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You raised a legitimate concern so I took time to test the capabilities of the silicone coupler to resist collapse under vacuum. The stock turbo has a flow potential of ~480cfm based on the information I have found and the K&N RU-5111 has a flow of 435cfm @ some pressure drop, which I think is 1psi (2 inHg). Therefore, I would expect the RU-5111 to create additional vacuum in the turbo inlet because of the greater pressure differential required to support 480cfm.

Keep in mind these tests are done at room temperature so I don't know the impact of heat on the structural integrity of the silicone coupler. I pulled 5 inHg on the silicone tube and it can withstand collapsing even if I squeeze the tube. However, once I reached 7 inHg the tube could not maintain is shape and collapsed.

SETUP
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5 inHg
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7 inHg
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I am going to weld an 1/8" NPT bung to the bottom of the inlet and run the setup as is for now and measure the vacuum within the tube under full boost. I think long term I am going to add a 45deg aluminum bend to my setup and use a straight coupler as most have done.
awesome! love how you think and work! can't mess with science. I have a feeling you are going to be setting a lot of people straight. glad you joined the forum!
 
There are several companies that make full silicone intakes for turbocharged vehicles. I ran 26psi on a gtx3076 through one with zero collapse issues. I don't think they pull in as much vacuum as one might believe. Good job on the testing though.
 
Discussion starter · #47 ·
James is the man. He gave me an idea of what he does for a living. Now I feel like people are watching my house since he left yesterday lol
Thanks for the ride and your Alpha 6 is one sweet GTR.
 
Discussion starter · #48 ·
I took an hour this evening to tune the car for 17psi. I think this was stated, but I started with the Cobb Beta Stage II map for 93 octane and the only current mods are midpipe. I want to thank Doug at WeaponsGradePerformance and Chris from SBD for spending 10min to answer a few questions since I have not tuned a MAF setup and had a few questions. Once they explained the map relationships it was cake to tune. For anyone considering AccessTUNER Race I would highly recommend spending the $700 if you plan on a staged build.

After the initial run, the STFT's were looking good, but the car was seeing a bit of knock. I was actually glad to see knock so I don't have the play the game of adding timing to see knock and then backing off. Below is the log...
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Since the timing map is RPM vs Theoretical Pulsewidth I logged the two to understand where within the map I needed to make changes. A quick change of the timing map in the affected area and the car was consistently running clean with ZERO knock. I personally don't want to see any knock even though you can see minor knock without reverting to the secondary timing map.
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I will likely install the pumps/injectors/intakes next weekend and hope to follow up with the modification of the exhaust. After that I will head to the dyno for a baseline run.
 
Mad props to this man. I we need more like him trust me. When people like him start to debunk old theories and show that things can be done for cheaper everyone wins including vendors. Your probably gonna say how are vendors winning? They may not make as much off of their individual parts sales but they will more then make up for it volume wise and installs because people will be able to afford both instead of just one or the other.
 
Mad props to this man. I we need more like him trust me. When people like him start to debunk old theories and show that things can be done for cheaper everyone wins including vendors. Your probably gonna say how are vendors winning? They may not make as much off of their individual parts sales but they will more then make up for it volume wise and installs because people will be able to afford both instead of just one or the other.
I was thinking more of in the line of allowing the average Joe Bloe (me) purchase those performance parts...in the end it is still a Nissan...an exhaust is still an exhaust...designed to take the by-product of combustion out of the car...

Pikes Peak R35
 
Discussion starter · #52 ·
Due to weather my business trip was cancelled for today so I was able to install the Denso 265lph pumps this evening. There are plenty of threads detailing the pump install so I won't repeat this topic. Install took about 2hrs total taking my time, but is much easier if someone can hold the pump assembly as you unfasten the clips holding the pump assembly together. I will make one contribution to the topic by providing advice for the DIY folks.

When you reinstall the pump make sure you remove the o-ring for the pump outlet from the housing. I used a piece of welding rod and bent the end to a hook to pull it out. Make sure you seat the o-ring on the pump when installing or you will likely experience issue with the o-ring sealing on the pump.
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I would also recommend that you attached the pump filter to the bottom of the pump before reinstalling as it makes it much easier to install the filter prior. I also slightly lubed the o-ring before reinstalling.
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The car took a few seconds to fire up but once it did everything was fine. I took it out for a spin and checked STFT and I was able to verify pumps were working well. The STFTs at idle are showing too much fuel, which is expected when running larger pumps as it will typically increase the baseline fuel pressure. I hope to install the ID1000cc's this weekend with intakes and retune.
 
You raised a legitimate concern so I took time to test the capabilities of the silicone coupler to resist collapse under vacuum. The stock turbo has a flow potential of ~480cfm based on the information I have found and the K&N RU-5111 has a flow of 435cfm @ some pressure drop, which I think is 1psi (2 inHg). Therefore, I would expect the RU-5111 to create additional vacuum in the turbo inlet because of the greater pressure differential required to support 480cfm.

Keep in mind these tests are done at room temperature so I don't know the impact of heat on the structural integrity of the silicone coupler. I pulled 5 inHg on the silicone tube and it can withstand collapsing even if I squeeze the tube. However, once I reached 7 inHg the tube could not maintain its shape and collapsed.

SETUP

5 inHg

7 inHg

I am going to weld an 1/8" NPT bung to the bottom of the inlet and run the setup as is for now and measure the vacuum within the tube under full boost. I think long term I am going to add a 45deg aluminum bend to my setup and use a straight coupler as most have done.
Kudos for testing it out. Another thing to realize is that in the engine bay when they are hot as hell they will be softer and thus collapse at less vacuum I predict. I faced this years ago on my blower inlet. What I did (kind of a hack but it worked) was to cut a 1" wide section of pipe and put it INSIDE the silicone coupler in the middle. Then put a t-clamp on the outside around that... so you basically make a reinforced sandwich (pipe -> silicone -> clamp) that keeps it from caving in.
 
Kudos for testing it out. Another thing to realize is that in the engine bay when they are hot as hell they will be softer and thus collapse at less vacuum I predict. I faced this years ago on my blower inlet. What I did (kind of a hack but it worked) was to cut a 1" wide section of pipe and put it INSIDE the silicone coupler in the middle. Then put a t-clamp on the outside around that... so you basically make a reinforced sandwich (pipe -> silicone -> clamp) that keeps it from caving in.
After additional searching you can find YouTube videos of turbo inlets collapsing under boost so I have decided to modify the setup. I ordered some 60mm to 76mm straight reducers last week for $24 shipped and have enough material in my scrap bin to make the change. It will add two additional welds to the setup and $25 shipped for new shinny pipes had I ordered the pipe. I still plan on measuring the turbo inlet pressure, but I agree that with temperature the structural performance of the silicone coupler will be too close for comfort.
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Discussion starter · #55 ·
My new silicone couplers have not arrived so I went ahead and installed the intakes as well as the ID1000cc injectors. I switched to the Cobb Stage III map and transferred the revised timing map from the previous tune. The car fired up with no issue, but I did have some fluctuating idle that was fixed by adding a bunch of fuel at idle. I was only able to make a few pulls at 15psi, but the STFT's were in the 0.96 range so the OTS map was fairly close and will not require more than about 1hr of street tuning to dial in the MAFs. The next step is to modify the stock exhaust, which I hope to start next weekend.
 
Nice to see you making parts for your GTR. I followed your thread on evom. Cant wait to see more progress.
I took a break from the EVO to put time towards the GTR. I did just pick up the wiring harness and programmable transmission controller for the W4A51 auto tranny swap and I will be getting the paddle shifter on Monday. I hope to have some updates on the EVO next week just showing all the hardware. Minus the intercooler setup, I should have the GTR completely in 4-6 weeks.
 
Discussion starter · #58 ·
I decided the pull the trigger on TCM with Cobb and put down $400 for the license. My car has 6100 miles and had never done the clutch relearn and I wanted to swap to LC5. Software install went well and I don't feel a huge difference in shifting, but the trans seems to make more noise with LC5 vs LC2.
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I spent some timing refining the MAF curves, but I really need to get my wife to drive the car so I can tune the MAF realtime when it is in steady state at various MAF voltages. Regardless, the tune is doing well so I decided the up the boost and currently have it set to 18psi with zero knock count. If my wife permits I am going to do the exhaust mod next week, which I hope will only take 4-6hrs.
 
I decided the pull the trigger on TCM with Cobb and put down $400 for the license. My car has 6100 miles and had never done the clutch relearn and I wanted to swap to LC5. Software install went well and I don't feel a huge difference in shifting, but the trans seems to make more noise with LC5 vs LC2.
Image


I spent some timing refining the MAF curves, but I really need to get my wife to drive the car so I can tune the MAF realtime when it is in steady state at various MAF voltages. Regardless, the tune is doing well so I decided the up the boost and currently have it set to 18psi with zero knock count. If my wife permits I am going to do the exhaust mod next week, which I hope will only take 4-6hrs.
lol "if my wife permits"
been there my friend
 
I decided the pull the trigger on TCM with Cobb and put down $400 for the license. My car has 6100 miles and had never done the clutch relearn and I wanted to swap to LC5. Software install went well and I don't feel a huge difference in shifting, but the trans seems to make more noise with LC5 vs LC2.
Image


I spent some timing refining the MAF curves, but I really need to get my wife to drive the car so I can tune the MAF realtime when it is in steady state at various MAF voltages. Regardless, the tune is doing well so I decided the up the boost and currently have it set to 18psi with zero knock count. If my wife permits I am going to do the exhaust mod next week, which I hope will only take 4-6hrs.
I felt the same thing on my 2009 when I upgraded from LC2 to LC5. More noise from the gearbox especially when taking of.
Ive read somewhere that with never software you needed to go upp on the TP OR if it was the CC?
This for clutch B not A.
Will try that as soon as I get my car back from the dealer.

Btw Im following your thread with big interest. Hate the felling of beeing ripped of by GTR tax. :)
 
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