The Superboxer, a new heart for the Silver Bullet

[silverbullet]

Since this now seems to be the Silver Bullet's own thread (having never being introduced properly and despite the Subaru engine threads, which eventually lead to a cure), here's the story and where it's go to so far, in breif:

The bus is a 1990 SA-built Microbus that came to the UK via Cyprus, in the ownership of a serviceman, or so the story goes. It made it's way to WagenWorks up Birmingham way where it was made over/planked and squared, re-sprayed in the same clour and re-trimmed in black "leathercloth". It was a very early TSR-ish conversion to run a Subaru EJ22 with a Kennedy adaptor and flywheel, a later 5-speed SA big-flange gearbox (originally 4-speed with a 2.1 wbx) and lowered with a spoiler-scraping early H&R Cup Kit, which was very low at the front.
The bus changed hands, went round Europe at the hands of two brothers on a weed'n'shroom trip, collecting the odd dent and then I aquired it when they needed the cash for a house deposit. I am the 4th owner afaik.

After a fair bit of corrective work along the way by me including fitting a proper exhaust from RJES, re-instating the front Konis, bump-stop trimming, spring spacing, a lot of engine wiring fault chasing etc brings us up to date, save for a spell in a mate's body shop where he repaired the top n/s/f corner of the roof (a common fault with all SA buses in the damp UK it seems) and a new n/s sill...oh and the fitting and subsequent removal of EPAS, after I aquired a genuine RHD PAS kit.

There's nothing wrong with EPAS, honest!

The latest thing is the gearbox, that was repaired at some time due to a broken sychro hub, which has recently shown a reluctance to select first or reverse when hot. At Aidan's advice I stopped driving it and today had a pleasant couple of hours (no, really!) bumbling about, taking it out and adding to the photo diary. This is quite timely as it's going to get a bit of torque abuse eventually

Note the 108mm flanges:


It's also going to get this little number installed

made by ZF if you're wondering

[Fin]

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.

I'll have a bunch of parts up for grabs once my Scooby project is in...
Unfortunately my old engine isn't healthy - but have everything else if you are interested
I dropped all of the coolant out of my engine on the A303 - so it wasn't very happy when I eventually limped home

[silverbullet]

OK Fin, stay in touch.

Having drained the trans and found that the oil was clean and sweet-smelling; next to nothing on the magnet but I have found that with the selector shaft "out" (first - reverse I think) it's definitely difficult to go from one to the other...very snaggy

Broken hub or selector shaft bearing?

[Aidan]

Ian fully in (against spring pressure)is 1st and reverse, first is forward, reverse is back
natural detent position (against spring) is 2nd and 3rd, 2nd is back, 3rd is forward
fully out (no tension) is 4th and 5th, 4th is back 5th is forward

[silverbullet]

Thanks Aidan. Of course it is! I'll stop trying to be clever and get it crated...

[ELVIS]

You registered on STF yet?

Reregistered the other day (havnt been on for about 8 or 9 yrs and forgot login/password ) and saw they had quite a good EMS section

[silverbullet]

I have indeed Elvis. Not posted up yet, unsure where to put this engine build. I don't doubt there'd be loads of relevant knowledge and experience on tap.

Had a useful chat with the chaps from NAR (Northampton Auto Rads) and will be sending them some info and sketches for a pair of chargecoolers. Cheaper in the long run to make exactly what's needed, rather than trying to re-work standard parts from another engine, they reckon. Diesel boys should take note!

I'll still make the plenums though

[silverbullet]

Not much progress, but this evening I was introduced to the 2nd owner of the bus that was originally fitted with the supercharged engine...not much more on the early history but the Carat was apparently good for a 0-60 time in the 9's with a thirst to match!

This was on an auto and reputedly only around 155bhp on tap, so there must have been torque a-plenty. That'll be the result of the tiny plenum chamber then, it was well choked down. I think we can improve on that

Then we chatted about the Polo Sprint that he had a good nose around at the VW museum and remarked on the similarities...

[t25adict]

i think the polo sprint was a 1.9 rather than 2.1
ive read info that states they used a g lader charger and other info stating they tried the ¨G¨ chargers and then used a different item.
i have looked a number of times at the eaton chargers and thought the layout would be quite suited to a wbx.

its hard to find info on the polo sprint.... sadly when we had a walk around the vw museum (by ourselves, the place was shut but they let us in) the polo sprint was not on display.

ive got a book from the states with a number of modded wbx engines in, one is all about the alpine turbos conversion.

will have to hent it out and scan it.

[texasuk]

I used to be fan of superchargers in my hot rodding days, but over the last 20 years I've moved further and further over to turbochargers as a boost of choice.
I think as far as bang for buck goes you will get a lot more from a turbo, plus it should be a lot easier to mount and run.

But then again there always has to be a first, and if wasn't for people trying to do something different just because they can then we probably wouldn't have any advancement in knowledge.

[silverbullet]

Thanks for the input guys. TBH it's horses for courses but the Opcon kit was there and the price was right. A new turbo built to spec would have cost more on it's own than I gave for the whole engine with supercharger, I can't go wrong really. The rotors are in very good condition and there doesn't appear to be any backlash. It's (just) the tiny plenum and cruddy blower mounting bracket that need re-work.

The Opcon / Sprintex / Lysholm is far superior to the Eaton (crude but cheap) and doesn't really need intercooling as it's so efficient over such a massive rpm range. By the time I've installed a bypass for light-throttle off-boost cruising it should work pretty well. All the online calculators seem to point to around the 230-240 bhp at 6000 rpm max for the 2076 blower on a 2.1 litre which should be ideal for a road vehicle with good driveability. The blower will be max'd out at 15000 rpm, where they start to go off song anyway (and get into the red) so I'm now looking at a 2.4 or 2.5:1 drive ratio to get the most from this little 0.76 litre unit.

I understand that the Polo sprint was indeed a 1.9 DG with water injection intercooling, which I think was good for 156 bhp at about 6500 rpm? I've never seen a pic of the engine bay so I've no idea of what blower they were using. As for road manners, who knows but it was the mid 80's...the Polo was a lot lighter that a T3 though!

[toomanytoys]

If the Polo is the one I think it is.. I may have a performance car mag of the 80's with a feature on it......... wont know until I go check my stash of mags in the barn..

[silverbullet]

Dusty old "performance" mag stash eh Si? Go for a rummage before the rats turn it into bedding

Polo Sprint was the wbx mid-engined MK1 "estate" with a wide bodykit, in red:

http://retrorides.proboards.com/index.c ... st=1278499" onclick="window.open(this.href);return false;

Second colour picture (engine) centre left, looks like a wbx flywheel inspection "bung" hole? There's enough plumbing for a wbx that's for sure. Plenum looks like it goes to the middle on the skew, then two throttles go left and right...and you can just see the breather tower next to the alternator bottom right, with the distributor vacuum capsule centre bottom

Looks like it was turbo after all...

[silverbullet]

More info! It used a g40 prototype:
http://www.polodriver.com/polo-1981-199 ... 8-seconds/" onclick="window.open(this.href);return false;

[toomanytoys]

Thats the kiddy...

My mum had a "bread van" Polo for years.. cracking little car, apart from the wooden non assisted brakes..