There is a lot to this....We tested several styles of "X" system (no mufflers, one muffler each side, inline mufflers and our single muffler with internal "X") during the R&D phase of our X-cellerator exhaust. All provided a different sound and varied levels of resonance. We then tested various sizes of piping, even curve radius, which also had varying effects on resonance. Finally, we experimented with tip shape, diameter, length, etc. - again, all having an effect on resonance. By learning, testing and tweaking the properties of each component, we were in a unique position to "tune" our systems for what we considered the most desirable sound attirbutes, while moving away unwanted resonance. We preferred our large single muffler with an "internal X" as our base platform (least resonance/best high end sound) and then tweaked all the components to work in harmony to virtually eliminate resonance, while providing a fantastic GT3 type wail at high RPM's.

I was in a Mixed marque rally last weekend with Ferraris, Porsches, Lotuses, Audi R8's and many other exotic cars and the compliments and inquiry's I received on the sound of our 996TT X-Flow exhaust were overwhelming. Everybody was listening to it and loving it - one person commented that he never thought it was even possible for a Porsche to sound so good!

It's all about R&Ding a proper design...a lot of the systems that do not have sufficient R&D suffer because of it - a well designed system is worth the premium, as you will love driving your car every time you use it vs. a bad design ("X" or otherwise), which will make you wish you had something different every time you drive your car.

 

That was the exact RPM range I couldn't stand in the original design. You'll see in my video my buddy and I trying to capture the drone (you hear me say "yea, right there"). It was literally rattling parts in my interior.

After the modifications, the drone in the 2-3k rpm is gone. I can still hear the exhaust (and that sound level can be modified with mufflers) but the drone, that low vibrating frequency that seems to rattle your brain, is now gone.

 

I think and some others do that drone is at a constant steady speed which is annoying in the cab, as I am sure you agree BUT are we talking now about when you give it any gas,part throttle, in that 2,000 to 3,000 range it gives a low pitch louder elevated volume sound..That is just as annoying to me as constant drone..Maybe I am wrong but I don't call that drone ...

 

I'm not sure I understand what you are asking. Whether I'm cruising (foot hardly on the gas pedal) or giving it part throttle between 2k-3k rpm, that low pitched drone is now gone.

 

Hi,,Thanks..You answered it with giving it part throttle..

 

Dr.Jekyll:
Science and math are wonderful!! I hope you are driving it near and far, and fast!


Top:
Looks good. It's a very light exhaust, 10lbs with clamps.
I'd love a sound clip at full howl...!

New one similar to the protomotive one coming soon. Hopefully with some testing as well.

 

beautiful looking exhaust. That drone would kill me as a daily driver in traffic too. Glad there is a fix. I may go this route as its one hot looking and hot sounding exhaust.

 

I'm still loving this exhaust! Just had it out this morning getting some logs for EPL. They are retweaking my tune to take advantage of the much freer flowing exhaust and GT2RS intercoolers Even at 1.2 bar this thing has traction problems. Next revision will be back up to 1.4-1.5 bar A set of Toyo R888's might be in my future...

I did get some interior dB levels today. Previously, part throttle cruising (2500-2600 rpm) was 103 dB in the interior with the windows up. With the changes to the exhaust it's now 91dB at the same rpm/speed. IIRC, every 3 dB's is doubling in volume, so this is a HUGE decrease in interior volume/drone.

 

^^ That's awesome to hear. Thanks for this. I know this is what I plan on ordering now.

 

[QUOTE=daedalus;3962049]^^ That's awesome to hear. Thanks for this. I know this is what I plan on ordering now. [/QUOTE

I wonder if they are going to produce that exhaust in that form for sale, if its not that bad of drone for a 3'' catless they will have more orders..
Hope its in a reasonable price range..

 

[QUOTE=johnspeed;3962081] i emailed unobtanium and they were more than happy to build me this exact exhaust with either cats or catless.

 

[QUOTE=32krazy!;3962103]Did they believe that type of construction would do that?

 

[QUOTE=johnspeed;3962106] would do what?

 

Take most of the drone away in that range, the reason for that special chamber.

 

based on the videos the op posted im going to guess yes. the video inside the cabin had little to no drone . to me its the best sounding exhaust i have heard to date