Compound turbo rb25 in s13 - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

FutureFab · 12-05-2011, 09:41 PM

Ive been running a modified stock log with ebay t70 for two years or so and I had two broken exhaust studs that were bothering me. After taking it apart and fixing them I just couldnt put the stock log back on. So I figured it was time to build a new manifold. I didnt want just another top mount either. It was time to go compound and loose the lag.

The diesel boys have been doing this for years. For those unaware how it works, basically all the exhaust runners go into the little turbo first, it spools and the down pipe goes up to the inlet of the larger turbo. A waste gate before the little turbo opens at X psi and bypasses the little turbine and is routed back into the big turbo before the turbine wheel. A second gate controls the boost of the big turbo and vents to atmosphere.

On the Compressor side, the lil turbos inlet is drawing thru the big turbo until the big turbo spools and pushes thru the compressor of the little one.

So the little turbo spools quick then runs out of top end, as its doing so, the big turbo finally has enough energy and starts making psi and takes over up top. Its a seamless transition and it works great!

I did this on a budget and salvaged parts that were either on my car or on my spare sr sitting in the back. Some things like head flange and stainless elbows I had to buy.

Hardware.

Bb s15 spec r t28
Journal bearing ebay t70 t3
Tial 44 mm to bypass t28 and feed t3
Tial 38 mvs to control boost of big turbo

Empty exhaust side.

The hardware.

I was previously making 1 bar at 4500 with my log/t70 setup. Now I am making 1 bar at 3000. This is still on pump gas. There is lots more to go, now I need to switch back to draw thru maf (maxing out with blow thru) and upgrade injectors beyond the 550s in there now. It actually has more traction in a strait line since there isnt a "hit" of power at 4500, it just spools asap and keeps pulling. If I turn the wheel just a tad, it just breaks traction and goes to limiter unless i feather it. Dont even need to clutch kick, just mash that skinny pedal and chong.

Flicktitty · 12-05-2011, 10:34 PM

VERY COOL!

i've seen a few people do this on the 2JZ with great success.
IMO this is the way to go if you have fab skills, great work!

fearlessKouki · 12-05-2011, 11:03 PM

unique setup for sure!

ch1873857 · 12-05-2011, 11:22 PM

this is GOOD SHIT. Impressive stuff! would love to see some videos of that..

Jtuned_andy · 12-05-2011, 11:57 PM

Wow, looks like a technical nightmare but if it works that is downright awesome! haha

mikey976 · 12-06-2011, 11:35 AM

i think everyone will agree when i say give us some videos

turbociv910 · 12-06-2011, 02:54 PM

very cool, looks like a pita to install!

FutureFab · 12-06-2011, 06:36 PM

Its not too bad to install, just has to be in order. Making it was the pita.

Going to the track after dinner, will take some video.

azn2nr · 12-06-2011, 11:01 PM

subscribed for results.

ive always wanted to do a compound turbo settup but was always troubled by the complications that come with it.

one problem that troubled me in my research was the recompression that occurs when the big turbo comes on. because the small turbo doesnt care that the air is already compressed it continues to compress it at whatever rate it can, and due to natural backpresure its impossible to slow shaft speed of the small turbo to the point that it wouldnt recompress the air. sort of like the way stacking in line fuel pumps works.

i have no direct experience with it but draw through just seems like a bad idea because of recompression.

mxracerjason · 12-06-2011, 11:38 PM

What ECU are you using. I curently have the stock RB25 ecu in mine and the two things that need to change are the rev limiter the stopes at 6100, would like it moved to 7200ish and the speed limiter needs to go. It cuts out at 123mph. I will be upgradeing to a Vi-Pec that will fix all of that, and after it gets tuned it should make about 400+ rear wheel.

idahotuner · 12-07-2011, 12:31 AM

awesome, wish you had pics ofit on the motor out of the car

FutureFab · 12-07-2011, 12:36 AM

Well my phone battery was dead so i only got one video. Need to host it then post. Will have to do until next week.

Ecu is power fc.

Imageshack wont let me log in from phone or laptop. Have to play that game tomorrow.

FutureFab · 12-08-2011, 07:15 PM

Finally got the video

2011-12-06_21-03-25_509.mp4 - YouTube

rb20240sx · 12-08-2011, 07:22 PM

sweet setup always have thought about doing this

twinspool · 12-08-2011, 07:34 PM

that is amazing, just the other day I was thinking about this set up too hahah

PoorMans180SX · 12-08-2011, 08:31 PM

Dang, that looks like a blast. I would really like to do a compound sometime in the future.

If you wanted to even add more complexity, you could add a quick spool valve to the T70. Would be interesting to see how it worked.

AS240 · 12-08-2011, 09:19 PM

that is awesome man! do you still have the old stock manifold you were using? did you modify it in any way?

FutureFab · 12-09-2011, 01:22 AM

No more room or else Id try and put a QS valve on there. I still need to play around with it if im going to make any more power. Ill probably go dyno to get a baseline, then up the injectors and lean on the big one a bit harder. After that is Neo cams and extra capacity oil pan.

The stock mani was modified in two ways, 1st I put a hole in the collector for tial 44, 2nd was a spacer was welded to the t3 flange of mani to space turbo out to get compressor clearance. I already sold it just to make sure I finished the project and didnt go back to stock.

PoorMans180SX · 12-09-2011, 07:44 AM

Are you routing the copper gate to atmosphere? Doesn't that kind of waste the exhaust energy that could be going to the T70? Obviously you don't have much room to work with but...

I guess it would definitely regulate boost better that way.

FutureFab · 12-09-2011, 09:56 AM

Good eye, that was a experiment. It was using the internal gate routed back in to the big turbo. I could have left it as there was no noticable gain.

Fred Allen Burge · 12-09-2011, 11:13 AM

I can not believe you fit all that in there! Nice work, I'm glad it actually worked for you.

AS240 · 12-10-2011, 08:28 AM

Quote:

Originally Posted by FutureFab

The stock mani was modified in two ways, 1st I put a hole in the collector for tial 44, 2nd was a spacer was welded to the t3 flange of mani to space turbo out to get compressor clearance. I already sold it just to make sure I finished the project and didnt go back to stock.

did you use a 10mm plate to space the turbo, and did you have any clearance issues with the steering shaft? i have been looking at doing this but there isnt a whole lot of info out there.

PoorMans180SX · 12-10-2011, 10:38 AM

I PM'd you some questions good sir.

FutureFab · 12-10-2011, 11:18 AM

For stock manifold you can use a 10mm spacer on turbos with E compressor housings, like a 57 trim. My turbo had a S compressor cover, so i used two t3 flanges, one cut diagonally from one face to the other making wedges. I turned them the same way to"make a bend" away from the manifold. The second flange was then placed on for the turbo to bolt to. Down pipe clearance was close but some bends made it in there none the less.

AS240 · 12-10-2011, 02:48 PM

would you happen to have any old pics of fabing all that? my brother just got a miller dynasty 200 so i want to start fabing up my own stuff. thanks again

FutureFab · 12-11-2011, 03:06 AM

Looks like so..

AS240 · 12-13-2011, 04:45 PM

you have true talent man. im going to hopefully modify my manifold this weekend once i finish all my finals. i want to fit a pte5857 with the S housing down there. any advice that you learned along the way is greatly appreciated since this will be my first time fabricating anything. you can pm me if you do so it doesnt clog up your thread. thanks man!

FutureFab · 12-13-2011, 10:28 PM

My old megan camber arms were totally maxxed out in length and I still had negative camber, so I cut them up and made some new longer ones. They are even lighter than the old ones too. I had Eleven's Paint and Fiber blast these mofo's with a custom blend of red and pearl.

And some more compound pics..

Down pipe vs brakes

4" down pipe clearance.

smgopedguy · 12-20-2011, 08:21 PM

Cool Car bro!

FutureFab · 12-21-2011, 01:05 AM

A couple more videos from this week...

http://www.youtube.com/watch?v=CoIf0hRRXj4

http://www.youtube.com/watch?v=G_6Hy...d1AUAAAAAAABAA

a little blurry on this one
http://www.youtube.com/watch?v=r-VJdIYTqyQ

12-05-2011, 09:41 PM	#1
FutureFab Zilvia Member Join Date: Nov 2011 Location: PHX Posts: 276 Trader Rating: (32) Feedback Score: 32 reviews	Compound turbo rb25 in s13 Ive been running a modified stock log with ebay t70 for two years or so and I had two broken exhaust studs that were bothering me. After taking it apart and fixing them I just couldnt put the stock log back on. So I figured it was time to build a new manifold. I didnt want just another top mount either. It was time to go compound and loose the lag. The diesel boys have been doing this for years. For those unaware how it works, basically all the exhaust runners go into the little turbo first, it spools and the down pipe goes up to the inlet of the larger turbo. A waste gate before the little turbo opens at X psi and bypasses the little turbine and is routed back into the big turbo before the turbine wheel. A second gate controls the boost of the big turbo and vents to atmosphere. On the Compressor side, the lil turbos inlet is drawing thru the big turbo until the big turbo spools and pushes thru the compressor of the little one. So the little turbo spools quick then runs out of top end, as its doing so, the big turbo finally has enough energy and starts making psi and takes over up top. Its a seamless transition and it works great! I did this on a budget and salvaged parts that were either on my car or on my spare sr sitting in the back. Some things like head flange and stainless elbows I had to buy. Hardware. Bb s15 spec r t28 Journal bearing ebay t70 t3 Tial 44 mm to bypass t28 and feed t3 Tial 38 mvs to control boost of big turbo Empty exhaust side. The hardware. I was previously making 1 bar at 4500 with my log/t70 setup. Now I am making 1 bar at 3000. This is still on pump gas. There is lots more to go, now I need to switch back to draw thru maf (maxing out with blow thru) and upgrade injectors beyond the 550s in there now. It actually has more traction in a strait line since there isnt a "hit" of power at 4500, it just spools asap and keeps pulling. If I turn the wheel just a tad, it just breaks traction and goes to limiter unless i feather it. Dont even need to clutch kick, just mash that skinny pedal and chong. __________________ futurefabrication.com

12-05-2011, 10:34 PM	#2
Flicktitty Post Whore! Join Date: Apr 2007 Location: Wisconsin Age: 34 Posts: 3,685 Trader Rating: (13) Feedback Score: 13 reviews	VERY COOL! i've seen a few people do this on the 2JZ with great success. IMO this is the way to go if you have fab skills, great work! __________________ 2JZ-GTE Swapped S13 Coupe - 1994 Supra Turbo

12-05-2011, 11:57 PM	#5
Jtuned_andy Zilvia FREAK! Join Date: Apr 2006 Location: East Coast Posts: 1,083 Trader Rating: (27) Rides Gallery: Jtuned_andy Feedback Score: 27 reviews	Wow, looks like a technical nightmare but if it works that is downright awesome! haha __________________

12-06-2011, 11:35 AM	#6
mikey976 Zilvia Member Join Date: Apr 2007 Location: North Jers, Parsippany Age: 37 Posts: 215 Trader Rating: (6) Feedback Score: 6 reviews	i think everyone will agree when i say give us some videos __________________ KAe-T goal 400whp with A/C - Hatch VH45 track duty - Titan VK56 tow rig

12-06-2011, 02:54 PM	#7
turbociv910 Zilvia Member Join Date: Oct 2011 Location: wilmington nc Age: 32 Posts: 241 Trader Rating: (0) Feedback Score: 0 reviews	very cool, looks like a pita to install! __________________ www.carolinadyno.com s13 LSx turbo drag car- 1.42 60 ft, 6.32 1/8

12-05-2011, 11:03 PM	#3
fearlessKouki Zilvia Member Join Date: Oct 2010 Location: Ohio Age: 30 Posts: 278 Trader Rating: (2) Feedback Score: 2 reviews	unique setup for sure!

12-05-2011, 11:22 PM	#4
ch1873857 Nissanaholic! Join Date: Sep 2003 Location: Andrews Air Force Base Posts: 1,905 Trader Rating: (1) Feedback Score: 1 reviews	this is GOOD SHIT. Impressive stuff! would love to see some videos of that..

12-06-2011, 06:36 PM	#8
FutureFab Zilvia Member Join Date: Nov 2011 Location: PHX Posts: 276 Trader Rating: (32) Feedback Score: 32 reviews	Its not too bad to install, just has to be in order. Making it was the pita. Going to the track after dinner, will take some video. __________________ futurefabrication.com

12-06-2011, 11:01 PM	#9
azn2nr Join Date: May 2008 Location: slc Posts: 1 Trader Rating: (0) Feedback Score: 0 reviews	subscribed for results. ive always wanted to do a compound turbo settup but was always troubled by the complications that come with it. one problem that troubled me in my research was the recompression that occurs when the big turbo comes on. because the small turbo doesnt care that the air is already compressed it continues to compress it at whatever rate it can, and due to natural backpresure its impossible to slow shaft speed of the small turbo to the point that it wouldnt recompress the air. sort of like the way stacking in line fuel pumps works. i have no direct experience with it but draw through just seems like a bad idea because of recompression.

12-06-2011, 11:38 PM	#10
mxracerjason Zilvia Member Join Date: Oct 2011 Location: Puyallup, WA Age: 52 Posts: 248 Trader Rating: (0) Feedback Score: 0 reviews	What ECU are you using. I curently have the stock RB25 ecu in mine and the two things that need to change are the rev limiter the stopes at 6100, would like it moved to 7200ish and the speed limiter needs to go. It cuts out at 123mph. I will be upgradeing to a Vi-Pec that will fix all of that, and after it gets tuned it should make about 400+ rear wheel.

12-07-2011, 12:31 AM	#11
idahotuner Zilvia FREAK! Join Date: Jan 2008 Location: St. Maries, Idaho Age: 32 Posts: 1,276 Trader Rating: (17) Rides Gallery: idahotuner Feedback Score: 17 reviews	awesome, wish you had pics ofit on the motor out of the car __________________ My Twin Scroll Gt30r Sr22det Build

12-07-2011, 12:36 AM	#12
FutureFab Zilvia Member Join Date: Nov 2011 Location: PHX Posts: 276 Trader Rating: (32) Feedback Score: 32 reviews	Well my phone battery was dead so i only got one video. Need to host it then post. Will have to do until next week. Ecu is power fc. Imageshack wont let me log in from phone or laptop. Have to play that game tomorrow. __________________ futurefabrication.com Last edited by FutureFab; 12-07-2011 at 01:13 AM.. Reason: didnt need to make another post

12-08-2011, 07:15 PM	#13
FutureFab Zilvia Member Join Date: Nov 2011 Location: PHX Posts: 276 Trader Rating: (32) Feedback Score: 32 reviews	Finally got the video 2011-12-06_21-03-25_509.mp4 - YouTube __________________ futurefabrication.com

12-08-2011, 07:22 PM	#14
rb20240sx Zilvia Junkie Join Date: Feb 2007 Location: 850 Age: 31 Posts: 392 Trader Rating: (12) Feedback Score: 12 reviews	sweet setup always have thought about doing this __________________ 95 SE Serengeti sand- RB25 Neo

12-08-2011, 07:34 PM	#15
twinspool Zilvia Junkie Join Date: May 2006 Location: mississippi Posts: 349 Trader Rating: (7) Feedback Score: 7 reviews	that is amazing, just the other day I was thinking about this set up too hahah

12-08-2011, 08:31 PM	#16
PoorMans180SX Zilvia.net Advertiser Join Date: Nov 2005 Location: Michigan Age: 33 Posts: 5,431 Trader Rating: (16) Rides Gallery: PoorMans180SX Feedback Score: 16 reviews	Dang, that looks like a blast. I would really like to do a compound sometime in the future. If you wanted to even add more complexity, you could add a quick spool valve to the T70. Would be interesting to see how it worked. __________________ Build: http://zilvia.net/f/showthread.php?t=643065 Friends don't let friends buy knock-offs.

12-08-2011, 09:19 PM	#17
AS240 Zilvia Addict Join Date: Jul 2007 Location: Austin, Tx Age: 31 Posts: 683 Trader Rating: (18) Feedback Score: 18 reviews	that is awesome man! do you still have the old stock manifold you were using? did you modify it in any way?

12-09-2011, 01:22 AM	#18
FutureFab Zilvia Member Join Date: Nov 2011 Location: PHX Posts: 276 Trader Rating: (32) Feedback Score: 32 reviews	No more room or else Id try and put a QS valve on there. I still need to play around with it if im going to make any more power. Ill probably go dyno to get a baseline, then up the injectors and lean on the big one a bit harder. After that is Neo cams and extra capacity oil pan. The stock mani was modified in two ways, 1st I put a hole in the collector for tial 44, 2nd was a spacer was welded to the t3 flange of mani to space turbo out to get compressor clearance. I already sold it just to make sure I finished the project and didnt go back to stock. __________________ futurefabrication.com Last edited by FutureFab; 12-09-2011 at 01:30 AM.. Reason: pic upload

12-09-2011, 07:44 AM	#19
PoorMans180SX Zilvia.net Advertiser Join Date: Nov 2005 Location: Michigan Age: 33 Posts: 5,431 Trader Rating: (16) Rides Gallery: PoorMans180SX Feedback Score: 16 reviews	Are you routing the copper gate to atmosphere? Doesn't that kind of waste the exhaust energy that could be going to the T70? Obviously you don't have much room to work with but... I guess it would definitely regulate boost better that way. __________________ Build: http://zilvia.net/f/showthread.php?t=643065 Friends don't let friends buy knock-offs.

12-09-2011, 09:56 AM	#20
FutureFab Zilvia Member Join Date: Nov 2011 Location: PHX Posts: 276 Trader Rating: (32) Feedback Score: 32 reviews	Good eye, that was a experiment. It was using the internal gate routed back in to the big turbo. I could have left it as there was no noticable gain. __________________ futurefabrication.com

12-09-2011, 11:13 AM	#21
Fred Allen Burge Zilvia Junkie Join Date: Aug 2006 Location: Missouri Age: 41 Posts: 524 Trader Rating: (1) Feedback Score: 1 reviews	I can not believe you fit all that in there! Nice work, I'm glad it actually worked for you. __________________ Silvia, built 5.3 turbo, 4l80e, [email protected]

12-10-2011, 10:38 AM	#23
PoorMans180SX Zilvia.net Advertiser Join Date: Nov 2005 Location: Michigan Age: 33 Posts: 5,431 Trader Rating: (16) Rides Gallery: PoorMans180SX Feedback Score: 16 reviews	I PM'd you some questions good sir. __________________ Build: http://zilvia.net/f/showthread.php?t=643065 Friends don't let friends buy knock-offs.

12-10-2011, 11:18 AM	#24
FutureFab Zilvia Member Join Date: Nov 2011 Location: PHX Posts: 276 Trader Rating: (32) Feedback Score: 32 reviews	For stock manifold you can use a 10mm spacer on turbos with E compressor housings, like a 57 trim. My turbo had a S compressor cover, so i used two t3 flanges, one cut diagonally from one face to the other making wedges. I turned them the same way to"make a bend" away from the manifold. The second flange was then placed on for the turbo to bolt to. Down pipe clearance was close but some bends made it in there none the less. __________________ futurefabrication.com

12-10-2011, 02:48 PM	#25
AS240 Zilvia Addict Join Date: Jul 2007 Location: Austin, Tx Age: 31 Posts: 683 Trader Rating: (18) Feedback Score: 18 reviews	would you happen to have any old pics of fabing all that? my brother just got a miller dynasty 200 so i want to start fabing up my own stuff. thanks again

12-11-2011, 03:06 AM	#26
FutureFab Zilvia Member Join Date: Nov 2011 Location: PHX Posts: 276 Trader Rating: (32) Feedback Score: 32 reviews	Looks like so.. __________________ futurefabrication.com

12-13-2011, 04:45 PM	#27
AS240 Zilvia Addict Join Date: Jul 2007 Location: Austin, Tx Age: 31 Posts: 683 Trader Rating: (18) Feedback Score: 18 reviews	you have true talent man. im going to hopefully modify my manifold this weekend once i finish all my finals. i want to fit a pte5857 with the S housing down there. any advice that you learned along the way is greatly appreciated since this will be my first time fabricating anything. you can pm me if you do so it doesnt clog up your thread. thanks man!

12-13-2011, 10:28 PM	#28
FutureFab Zilvia Member Join Date: Nov 2011 Location: PHX Posts: 276 Trader Rating: (32) Feedback Score: 32 reviews	My old megan camber arms were totally maxxed out in length and I still had negative camber, so I cut them up and made some new longer ones. They are even lighter than the old ones too. I had Eleven's Paint and Fiber blast these mofo's with a custom blend of red and pearl. And some more compound pics.. Down pipe vs brakes 4" down pipe clearance. __________________ futurefabrication.com

12-20-2011, 08:21 PM	#29
smgopedguy Join Date: Dec 2011 Location: Los Angeles Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	Cool Car bro!

12-21-2011, 01:05 AM	#30
FutureFab Zilvia Member Join Date: Nov 2011 Location: PHX Posts: 276 Trader Rating: (32) Feedback Score: 32 reviews	A couple more videos from this week... http://www.youtube.com/watch?v=CoIf0hRRXj4 http://www.youtube.com/watch?v=G_6Hy...d1AUAAAAAAABAA a little blurry on this one http://www.youtube.com/watch?v=r-VJdIYTqyQ __________________ futurefabrication.com Last edited by FutureFab; 12-21-2011 at 02:05 AM..

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