Rb25de (supercharged) Project

[r33_racer]

Since half way through last year ive been inspired to supercharge my road skyline(White 96 R33 S2) after discovering the thread on the GTR UK forums.

Basically in a nutshell this project is going to involve me pulling all the turbo/exhaust/manifold setup off and replacing it with my newly aquired 2.1L twin screw blower.

Its going to be quite involved as I will need to fabricate a mounting bracket with belt tensioner setup, a new intake with custom throttle body setup, new intercooler piping from outlet to existing piping, fit the bypass valve and probably a boost controller bleed valve(otherwise known as an overboost valve), machine a drive pulley to adapt to the standard damper or an aftermarket one if its not achievable, fabricate a custom set of headers and basically a full new exhaust system. At the same time im planning on upgrading injectors and the rest of my fuel system setup to allow for the running of E85 when Brisbane finally catches up with the rest of the world.

I havent actually started anything yet as im waiting on space to free up at my old mans place. But its been started in my head and ive been thinking about it nonstop as I try to figure it all out and allow for possibilities that may arise which could force an early bail. But I have every intention of finishing it and it looks promising as to the results this setup can provide.

I want to document everything I do on this so if others wish to follow in my stead they may use this and myself as a guide to venture to the dark dark side of forced induction tuning.

Previous history of my car is decent already. I fried the standard pistons some time ago when i had a turbo setup that wasnt very good and resulted in some lean conditions arising. So I rebuilt the motor, with some acl (ross) forged pistons, reused standard rods, crank was fine, everything else except the bore which had to be machined for the new oversize slugs was fine. The head was cleaned up with new valve stem seals and a slight deck. New acl bearings for the bottom end and cometic headgasket was used and ended up with a 8.0:1 CR as I wasnt aware that the acl pistons dropped the CR by .5 already so the head gasket was bought slightly thicker to drop it another 0.5.

Car sports a PWR gtr intercooler, greddy inlet manifold, sard 550cc injectors, powerfc, hks bov which is going(thank f*ck.)

To the good stuff. This is the supercharger in question which I acquired from a company in Perth called Sprintex. They make these superchargers which are based off the autorotor design, also the same as the Kenne Bell twin screws. Actually they are identical. Autorotor being the original manufacturer of these superchargers.

Based off my research into superchargers these bad boys are the most efficient internal compression superchargers around. The 2.1L unit I have is rated at about 650hp. So the equivalent of a GT35R. Im going to be spinning it at 2 times engine speed (rev limit of 7,000rpm) with the superchargers maximum continuous rpm being 14,000. But they tell me they can happily go upto 18,000rpm for short periods of time in racing conditions if needed. But I dont want to push it all and will have no need to do so because of this reason...

Here is the best bit about this unit. By all accounts I will have full boost, which will be whatever it is by 2,000 engine rpm (4,000 supercharger rpm). That my friends is all I needed to know about this setup that sold me! So much to the point that I dont care about anything else regarding it all. When its all done I will know for sure just how it all pans out power and response wise!

Im hoping for awesome things. Ive gotten many bonars over this project just being in my head for so long. Im sure that I will no doubt cream my pants when its all done!

Stay tuned...

Sorry for the long arse post!

[N1GTR]

Awesome, I was literally looking at Kenne Bell stuff last night for a car I'll be doing soon

great timing!

Following this with keen interest

[XRATED]

It's about time someone had a decent crack at SCing an RB.

What is the hp drive requirment?

Where are you going to mount it? Under the intake manifold with a sandwiched water to air cooler?

I've allways thought about a twin charge rb26 set up... especially with the new rotrax centrifugal SC's available.

Anyhoo... looking foward for the updates.

J.

[r33_racer]

Yeh i figured its worth a try.

Im not sure exactly what the drain is...but im going to assume about 100hp which is probably a good overkill. I think the Kenne Bell website states lower numbers. But its been a while since i looked. I should ask the people at Sprintex.

My plan is to mount it vertically on the passenger side above the power steering pump and off towards the wheel arch abit so it can plumb straight back into my original intercooler setup. If I cant make it fit there I will be removing the power steering and using its spot to mount it. I have sourced a plan B option of an aftermarket electric power steering pump/tank setup to replace the mechanical pump. Im hoping it doesnt come to that, but if so then atleast ive got that problem covered.

Ive looked at the rotrex units. I didnt like that you need their special cooler and oil for it because it spins at super high speeds. I have also heard from a bloke whose used a couple of them that when they overheat there is some problem with a part in the gearing that expands too much and they can cease up and you throw/chew belts. But the main thing about centrifugal superchargers is that you still have to wait for fullboost as you only get it at redline. Its good in the sense that its progressive, more accurately then a normal turbo setup but you still have lag. The common understanding of superchargers is that there is no lag. Ive found that only to be true with the twin screw style superchargers. Hence why ive gone for this style. At the end of it all the only lag I 'should' experience is the time it takes for the air to travel from the discharge port of the charger to and through the intercooler and then into the greddy plenum and fill the cylinders. Which is the same in any typical turbo setup except I get full boost instantly not at peak rpm/redline.

Closest update at the moment is im trailering the car to my old mans garage tomorrow morning and will start pulling everything off and start looking at it all in finer detail

[TRB-001]

goodluck!!.... u will need it.

hope uv got a big wallet to go with those bonars!....

i admire your passion and drive i just hope u dont give up when u hit the first hurdle.

i dont kno that much bout superchargers, but why not use the other side mount ones u see on v8 commo's?

seems to be abit smaller and alot easier to fit.

Edited February 6, 2010 by TRB-001

[NA_Goodness]

They're centrifugal SCs. He explained why he isnt doing that in the post above.

[dkbcleaner]

All the best mate! Make sure you keep us posted

[OKBANANA]

Looks like an excellent project - Can't wait to see it all come together.

[zebra]

Could you mount it straight on the intake manifold and use WMI injection to keep the intake temps down, twin screw blowers do run much much coolers that a roots type straight out of the box...and if you are going to run E85 not having an intercooler might not be a big drama.

If would require a custom snout on the blower and a custom intake manifold, but you were going to do that already.

[Duncan]

The common understanding of superchargers is that there is no lag. Ive found that only to be true with the twin screw style superchargers. Hence why ive gone for this style. At the end of it all the only lag I 'should' experience is the time it takes for the air to travel from the discharge port of the charger to and through the intercooler and then into the greddy plenum and fill the cylinders. Which is the same in any typical turbo setup except I get full boost instantly not at peak rpm/redline.

yeah I've been driving the march super turbo lately and it does indeed have full boost by 1500rpm (ie immediately after idle). which is just as well because it is only 900cc, its a real slug off boost. But the thing to remember is that even though you have full boost you obviously don't have full torque and/or power, there is still a torque curve you are climbing up and the revs for peak torque are unlikely to move much unless you are changing cams as well.

yes you get more sooner, but lets say you run 10psi of the charger, at 2000rpm you effectively have almost twice the normal capacity (twice the power?) as standard but that is still not very much (maybe it only makes 50 or 60rwkw at 2000rpm)

[XRATED]

Are you keeping the VCT?

[r33_racer]

Yeh Duncan, im not exactly sure what the power is going to be like down low or even up high. Im not expecting big numbers. But im expecting a good amount of get up and go straight off the bat as opposed to how it used to be with the GT30r.

If it works out right, I should see about 20+psi at 2000rpm or thereabouts. Hopefully a nice fat torque curve too. Wont really know for sure until its all done though.

Justin, yeh im keeping the vct. It is still a standard rb25, std head, cams and everything else. Just the forged pistons, acl bearings and mls headgasket thats already in it.

Ive had parts rolling it from the states over the last couple of weeks. And in what free time I have ive been stripping away stuff off the engine that needs to go. Power Steering is definitely gone. Already removed and I have acquired a MR2 spyder 2003 model electric hydraulic power steering pump. It looks to be in good cond. It was my first purchase off Ebay!

I have got an aftermarket oval throttlebody, accusump, new inline canton filter setup which ill be using/fitting at the sametime. Throttlebody is huge in comparison, but needs to be since it will be infront of the supercharger.

I was hoping to keep the airconditioning, but after some more measuring this arvo im thinking its also a gonna. No drama I guess. All for the sake of fun. I will get some pics of the parts sometime soon.

[XRATED]

Hey Michael,

Accusumps are definatly the go... I don't know why more people dont run them. Especially with rb oil pump issues.

Are you going to play with VCT timing?

Do you have a mock up pic or 2?

mmmm... twin charged. H ha ha h.

[r33_racer]

zebra - I never replied, sorry. Your way probably could be done, but it sounds like alot more work to do. The snout isnt an issue as the supplier does machine them and you can get them in a variety of lengths. But making a new inlet manifold to incorporate the s/c on it to me sounds quite daunting. I like the idea of keeping my intercooler and if need be I can still add the WMI ontop of it all.

I took some quick pics this morning of the stuff ive gotten so far. It aint much. I did however leave the filter unit and accusump at home. Forgot to bring it with me, but everyone knows what they look like.

That is the first attempt at my bracket which will mount off the block/head as the power steering pump did. I used 1/4" plate and just cut it out by hand and overlayed the p/s pump bracket ontop of it for the hole centres. I then had to machine up the bushes(stainless 304, have lots of it at work) for the back of it to space it out enough so it would give some clearance off the block/head/timing backplate. Top bush was machined @ 35mm long, bottom two @ 20mm with 10.5mm holes in all of them. I then bolted them to the plate and just tacked them on, but found the plate bent ever so slightly just from the short tacks. That will cause a silly pain when I then build off it to attach the plates which will hold the s/c. So ive since drawn up the bracket in CAD and will be getting it lasercut out of 8 or 10mm so I have a super strong base to build on. In heindseight I should have just clamped the plate down instead of being lazy, though I honestly didnt expect it to bend. Good thing you never end up using the first mock up anyway.

Ive drawn the front and back mounting plates in CAD as well. So hopefully they will all get cut at the sametime and then I will be putting the whole mounting bracket together within the next week or so.

Ive been slack with the updates, though not much has happened yet, mainly cause over the last few weeks brisbane has seen abit of rain on and off and my car is being worked on outside still

Hopefully it will pick up from here on out.

[XRATED]

I'm hanging out to see the low end... say 1500-3500rpm power band.

Once you have the SC'er sorted out.... I say twin charge the biarch!

Yeh haa! ha ha ha

J.

[DRD-00F]

hangin out for this!

People have SAID they were going to do it, but these people were all people without an idea in their head.

[r33_racer]

Yes, well ive spent enough money on it so far that its definitely not getting canned.

Its happening, that is for damn sure!

[fletch rb30]

is the blower 2.1L per revoultion?

Thats like 2.36bar boost.

your rb25 sucks 1.25L per rev, and your blower pumps 4.2L per rev. thats 3.36x engine volume.

Should go good!!

[RB25PWR]

Very keen to see how this turns out!

[Duncan]

jesus 20+psi....

anyway....its not an rb25de....it will be an rb25der lol (mine is a ma09ert). good old nissan engine codes