Heavy Dupree

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https://stillen.com/products/2023-n...xhaust-street-series-sku-504503-504504-504505


After months of exhaustive testing the team determined that the best design starts with a stainless steel flange precision tig welded to 2.5” tubes leading into a CNC bent and CNC machined X pipe. During the development the team tested a true dual exhaust system and determined that it was too loud and too “flat” sounding. Something very common with twin turbo V6 engines. However, in an effort to get the best performance possible we did not want to restrict the engine by going from dual 2.5” tubes to a single 3” mid-pipe. The perfect solution was an X pipe which offered a cross-sectional area of around 4”. This allowed the team to merge the left and right banks which improved the sound tremendously without restricting the exhaust flow. Additionally, it allowed the team to fit the largest possible collector through the narrow chassis tunnel in the center of the car.

504503_IMG008_2023_Nissan_Z_STILLEN_Cat_Back_Exhaust_Street_Series_Polished_Tip_v1_1024x1024.jpg

504504_IMG002_2023_Nissan_Z_STILLEN_Cat_Back_Exhaust_Street_Series_Burnt_Tip_v1_1024x1024.jpg

504503_IMG004_2023_Nissan_Z_STILLEN_Cat_Back_Exhaust_Street_Series_Polished_Tip_v1_1024x1024.jpg

504503_IMG003_2023_Nissan_Z_STILLEN_Cat_Back_Exhaust_Street_Series_Polished_Tip_v1_1024x1024.jpg

504503_IMG001_2023_Nissan_Z_STILLEN_Cat_Back_Exhaust_Street_Series_Polished_Tip_v1_1024x1024.jpg

504504_IMG007_2023_Nissan_Z_STILLEN_Cat_Back_Exhaust_Street_Series_Burnt_Tip_v1_1024x1024.jpg

504503_IMG007_2023_Nissan_Z_STILLEN_Cat_Back_Exhaust_Street_Series_Polished_Tip_v1_1024x1024.jpg
 
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Heavy Dupree

Heavy Dupree

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"However, in an effort to get the best performance possible we did not want to restrict the engine by going from dual 2.5” tubes to a single 3” mid-pipe. "

vs

"There is no substitute for physical validation especially when it comes to the Nissan’s VR30 Engine. Numerous Infiniti Q50 and Infiniti Q60 Cat-Back Systems were tested through dyno pulls and extensive data logging. STILLEN’s rigorous procedures even included testing different merge angles between pipes. The result of STILLEN’s rigorous program found a “Y-Pipe” layout similar to what is found on the Nissan GTR VR38 Engine produced the best result.
-
Jun 25, 2019

"Having developed a wide range of prototype exhaust systems our engineering team hit the dyno to see which configuration produced the best results. After all of the tests were completed, we were a little bit surprised to learn that the best exhaust system was lying in front of us the whole time. The twin turbo V6 Nissan GT-R favors a dual into single back to dual configuration and after our testing was complete we learned that the Infiniti Q60 VR30DDTT does too. This exhaust system features a 2.5” Y pipe which flows into a 3” mid-pipe. The 3” mid-pipe then carries the exhaust gases to the rear of the vehicle where it branches back into 2.5” dual rear exit. "
-Feb 18, 2019

So was Stillen's validation off from 3+ years ago, or are they just responding to customer demands?
 

Turbo_P

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LMAO sounds like stillen is making shit up as they go. Best exhaust for these motors are dual 3" or a single 4 inch. Everything else is inferior.
 

Blackbeard

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man i wish Awe made burnt and rolled double wall tips , these look close to it if they are double walled and rolled
 
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Heavy Dupree

Heavy Dupree

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LMAO sounds like stillen is making shit up as they go.
Stillen has, at the very least, just contradicted themselves. They clearly stated in 2019 that their own "in house dyno testing" on the VR30 led to that particular exhaust design. Those same test results eliminated their other prototypes from contention.

Flash forward approximately 4 years and now we have the same engine in a 2 seat sports car.

Logically, I thought we'd be seeing a chopped-down version of their Q50/Q60 exhaust on the new Z. This would have provided additional validation for their prior claims. This is not what has happened here.

If I were guessing, their Y-into-single 3"-into-2.5 inch dual exit undersold on the Infiniti platform. They lost potential sales to buyers looking for a true dual design, and/or probably one that sounded louder/more agressive as well.

Best exhaust for these motors are dual 3" or a single 4 inch. Everything else is inferior.
So how does using the term "best" without details contribute to this discussion?
 

Turbo_P

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Their Y to Single 3" was one of the worst performing and sounding exhaust on the Q market. I have dyno'd a few of them and they have always made less than a dual setup.

If you look at most fast Qs they all have 3" dual. I was one of the biggest proponent of this setup with my Q when everyone was running VQ sized exhausts on these cars. The theory worked when I made 620 AWHP with Stage 1 turbos about 3 years ago on my car.

One of the biggest reason for this is less back pressure and more flow. The X or a Y actually show more resistance since scavenging is basically negligible on these turbo'd applications. You are making more boost with less WG with 3" True Dual and carrying it higher on the powerband.
 

 
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