StockyMcStock

brilliant, good answer. thanks dude! i won't be running more than 1bar to reach 450hp so that'll do me just fine. odd, though, that the turbo and n/a cams would be the same...... nissan must have got lazy and started mass-producing them cheaper. this head is still a direct bolt-on (after i re-route the VCT feed of course, and blank off the hole in the head for it) to an RB30 block isn't it?

okay 93 pages is a bit much for me, need a quick answer for this one: i am looking at purchasing an R33 RB25DE head, supposedly with VCT. 1. did they come with VCT? 2. is the presence of different cams the ONLY difference between this head and an R33 RB25DET head?

Do non-turbo R33 skylines exist? have a guy trying to sell me an R33 RB25DE head but i was under the impression the R32 was the last one that came out with a non-turbo variant.

mah grammar ist goot today. haha just taking the piss. yeah i was going to get a 25T pump as well, just waiting for one to show up for cheap. plus i don't need mine to feed a turbo, just twin cams. was going to use an oil cooler front-mounted somewhere too.

don't laugh luke - i am seriously considering putting cooling fins on the sump! what's your objection to using an oil/air cooler say mounted in the spare area in front of the right front wheel? don't say the option of leaking because if you use proper fittings and lines like speedflow jobs and high-pressure braided line it won't be an issue. more oil flow resistance could be a problem, what oil pump are you using?

very good idea, 100 bucks for a week of usage is not bad. i'd be in for sure, will need to do some basic tunes to get the car with new management around till i can get it on a dyno.

ah, that's pretty much exactly what i was going to do, with a turbo external gate. i am already using a garrett 32mm wastegate as a bypass valve for the blower i have now, i was thinking about getting a second one and doing exactly what you just described. however hiding two wastegates in the piping could be somewhat interesting, at least the coppers wouldn't know what it was....... p.s. i've personally never seen a BOV with two fittings like that, and i suspect they'd be expensive? can you throw me a brand or a link or something?

how? the BOV only has a fitting on the top, to help it open under vacuum obviously. wouldn't you need something like a wastegate which has a pressure fitting such that compressed air will force it open against the spring pressure? the only way i can think of doing it with a BOV is by altering the spring rate till it was just right, but i doubt it would work properly?

yeah good stuff - wasn't sure on the conversion stuff (BHP to airflow particularly) so that's nice work. i'm thinking if running the blower at 2x crank speed and venting the excess air via a turbo external wastegate in the induction piping somewhere, so i can vary the boost if i want to. the charge will be heavily intercooled, yes, i am using a good front-mount and thinking of running a custom water/air after the other intercooler which i can pack with icy water for dyno runs/drag runs.

this is a lysholm 2300 (marketed as whipple) flow chart. give me opinions on what sort of final pressure i would be looking at for an RB25/30 combo engine (standard head + cams, 8.3 compression ratio and standard bottom end) if the engine revved to 6,500 rpm and the blower was driven at 2x crank speed to keep the rev ceiling at 13,000rpm. just after opinions if anyone can interpret the flow chart better than i can! i expect the engine to produce roughly 400-450 horsepower at the crank.

there are two inlets to the intercooler, one from each turbo. (duh?) if the blower outlet joined into the two turbo outlets as it appears to, then as soon as the turbo outlet pressure got above the blower's outlet pressure it would try to reverse the direction of the vanes and most likely destroy the blower. certainly it would destroy it if the pressure difference was large, as it most likely would be with turbos of that size. unless there is some extremely tricky pressure switching device under the piping somewhere which is used to switch from blower to turbo only at a certain boost level then it's definately fake. it simply wouldn't work. there does not appear to be any room for such a device in the picture. also the turbo outlet pipes would have to be pressure equalised somewhere before the solenoid switch, there is no evidence of that either.

the above picture is definately a photochopped fake. think about the pressurised flow direction through the turbos and blower. it simply would not work.

shit

send me the photos - [email protected] pretty keen.

there is an even cheaper option which will work extremely well. find a Norgren Industries (pneumatics company) outlet near you and go there. purchase a pressure relief valve and a pressure regulater valve. make sure you get the screw-in adjustable ones! they come with 7bar springs in them standard, you will need two .7bar springs. also get four barbed hose fittings to fit your wastegate hose. all up it should cost you about 80-90 bucks. install them in series (with the new springs!) in the wastegate-compressor housing feed line, with the pressure relief valve first and the pressure regulater valve second in order of pressurised airflow to the wastegate. what will happen is that at any boost below, say, 12psi (they are completely adjustable) the pressure relief valve will not let ANY air through at all. this eliminates ALL wastegate creep. you will get full boost as fast as possible with your setup. at 12psi the relief valve will open and let air through to the regulator valve. the regulator valve will hold the air coming to it at exactly, say, 13psi. this means your wastegate will open at 13 psi. the system will then instantly reach an equilibrium at your desired boost level of 13 psi and will open/close the wastegate as desired to maintain that boost level. if boost falls below 13psi, the wastegate will instantly close fully until that level is reached again. so there you go, a fail-safe and excellent cheap anti-creep, anti-spike boost control setup. both the valves are fully adjustable and have "lock-down" ability once you set them. because they are built to handle 7+bar of air pressures (100+psi!) they are extremely accurate and fail-safe. give it a go and see if you don't like it, hell it's even cheaper than a stupid bleed-valve from turbosmart or similar.

regrinding the cams results in you needing to tip the lifters as well, they're not like the RB30 SOHC cams in that you can machine the lifter blocks to lower to the cam when it's physically smaller. tipping your lifters could be exxy, very exxy.

the 25/30 shown in the pic above is NOT going to be twincharged, it is simply an SC-14 mounted on a 25/30 combo. i have my doubts about it, but nizmodore is going to find the limits of the little SC-14 on that engine i have no doubt. i am currently gathering parts to build a twincharge system on my RB30 with an SC-14 and a giant turbo. don't worry about switching between the two compressors or anything, just set it up as a simple blow-through system. here the turbocharger feeds straight into the blower, which is primarily there to increase "off-boost" response (not that there is such a thing with this setup) and spool the turbo up very early. this means you can run a BIG exhuast housing and have a huge stonking top end power figure with solid midrange and low-end torque. say the blower makes 4psi (as it does at the moment for me) right off idle, you will get massive exhaust gas flow at very low rpm. turbo spools early, and you then simply add the two pressures to get your final boost level. 4psi +10psi = 15psi (the blower gets more efficient as it's intake pressure gets above atmospheric) into the manifold and viola, easy twincharge setup. fitting it all in and stopping belt slips are the two main challenges. charge cooling is another, but i'm just going to run an intercooler and an aftercooler. water/air and air/air respectively.

that price is ridiculously low, i don't get it. are they made of paper mache or something? i take it that these are the generic "Hybrid copy" cores from china? that almost everyone sells but not that cheap? having said that, i think i might take one, that's just too cheap to resist.

if i come and pick it up, how much is it?

higher compression in the RB30E vs ET - keep the boost about 7-9 psi and you will make 130 easily. it's only 160-170 at the flywheel, not that much really. there is another, different way to make 130rwkw on an RB30E, that is exactly my power output and i am pushing a whopping 3psi. can you figure it out?

perhaps there's a water/air intercooler between the blower outlet and the inlet ports on the head? they don't have to be large in volume and can be packed with icy water for quick track sprints. i like the remote-drive they set up for the eaton there, very innovative.

a few points i noticed: 1. blower looks like an eaton M90 or M112 lysholm type. 2. that's a big enough twin-screw on a little 4cyl honda on its own, let alone twincharging it like that. 3. no aftercooler between the system and the engine = ridiculous intake temps, it must run meth or C16. 4. maybe the turbo has a large a/r exhaust housing, the main reasons to twin charge like this are to spool up a large turbo very quickly, and to keep intake pressures above exhaust back pressure, so the theory is you can run a larger snail for a smaller engine, with no real drawbacks. all in all, a very strange looking twincharge, but the principles are the same as my setup.

riceline: can you pm me your mobile number (i think i have it already, but not 100% sure - got it off someone else who bought an inlet manifold off you a while back) i'm interested in the plenum, the 25DE exhaust manifold, and whatever else you have lying around. need stuff for the top half of my 25/30DETC build. you haven't, perchance, had the plenum flow tested or anything have you? and who built it?

very good info, thanks for that. looks like i'll stick with the 25DET side feeds and run large fuel pressures. if that doesn't get me to 300hp at the rears i'll run an extra injector or two somewhere in the induction tract.

nobody knows the answer to this, do they. guess i'll just have to try it....