High Revving Rb30 Hybrid

[Mi5Fi7]

Hey I'm wanting to make a RB30 hybrid that's strictly NA and high revving. Just would like to know what to do and what not to do, as well as where I can save money, full list of parts I'm going to need, etc. I'm looking at having a budget of between $5,000 and $10,000 this is to go into a 1990 BNR32

Edited April 19, 2010 by Mi5Fi7

[zebra]

What do you see as high revs? 7k?, 10k?

[XRATED]

Start with a re-freshed rb26 head with custom NA cams. Keep the ITB's and throw some ram tubes on the induction side- You'll need to run a MAP sensor based ecu. Custom exhuast manifold/headers and exhaust.

Bottom end will need alot of work, machined up crank, really good rods and lightweight high comp pistons... not to mention a super oil pump/collar, ballancer, light weight pullies, lightweight flywheel and clutch and a wholle lot of ballancing.

Expect to spend 10k and still produce less power than a lightly boosted rb25.

If you want anymore than 9000rpm then start looking at a custom billet counter weighted cranks, alluminium rods and a dry sump oiling system.... so double your budget.

[Messiah]

been doing some reading on rb30's lately...

seems the average rpm limit is approx 7k, not exactly high revving. According to places like wikipedia (not the foremost experts in the field) 10k can be acheived with a lot of balancing.

So, given that the 30 block can be bought cheap, 26 head for lets say 3 grand (not sure what you'd use for an rb30 na to tbh... 25de head?? 1.5k?)... rods and pistons for lets say another 1.5 grand. thats 4.5k fore bits leaving 5.5k for all labour, prep work AND balancing.

Not sure how far 5.5k-6.5 will get you in those terms.

[SKiT_R31]

You probably wouldn't want a MAP sensor with high end cams and ITB's, probably better off with a Q45 AFM. I agree that RB26 head is the way to go, solid lifters, ITB's alot of high lift/duration cams and no vct (adj cam gears on intake and exhaust).

With a balance, RB25DE pistons >225whp would be easy

With higher rev's you will have to do some research into oil pumps & restrictor setups as well

And if you only wanted to rev to ~ 8000rpm, you could get this http://www.spoolimports.com/content/SPOOLN...TROKERCRANK.asp

With some thing like that, I'm sure you could net ~ 250hp

Edited April 20, 2010 by SKiT_R31

[Mi5Fi7]

Thanks for the info guys, I would like to get it to around 10,000rpm

[N1GTR]

Ok, firstly you say its for a BNR32, but your profile thing says BNR32 GTS. Do you mean a GTS, or a GTR? If you mean GTS, that is not a BNR32, the "BN" code is for GTR only, please keep that in mind when we're all trying to help as it could mean different answers/parts in your case

Secondly, why do you want it to rev so high?

Mine (RB2630DETT) on its old tune, had the limiter at 9500rpm and i revved it that high. Now its a tad lower as the wear on the rotating assembly isnt worth being able to rev it that 1000rpm more. Especially when it makes so much more low end grunt than the 26 it replaced.

What sort of power goal are you trying to reach?

Are you on p plates? If you are, and you plan to turbo the car in the future, drive it as is until you get to that point and only spend money on fuel, oils and filters. Save every dollar for the build that you'll keep for a long time.

If you are doing this to maximise the speed out of the car you're allowed to have under the p plate laws, dont forget to get rid of any weight thats not needed in the car (big silly stereo etc)

At 10,000rpm there's a LOT going on in any motor, its not just a case of choosing a number out of the air that sounds cool and going with that

[N1GTR]

And if you only wanted to rev to ~ 8000rpm, you could get this http://www.spoolimports.com/content/SPOOLN...TROKERCRANK.asp

With some thing like that, I'm sure you could net ~ 250hp

Funny someone mentions this kit.

My next motor which is being built now, is bigger than that spool kit, better rod stroke ratio, and will rev without issue to 9000rpm plus.

Yes, still inside an RB block. For an NA application is would be an animal, but turbos are too much fun

Edit: If this is a car being built for twisty roads with pretty much no long straights, even 250hp at the wheels could be a real blast to drive with such instant throttle response

[Marco-R34GTT]

Funny someone mentions this kit.

My next motor which is being built now, is bigger than that spool kit, better rod stroke ratio, and will rev without issue to 9000rpm plus.

Yes, still inside an RB block. For an NA application is would be an animal, but turbos are too much fun

Edit: If this is a car being built for twisty roads with pretty much no long straights, even 250hp at the wheels could be a real blast to drive with such instant throttle response

Sorry for the minor hijack. However, in your opinion, which method of increasing displacement in an RB 25/26 to you know of has the 'best' stroke ratio of the available options??

[SKiT_R31]

^ There are calculators on the net about stroke vs RPM, they work it out by calculating the speed of the explosion vs the distance it has to travel i.e. it cant pass mach 0.5 or something (I'm really rusty on this, looked it up years ago)

N1GTR, what crank and size bore are you running? Do you know what these kits cost?

I've been pondering a new build for a while now, and i was thinking of keeping the compression a bit lower this time (10.5 - 11.0:1) GTR head/ITB's, and stroker, aiming for 250whp with some meatier cams (only after 7500 - 8000rpm limit though, want peak power at 7000).

[Mi5Fi7]

Ok, firstly you say its for a BNR32, but your profile thing says BNR32 GTS. Do you mean a GTS, or a GTR? If you mean GTS, that is not a BNR32, the "BN" code is for GTR only, please keep that in mind when we're all trying to help as it could mean different answers/parts in your case

Secondly, why do you want it to rev so high?

Mine (RB2630DETT) on its old tune, had the limiter at 9500rpm and i revved it that high. Now its a tad lower as the wear on the rotating assembly isnt worth being able to rev it that 1000rpm more. Especially when it makes so much more low end grunt than the 26 it replaced.

What sort of power goal are you trying to reach?

Are you on p plates? If you are, and you plan to turbo the car in the future, drive it as is until you get to that point and only spend money on fuel, oils and filters. Save every dollar for the build that you'll keep for a long time.

If you are doing this to maximise the speed out of the car you're allowed to have under the p plate laws, dont forget to get rid of any weight thats not needed in the car (big silly stereo etc)

At 10,000rpm there's a LOT going on in any motor, its not just a case of choosing a number out of the air that sounds cool and going with that

Sorry for the mix up with that I've only just bought the car not long ago and still don't know much about it, if the GTR is the BN does that make mine a HR?

I've always liked the idea of making the hybrid RB30/RB26 engine, I don't plan on putting a turbo on it I just want to keep it NA, and it's the car and engine I plan on keeping for a long time.

With the revving so high, I've always liked that to since my bike that I own doesn't start redline until 19,500rpm. So I thought that would be cool, but that's why i'm on here asking you guys about it, because you have the know how and honestly I know very little about what I'm doing so all help in appreciated.

With a power goal I just wont it to be the best I can make it without forced induction.

Thanks again for all the help.

[Messiah]

shame you just bought one, i saw a post in the last 24h's where a rb26de is up for sale in japan.

As for high reving, high reving is good... but 10k rpm is ALOT. and for an rb30 it would need major balancing and a big spend.

Keep in mind you bike only has tiny moving parts, so high rpm is no biggy.

my rule of thumb is big displacement == slow lazy torque, low disp == high strung power.

you can mix the two but its not always cost effective.

[Mi5Fi7]

shame you just bought one, i saw a post in the last 24h's where a rb26de is up for sale in japan.

You have the link for that post?

[Messiah]

http://www.j-specimports.com.au/dealer/199...ON-3433768.html

[Mi5Fi7]

http://www.j-specimports.com.au/dealer/199...ON-3433768.html

Thanks for the link, wouldnt have gotten that one though since its auto plus mine has only 110,000 on the clock and I got it for $7000

[iseekool]

RB30 isn't really meant to be revved hard.

However it will have much more poke in the low to mid range in comparison to the RB25 and RB26 - Which will make it easier to drive on the twisties.

I'd say around 7500RPM would be a safe limit - even at that RPM you would be pushing much more power than the lower displacement RBs.

There really is no replacement for displacement.

Another thing to consider "if" you ever decided to go turbo - the RB26/30 will be able to spin that turbo much earlier in the rev range - which will make it faster overall.

[N1GTR]

Sorry for the minor hijack. However, in your opinion, which method of increasing displacement in an RB 25/26 to you know of has the 'best' stroke ratio of the available options??

I'm not an engine builder, but my stock stroke rb30 is fine. The new one is 1.546, which to put into perspective, hks 2.8 (we all know how revvy they are) is 1.5, tomei 2.8 is 1.6. Most builders will tell you anything from 1.5 to 1.65 ideal for rb motors

[N1GTR]

^ There are calculators on the net about stroke vs RPM, they work it out by calculating the speed of the explosion vs the distance it has to travel i.e. it cant pass mach 0.5 or something (I'm really rusty on this, looked it up years ago)

N1GTR, what crank and size bore are you running? Do you know what these kits cost?

I've been pondering a new build for a while now, and i was thinking of keeping the compression a bit lower this time (10.5 - 11.0:1) GTR head/ITB's, and stroker, aiming for 250whp with some meatier cams (only after 7500 - 8000rpm limit though, want peak power at 7000).

It's a custom billet full counterweight crank, 87mm bore.

The kits will be commercially available once I successfully test mine to the 400kw mark

[mad082]

don't plan to build a high revving motor just for the sake of it and because your bike can. for a motor to rev high reliably it needs to be set up for it in the first place. there will be a limit as to how much it will take without spending stupid amounts of money. and the higher you go, the more money it will take to make it go that little bit higher again. also getting an engine to rev high can result in a loss of low end power, meaning that if you plan on driving it as a daily driver it can end up being a real cop. you bike would be a prime example. i bet that if you rode around keeping it below 8,000 or 10,000 it wouldn't have much go now would it.

[zebra]

there would be at least $5k in parts alone for the head to cop 10k rpm, let alone all the port work it would need to flow enough air at that rpm.

then intake and exhaust manifolds would need to be custom for an NA engine...and that would mean megga dollars in development to get them to work properly and make power.

By now you would be well into 5 figures without touching the bottom end