CAVEAT EMPTOR - Buyer Beware: Why Certain Exhausts Systems Aren't Worth Making

At Fabspeed Motorsport USA, whenever we dive into a new exhaust research and development project we always start by evaluating how the original equipment manufacturer, OEM, chooses to design the exhaust system. In certain cases we have seen the occasion in which the car manufacturer’s engineers have done an excellent job designing an exhaust system that flows well, delivers good power and decent sound. However, this isn’t often the case because OEMs have to create an exhaust that complies with various emissions and strict noise regulations, not to mention the general public’s desire to have a car that quietly gets them from A to B.

Occasionally, at Fabspeed Motorsport, we witness that a manufacturer has designed a system that sounds good. When a manufacturer accomplishes this our engineers and founder, Joe Fabiani, simply admire their work, absorb the design and incorporate their techniques into our own designs. We then do not find it necessary to make a system for that vehicle - we prefer to research and develop, not rip-off, and duplicate.

Wait, I shouldn’t buy an aftermarket exhaust?

Yeah, that’s right. For an aftermarket exhaust company like Fabspeed Motorsport, you’re probably thinking we’re a bit crazy. This 641-hp Italian monster adds plenty of rowdiness to you and your 4 passengers, a near perfect out-of-the-box exotic SUV not needing much change.

Several years ago Fabspeed Motorsport was the 1st company to design, develop, and manufacture performance parts for this 5 seater monster. Our engineers evaluated the entire OEM exhaust system both on the dyno and on the street, we did non-destructive testing using a fiber-optic camera to learn how the exhaust flowed through the electronic valved muffler. What did Fabspeed discover? With the factory electronic valves open, which are controlled by the car’s ECU (electronic control unit), the entire cat-back rear muffler system is a dual, 2.5 in 63.5mm open straight pipe.

 How do we know? As mentioned above, we took a borescope (fiber optic surgical tool equipped with a tiny camera on a flexible rod) and we fished it through the exhaust to confirm that with the valves open you could roll a golf ball right through the whole exhaust system and out the tips. With the valves closed the OEM muffler effectively cuts down on sound without too much restriction. Case and point - no reason to ditch this URUS muffler.

Therefore, there was no justifiable way that Fabspeed Motorsport was going to make this exhaust better than Lamborghini already had. This frequently happens with rear cat-back muffler development on certain late-model Ferrari and Aston Martin cars. Typically, once the valves are open these lightweight mufflers on most Ferrari V8 and V12 late model engines are straight through.

Add Power & Sound the Right Way

What sound does the bull make? What we focused on was improving the highly restrictive factory OEM 700 cell catalytic converters. Fabspeed Motorsport engineering worked closely with HJS Emissions Technology in Menden Germany to design ultra-high flow European 6 homologated tri-metallic catalytic converters that truly wake up the sleepy bull.

A quick internet search will reveal a few different aftermarket cat-back exhaust options for the Urus. Unless you really must have a shiny polished muffler underneath your SUV, these systems should be avoided.

We recently had a customer come to Fabspeed with his Urus that was equipped with an expensive aftermarket cat-back exhaust. The owner said it was quieter than stock and felt significantly down on power. He was aggravated and annoyed about the system and it also vibrated and was hitting the transmission.

What we observed was that the aftermarket system, while looking and fitting decently, actually flowed worse than the factory muffler. And not only that, but the new shiny system eliminated the factory AUDI electronic exhaust valves for vacuum actuated valves.

Why are vacuum actuated valves an issue with this application? Because you lose the OEM functionality and reliability of the electronic valves which are tied into and control the car’s ECU engine control unit. This was a strange choice and poor engineering and planning.

The entire car had to be rewired and vacuum lines ran all the way to the front of the car at great expense, and none of this was tied to the factory ECU. So the OEM functionality of selecting your driving mode and getting a different exhaust note was completely lost, not to mention the reliability of an OEM valve. The driver had to use a key fob to open the valves, not nearly as user friendly and logical as using the OEM driving mode selector.

We also investigated how well the aftermarket system flowed by using our fiber optic camera to do non-destructive testing. It actually had smaller diameter internal piping than the factory Urus muffler! That would account for the owner’s claim that it was down on power. Not only that, but the system actually weighed more than the OEM exhaust system.

The owner ended up asking us to remove the aftermarket cat-back exhaust and install the OEM URUS system. Unfortunately, the owner wasted a lot of time and money purchasing and paying for the installation of an inferior exhaust system. By request and our recommendation, they had us install our Carbon Fiber Deluxe Quad Tips as well as our thoroughly engineered HJS Sport Catalytic Converters which have dyno-proven power gains and significantly better sound.