The Superboxer, a new heart for the Silver Bullet

[silverbullet]

Yes I know of Busprojekte, but everything is specific to either Tdi or Subaru that I can see. 350 yoyos for a pair of flanges? Ok they are nice but these ones have cost me nothing other than time.

Their 12mm sandwich plate looks good value for 125 Euro mind you...

[silverbullet]

These will do for now

[silverbullet]

Mad a special peg tool to get the cush drive dog bolt undone in the compressor nose, to see about shortening it. Simple ball races preloaded with a light spring, not quite sure why...

Raises a few more issues, mostly coolant related

[silverbullet]

To elaborate: I might just be able to do away with most of it and put the compressor drive pulley *behind* the crank pulley, so avoiding having an overhung 185mm x 25wide K6 pulley and all the problems that go with it.
But... I will have to rework the waterpump outlet that feeds the RH side of the engine and I was going to put the crank trigger wheel in there (as has been done by others)
The trigger wheel is thin and light though...

[weimarbus]

I seem to remember that on my shorrock setup on the beetle they would not recommend a toothed belt drive because the v belts allowed some give in the torque to the vanes , not sure that's relevant to a modern compressor though, but worth checking?

[silverbullet]

Ta. Different animal though. I would never use a toothed belt, just too noisy and sensitive to alignment.
It came with a modern 6 groove PK/polyvee belt and I am also considering going serpentine for all the ancilliaries (I have some pulleys left over from a past project that never made it to fruition) but that might give me a headache with the a/c compressor.

[silverbullet]

Sime basic dimensional info for anyone thinking of hunting down a UN1:
The 5th/reverse cover is 150mm long over the various shaft ends etc
The gearshift gate as marked is with the lever pointing down as per Renault. For a T3 it has to be completely reversed i.e. push is pull, L is R, so needs a little relay lever and some "rose" joints.

Best to allow 160 minimum to the mounting lug face:

The CV shaft centres are 70mm from the bellhousing face, the transaxle is 590 overall inc.10mm min. clearance:

The Diff centreline appears to be around 75mm below the input shaft/crankshaft axis (I scribed a line via an access hole in the side off the bellhousing) :

Might help someone chasing big petrol horsepower, you never know...

[silverbullet]

By way of a comparison, the 094 measures 80mm from CV shafts to the bellhousing face, circa 60mm vertical offset.

When installed in a petrol T3 there is only 460mm or so from the shaft centres to the back of the rear crossmember.
The UN1 needs 520mm to clear...

[what2do]

What's your plan to 'find' or 'lose' the 60 mm?

[silverbullet]

Cut rear crossmember and move the middle portion forward (all been done before) with reinforcement under rear bench along with other bodyshell stiffening.

[silverbullet]

Still playing with drive belts... this could be a possible solution i.e. a longer w/pump and alternator belt, using the a/c belt to also drive the relocated pas pump, then modding the crank pulley ao that the outermost pas groove carries a PK7 pulley to drive the supercharger.
But only if the PAS and a/c can be driven with around 120 degrees of belt wrap... other wise I will have to alter the a/c compressor to run a polyvee belt too and that will be a PITA....

[Aidan]

aircon runs its own belt normally so 180' and the p/s pump is about 130' as is the water pump so they should be fine ?

[silverbullet]

Not sure about the wrap on the crank pulley, its barely 90' so worse than oem for the w/p; alt has plenty of wrap, of course.
Need to look at an EJ again to see what is acceptable with a polyvee belt.
Its going to need a couple of idlers if I go that route though.

[silverbullet]

Food for thought about belt wrap... I need to get more around the crankshaft:



No, I am not going Tdi...

Or do I just say "ah sod it" and beat the tinware back and hang the 'charger pulley off the end?



Thanks to Chris Corkins for the really clear shot

[silverbullet]

I think that I will be taking the easy option of mounting the blower drive pulley on the end of the 3-groove pulley, but I am concerned about the damn thing coming loose!
Giving some thought towards asking DPR to make me a 76mm full counterweight crank with an extended nose, so the pulley hub has more support.
I have an old RV8 crank pulley/damper with a 185mm PK7 polyvee pulley that also has interchangeable vee belt pulleys, so I can choose the sizes I need (within reason) and the bore of the hub means either it or the crank would machine to fit.
Unless, of course, I still go for the full serpentine setup, but the a/c compressor pulley is the tricky bit with that option.