StockyMcStock

i'll give him credit for having too much money to spend on a car! that, sir, is the main object of certain people's builds. mine, in particular.

so does all that shiny shit in the bay make it go faster?

here we go: #1: do some reading on the different types of blowers out there. not being a dick or anything, but you need to understand how and why they work before you can even think about twincharging. it is IMMENSELY complex, even if you try and make it simple. a roots blower is what you want, to make bulk pressure at the lowest RPM possible. a twin screw whipple would be better, but prohibitively expensive, and you might as well just use it on its own. as far as options go in canada, i'd look straight at an eaton M90 or M112 if you can. ebay in the states has HEAPS of them for cheap, that's where i got mine. #2: mounting. let a shop do it, unless you have a lot of patience, time and experience doing it beforehand. the blower must be rigidly mounted to the block, and the drive belt perfectly straight, or you will have problems. #3: piping. make it as simple as possible. turbos pull air in through filters, the turbo outlets feed straight into the blower INLET. the blower OUTLET feeds through your intercooler, round into the engine. in effect, all the turbos are there to do is pressurise the inlet of the blower. have a think about why this works, then think some more. there are problems with the blower providing boost even at idle, so as soon as you open the throttle 1% you get full upstream boost. this is why a proportional blower bypass is required in the piping somewhere. it does, however, introduce a whole new series of problems. honestly, i can not see it physically fitting at all, in any kind of engine bay with power steering and air con. there simply isn't room. remember you will want to run exhaust housings roughly twice the size of a normal turbo setup, this means they are BIG turbos on there. then you need to fit a blower in front, or under them somewhere. it is truly a logistical packaging nightmare, but the end results are worth it. i would consider going a single large turbo, with the blower in front. remember there is no use to running two turbos any more, as the lag which you were trying to defeat by lowering shaft inertia is now defeated by a roots blower. it's much more effective anyway.

I am. don't use a switchover point. it defeats one of the great advantages of a twincharge anyway, in that your inlet pressure gets back up to close that of your exhaust pressure. using a simple blow-through (turbo outlet into blower INLET) your inlet pressure will always be substantially higher than exhaust back pressure. where did you ask the question before, i can't find a thread?

anyone?

i've seen a picture with a 26 on a stand with a roots blower and two turbos, but there was some serious conjecture about it's authenticity. i know someone who twincharged a 1.6 twin cam ford laser engine with a T03 highflow and an SC-14 blower. i am currently setting up my twincharged RB30DE with an M90 blower and GT40 turbo. any specifics you wanted to know?

nobody?

i have heard talk that you can go to certain gearbox shops around the place and they have a test stand setup for manual boxes. it's probably just a lathe with an adjustable holding jig and some sort of output shaft RPM measuring thing hooked up to a computer. have heard it doesn't cost much to get em tested either.

This is a pretty straight forward one. There's an R34 N/A 5 speed up for sale, i'm wondering how strong they are? apparently the outer dimensions are similar to an RB25 box...... any ideas? cheers

i f**king hate those bolts. why are they even there?

you can do either, might as well give it a crank for a bit. can't really hurt anyway. it's mainly just to get oil in the high pressure OUT line from the pump to the high pressure bearing galleries. once it's there, and full, the pump is ready to go.

pour like 12 litres of cheapass oil into her, so that the oil level is above the pump. take it all out, put good stuff in and go. it will work first time, i guarantee.

you will need to use the R33 RB25DET loom, and all the sensors should then plug in. the lack of VVT will not be a problem at all. mine isn't plugged in at all. your tune might need some patching up though, due to the camshaft timing not changing any more.

it's not really any different to tune, just pull some timing out below 3000rpm, add more fuel everywhere and away you go. being able to run a giant exhaust housing is a nice positive to this setup. as a reference, the exhaust housing i have is recommended for a 13B rotary drag engine producing 700-800hp at the wheels. i've never seen one this big on an RB30. it was very very very carefully selected after much debate and turbine flow chart analysis. i hope that it is small enough, the next step up was a GT42 but the smallest compressor i could get on that would be surging due to only having to supply 7psi pressure @ 500hp worth of flow. as it is, my compressor stage will be skating on thin ice to do this. i haven't mounted or driven the blower yet, it is still in the machine shop getting modified. i'll take some photos next weekend if i can, with just the turbo in there. as you can guess, packaging is a big issue.....

hi guys - haven't checked in on this thread for a while now but good to see some progress from the new 30DET guys. my engine is physically in now, i have fabricated the dump pipe and am in the process of making up the cooler piping now. i'll take some photos of the state it's currently in for future reference. as cubes mentioned i'm twincharging this engine, however i will be running it in with the turbo only until i get the blower mounted and driven - which is surprisingly difficult i assure you. Parts list: 3ltr block ACL casties, standard bore size, ACL race series rings. rods - standard. Crack tested, cryo treated, beam polished then shot peened. bearings: Nissan mains, clevite 77 rods. R32 GTR oil pump. (EDIT: for the love of god, don't start this conversion with a series 1 block!) R33 RB25DE head lightly ported exhaust side fully rebuilt, new valve guides, reseated valves etc stock cams stock cam springs <--- probably not for long, we'll see..... RB25DET 380cc injectors for now. Custom JD plenum XF throttle body (3 inch) Hot side: Stocky Racing Industries tubular, split pulse exhaust manifold 50mm HKS racegate off turbine housing. Full house GT40 turbo. 1.34 exhaust A/R, split pulse. 0.72 A/R compressor. 4 inch inlet. Stocky Racing Industries 3.5 inch dump pipe. Stocky Racing Industries 3 inch cat-back mandrel bent exhaust. Stocky Racing Industries 3 inch stainless cooler piping. Eaton M90 supercharger, custom shortened drive snout for clearance. 1.8x crank speed drive. Garrett 32mm wastegate setup as a bypass valve for the blower. Hybrid front mount. PowerFC. Q45 AFM in the piping. As you can guess i've done 90% of the work on this engine myself, to the point of building the bottom end and making my own exhaust manifold. overall, a great learning experience i must say! I have oil pressure, spark and fuel now so my wiring job has worked, just waiting on my mate's TIG to finish the piping and a few little things, then she'll be ready to go. will update with pics soon.

Looking for a high mount RB25 manifold, preferably with a T4 flange. Not concerned about external gate provision. Needs to have clearance for a very large turbine housing with regards to the exhaust rocker cover. Willing to buy interstate if the price is right. cheers

try running a bit more tension in it, might ease the flap out.

inlet cam and exhaust cam mixed up somehow? though there's a keyway for the CAS in the exhaust cam i guess that would be hard....

out of interest, why are the bearing faces still black? i would have thought they'd need to be linished back to bare steel before assembly. nice looking piece of gear though, looks a lot neater than the goddam RB30 cranks i have had out. balancing holes drilled all over the place, looks like a dog's breakfast. edit: i don't understand why people pay so much for an extra 100ml capacity when you can have an RB30 for such little cost these days. the only advantage i can see is the giant revs the 2.7 is capable of, but that's still a moot point as the RB30 can make the power more easily on lower revs. i guess you can keep your engine number though

here is what i recommend: castrol GTX straight up. change it at 50km, with the filter. change it again at 250km. change it at 1000km change it at 5000km, with the filter, to a synthetic oil of your choice (mobil 1 is good gear)

so i take it that's not a standard crank, but a custom grind job? who did it and what did it cost?

spot on. it would work to start with, but as soon as turbo airflow became greater than the blower's possible airflow at any rpm, it would restrict and be useless. remember that a roots blower is just a big vacuum pump, it is purely mechanical in nature. so it takes a gulp of air, and moves it to the other side of the cartridge. do it quick enough, and you get a pressure difference across the thing. increasing the number of air molecules in each gulp of air by adding pressure to the inlet side is an easy way of making it move more air. think of the setup this way: the turbo is only there to increase the possible amount of air that the blower moves, by forcing more in at the inlet side. edit: addon - a lot of people figure the only way to twincharge is to use a complex system of valves and shit to switch the two airstreams over at the correct point. this is a silly way of doing it because you negate the effect of having inlet pressure much greater than exhaust back pressure. this is one of the primary reasons it works so damn well, but if you switch your blower off in the high RPM and the turbo only is working, your back pressure is exactly the same as it would have been with just a single turbo setup. (granted, you have a giant exhaust housing so the in-ex pressures are probably still pretty good)

if you're "totally keen" here's a basic overview: 1) Find a place to put the blower 2) mount it, and drive it. This is very hard. Expect a number of destroyed belts before you perfect it all. the mounts must be perfectly rigid and perfectly aligned to the drive belt. 3) Piping. The cold air pickup is on the inlet of the turbo, just as normal. the turbo OUTLET feeds into the blower INLET. the blower OUTLET then feeds through your intercooler, on the other side of the intercooler you position your bypass gate (another whole topic). between the bypass gate and the throttle body, you then place your AFM if you have chosen to run one still. the basic premise is that the roots blower will give straight up boost right off idle, pulling air in through the (combined) inlet of the turbo. this low rpm boost creates much greater exhaust gas flow, much earlier than normal. this spools your turbo much earlier, which now PUSHES air into the blower inlet. the delta pressure across the blower goes up a bit, as it becomes more efficient with positive inlet pressure. say it's giving you 10psi, and the turbo pushes 9psi into it, then you might come up with 20psi at the plenum. advantages: massive torque spread. no lag. power delivery is much easier to control than a big single turbo setup, everything is linear instead of all-or-nothing top end power. you can run a GIANT turbine a/r and wheel, with no lag, as the blower can help spool up a much larger than normal turbo, much quicker. this means your exhaust back pressure goes down heavily, which increases top-end power further. if everything is sized correctly, you can achieve inlet pressure > exhaust back pressure. again, huge gains in top-end power. disadvantages: packaging, and driving the blower. this can be difficult, but you can make it work with a bit of know-how and testing. if you were doing it to an RB20, i'd get an SC-14 blower (make sure you get the one off the 1g-gze, NOT the one off the 4AG-ZE) and get it running on the engine first. then fit your turbo and pipe it all up. turbo selection is critical, you basically want it much larger than you normally would, especially in the turbine stage. perhaps a GT35/40 .86 or 1.06 rear if you were shooting for 10psi/10psi boost spread. half-half is a good place to aim here. as a guide, my setup is an RB30DET with 8.3 CR, i have an Eaton M90 blower which i will set up to provide 6-7psi. the turbo i chose was a full house GT40 with a 1.34 rear housing and 84mm rear wheel, which is rather large. it would be fairly silly on the engine on it's own, boost up around 4500rpm i would imagine. the other thing to think of is compressor stage surge line, you will generally want the largest A/R on the compressor that you can, so that it can provide big airflow at low pressure without being beyond the surge line. mine is a .72 A/R compressor.

i'd say it's sized pretty well indeed. your lack of power comes from your lack of capacity. are all the supporting mods there?

if any of you guys are serious about twincharging, i can explain a few things and how best to go about it. i don't think softy is keen on the idea, moreso wants to try a straight blower setup. for the RB20 i'd use either an SC-14 overdriven to 14,000rpm or if you could afford it, an Eaton M90 twisted-vane three lobe twin rotor roots blower. the eaton *may* be slight overkill but better to oversize than undersize.