The Superboxer, a new heart for the Silver Bullet

[silverbullet]

I've been after this one for a while, ever since I heard about it. Circa 1988 the owner of a nearly new Carat Auto felt that it just wasn't quick enough, so had this conversion commissioned to perk up the MV. Apparently it was fitted onto a competely standard engine and ecu, with just a modified AFM and rising-rate fuel regulator! No mapping or lambda back in those days...

It's going to need a bit of re-work and updating, but should really move the bus in an old-school style, but with modern fuelling and ignition control; along with a vacuum bypass, bigger plenum, charge cooling etc.



I wonder what kind of rpm that idle pulley is doing when the engine's at 5k
More later as the project progresses, but it's going to be little while to get a decent engine built to make the most of it. I won't be expecting Aidan to offer any kind of transmission warranty!
P.S. It's Sprintex, aka Lysholm screw compressor.
Anyone want to buy a Kennedy Subaru 2.2 conversion c/w RJES exhaust?

[ghost123uk]

Watching with interest on both counts

[mm289]

About time you got this - been waiting with my mouth shut for months

So what is the plan, rebuilding the original engine or starting afresh. Going up to 2.2 or staying at 2.1?

Want to see how this goes as I figure there must be mileage in rigging up a G40 or G60 setup on a WBX

MM

[axeman]

yummmmmmmmy.

i take it that you have now taken delivery?

neil

[ghost123uk]

Wasn't there someone else on here talking about building stronger and more powerful WBX's recently ? (toomanytoys ?)

Perhaps a project collaboration, a BLOWN stronger more powerful WBX (now where would you put the nitrous bottle )

[silverbullet]

I've done some home work and I've got a "sensible" spec in my head:
2.1, 9:1 ceramic coated forged pistons, H-beam rods, Main bearing and oil system modifications Megasquirt EMS. Cam to be decided. Still got to do more research on blower gearing, delta T's, intercooling etc.
I've lifted the assembly off the mock-up MV that came with it, looks like the front pulley has shook loose in the past The "engineeering" to mount the compressor is unbelievably crude, plenty of room for improvement but it at least gives me a start point.
I could really do with a complete healthy MV installation to return to wbx: everything from the coolant bleed rail to ecu, engine bar to the airbox, the whole shooting match as it's all long gone when the EJ22 was put in.

[toomanytoys]

Wasn't there someone else on here talking about building stronger and more powerful WBX's recently ? (toomanytoys ?)

Perhaps a project collaboration, a BLOWN stronger more powerful WBX (now where would you put the nitrous bottle )

Recently???? its been on the cards for the last 5 years...

I'd gladly give up my day job if if there was reasonable interest....

Ian and I have talked.. a lot.. Several boxes of parts will be heading his direction early Dec....

I know what specs I will be biulding in the new year.. both NA.. (a forced induction tester is after them )

[toomanytoys]

About time you got this - been waiting with my mouth shut for months

MM

me too...

[Cableguy]

Wow, that's gonna be fantastic. Can't wait to see the project unfold.

[ghost123uk]

Wasn't there someone else on here talking about building stronger and more powerful WBX's recently ? (toomanytoys ?)

Perhaps a project collaboration, a BLOWN stronger more powerful WBX (now where would you put the nitrous bottle )

Recently???? its been on the cards for the last 5 years...

I'd gladly give up my day job if if there was reasonable interest....

I am sure there would be.

I would be for a start, and I am sure many of the Syncro owners would be too.

[silverbullet]

I've decided that intercooling would be a good idea, so will see about picking up a pair from of one of these babies at a show in a couple of weeks and set about making new plenums:



Should give plenty of cooling and heat-soak overcapacity so they won't need a massive radiator!

[silverbullet]

It looks like I've slightly mis-identified the compressor...it is a Lysholm-type design but is most likely an Opcon Autorotor SR2 2076, made in Sweden. Unless it's a Sprintex made before the Opcon licencing deal, hard to say really.

Anyway, by cross referencing the few tech drawings and datasheets that are on t'web it looks like it can safely be run to 15k rpm continuously; 18k is possible for short bursts. It's only got a displacement of 0.76 litre, so geared at 2:1 with the pulleys it's got will give ~11psi boost, but that's only pushing it to 12k rpm.

Geared up to the max continuous speed would mean 2.5:1 gearing, but would exploit it's max flow capacity of ~180 litres/second.
Fed into some online hp calculators suggests it can provide a 2.1 with enough air for...

240 bhp@5500rpm

Without intercooling.

[Aidan]

240 bhp@5500rpm

as long as it's less than 300Nm I'll warrant the box

[silverbullet]

I was starting to think that I'd ultimately have to nail a late 915 on the front of it, rather than distress another T3 transaxle. Either that or go Auto

But since I've already got a grumpy 5-speed, it's coming to you along with a lump of ZF slipper, in due course. I promise not to hoof it in first

[silverbullet]

Reading the Bible today (Forced Induction Tuning, A. Graham Bell) I realized that I'd got a couple of figures wrong...not on the blower potential for bhp, but the boost figures:
Current gearing is 150:68 but for a 0.78litre blower on a 4-stroke 2.1 this would give max boost in the order of 22psi, not 11 (half engine capacity needed per revolution - duh!)
And a combined engine/blower redline of 6800 rpm