developed as de-cat pipes for the Euro M3’s.  Nevertheless, if the Larini Section 2 were fitted also, there would be a reduction in the overall amplification of the rasp.

Q. Will an aftermarket pipework-only Section 2 eliminate all the rasp?
A. No, and drone or vibration may become an issue, particularly on modified cars.

Q. I have a massively modified US E46 M3. If I fit the Larini Section 1, will any trace of rasp remain?
A. Modifications such as aftermarket superchargers and pipework-only exhaust sections may further exaggerate the M3’s raspy tone.  In this rare instance, the Larini Section 1 plus the Larini Section 2 may also be required, to reduce amplification of any remaining raspy tone.

Q. Will I feel a positive difference in performance with a Larini Sports Section 1 + 2 fitted to my US M3?
A. Yes.

FAQ (Euro Exhaust Spec):

Q. If I fit OE Euro headers and cats, will they eliminate the rasp on my US M3?
A. The OE Euro set-up will massively reduce the rasp, but a small amount or raspy engine tone will remain (as even the Euro spec M3’s rasp slightly).  To eliminate all trace of the rasp the section 2 area must be looked at.

Q. Why is the OE section 2 the main contributor to the raspy sound?
A. The Euro section 1 incorporates 2 catalysts.  The US spec section 1 doesn’t (as the cats are fitted into the headers).  So, the Euro spec M3 doesn’t rasp as badly as the US version.  The rasp you hear on the Euro M3 is the mild raspy tone of the engine being massively amplified by the OE center section 2.  To eliminate all noticeable trace of the rasp the section 2 area must be looked at.

Q. What happens if I fit a Larini Section 2 only to an OE Euro exhaust spec M3, in terms of the rasp?
A. It will eliminate the rasp, without reducing overall volume levels.

Q. What happens if I fit a Larini Section 1 only to an OE Euro exhaust spec M3, in terms of the rasp?
A. It will not eliminate the mild raspy tone of the engine.  Instead, swap out the OE section 2 only with the Larini Section 2 to eliminate the raspy tone.

Q. Is a Larini Section 1 a road-legal alternative to the Euro catalysts on a Euro exhaust spec M3?
A. No.  Law in both the United States and Europe requires fully functioning catalysts to be fitted to all road going M3’s at all times.

Q. Is a Larini Section 1 an off-road use alternative to the Euro catalysts on a Euro exhaust spec M3?
A. Yes, it offers a physical bolt-on fit.

Q. Will an aftermarket pipework-only section 2 eliminate all the rasp?
A. No, and drone or vibration may become an issue, particularly on modified cars.

Q. Will an aftermarket pipework-only section 1 eliminate all the rasp?
A. No.  Excessively lengthy pipework in the section 1 area typically exaggerates the rasp.

Q. I have Euro headers fitted, de-cat pipes (pipework-only section 1), and a pipework-only section 2.  Will fitting of the Larini Section 2 only completely eliminate any rasp, as it does on Euro-catalyzed M3’s?
A. Pipework-only exhaust sections may further exaggerate the M3’s raspy tone.  As always the Larini Section 2 will cease amplification of any rasp (and on a catalyzed M3 that would be enough to eliminate the rasp completely).  But in this quest for total rasp removal, fitting of the Larini GT Sports Cats (highway use), or the Larini Section 1 (off-road use), may also be necessary.

Q. I have Euro headers fitted, de-cat pipes (pipework-only section 1) and a pipework-only section 2.  Will fitting of the Larini Section 1 only completely eliminate any rasp?
A. Pipework-only exhaust sections may further exaggerate the M3’s raspy tone.  In this case, the Larini Section 1 will massively reduce any rasp to nearer stock Euro levels.  In this quest for total rasp removal, fitting of the Larini Section 2, which will cease amplification of any rasp, may also be necessary.

Q. I have a massively modified Euro exhaust spec E46 M3. Which Larini components will eliminate any rasp?
A. Modifications such as aftermarket superchargers and pipework-only exhaust sections may further exaggerate the M3’s raspy tone.  Fitting of an alternative aftermarket section 2 with a large mid-silencer will only lessen the rasp by silencing the overall volume of the vehicle.  Therefore the Larini Section 2 plus Larini GT Sports Cats (highway use), or the Larini Section 1 (off-road use), may be necessary, particularly if the car has been de-catted.

Q. Will I feel a positive difference in performance with a Larini Sports Section 2 fitted to my Euro exhaust spec M3?
A. Yes.

This article is copyrighted © 2005 Larini Systems. All Rights Reserved.
All content included herein, is solely the property of Larini Systems, and is protected by United Kingdom and international copyright laws.  You may therefore not extract, use, copy, reproduce, duplicate, sell, or resell, any parts, components, or content of this article for utilization in any commercial purpose, without Larini Systems’ express written prior consent.

Purchase Larini E46 M3 Sports/Anti-Rasp Section 1 + 2

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