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Going for 500+hp, need advice


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On 11/8/2021 at 5:31 PM, Predator1 said:

BRB... I'll go call Nitto/HKS/Tomei/Nismo and tell em to throw their their billet cranks and oil pumps as their R&D is questionable and weaker then oem piss.

Is anyone out there that can competently say whether the Nitto sine drive pumps are better than the PRP spline drive gears in say a Tomei oil pump? What about Supertec's spline drive pump gears in a Tomei pump? What about the Spool Imports spline drive gears? What design features are relevant here? So far every time I've seen this question asked it just ends with a lot of ego, a lot of FUD, but not a lot of information. Seems like anyone who has spent the money to get the data has no interest in sharing it.

We can repeat this exercise for basically every part out there. Even if the information is out there so many parts are not at all built for anything other than circuit or drag racing. Your average forged piston is just not at all suited for street use for example. They tend to require larger than stock piston to wall clearance and tend to not last very long as a result. The factory RB26 piston has a special oil cooling channel cast into the piston to help cool off the combustion chamber and eke out a bit more knock margin. I can name maybe one aftermarket piston that replicates this design feature and I have no idea if the ringpack/p2w clearance/ring tension/etc is what I would want if I ever had to open up the bottom end because this stuff is apparently some kind of trade secret judging by how every manufacturer makes you buy the product first if you want to get those specs.

The trade-off space is huge and I don't think people on the balance are really doing their research. So if someone starts by asking about supporting modifications in a way that suggests they haven't even tried my answer is going to be reconsider whether it's even worth it to bother going down this path.

As for whether Kinugawa turbos are worth it, just some Google will put up results like this that would scare me off from bothering: https://www.evolutionm.net/forums/evo-engine-turbo-drivetrain/714884-kinugawa-td06sl2-20g.html

500 whp from these engines is totally possible, clearly at Cootamundra they're doing way, way more than that from RBs. But getting to 500 whp with the kind of reliability/durability that allowed my R33 to get to 280,000 km on the original engine still compression testing around 170 psi for all cylinders in addition to having good street manners is a real challenge.

Edited by joshuaho96
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Personally, I'd rate Tomei highest, followed closely by Nitton Sine Drive, PRP would probably be slightly better then N1. Not sure how they've managed their R&D, I'm guessing its a Nitto copy.

A good friend of mines running a very similar motor(RB30 with extended sump and restrictors), hes running a Nitto oil pump, and I'm running a Tomei. We both run the same oil - I get slightly higher oil pressure at any oil given oil temp. Not saying that having higher op is 'better', but that's just an observation.

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On 09/11/2021 at 2:44 PM, Predator1 said:

Of course, which is why you don't see the likes of Nitto, or any other flavour make their own cars. Imagine that, billet R32 GTR... You could even crash it multiple times, without breaking, just not sure about the occupants though.

speaking of which, we just watched deathproof on the weekend.

also on topic, oil pressure is affected by main bearing clearances just as much as the oil pump. Ultimately all of those aftermarket vendors just took OEM solutions from other cars and applied them to RB applications. Only 1% of cars out there actually need more than a standard or n1 pump on a long nose crank anyway

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Ok, so I should buy something better.. How about the new tomei T550B twins? They got ball bearing but cant find much experience with them. They got really small turbine wheels, how does this affect power?

Allso thinking of HKS gt3ss but they are journal bearing.

I want to run a no bov setup to get the fluttering sound and ball bearing would be preferable as they can handle more force.

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On 11/9/2021 at 12:48 PM, The Skyline Guy said:

Ok, so I should buy something better.. How about the new tomei T550B twins? They got ball bearing but cant find much experience with them. They got really small turbine wheels, how does this affect power?

Allso thinking of HKS gt3ss but they are journal bearing.

I want to run a no bov setup to get the fluttering sound and ball bearing would be preferable as they can handle more force.

HKS GTIII-SS opinions are very mixed. If you talk to UP Garage they say it's the most responsive turbo they've tested. Their dyno charts will claim stuff like 10 psi boost by 2500 RPM, 16 psi by 3000 RPM, 400 awhp at 6800-7000 RPM, etc:

image.thumb.png.aef8c96defca88f8cf7d830836dfb461.png

But not even HKS' own marketing literature makes claims like that, usually it's much more conservative about showing the response of the turbo. More just a small step up over the GT-SS/-9s, not a huge leap in the mid-range like they found. Midori Seibi has also tried the GTIII-SS and peak torque happens closer to 4300 rpm, not ~3500 RPM like the above chart, their results are a lot closer to what I expect frankly: http://midoriseibi.co.jp/blog/4697

And of course most people are just super questionable on the idea of paying 3k USD or so for a glorified journal bearing turbo. HKS probably has seen sluggish sales of these turbos as well which is why they've started going back to ball bearing Garrett turbos. I did it and I'll try and find the reality of how these turbos are but that's going to take forever.

As for the Tomei T550B nobody has published any dyno charts. Tomei's M7655 turbos that they sold before the T550B were horrible, worse than -7s in pretty much every way.

As others have said I would not recommend removing BOVs, I have read of people's experiences with snapping turbo shafts due to the compressor surge when snapping the throttle shut. I doubt this would happen with anything modern but something to think about. I would avoid anything that risks metal fragments ending up in the engine unless you enjoy engine rebuilds.

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On 11/9/2021 at 2:47 PM, Dose Pipe Sutututu said:

Do yourself a favour and don't get turbo with a HKS, Trust, or Tomei badge on them.

They're all shit.

I'm fully expecting the HKS GTIII-SS to be super disappointing, but I'm curious to see if they're anywhere near as good as what some tuners claim they are.

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So all I need is a set of GT2860R-7 or -9 turbos and a gasket set and im good to go, or do I need oil drain adapter as mentioned by Duncan? Do I need water and oil lines as well? Maybe someone can tell me all that I need?

What is the difference in -7 and -9, which is best? Looks like its hard to get -9?

Is this the right turbo?:

https://www.ebay.com/itm/303055603645

Thanks so much for helping me here, im a newbie and want to learn all that I can.

Edited by The Skyline Guy
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I'd contact a reputable supplier and talk through what you're doing so they can make sure you've got all the adapters etc to go through.  Kudos are very helpful.  Just think through your goals - -5,-7,-9 all have different characteristics (comes down to lag and top end power).  -7 and -9's from memory are like HKS GTSS and Nismo N1 turbo's so are great upgrades but aren't high power but you get a very linear power curve.  -5's are a tad laggier but get the higher power easily.  There is heaps of info on the dyno charts page. 

 

Weigh it all up though - a single might still be cost effective when you consider all of the labour (and future labour) and the supporting mods you have to do anyway like ECU, fuel pump, injectors, cam gears.  You probably want to check if factory dumps and exhaust will flow well enough so if you're changing that, then you may be better off with single as well.

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-7s are the r34 n1 turbos (and the nismo r1) they are direct bolt on and will make 500hp at the wheels with e85 and cams 

-9s are the same as hks gtss turbos are will bolt also bolt directly on and make the same power as the -7 (some believe with slightly better response)

the -5 is slightly smaller then the hks 2530 and are a lot more laggy then the -7/-9s, they require different oil drains that are easily sourced which then makes them a bolt on turbo and can make more like 600hp at the wheels if the rest of the set up is done right  

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On 11/11/2021 at 12:11 PM, The Skyline Guy said:

So all I need is a set of GT2860R-7 or -9 turbos and a gasket set and im good to go, or do I need oil drain adapter as mentioned by Duncan? Do I need water and oil lines as well? Maybe someone can tell me all that I need?

What is the difference in -7 and -9, which is best? Looks like its hard to get -9?

Is this the right turbo?:

https://www.ebay.com/itm/303055603645

Thanks so much for helping me here, im a newbie and want to learn all that I can.

http://www.kudosmotorsports.com/catalog/turbocharger-install-suit-nissan-skyline-stagea-wgnc34-260rs-rb26dett-p-5.html

  • Genuine Nissan turbocharger gasket kit
  • Genuine Nissan or Wurth Turbocharger turbine fasteners kit
    • 8 x Turbocharger to manifold studs
    • 8 x Turbocharger to manifold nuts
    • 10 x Turbocharger turbine housing studs
    • 10 x Turbocharger turbine housing nuts
  • Exhaust manifold gaskets (optional)
    • Genuine Nissan
    • Cometic multi-layered steel (3-layer)
    • HKS or Tomei multi-layered steel (3-layer)
  • Genuine Nissan turbocharger oil drain hose & clamp kits (optional)
  • HKS turbocharger oil feed banjo bolt w/built in oil restrictor & genuine Nissan crush washer (optional)

The -7 and -9 turbos are both ball bearing turbos. -7s are 836026-5004S, -9s are 836026-5002S. If you get the -9s you will need to add actuators on top which are extra cost. You will need some method of controlling oil pressure supplied to the turbos, you may not have problems if you have the R34 setup as those came with ball bearing turbos from the factory but the R32 and R33 for sure will cause oil to be pushed out of the seals as those had journal bearing turbos which means much larger oil feeds. I haven't compared part numbers or anything like that to figure out whether the oil feeds are different across the generations, you can use the Nissan parts catalog to figure it out yourself. As for the difference, -7s are the following:

Bearing: Dual Ball bearing
Cooling: Oil & Water cooled bearings

image.thumb.png.d73b8a2c4e5e317d153588929d454e74.png

Compressor
Inducer: 44.60 mm
Exducer: 60.1 mm
Trim: 55
A/R 0.42

image.thumb.png.3c9ffbb0c30d48ef62189fc80ceebeea.png
Turbine
Wheel: 53.90 mm
Trim: 62
A/R: 0.64
Wastegated
Turbine Flange: T25 with studs
Turbine outlet: Unique "compact" 5-bolt pattern

-9s have the following spec:

image.thumb.png.2dcf2f1d38d0f6962979254315633faa.png

Bearing: Ball bearing
Cooling: Oil & Water cooled bearings
Compressor
Inducer: 44.5 mm
Exducer: 59.4 mm
Trim: 56
A/R 0.42

Turbine
Wheel: 53.9 mm
Trim: 62
A/R: 0.64
Wastegated
Turbine Flange: T25
Turbine outlet: Unique "compact" 5-bolt pattern

Do not try and order the 0.86 a/r turbine housing unless you enjoy turbo lag. The key point is to see that the -7s have a wider region of operation on the compressor but trade that with lower compressor efficiency. For example the -7 compressor will be able to operate at 7 lb/min flow and 1.5 pressure ratio (0.5 atm boost) but the -9s are going to be right on the surge line if you do that. What this translates to is the -7s will make less power, but they will be able to get the engine into boost sooner and will respond better to any breathing modifications done at low RPM like VCAM, longer intake runners, etc. The -7s and -9s are both roughly 400 hp to the wheel turbos though, not 500 whp like the -5s. And as others have said if you're chasing that much power you probably should think about going single turbo as well, that kind of power is well within the range of single turbos that are relatively well understood and with big power the problems inherent to the RB26's factory twin turbo setup become much more apparent like that pretzel-esque intake and exhaust piping is restrictive and leads to fun problems like turbo shuffle where they cyclically cause each other to go into compressor surge instead of boosting cleanly together.

Sources:

https://turbochargerspecs.blogspot.com/2012/09/garrett-gt28r-gt2860r-55-trim-310-hp.html

https://turbochargerspecs.blogspot.com/2011/03/garrett-gt28r-gt2859r-56-trim-310-hp.html

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On 11/11/2021 at 2:40 PM, Duncan said:

Thanks for the note about the oil restrictor, that is an important difference too. 

Also, it is a good time to change the factory dump pipes to something larger at the same time.

At least part of the reason why I actually was ok with a journal bearing turbo over a ball bearing turbo despite the downsides was just to avoid any questions/complications regarding oil pressure and flow to the turbo. It is a minefield IMO. Some ball bearing turbos have integral oil restrictors in their oil feeds, some don't, sizing will vary as well depending on your particular engine, oil pressure at the inlet obviously also varies with engine RPM and oil temperature, oil viscosity, etc. If I ever went with a ball bearing turbo I would probably just get an oil pressure regulator for the feed just for the peace of mind.

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