Dicharged Rb30

[johan.p.g]

K heres the problem I want 2 build a dicharged rb30 but the conventional method of running the turbo directly through the supercharger doesn’t appeal 2 me.

What I wanted 2 du was run a y joint with 2 non return valves with a clutched sc14 supercharger geared to cut out by 4000rpm and a turbo that should hit full boost at 3500rpm and carry on up 2 redline

Hopefully the diagram helps clarify my description basically the way I c it is that at low revs the supercharger (sc) will be producing about 10 psi which will produce a back pressure against valve2 as the turbo wont be blowing much air if any it will therefore seal it off. As the revs increase and the turbo spools the pressure equalises on ether side of the valve then eventually opening it as it increases. As we get a little higher up in the revs the turbo will over take the supercharger and therefore closing valve 1 then at 4000rpm the sc will completely disconnect using the electronic clutch they come with from factory

Now the question I have is how would you advise I make these valves that can handle 20 psi without leaking

[VB-]

would probly be better off doing the turbo through supercharger thing. what have you got against it specificaly? guy on calaisturbo and i htink he might be on here aswell twin-charged his VL with RB25 head (maybe 20 head) but did it turbo through sc and it seemed to work pretty well. think theres some videos on youtube of it too

[PLYNX]

Ive messed about with superchargers over the years ! Maybe a better idea would be a single valve or flap that is mounted at the point where the Y section pipe meets it simply swings back and forth to each side closing of or opening up progressively as needed. Maybe it can be pressure operated from either the turbo or the supercharger ?

[Craved]

Ive messed about with superchargers over the years ! Maybe a better idea would be a single valve or flap that is mounted at the point where the Y section pipe meets it simply swings back and forth to each side closing of or opening up progressively as needed. Maybe it can be pressure operated from either the turbo or the supercharger ?

that reminds me of a exhaust add in i saw for sale somewhere.

They ran an actuator that controlled a throttle type valve that opened on boost pressure releasing the exhaust gas out a bypass exhaust pipe.

think of a wastegate actuator that opens a trottle body instead of a cable

perhaps trying to run 2 of these, or one via boost pressure and one via electric motor that shuts off along with the supercharger.

but dont forget that even sequential turbo systems have a hole in the tune between the 2 turbos transition point. Atleast running the turbo through the supercharger should allow for more linier power

[funkymonkey]

can't you run two electronic throttle bodies like on some cruise control units, and trigger the solenoids using a switch that activates on desired boost or throttle level? Wouldn't you be in a whole lot of trouble if both those valves closed at the same time for some reason?

[Beer Baron]

you will need to have a recirculation port too before the one way valve otherwise the turbo is just blowing into a brick wall.

[Beer Baron]

and what the hell is "dicharged"?

[johan.p.g]

i hav thought of using a flap as described by PLYNX but thought it would be a little more difficult 2 make. i was planning on using 2 throttle bodies but wasnt sure if it would leak under the pressure. i dont like the blow through method as the supercharger has 2 suck throught the turbo at low revs causing a restriction and at heigh revs it has 2 blow through the supercharger causing yet more restriction just thought my method would eliminate this. a dicharger is the name given 2 a system where a supercharger and turbo is ran on the same engine or at least thats what the european car companies call it

[PLYNX]

Im sure Ive see something similar but it was a very long time ago ! My old timers is kicking in real bad after a few belts !

I think it was on a twin sequential supercharger set up from the late 50s early 60s. Maybe on a 2.6lt inline Alfa 6 engine, maybe a Sebring or a Fiat 6 ! Agrrr ! to many brain cells gone !

But what caught my eye was the Y section was fabricated out of box steel tube which made it easier to hinge the flap at middle of the Y section.

The other thing that I remember they were running 42lbs of boost through it on a alcohol mix racing fuel ! Not bad for no intercoolers in their day(man was that an old fart statement!!).

[342Four]

why not use a twin throttle setup like funky said??

ive seen twin throttle setups on the factory plenums - use one for the sc and another for the turbo - have a solenoid switch that closes the sc throttle at a set boost pressure from the turbo, and also a switch that turns the clutch off on the sc

it could work....

[johan.p.g]

the box steel y joint would make things easier but im not sure how i would go about making the flap seal yet be free moving.

il get hold of some new throttle bodies n hav a play i threw away a hole pile a few weeks ago so kikin me self nw

[Lazy-Bastard]

Either StockyMcStock or Macguiver is running a twin charge system, maybe get details from whichever one it is.

[Craved]

Either StockyMcStock or Macguiver is running a twin charge system, maybe get details from whichever one it is.

its stocky, but he is feeding the turbo into the charger

[SABBAi]

and what the hell is "dicharged"?

when the charge air falls out of the engine. Dah....

[Dj laBBy]

On some of the old style Detroit 2 stroke Diesel engines, the were Di charged(or whatever) basically being 2 stroke, they needed a blower(sc) to force out the exhaust gasses out of the combustion chamber when the piston was at BDC. The roots type blowers were there basically there till the turbos kicked in. They didn't force air through the SC, but like a flap valve, like what has already been said. Works well. The flap doesn't have to be perfect. I like the idea about the square pipe, it would make it easier. It could be done with say 3 1/2" pipe (3" normal ic pipe) so the flap would be around 3" and spring or weight (similar to what a truck has on its stack) loaded. As soon as the turbo spools up, the flap would open and bob's your uncle. It comes off boost, flap shuts and bam, the sc takes over. What comes to mind about the weight loaded flap is these brass check valves i use for saltwater systems. I know its not really the same though but its an idea...

Edited December 15, 2007 by Dj laBBy

[CEF11E]

in all reality, if you ask anone that has a well set up rb30det there is really no point twincharging. I have built my rb30det with a midsize turbo and it will make close to 300rwkw if pushed. and full boost by 3000rpm. off boost torque is better than anything else you can buy bar a big cube V8. and as soon as you get moving you have atleast 200rwkw on tap and god knows how many NM of torque.

also if you put it in an r32 it is a damn fast combination.

I spent months working out the best way to twincharge and decided against it as it was far to complex. and would never be legal.

[PLYNX]

Do a google search on Eldred Norman. He had a on/offswitch on his supercharged 1967 HR holden 6.. Normally asparated through the carb and filck the switch and it would redirect throught the supercharger !