JesseDeanZ

I am starting a build for my 75 280 Z and have decided to go with the RB25. It was a tough choice between and RB and an LS but I decided to go back to the Nissan roots. The car has a huge history and was my fathers car. He bought it new and in 1980 swapped a Chevy 350. Long story short is in now mine and I am Rebuilding the car. I have a goal in mind of roughly 600 RWHP. After some research I have a list for my build and want to see if it seems enough to build a reliable RB.

I am going to start with an RB25 series 1 or 2 (decided to stay away from the NEO)

-Wiseco Pistons 8.4:1
-Manley Rods
-N1 oil pump
-ARP head studs
-Cometic head gasket
-Tomei Solid lifters
-Tomei Camshafts 270 10.25lift
-Supertech dual springs
-Supertech retainers
-Supertech Valves

This is all the internal and I realize that I will need the right turbo set up and tune to make the power and make it reliably. Would anyone make changes?

PrimeDirective

N1 water pump.
Crank extension collar.

JesseDeanZ

Ahh I forgot to add that to my list! Thanks Other than that does this seem to be a build capable of 600ish HP?

FRpilot

Just curious, what were your reasons for not going with the NEO?

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JesseDeanZ

Out of the box the NEO seems to be the better choice but when it comes to part selection and stuff the series 1/2 seems to be a better fit.

wolf92

I went with a Garrett gt3582r on my series 2

wolf92

Stock internals just to see what would be the out come when making the power

JesseDeanZ

How much power were you making and on how much boost?

smoked240

Have you thought about changing the bore and stroke? Whats the reason for changing the compression ratio? as far as Ive read the rb25 loves the 9:1 ratio. Either one will be fine.

I'd just source a Rb26 gtr rotating assembly and drop it in. Extended crank collar and good for 600hp. I'd get arp mains as well.

Only issues around that power is oiling, head-gasket and ring-lands.

What do you plan to rev to?

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JesseDeanZ

I must say i am pleased with people on this forum so far. Nobody seem to be completely rude. The reason for keeping bore is i feel keeping it at a stock size i wont run into any issues with thin walls and running hotter than normal. And the reason for going fully built bottom end is i like to build for higher numbers. For example i am aiming for 650 or a little under so i wanna build for 800+. Also it seems tough to find 9:1 compression pistons. Do you recommend the 9:1?

JesseDeanZ

Also i wasnt sure of what i wanna rev to. Whats safe? I planned on leaving that to my tuner. But knowledge is power

smoked240

Yeah that's a good reason. You could go Rb26 assembly and forged pistons and rods and be good to 1000hp with some serious head work. The head is where I would spend the most money when you want some serious power.(besides tune) The stock head should be able to flow 600hp. I would have a street Port and Polish done though. Anything over 600hp I would go solid conversion then with some big cams.

Orrr just fit an rb26 head with itb's

I am going to try for 500hp all stock with Rb26 rotating assembly. No port and polish. Stock head-gasket. We'll see what the tuner can do, I like the Vct but if I get sick of it I'm going to find an rb26 head with an HKS V-cam one day!

The setup you posted without port and polish safely 8000-8500. After some amazing head work you could break 9000 and maybe even push 9200 depending on fuel and tune.

It's all going to depend on what EMS you choose and the tuner. I would suggest Haltech or Aem. Both amazing ecu's.

Cheers!

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rbs14kouki

Built info from one of the best rb25 out there !!!

Driver: Jake Jones (DriftSquid)
Engine: RB27DET 2.7-Litre Turbo
Power: 370Kw+

ENGINE
• RB25DET Block
• R33 GTR Crank
• R34 GTR rods
• GTR ACL Forged Pistons, rings, bearings
• N1 oil pump – Steel gears
• RB25DET head rebuilt
• Greddy Intake Manifold
• Tomei cam gears
• Custom rewired engine bay
• GARRETT GT 35/40
• Trust 50mm External gate
• 1300cc injectors
• Standard RB25 T/B
• Helps Metalworks cooler pipes
• Helps Metalworks Intake
• Helps Metalworks oil catch can
• Nismo 1.3bar radiator cap
custom Oil cooler
• Remote oil filter
• Helps Metalworks Steam Pipe Exhaust Manifold
• 3″ straight through exhaust ‘ET spec’
• Haltech Pro 2000 ECU
• Custom engine mounts

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AV FABRICATION

Built thread sr20vet s14
http://zilvia.net/f/showthread.php?t=535574

rbs14kouki

More info on is car here : http://www.driftsquid.com/index.php/the-car/

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AV FABRICATION

Built thread sr20vet s14
http://zilvia.net/f/showthread.php?t=535574

smoked240

Really nice setup! Just curious what's making it a 2.7? Are the pistons stock size or does the r34 rods make it 2.7?

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AWD260R

go with 9.1:1 or 9.5:1 you'd spool the turbo more efficiently, also if you go super high lift cam it will pull power from your low end. This will a choice of what you are wanting out of the car, highway runs or ripping around corners(like I like).

JesseDeanZ

Okay this is also all very useful. So on the subject of cams. I am looking into the 270° which would you use. 10.25 or 9.25?

Darius

I saw you were going to lower the compression and was going to say leave it stock or even bump it up as AWD260R said, especially if you have E85 near you. I assume Ohio has it readily available?

And if you want a modern turbo, don't get a Garrett at all. Pick up a Borg-Warner EFR or even a Precision if you want something slightly more affordable.

JesseDeanZ

I found weisco's with 9.0:1 and i am going with those. With higher compression should i go higher lift or stay at 9.25?

AWD260R

honestly for a 11.5mm lift 280 degree cam I can't find any reviews on them, I know I wasn't impressed with my setup on pump gas but I do have other factors that are holding me back. If you can go with a lower lift 262 or so and achieve what you are looking for I'd say do it. I would drop down to a 10mm (9mm or so in your case) and less duration, I wanted the car to be aggressive from the bottom up and right now I have the fucken Lagnest monster believe I had 5 lbs of boost built at 4800rpm what a slug

JesseDeanZ

Okay awesome. Ill stick with a 9.25 then. you guys rock

Darius

Like AWD260R said, stick with 9.0:1 compression especially if you have E85 available locally. The turbo will spool so much quicker. Furthermore, if you go with a Precision 6266 or have the funds to splurge on a BW EFR turbo, it will spool extremely early and feel more linear than a 35R.

You don't need to go with that aggressive of a cam for 600HP either. It requires clearancing of the head casting to clear the lobes (more work, more $$). I have HKS cams with 8.8mm lift on hydro lifters and I put down 738 whp. I'd recommend keeping the cam as mild as possible because it is mostly just shifting the power curve higher, which you don't necessarily need or want.

You don't necessarily need Manley rods ($$). Source some used RB26 rods and get them balanced/honed and they will be good for well over 600 whp.

I'm also not sure you NEED to do the valve train work to reach 600 whp either. A good tune, good exhaust manifold, quality turbo, and adequate fuel/spark systems should get you there.

Another thing that is internal-related that hasn't been mentioned is either enlarging the rear oil drain ports in the head and block or adding an external oil drain line at the rear of the head.

Syncade

Darius I'm curious as to what you're driving now? I remember your red S14 was for sale many years ago? Am I mistaken?


OP, there is good advice in this thread. I would suggest against the NEO-6 from my personal experience.

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Jets > Cars

Darius

I still have it...but only for a few more days. I have had it for sale for about a year and a local buyer is planning on picking it up this week. I took a blood bath on the money I dumped into it (41k in total spent) and will probably never build another Nissan again. I'd rather flush money down the toilet other ways I probably won't be around much after this.

feito

your car is one of a kind man, from wheels to powertrain, very few real enthusiast out there nowadays. And your advise will always be accepted (and certainly needed) over here.

dftsilvia

stay away from the n1 oil pump, if you can fork the cash out get a nitto. if not just put the spool gear set in with an extended crank collar.
as stated before you might wan tot consider bumping the c/r up to 9.0/9.5
what size turbo you plan on running?

smoked240

What's the reason for staying away from an n1 pump?

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Darius

That's overkill. Don't drop $1500 on a Nitto oil pump. Just get an N1. As long as you have the extended drive collar on the crank, it will be fine as long as you aren't revving to 9k all day.

dftsilvia

n1 pumps break just as easy as the stockers. best bet is to just rebuild the stocker with spool gears.
and how is dropping 1500 on an oil pump overkill?? its supplys youre engine with oil, which is kind of important. worth the money if u ask me comsidering the oiling system is one of the downfalls of the rb engine

smoked240

They only grenade because of the short snout. A new factory oil pump or n1 pump on a long snout crank won't break unless you go into high rpm and hold it there. $1500 is a waste on an oil pump when you can drop $500 on gears and rev high. Plus have $1000 extra to put into head work so your RB won't fall flat on it's face when you break past 8000rpm.. The oiling is only a problem when they're held at high revs. Block an oil feed and do the drain mod for the head and you're set.

Every build is different and yeah if it was a track queen that was breaking 9000rpm every corner then a nitto,tomei pump would be ideal, but at that point you should have already went dry sump.

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