Turbo(s) question
 

Hey everyone!
Been around the forum off and on, though I'm hardly active on it, except in the classifieds. However, I'm in the process of building a custom twin turbo kit. (Not sure if this is the right section for this)

I'm currently building my sport touring 6 speed manual

Current support mods/Currently installed
Takeda cold air intakes (will be reused with intercooler piping
ZSpeed Stage 3 Super
ZSpeed CMAK CSC Delete
Custom/DIY oil cooler
Custom/DIY fuel system (walbro 450) and return line
Custom/DIY anti-starvation kit.
Stock block (until I full send it)
Stock tranny
Fast intentions 18" non turbo exhaust (will be a restriction at higher HP levels)
And I'm sure I'm forgetting stuff

To be installed:
All necessary custom intercooler piping/flanges
All necessary custom exhaust piping/flanges either mid mount off the OEM headers or custom equal length headers to retain the scavenging effect
R35 GTR intercoolers
TiAL MV-S 38mm wastegates (X2)
HKS SSQV4 Blow Off Valves (X2)
Bosch 1000cc injectors
Flux fuel sensor
SZ Boost Control Solenoid
Omni 4 Bar MAP Sensor
EcuTek
Turbos...... And this is where my issue is. I was originally going with a pair of Greddy Td05h-18g, then I was going to upgrade those to Td06-20g and I eventually scrapped that plan. I've decided to go with Garrett GTX series turbos, though I'm not sure which one will suit my needs.

I also have a Mercedes E550 bi-turbo (read twin turbo) and I love the crazy fast spool on that thing though, the Z is still faster.
So, I'm looking for turbos that have a similar spool to that, while giving me the option to hit 600whp with the eventual build block

I'm trying to decide between Garrett GTX2863r, GTX2867r, GTX2871r, GTX3067r or GTX3071r
Hotside a/r .61, .64 or .73 I believe the .83 will to far to laggy on twins
What I'm looking for is great spool, hardly any lag, with a decent power potential around 600whp, this is a daily and will see light track use.
Why Garrett? Because I can get them reasonably priced

Future mods
Build block

Thanks for taking your guys time to help me, my apologies for any typos as I'm currently at work and it's 3:05 A.M.

G'day Mate,
I have built my own TT Kit on my 370GT here in Aus (G37 in the US).
I used GTX 2867r's on it. .86ar Tial V Band Exhaust housings.
Starts making boost @2200rpm.
Currently making 500whp with Cats @9.5 psi on pump gas.
Capable of quite a bit more but I need to rebuild my trans (auto 5at)
The full build is on my youtube channel, it may help with some of your decisions.
Just search through my posts & you'll find it. Or on Youtube I am The Aussie Shed.
No Idea of your Skill Level, but its not a job for the faint hearted.
I did the entire build myself, inc all fabrication etc, so yes it can be done.
However, I am an old man with a lifetime of experience with this type of thing & a fully equipped workshop inc a lift.
Not trying to scare you, but there is a reason commercially available Twin Kits for this platform aren't cheap.
Good luck with it Mate. Cheers.

I've actually seen and watched your videos and they're amazing and quite helpful. As for my skill level I picture myself as a junkyard mechanic, there's not really anything that I wouldn't dive into head first, so are for the build and fabrication part, I'm completely fine with it.

And while there are plenty of commercial kits and they're pretty much plug and play, I truly enjoy the challenge of making something myself. Plus I currently have 90% of the parts sitting on my kitchen floor just waiting on turbos lol


So with the .86 hotside, where in your rpm range do you hit your 9.5 psi?

If you go to the FI TT kit thread you will see a number of builds with there stage 1 kit that have made over 600 whp using GT 2860rs turbos. I was tuned between 600 and 620 whp on pump e85.

BTW I can save you a bunch of money on your turbo's and injectors for your build as my GT 2860rs are for sell as well as my 1050cc injectors that just came off my motor. Shoot me a PM and if you have any questions about parts I will put you in contact with Sebastian at Specialty Z as he took remove them from my blown motor.

Good stuff, sounds like you'll be fine with the build.
I really wouldn't go smaller than .86 on the hot side.
There's just simply no need & you will restrict the top end.
Pretty sure the Fast Intentions kit uses .86 also.
I consider them to be the Bench Mark for Twins on this Platform.
I'll attach one of my Dyno Graphs that shows Boost Vs RPM, you can see Boost comes up real fast once over 2200 its almost instant.
Boost is always available when you want it, just roll into the throttle & start Smiling.
Cheers.

That's an amazing powerband with that setup, and fast intentions does use the .86 hotside

I know it would be more restrictive, but I'm genuinely curious on what a V-band in and out at .72 would do for the responsiveness, I would assume not too much and it would reatrict the top end, I might buy a set of .86 and .72 just to compare on a dyno.

Thank you so much for answering my questions, I appreciate it. Stay tuned for a future build thread guys, I'll be documenting the custom parts along with how the system will be build and designed.

It's been a frustrating fun blast so far

I'll definitely send you a PM.
Just curious, was it just stress overtime that blew your motor or was it some other factor(s)?

I will be using specialty Z for my tuning needs in the future

Right on! There are none finer at tunning than Seb and he is a wealth of knowledge.

It through a rod! Fatigue after five years of use and abuse. I was not surprised that it let go after three years of track use and two years of daily driving. I had purchased a block a year before she let go because I knew she was on borrowed time. Do yourself a favor and pick up another motor when one comes available and save it for when the inevitable happens. I already have one set aside. Other that she was running like a champ!

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Dang, that lasted a long time, especially if you ran it daily at 600+whp

My hopefully Seb will be able to provide an e-tune for it so I can drive it down when it's all finished up as I'm up in northern California so it'll be interesting on how to get it down there safely, either trailer it or whatnot.

The second block is the plan, once this is complete I'll purchase a used one (assuming it's VVEL isn't damaged) and I'll build that block with some nice forged internals.

Theres a place in Sacramento that sells complete used blocks for about $850

Right on! I'm sure Seb will hook you up on the etude. I think you have a solid plan.

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