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My New "MEGADump" midpipe

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#1
240Z TwinTurbo

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I don't start too many threads on this forum, but thought I would share.  I had contemplated fabricating a 4" exhaust for my GTR, but then decided to go forward with a design I had in my head for some time regarding a new midpipe.  It's not a new concept to run a dump off the midpipe and I have seen others do the same with either electric valves or wastegates.  However, I wanted the dump to be the primary exhaust flow path and have the bypass portion be the stock routed exhaust.  I figured if I was going to run a dump I should either go big or go home. 

 

I removed my Cobb midpipe and used it to create the jig as shown below.

 

Jig6.JPG

 

 

I next started fabricating the new midpipe, which is two 3.0" primaries that merge into a 3.5" merge collector and then transition to a 4" tube.  I added some bullet mufflers because I wanted to somewhat tame the noise prior to the dump.

 

Fab3.JPG

 

 

I next added the flex sections followed by the merge collector.  You can also see the 3.5" to 4.0" transition on the outlet of the merge collector.  Unfortunately, the merge collector I ordered was too long so I sacrificed the collector on the Cobb midpipe for the new design.  I'll just rework the Cobb midpipe to add in the longer merge collector.

 

Fab6.JPG

 

 

The next task was to integrate the 4.0" piece that came with the http://www.loudvalves.com, which is a 4.0" pipe with a 4.0" Y-merge.  You can see from the pic below that after the 4.0" Y-merge I use a 4.0" to 3.5" transition to allow me to connect to the 3.5" 2-bolt exhaust flange.  You can also see in the pic below the massive 4.0" boost actuated dump valve.

 

Fab9.JPG

Fab8.JPG

 

 

I next tacked together the 3.5" pipe to the 3.5" 2-bolt exhaust flange and then guaranteed that it bolted to the car with no fitment or clearance issues.

 

Fab16.JPG

Fab12.JPG

Fab11.JPG

Fab17.JPG

Fab19.JPG

Fab22.JPG

 

 

The final step was to weld the valve to the midpipe and weld the turndown to the valve.

 

Finished2.JPG

Finished1.JPG

Finished3.JPG

Finished4.JPG

 

 

I was able to take the car to the track Friday and improved on my previous time from before, which was a 10.95@128.66.  Unfortunately, I did not get a chance to run it with valve closed, which I hope to do this Friday.

 

Run3.JPG

 

 

It is definitely LAF inside the car, but based on the video below a lot more tame on the outside vs what I thought.  Overall I am happy with the new midpipe as well as the results and the final item is to hook up the valve to a Mac 3-way solenoid in line with a 10psi Hobbs switch so I can cut this on and off.  The Hobbs switch is because the valve starts cracking at ~2psi so I want it to open much later.  Below is a link to one of my runs....10.85@129.4.

 

http://www.eng.famu....es_vs_Vette.mp4


Edited by 240Z TwinTurbo, 28 August 2017 - 09:00 AM.

  • Tim, ian.r, 7racer and 1 other like this

2006 EVO IX (573hp/439tq)

2009 GTR Premium

Built RB26 with no home (everything is for sale...lots of stuff)

Garrett V-band TwinScroll GTX35r Topmount Experiment
Garrett V-band TwinScroll GTX3576r, Curt Brown 10:1 2L, R2's, 110octane, 573hp/439tq


#2
Tim

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That is cool dude and your right it really isn't to loud outside the car. Nice work!!
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post-273-0-31146100-1438786356.jpg

#3
240Z TwinTurbo

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I was able to install the MAC valve, but have yet to hook up the 10psi Hobbs switch.  With the valve hooked directly to a boost source it starts cracking at ~2psi, which is annoying for everyday driving.  Integrating the MAC valve allows me to turn the valve on and off and with the Hobbs switch in series with the MAC valve it won't open until 10psi.  Due to packaging I will weld a flange to the bottom of the upper IC pipe and drill/tap 1/8" NPT for the Hobbs switch, which I hope to complete this weekend.

 

MAC_1.JPG

MAC_2.JPG

MAC_3.JPG


Edited by 240Z TwinTurbo, 19 September 2017 - 09:13 AM.

  • Tim, 7racer and BAZ007 like this

2006 EVO IX (573hp/439tq)

2009 GTR Premium

Built RB26 with no home (everything is for sale...lots of stuff)

Garrett V-band TwinScroll GTX35r Topmount Experiment
Garrett V-band TwinScroll GTX3576r, Curt Brown 10:1 2L, R2's, 110octane, 573hp/439tq


#4
gtrguyinaz

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The most wild and wicked Mid Pipe ever.............

Great welding skills , concept is great but dump at 2 PSI  ????????


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#5
240Z TwinTurbo

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The most wild and wicked Mid Pipe ever.............

Great welding skills , concept is great but dump at 2 PSI  ????????

 

Thanks for the feedback, but if you look at post #3 I can turn the dump valve on & off with the MAC Valve and when on, it opens at 10psi because of the Hobbs Switch.  Therefore, no longer does it crack open at 2psi.


Edited by 240Z TwinTurbo, 10 October 2017 - 05:22 PM.

  • 7racer likes this

2006 EVO IX (573hp/439tq)

2009 GTR Premium

Built RB26 with no home (everything is for sale...lots of stuff)

Garrett V-band TwinScroll GTX35r Topmount Experiment
Garrett V-band TwinScroll GTX3576r, Curt Brown 10:1 2L, R2's, 110octane, 573hp/439tq


#6
240Z TwinTurbo

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I finally finished wiring the Mac Valve along with the Hobbs switch for the exhaust dump.

 

Wired from the solenoid to the Hobbs switch and covered the wire in some nice black loom.

wiring5.jpg

 

 

Connected to the Hobbs switch

wiring4.jpg

 

There is a great place to run the wiring harness through the firewall under the access panel for the brake booster.  Just remove the OEM plug and I inserted a grommet to my specs.

wiring3.jpg

 

And from the inside of the car.

wiring2.jpg

 

And where I mounted a low profile switch from Discount Auto.

wiring1.jpg

 

Finally, how I ran power to the MAC Valve.

wiring6.jpg


  • Tim, 7racer and shawnhayes like this

2006 EVO IX (573hp/439tq)

2009 GTR Premium

Built RB26 with no home (everything is for sale...lots of stuff)

Garrett V-band TwinScroll GTX35r Topmount Experiment
Garrett V-band TwinScroll GTX3576r, Curt Brown 10:1 2L, R2's, 110octane, 573hp/439tq


#7
shawnhayes

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Nice work...

 

Shawn



#8
240Z TwinTurbo

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Nice work...

 

Shawn

 

Thanks...it's LOUD in the car, but I like that I can turn it off.


  • Tim and 7racer like this

2006 EVO IX (573hp/439tq)

2009 GTR Premium

Built RB26 with no home (everything is for sale...lots of stuff)

Garrett V-band TwinScroll GTX35r Topmount Experiment
Garrett V-band TwinScroll GTX3576r, Curt Brown 10:1 2L, R2's, 110octane, 573hp/439tq


#9
GDZ1LLAH

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AWESOME!  I love it when skilled people can make exactly what they want.  Very cool design



#10
240Z TwinTurbo

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AWESOME!  I love it when skilled people can make exactly what they want.  Very cool design

 

Thanks for the compliment.  I have been eyeing to add a high flow cat to the midpipe.  I have a little more than 8" of straight pipe in the area circled below, but likely have to modify the dump pipe for clearance.  Just debating on whether to spend $410 on the high flow cat (vibrant 7835) or use a cheaper standard 100 cel cat for $110.

 

AddCAT1.jpg


2006 EVO IX (573hp/439tq)

2009 GTR Premium

Built RB26 with no home (everything is for sale...lots of stuff)

Garrett V-band TwinScroll GTX35r Topmount Experiment
Garrett V-band TwinScroll GTX3576r, Curt Brown 10:1 2L, R2's, 110octane, 573hp/439tq


#11
gtrguyinaz

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I would think this would change the tune to maybe running too lean ??



#12
240Z TwinTurbo

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I would think this would change the tune to maybe running too lean ??

 

ECU runs closed loop wideband O2's so it can compensate +/- 20% (maybe 25%) and my STFT's are within 3-4%  Therefore, even if it does require more fuel the computer compensates with STFT to achieve the targeted 11.5:1 AFR.


2006 EVO IX (573hp/439tq)

2009 GTR Premium

Built RB26 with no home (everything is for sale...lots of stuff)

Garrett V-band TwinScroll GTX35r Topmount Experiment
Garrett V-band TwinScroll GTX3576r, Curt Brown 10:1 2L, R2's, 110octane, 573hp/439tq


#13
gtrguyinaz

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ECU runs closed loop wideband O2's so it can compensate +/- 20% (maybe 25%) and my STFT's are within 3-4%  Therefore, even if it does require more fuel the computer compensates with STFT to achieve the targeted 11.5:1 AFR.

This is great..........When do ya start production....... Fabulous job........



#14
240Z TwinTurbo

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Production completed, one of one in the books😉

I did this in my garage so not something I intended for additional copies. I'm about to get a floor lift for my garage to install the Xona Greens that have been collecting dust so don't really have time.

I've been finishing the resto of my daughters 83 928s and have a 71 240Z I purchased for my son that is awaiting my attention.
  • 7racer likes this

2006 EVO IX (573hp/439tq)

2009 GTR Premium

Built RB26 with no home (everything is for sale...lots of stuff)

Garrett V-band TwinScroll GTX35r Topmount Experiment
Garrett V-band TwinScroll GTX3576r, Curt Brown 10:1 2L, R2's, 110octane, 573hp/439tq


#15
7racer

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Production completed, one of one in the books

I did this in my garage so not something I intended for additional copies. I'm about to get a floor lift for my garage to install the Xona Greens that have been collecting dust so don't really have time.

I've been finishing the resto of my daughters 83 928s and have a 71 240Z I purchased for my son that is awaiting my attention.

 

do a build thread on those!


In7anity!!


#16
240Z TwinTurbo

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do a build thread on those!

 

I did for the 928s

https://rennlist.com...-other-day.html

 

I just finished replacing all the suspension stuff and the only things remaining are to install front air dam, redo rear interior panels, install DIY cup holder, fix ds seat recline, as well as a few minor knick knacks.  However, I completely paint corrected the car and it runs and drivers like a champ and doesn't burn a drop of oil.

 

928S_4.jpg

engineremoval_1.jpg

928S_2.jpg

 

 

The 71 240Z on the other hand....needs a lot of work and will be the first time I have attempted replacing rusted panels.

240Z.jpg


Edited by 240Z TwinTurbo, 23 January 2018 - 07:25 AM.

2006 EVO IX (573hp/439tq)

2009 GTR Premium

Built RB26 with no home (everything is for sale...lots of stuff)

Garrett V-band TwinScroll GTX35r Topmount Experiment
Garrett V-band TwinScroll GTX3576r, Curt Brown 10:1 2L, R2's, 110octane, 573hp/439tq


#17
gtrguyinaz

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Great projects , your kids are lucky for many reasons......... Great older daily drivers and they get to learn auto mechanics  101 and 404 at home ..



#18
shawnhayes

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You're very talented.

 

I don't have the patience for restoration work.

 

Shawn



#19
7racer

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oh man that 928 is a beaut!

 

the 240 will be epic


In7anity!!


#20
240Z TwinTurbo

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new 3.5" cat showed up last week, but knew it would be a PIA to cut off the old 3.5" flange so I ordered and new one that arrived today.  I should be able to get this integrated within 3-4hrs.

 

cat1.JPG


2006 EVO IX (573hp/439tq)

2009 GTR Premium

Built RB26 with no home (everything is for sale...lots of stuff)

Garrett V-band TwinScroll GTX35r Topmount Experiment
Garrett V-band TwinScroll GTX3576r, Curt Brown 10:1 2L, R2's, 110octane, 573hp/439tq





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