Jordan_R
Stock Block Ready To Knock...er..Rock
So I recently decided that I wanted to change up the exhaust set up on my Taurus. Previously I had PPE Catless downpipes to dual 2.5" straight pipe exhaust with an x pipe to 2.5" vibrant resonators that were also sleeved with straight pipe. Effectively making it solely straight pipe with an x pipe. I recently changed from that set up to PPE Catless downpipes to dual 2.5" Y-pipe to 3.5" all the way back.
You can see the exhaust set ups here on my Youtube channel:
So let's get into some data here. First off I'd like to say every bit of information is based off of what I believe is correct information and shouldn't be seen as set in stone.
I have Gearhead's Gen 3 upgraded turbos and I am tuned through AJPTurbo. I chose the 3.5" straight pipe method because I believe that it flows better with the Y-pipe between the banks over an X-pipe. I believe this because a smooth transition between banks would cause a scavenging effect even on a turbo application over a possible disruption an X-pipe could cause with the exhaust gasses running into each other instead of funneling together. Nissan GTR's have been doing this since the beginning so surely they know what they are doing. And for the 3.5" choice I calculated the area of 2 2.5" pipes and found out it's within 2% of 3.5" area. That is the reason for the choice of dual 2.5" to 3.5" to maintain flow and promote scavenging. Yes, the exhaust is lighter but that isn't the main reason for the swap.
Examining flow between how much WGDC is needed to maintain Load or Boost PSI:
2.5" True dual exhaust to maintain 20psi it was taking 65%-70% WGDC from the lower rpms into the higher rpms before shift
2.5" Dual to 3.5" single exhaust to maintain 20psi it now takes 62%-67% WGDC from the lower rpms in to the higher rpms before shift.
So if we take out a bunch of other aspects it's about 3% more efficient in that sense. Take this within a grain of salt because there is a lot more that can go into this however trying to level the playing field in every aspect I am seeing that it's slightly more efficient.
Does it sound good? No. Does it look good? No. Does it perform slightly better? The data looks like it's pointing that direction. Does it weigh less? Yes.
Given what I have seen I would like to assume the stock exhaust would be quite a bit worse than my previous set up, but until someone is pushing the same amount of power out of a stock exhaust it's going to be all guessing as to how much it may be holding back the turbos.
I'd like to also reference a huge video that Gale Banks and Banks Performance came out with that references Boost to back pressure ratio and goes super in depth on exhaust after the turbine. Absolutely a wealth of knowledge:
Function over form has always been my thing in this platform so thought I'd give you guys some insight into this project I was trying. Let me know what you guys think. Out of respect for Brad's tuning I am not going to post any logs up and would hope you guys understand in that aspect.
You can see the exhaust set ups here on my Youtube channel:
So let's get into some data here. First off I'd like to say every bit of information is based off of what I believe is correct information and shouldn't be seen as set in stone.
I have Gearhead's Gen 3 upgraded turbos and I am tuned through AJPTurbo. I chose the 3.5" straight pipe method because I believe that it flows better with the Y-pipe between the banks over an X-pipe. I believe this because a smooth transition between banks would cause a scavenging effect even on a turbo application over a possible disruption an X-pipe could cause with the exhaust gasses running into each other instead of funneling together. Nissan GTR's have been doing this since the beginning so surely they know what they are doing. And for the 3.5" choice I calculated the area of 2 2.5" pipes and found out it's within 2% of 3.5" area. That is the reason for the choice of dual 2.5" to 3.5" to maintain flow and promote scavenging. Yes, the exhaust is lighter but that isn't the main reason for the swap.
Examining flow between how much WGDC is needed to maintain Load or Boost PSI:
2.5" True dual exhaust to maintain 20psi it was taking 65%-70% WGDC from the lower rpms into the higher rpms before shift
2.5" Dual to 3.5" single exhaust to maintain 20psi it now takes 62%-67% WGDC from the lower rpms in to the higher rpms before shift.
So if we take out a bunch of other aspects it's about 3% more efficient in that sense. Take this within a grain of salt because there is a lot more that can go into this however trying to level the playing field in every aspect I am seeing that it's slightly more efficient.
Does it sound good? No. Does it look good? No. Does it perform slightly better? The data looks like it's pointing that direction. Does it weigh less? Yes.
Given what I have seen I would like to assume the stock exhaust would be quite a bit worse than my previous set up, but until someone is pushing the same amount of power out of a stock exhaust it's going to be all guessing as to how much it may be holding back the turbos.
I'd like to also reference a huge video that Gale Banks and Banks Performance came out with that references Boost to back pressure ratio and goes super in depth on exhaust after the turbine. Absolutely a wealth of knowledge:
Function over form has always been my thing in this platform so thought I'd give you guys some insight into this project I was trying. Let me know what you guys think. Out of respect for Brad's tuning I am not going to post any logs up and would hope you guys understand in that aspect.
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