StockyMcStock

OEM manifolds for the RB sixes are all split pulse (to an extent) already. the flange will be the same, they will bolt on. personally i would never build a manifold with an open collector, even if i was using an open collector turbo. split pulse all the way. the less pressure spiking you get transmitted to the other three cylinders the better IMHO.

No i didn't bother changing the rod bolts. Have you ever heard of rod bolts breaking on an RB30? cause i hadn't i have only a vague idea of what power my engine is making as it's still running an RB25 base map for the time being. as i mentioned, it REALLY needs a tune. but i'm not going to bother yet, not until my blower is on the engine and piped up. basically i have a built RB30DET with custom manifolds and a GT40 turbo with 1.34!!! rear housing at the moment. it was all built to run as a twincharge with an Eaton supercharger, hence why the rear housing on the turbo is so large. it's still remarkably good to drive though, even with RB25DE cams and no tune the top-end power is astounding.

i have also heard this - the S1 packs with external ignitor don't seem to suffer from spark degeneration anywhere near as much as the series 2 ones. anyone know the reason? heat problems?

I should learn not to chat in the fs section or I will be banned for a week edit by BU5TER

i am of the opinion that the presence of two more cylinders will more than make up for it.

explain that one to me?

bah - get a twincharge up ya. changing cams is for pussies!

i still can't really see any point to using forged pistons in a street car. but each to their own, the extra $600 or so for the build might help you sleep at night anyway, if so it's money well spent i reckon. we'll see how long my casties last and what power i put down with them reliably anyway, might help some people see the light p.s. had my first run with a fastish car on the weekend - "200rwkw" 180sx down the gold coast. anyway murdered him through 2nd and 3rd - even with the laggiest turbo known to man. i really need a tune too.

or save yourself a grand and use high silicon content cast pistons (RB30E) from ACL. i won't wade into the forged vs cast piston debate here but i would actually never ever use forged pistons for a road car that was planning on running more than 50,000km between pull-downs.

convert to solid lifters. oh wait you said "cheap". my bad.

ynhrgt: you simply will not fit them in. besides, a single one is good for roughly 1000hp and as such i would just use one. there is honestly no point (for what you are doing) in running twins. if you're completely set on running two turbos with a twincharge, i would suggest twin GT35's or something of that nature, with 0.86 rear housings. but you still will have trouble fitting it all in.

oil pumps are not determined by power levels in any meaningful way. just get a VL n/a pump and set your idle to 2000rpm. it will be fine.

funny, i could have sworn the 20 and 25 had different bore sizes. last time i checked they did anyway. as BADR33 said, go straight to the 26. rebuild it as a higher-comp motor up around 10.5:1 and make some nice headers for it. it will be the cheapest and best way to do what you want. p.s. there's a reason you don't see many n/a RB's around.....

that's cool tex i wouldn't have bought the turbo if i was intending on using it on it's own, not even on a 3L setup. it's far too big IMHO.

i'll give you a grand for the gearbox with shifter and slave cylinder right now. whereabouts are you?

if it's any use as a comparison, i have a GT40 with a 1.34 A/R rear housing on my RB30 DET. standard cams, custom plenum and exhaust manifold. 1st gear: lucky to see 4psi of boost at 6000rpm. full traction. 2nd gear: 10psi around 4800rpm (hard to tell) lots of tyre frying. goes from 70km/h to 130km/h in the space of about 1 second. this gear feels roughly three times as fast as first did. 3rd gear: 10psi at 4000rpm. traction is borderline. very fast gear up top past 150km/h. 4th gear: load it up and you'll have 10psi at 3500. by then you're doing close to the sound barrier anyway so you better stop quick. on a 25 even the GT40 with smallest rear would be stupid, let alone the one i have. p.s. makes great noises though, this turbo!

pffft - just rev it straight through that little harmonic that they get at 7500. if you pass through it quickly enough, your crank will be fine i reckon!

oh yeah, i forgot about that. something isn't right there. i mean, i don't think he's lying, but there's so many variables there - not the least of which is the happiness of the particular dyno he's on. what's in a number anyway? i mean we all like to jerk off over what dyno number we get but it doesn't make a lick of difference as to how the car goes or feels on the road. i wouldn't get too hung up about it. take my car for example, i reckon right now it would put down a big number on a dyno of my choosing, but on the street some gimp with a highflow, cooler and exhaust on his RB30 would destroy me in a race. hell, i might beat him to 250km/h but certainly not to 100. everything's relative.

according to my resident expert on such things, raising 380cc injectors' rail pressure to about 70psi will allow them to go out to around 300rwkw, which fits neatly in with what conan is running. are they standard injectors conan?

but if there's only two more load points for him to go into, and it's currently making 218 at the rears, how do people say that the Q45 runs out of resolution up near 400rwkw?

i looked more at the turbine map for my turbo than the compressor map, but then again i had a very specific purpose behind my choice. it is possible to figure out the amount of airflow needed to make XXX amount of power, then you can find that point on your turbine map and get some idea of whether or not it's close to peak efficiency. other than that, i'm not too sure. disco might know a bit more about this than me i would guess.

Cubes i did a map trace earlier tonight - in 2nd gear it is hitting load point 17 at 5200rpm. what does that mean? it's a Q45 AFM too. bloody thing better not hit the ceiling on me before i get the power i want out of it!

too many variables. the best way to judge it is from other people's experiences with similar setups to yours. going from 0.63 to 0.8something will *generally* add between 300 and 500 more RPM to full boost. again, lots of variables. i'm not sure what you're talking about with that last question, but the reason the 0.63 housing restricts power compared to the larger housing is mostly in the back pressure changes in the manifold. bigger housing = less back pressure = less pumping loss of energy = more power.

if you're willing to separate the gearbox let me know

6BOOST will make you one - for a price. If you're in Brisbane i'm happy to make you one for a lot cheaper.