RB30-POWER

7.92 @ 172 sammut bros 300zx. sohc twin turbo rb30. vehicle had 750 up to 1000hp weight around 1000kg that was all done years back, this thing is alot lighter then the vl commodores that are out there now, but the vls have extra power.

i like the graphical content of most adds, was all rather chilling and drove a message home, except the school kid that got owned by the van thinking with his dick instead of his brain, surely your not meant to laugh in the middle of something so serious... and the aussie ad at the end is lame as.

porting like everything has it disadvantages as well. opening ports up, decreases port air speed at low rpm and can effect emissions, low rpm torque and fuel economy/efficiency. not a problem if power is an ultimate aim at the end of the day, but manufacturers have different requirements when these things are cast.

on a prepped track with good drag radials that mph should be a mid to high 10 easy.

got to be honest, that is massive power mate, can't be on pump fuel? i would be looking bigger then the 256 type deals. the biggest advantage should be the way the car drives, instead of the standard cams falling over (may not feel like it), bigger cams would extend the power band where you want it, which is high rpm with a turbo that size on the 2.5l engine. from higher power band will come higher power since it's basically a derivative of torque vs rpm, make torque at higher rpm and more power is the result, bearing in mind turbine back pressure, that also increases with rpm, depending on how much you are pushing it. just remember rod loads go up rather fast as soon as you extend the power band by any significant amount and will have a greater chance of breakages. also keep in mind the hydraulic lifters, if it was a neo head with solid lifters, you would only need to worry about the bottom end. in saying that 8000rpm still keeps the piston speed just under 4000ft/min and lifters should be ok at that rpm. as always cams will detract from low rpm drivability if you go too big, just depends on what the purpose is meant to be. if you only want more power for dyno days, just get a bigger turbo, if you want to track it, big cams might be the better alternative, if it's a street car a mild cam upgrade might be best with a nos system as an extra. never an exact science, mostly trail and error, which can be a reason to copy other peoples successful results if you can obtain them.

i have built an rb30det that has the r31 box behind it, holding up fine under moderate power. however the car doesn't have an lsd and uses street tyres and organic clutch, so more then likely the reason it is still alive. slicks/semis, lsd and button clutch would equal instant bye bye i reckon. by the same token there was a guy with a turbo r31, slicked and lsd, launched it and actually popped the 4 pinion diff, how the diff went before the box is anyones guess, but i put it down to luck more then a testament of the stock r31 box strength.

if the pedal is hard, i will assume it's been bled properly. if the master cylinder has an adjustable pushrod, make sure it is adjusted long enough so that when the pedal is pressed in, it is releasing the clutch properly/fully. if it isn't releasing you will have trouble getting the gears. how far do you have to lift the clutch to get it to take up/take off? if you barely lift the clutch and your moving forward, might need a little adjustment to lengthen the pushrod. by all means could be the fork bending, which will do the same and not allow it to release, but hell that is not very common at all in my books.

"OP6" is stamped/embossed on the turbine housing, but might be hard to see whilst it's on the car however. boost is the same as stock turbo really, you should just make more power for the same boost pressure due to the less restrictive housing. i say max of 14psi on the street, and max of around 10psi for track days if you want it to last.

yep the "op6" r34 rb25 neo/vg30det turbine housing will bolt to existing rb25 turbo. however you said yours is highflow, so the housing will need to be machined for the larger highflowed wheel still.

i checked the rb20 turbo and 25 turbo i have in the shed. the rb20 turbo has smaller banjo fittings for the water lines, so you may need to use rb25 water lines. there was talk about the later rb20 turbo being slightly different and having same size water lines, but i really can't confirm that one way or the other.

VG30 turbo come in three basic flavours. VG30DETT/Z32 300ZX Engine DOHC, T28 flange small turbo used in twin form, will not fit and is no good, too small. VG30DET/Nissan Leopard/Cima/Cedric Engine DOHC, T3 flange, ceramic turbine wheel, ballbearing, same as series 1 RB25DET turbo but larger turbine housing (OP6 same as RB25DET NEO) This is the straight bolt up turbo to other twin cam RB engines that you are after. Get it hiflowed with big steel wheels for bigger power and reliability. The bigger turbine housing means less back pressure so more power potential then an rb25 turbo, also slightly more lag, but not that noticable with standard ball bearing core. These turbo's run up to 9-11PSI as standard from factory FYI. VG30ET/Z31 300ZX Engine SOHC, T3 flange, will bolt up, but requires custom dump pipe, not worth the hassle to fit this turbo - to old school, it has steel wheels front and back, thrust bearing turbo, not suited to RB twim cam engines as a bolt up proposition. This is the same as the RB30ET turbo, but has different dump pipe orientation.

the elbow is smaller on rb20 turbo, you will need one from an rb25 turbo.

don't the xr6t have one from factory, inline filter? think they block up and that is why heaps of xr6t turbochargers shit themselves?

400rwkw at all 4?

castrol vmx80 or penrite manual gear oil 80 correct grade for these boxes, designed for boxes that are notchy when cold, i.e. nissan rb gearboxes. if you have problems when it's hot, most likely the syncros and baulk rings are stuffed and only a rebuild will help.

to much essay, not enough pics. without reading it all, who uses ebay/china parts on a gtr? factory setup is good to 300rwkw, after that a core upgrade might be required. maybe you have a big single upgrade and needed this kit, i'm not sure?

r32 gtr, i give it 6 months of thrashing before it spins a bearing, my predictions. it's only ever a matter of time with these engines.

look at the air temp reading for starters. tell them to leave it hanging on the machine or the figures are going to get overly inflated.

incredible, i know a guy that had the same thing happen, re the exhaust studs/drilling into head. however he made the mechanic pay for the f**kup, took it to another mechanic and got the first one to pick up the tab for head removal and all other associated repairs/parts. mistakes happen, but the story i got told was it was a bit of a mess once he was done.

race fuel, modified + 50mm external gate

get it put on dyno and check air fuel ratios, safest way. should get away with it, but double check the mixtures, before boosting away crazily.

bigger cams, ported heads, bigger turbine a/r, smaller compresor a/r are all things you can do to try and get the turbo away from the surge line. if that doesn't work, you need to select a more apporpriate compressor for the engine airflow characteristics. my car does this on part throttle around 0-5psi boost, boost just jumps up down constantly, you either have to gun it or downchange to get the load of the engine, really anoying. if it does it on full throttle, you can cause big trouble and should tend to it immediately. i'm guessing the turbo you have has some old school t4 compressor wheel on it, designed for low shaft speed, high airflow, when it's mated to a high speed small a/r t3 turbine you can get bad results.

out of curiosity why is the head coming off? what power is it pushing?

it is not worth the upgrade alone over a stock r33 turbo, but makes an ideal turbo to highflow because it has the larger rear turbine housing as stated. (same as vg30det) in saying that a vg30det turbo might be had cheaper as they are more common. get it highflowed and ecu mods/injectors to suit and make reasonable power typically around 230-280rwkw, plenty for a mild street car.

sik!