200Kw+ Rb20 Build.

[benecr32]

So I've blown my 380xxxkm RB25DE (just a ring or two) and think it's time to move forward on a build I started a year ago, my RB20.

I purchased most of what I needed and my friend has completed 90% of the head porting.

Poncams are what I'll be using as I already have them in my 25,

Tomei spirngs,

ARIAS 81mm forgies,

cometic 1.3mm MLS gasket,

SARD 650cc injectors,

NISTune,

NZ steam pipe low mount manifold,

ARP studs main and head,

Walbro 255lph in tank pump,

Maxima airflow meter (cheaper than Z32 and good upto 500hp),

Oil cooler,

6kg flywheel.

Bearings are something I'm waiting to purchase until after the crank is all measured and hopefully gravy.

I also haven't decided which turbo to use just yet but I am leaning towards the KINUGAWA TD06H 20G 8cm. It's internal gate and I want to retain a low mount. Also it's cheaper than most.

The thing that will be interesting with this motor, I think, will be comparing it with similar 20's that aren't ported. People just don't bother very often (with building 20's and/or porting them).

You'll also notice there is no mention of rods. They will be standard. Honestly the only reason I have forged pistons is because the motor like my 25 has blown rings, so while I'm in there I may as well enlarge the bore.

Intercooler is also something I'm not sure about, but I am leaning towards the PWR vertical core setup so the pipe work will be short as possible because I am retaining the standard intake plenum. Possibly a PWR radiator as well.

The goal is anything over 200rwkw and to see the difference in boost required in comparison to a standard head.

Pictures will come when there is something to show, an RB20 block looks the same as the next.

Any constructive input would be great

[GTSBoy]

200rwkW is easy as. So you should be aiming for 240+.

The porting coupled with the cams and the big turbo will likely make it a little soft down at the bottom end unless your porter is a guru who can really make it work without opening it up much at all (cross section wise). Shouldn't want to open it up anyway - hopefully he knows what he's about and has worked on the bowls, short turns and the low lift flow across the seats.

You are correct about rods. RB20 rods are tough. I would prep them myself though, rather than leave them comletely stock.

Consider a Hypergear turbo - even if you want a TD based turbo, consider a Hypergear.

Don't use the shitty vertical tube intercooler core. They have good low pressure drop but terrible cooling efficiency compared to a longer tube core. I have posted on this extensively before, so you could search my opinions if you like. Don't worry about the longer pipe runs - lag courtesy of longer pipes is a bit of a myth. Just buy a decent return flow core.

[benecr32]

You may be right, 240 is achievable it's just that I'm being conservative when saying what it will make so I'm not disappointed.

Yea it will very likely act like a 2 stroke power band wise, which is fine. If it were for grip I'd aim for a buff midrange. But it's drift and the peaky curve is suited to the way I drive.

He's a kind of backyard guru. I'm very confident in his abilities and knowledge having seen some of the heads and motors he's put together over the years.

Had a look at hypergear today and the ATR43SS1 might be the way to go. Bonus is it's an Australian company.

Ah, ok then. Will avoid the vertical core. Does make sense that the cooling efficiency is dismal in comparison to a cross flow.

Cheers man

[dopey]

Good to see someone giving a 20 some love, would love a 270kw one maybe more just because i think it would be amusing as a daily. Is the nistune ecu a budget thing just thought aftermaket or piggy back would give more room for improvement later down the track

[benecr32]

Yea some retard had to give a 20 a go. Didn't realise it would be me. Should have just built the 25, but I digress.

The Nistune was chosen because for what I'm after I couldn't see the point in spending another thousand on something like a microtech. But also I was planning to use it for my 25DE until it blew so I already had it just chilling in the parts pile. Not to mention it retains the factory cold tune so it will actually start and keep running first time it fires, which is nice.