R34 GTT Rebuild - Manifold/Turbo Advice

[macca911]

R34 GTT Rebuild - Manifold/Turbo Advice

Afternoon all, 

Long story short, I'm at the stage where my Rb25 Neo requires a rebuild and I need a little advice on the manifold/turbo inlet choice. 
My goal with this rebuild is a reliable/responsive 300 - 350rwkw. 

I have decided to rebuild, (forged not stock), the RB25 and not going the 25/30 route.
At the moment, I've decided on a GTX3076 and a 6 boost high mount manifold.

I have read many, many forums and discussed this with multiple different people including Kyle @ 6Boost. 
My understanding thus far, Twin Scroll > Single (Quicker Spool)  

My questions are: 

• What flange am I best to run? T3, T4, VBand?
• If I am to run Twin Scroll, should I change the housing size? Does a .82 Single Entry flow the same as .82 Twin? 
• A lot of people are telling me to go the GTX3582 route. I don't want more than the 350kw though, as it'll be mainly a street car and I'd actually like to put the power to the ground. (Proper suspension/tyre setup taken into account)  Is it better to hit max efficiency on the 3076 or run the 3582?

Any other personal thoughts/recommendations are welcome. 

 

Cheers,

Craig   

[GTSBoy]

3076 over 3582 for your power goal would have been my thought.  Have you considered other options though, like Hypergear?

T3 flange is fine.  What it really comes down to though is what housings are available for the turbo you're looking at.  If you can only get TS housing in T4, then T4 it is!

Definitely go TS if you have the choice.  And it will need to be bigger than a single entry housing for the same power level.  They are more restrictive.

[Dose Pipe Sutututu]

a stock neo would happily shit out 300~350kW all year round btw..

 

since you have cash to fry, I would straight out go twin scroll, T4, twin gates, and a EFR7670, basic cams no more than 260 degrees, and as much boost as you can b4 you reach the turbo's safe RPM zone.

OR GTX3576 with a 1.01 rear, same shit as mentioned above but in T3.. and put in as much boost as possible.. those GTX 11 blade compressors need boost to boogie.

 

 

[Kinkstaah]

GTX3076 isn't bad (I made 400kw on one) but again it's not amazingly paired.

If I were you I'd consider a GTX3071, or maybe even a GTX2971. Twin scroll if you can. External gate if you can.
But you could bolt this all to a standard manifold and save the hassle, and cost, for minimal loss and change the manifold later if you're upset about how it performs.

Budget? GTX3071R on std manifold, will look very stock. Could probably even escape with an internal gate. Much less hassle.
Full retard? Borg Warner

[macca911]

26 minutes ago, Dose Pipe Sutututu said:

a stock neo would happily shit out 300~350kW all year round btw..

 

since you have cash to fry, I would straight out go twin scroll, T4, twin gates, and a EFR7670, basic cams no more than 260 degrees, and as much boost as you can b4 you reach the turbo's safe RPM zone.

OR GTX3576 with a 1.01 rear, same shit as mentioned above but in T3.. and put in as much boost as possible.. those GTX 11 blade compressors need boost to boogie.

 

 

Definitely not cash to fry. As much as i'd like to be in a position like that... 

I comp tested my neo on the weekend , 110, 100, 120, 60, 90,100. Tired and Cyl 4   
I've looked down the path of buying a second neo, $2k-ish for something that's semi verified (leakdown/comp tested (incl. shipping)).

I'm not doing the build myself, so as for labor costs, it'll be the same if I go forged or not... 
I do realise that it will work out rather more expensive though building an engine as opposed to slapping in a new/old neo. 

I'd prefer to do something properly the first time, been bit before and in my opinion, 350kw on an unopened RB25 is pushing the limits. It's possible for sure, reliable though in my mind is questionable.

Twin gates on a setup that size? I was planning on going the single gate setup. Any reason you'd go for the twin? 
Cams I have. Tomei Pon - Type B - Which from memory were a 260 degree in. and ex.    

Cheers for the replies! 

[macca911]

46 minutes ago, GTSBoy said:

3076 over 3582 for your power goal would have been my thought.  Have you considered other options though, like Hypergear?

T3 flange is fine.  What it really comes down to though is what housings are available for the turbo you're looking at.  If you can only get TS housing in T4, then T4 it is!

Definitely go TS if you have the choice.  And it will need to be bigger than a single entry housing for the same power level.  They are more restrictive.

Any advantages in going the Hypergear over the Garrett? I have seen some impressive Hypergear builds but fail to see why I'd change from Garrett. - Ignorance 

Cheers  

[owen1r]

Stick in a stock RB25 neo, there's no need to waste 10k on a forged motor. I've lost count of how many 400kw+ builds on stock RB25 neos that have been reliable, there's even a few 800hp ones floating around. 

Twin gates as it allows the twin 'scrolls' to be better separated, I believe.

Stick with those cams, matching valve springs, ARP Head Studs and happily pump 30 psi into it. Use the money you would have on the forged motor for a Plazmaman/PWR intercooler and a custom 3.5 inch exhaust. 

[Cowboy1600]

Stock Neo replacement, HG 21u Highflow on e85.  It'll sing a responsive 300rwkw tune for half a million kays.

Benefit of HG is cost, support, ease of install, reliability, upgradeability and suitability for RBs.  Tao has basically made it his life's mission to build the perfect turbo range for RBs, bless his little cotton socks.

[Dose Pipe Sutututu]

Twin gates superb boost control, minimise back pressure and 100% gas separation from Cyl 1~3 and Cyl 4~6. However a twin scroll on a single large 50 to 60mm gate will also work provided it has been split all the way down to the gate seat.

A GTX3071 on a divided 0.83 on E85 with a RB25 would be a response weapon, however might tap out a little early.

I recently suggested the parts for this 180SX I tuned (SR20, Poncams, basic forged motor, GTX3071, 0.83 divided rear) - made 351kW and all in at 4200rpm (that's a non VCT motor)..

......... now image a RB25 with VCT.

However, if you're planning to spend money, I would say get into a GTX3576.. you'll get bored of a 300kW R33/R34 in no time.. and get toasted by Golf Rs at the lights with their fancy launch control, 4wd, DSG, dual zone climate control, sunroof, 7 airbags, independent ABS, oh fuuarkk I want a new car.

[niZmO_Man]

New STi looks good

[32psi]

What flange am I best to run? T3, T4, VBand?

Depends what turbo you find. VBand generally are lighter and flow better.

If I am to run Twin Scroll, should I change the housing size? Does a .82 Single Entry flow the same as .82 Twin? 

You could go 1.06 no problem.

A lot of people are telling me to go the GTX3582 route. I don't want more than the 350kw though, as it'll be mainly a street car and I'd actually like to put the power to the ground. (Proper suspension/tyre setup taken into account)  Is it better to hit max efficiency on the 3076 or run the 3582?

It depends what you want to use the car for. An RB30 bottom end with the 4.11 final drive and a GTX30 will be in wheelspin almost all the time on the street.

I'd suggest a GTX3576 on a 1.06 exhaust housing especially if you want to get closer to the 350rwkw than 300rwkw. These turbo's on an RB30 bottom end are far different to the 25. Very responsive and linear. On a 30 housing you will generally see fullboost a full 1000rpm earlier on RB30 than an RB25.

 

[macca911]

Gents, as always, thanks for the info. 

Now I'll need to make a decision between more power/built engine or ~300kw and a fresh stock.

Cheers again!  

[Dose Pipe Sutututu]

make sure you have money for a nice 1.5way or 2way LSD...

I constantly see morons on facebook saying "my 200kW skyline fries 3rd gear" or "my stock R33 can fry 3rds"... "what's wrong with your car, you can't even fry 3rds with 370kW"

Have the power, at least back it up by putting it down... I once had to pull out the Q-Starz to shutup this moron saying I didn't have that kind of power because I "couldn't fry 3rds"... yepp.. that's why the car did 197km/h down wakefield.

[KiwiRS4T]

Go Hypergear so that you can keep the stock manifolds and spend the money on the ECU, intercooler, exhaust and an LSD.

[Dale FZ1]

^^ Bob makes a lot of sense with this suggestion.  Especially when the application "mainly for the street" is considered.

IMO the engine is not going to need a huge amount of magic stuff.  If it's not tired, leave it well alone.  Lift the head and install a MLS HG, then do whatever turbo install you choose.  Keep revs under 76-7800.

Go with a flex fuel setup for E85 when you know the extra power is wanted.  Otherwise 300rwkw is pretty much the upper end of what most people could ever hope to use or justify for "street" use.  Biggest letdown is generally suspension, tyres, diff as per Johnny's comments if it's not going to the ground it's only for the pissing contest..

[hypergear]

lets say. I can get you 3582's power with better then 3076's response. and much cheaper in price.

[niZmO_Man]

7 hours ago, hypergear said:

lets say. I can get you 3582's power with better then 3076's response. and much cheaper in price.

Too good to be true?

[robbo_rb180]

I was in a similar position a while ago and bought a forged rb25, gt3076r. 82, 6boost, Poncam 256, Greddy plenum,  link g4, 1000cc injectors and run flex fuel. 300kW on gate pressure 14psi and  360kw on 24psi. Stupidly quick and responsive Street setup but cost alot of $$$$.

If I was to do it now 2nd hand motor,  headgasket with new studs, hypergear turbo on factory manifold,  hypertune plenum and fmic setup. Spend the money on suspension as there is no point having all that power if you can't use it.

 

[Dose Pipe Sutututu]

^ yep!

then buy proper tyres, a proper LSD, proper suspension arms to fix up the crappy Nissan rear geometry.. If you can't even put 200kW down to the ground, don't bother with power upgrades.

[robbo_rb180]

1 hour ago, Dose Pipe Sutututu said:

^ yep!

then buy proper tyres, a proper LSD, proper suspension arms to fix up the crappy Nissan rear geometry.. If you can't even put 200kW down to the ground, don't bother with power upgrades.

I can't emphasise how much good suspension and tyres are. 

This is in my sil80 with mca xr series coilovers,  all new bushes and ball joints and adjustable castor, Camber and toe arms with 255/40/17 hankook rs3. 

Only gets tail happy if you want it to.