Which head to use on RB30DET?

[Sydneykid]

For a reliable street setup:

1. For the argument sake, if you could get a RB26 head at the same price as the R32 RB25de head which one would you use and why?

2. What compression ratio would you aim for and (if not stock) what pistons and head gasket would you use to achive that?

3. What would be a reasonable power target?

Suggestions follow;

1. The RB26 is vastly superior, it has solid followers, better valve springs, cheaper and easier to get cams, no VVT, best inlet manifold design, multiple throttle butterflies, better water jacket design, better valves, higher oil flow return to the sump ........ I think you get the idea.

2. Compression ratio is 9 to 1. We use JE pistons and standard Nissan head gasket. Obviously the block is O'ringed and we use ARP head studs.

3. With good rods we are up to 950 bhp (that's using an annealed copper head gasket though).

Hope that helps:cheers:

[600hp]

Thanks SK! do you thinkif we use the 2835's a 7500rpm limiter will be high enough?

also do you have any idea when boost may come on with say 270 deg pro cams.

of coarse it will have all the other stuff done such as porting and oil pump, all the usual build up parts.

[nedb]

I get the idea. It's more than obvious it's worth paying a bit extra to get the superior head and with a bit of patience you can always find a good deal.

Thanx SK. That was a very helpful answer like usual.

[Cubes]

It does work out cheaper to buy the rb26 head off the bat.

Stuffing around with valve springs, solid lifter conversions etc adds up and ends up costing more.

Not to forget the GTR also runs sodium filled exhaust valves.

[Sydneykid]

Thanks SK! do you thinkif we use the 2835's a 7500rpm limiter will be high enough?

also do you have any idea when boost may come on with say 270 deg pro cams.

of coarse it will have all the other stuff done such as porting and oil pump, all the usual build up parts.

We have never used 2835's on an RB30, far too big for our applications. The numbers say 9,000 rpm on an RB26 is equivalent in airflow to 7,500 on an RB31. So they should be fine.

My own RB31 uses 272/280 Jun 10.8 mm lift cams for circuit racing, the 3.1 litres lets you run pretty bag cams that would kill a 2.5/2.6 litre.

[600hp]

Thanks! the whole topic of which one was started as the Neo has VVT and some other mumbo i'm not to sure about.

Sk to keep costs done could a use s stock GTR head with stock valve train execept for a set of drop in pon cams with the new RB 30 bottom end and have the rev limiter set at 7500,would that be ok for 400RWKW? with good reliability?

just as we want to get the car running first, and then we can build a big head for it later.

i was also thinking that since he wants to use the car for club racing, it maybe better that he uses our GT-ss turbos to make an easy 350WRKW with the 7500rpm rev limiter.

do you thinkthis set up would work or would it suffer to much up top?

Cheers Ben

[Cubes]

With the exact same setup on the 3ltr as the 2.6ltr the 3ltr will ALWAYS make the peak power earlier. IF it has maxed out the airflow for a given boost level.

What I'm saying is if you want it to make peak power around 7000rpm then setup the motor (cams and exhaust turbine a/r) as if it were an RB26 reving to and making its peak power around 8100rpm. For an RB26 to make peak power up around 8100rpm you will require larger than stock cams, and may need larger exhaust a/r's etc.

[Sydneykid]

Thanks! the whole topic of which one was started as the Neo has VVT and some other mumbo i'm not to sure about.

Sk to keep costs done could a use s stock GTR head with stock valve train execept for a set of drop in pon cams with the new RB 30 bottom end and have the rev limiter set at 7500,would that be ok for 400RWKW? with good reliability?

just as we want to get the car running first, and then we can build a big head for it later.

i was also thinking that since he wants to use the car for club racing, it maybe better that he uses our GT-ss turbos to make an easy 350WRKW with the 7500rpm rev limiter.

do you thinkthis set up would work or would it suffer to much up top?

Cheers Ben

Hi Ben, using a stock GTR head with Poncams would be fine, it just waists money as you have to dissassemble it again to fit the good top end. I believe the cost of duplicated labour plus parts like gaskets and seals, would outway the cost of doing it right the first time. Do the numbers and I am sure you will come to the same conclusion.

GTSS's are a bit small, I even disgarded the idea of using the larger 2530's on my own RB31. I reckon GTRS's would be the go, if you want twins. Mine has a big single as I wanted the lower weight, better weight distribution and less complexity.

[25t_sedan]

And then we come back to exactly where i left off......just use one big single turbo

[600hp]

What size would you recomend for a good club racing style turbo.HKS 3240?

[Sydneykid]

What size would you recomend for a good club racing style turbo.HKS 3240?

Any ball bearing turbo that supplies 60 lbs of air per minute at around 1.5 bar (or less) would be my choice. I chose a Turbonetics T66 with dual ceramic ball bearings and a titanium compressor.

[HKS-R33]

hey, just wondering what sort of budget would be required to build an engine with the rb26 head and rb30 bottom end making a reliable and responsive power output of around 300rwkw. Also, what would need to be changed to do this? (eg, cams, turbo's, pistons etc)

thanks

[R33S2]

modr33s2,

5k is around the mark with a set of forgy's.

Thats not touching the head, no port work etc. Just bolting it on.

Its also obviously not including labour to drop the motor in.

Yeah he did alot of the work himself melted 3 motors with the nos, was also sponsored by mod shop but work on motor was done by someone with expertise in that area.