The Superboxer, a new heart for the Silver Bullet

[silverbullet]

Oil pressure gauge might be a tad optomistic at 100psi full-scale and its got an LED clock!!!
http://i1103.photobucket.com/albums/g47 ... knqcb5.jpg" onclick="window.open(this.href);return false;
The proportions look good when sat on the T3 dash imho.

Ed1t: Book o' Rover Lies says speedo is electric from 1982! 12v in, pulsed output. Should be relatively easy to manipulate?
Handy SD1 blog with tech links:
http://www.vintagemodelairplane.com/pag ... cer01.html" onclick="window.open(this.href);return false;

[silverbullet]

Got stuck into the bellhousing, its the "easy" way for me to work out what I need to keep and get rid of the rest, ready for the mdf/filler.
Looks a bit skeletal...
http://i1103.photobucket.com/albums/g47 ... fnme7k.jpg" onclick="window.open(this.href);return false;
Plonked on the other half to see if all the bolt holes will miss each other and have enough metal betwixt...
http://i1103.photobucket.com/albums/g47 ... 2ysrlm.jpg" onclick="window.open(this.href);return false;

[silverbullet]

Could be useful

http://www.homemade-circuits.com/2013/1 ... t.html?m=1" onclick="window.open(this.href);return false;

[silverbullet]

4 cylinder Rover tacho, NOS, so cheap it's embarrassing! http://www.rimmerbros.co.uk/Item--i-DRC2746" onclick="window.open(this.href);return false;

(there was a mountain of CKD components re-imported from India a few years ago, for cars that were never built)

[silverbullet]

Started to get into the UN1 late today, but was caught out by the need for a 36mm socket to release 5th gear. Once thats out of the way I can seperate the cases, swap the input shafts, flip the diff etc
http://i1103.photobucket.com/albums/g47 ... uomr8y.jpg" onclick="window.open(this.href);return false;
Not forgetting that I need to drill the opposite half to move the speed transducer for the speedo trigger wheel on the diff.
http://i1103.photobucket.com/albums/g47 ... sps2ta.jpg" onclick="window.open(this.href);return false;
Two wires and an earth by the look of it.

[silverbullet]

Side bar notes:
Electric speedometers...

From what I can understand, an impulse-driven speedo uses a variable frequency input from a reluctor/toothed wheel combi to drive a D/A convertor i.e. its basically a tacho (which are driven by pulses from the low voltage side of the coil in older systems)

So... to make a different speedo read correctly, I need to test the device with a known input frequency to see the displayed speed is correct, then make or alter the trigger wheel to suit.

Would this do the job as a generator?

http://pages.ebay.com/link/?nav=item.vi ... 68&alt=web" onclick="window.open(this.href);return false;

I have got an old (working) twin-gun oscilloscope at work, not sure if this would do it though?

[silverbullet]

PS the UN1 has a 12-tooth trigger wheel; with its 9/35 diff and correctly sized tyres this will give 9660 pulses per mile:

637mm radius = 2m circumference

~1609m per mile ÷ 2 = 805 turns (of course)

805 x 12 = 9660

Frequency (in Hz) from pulses per mile per hour
9660 ÷ 3600 seconds = 2.68333

So 1mph = 2.68333 Hz

Does that look right?

[silverbullet]

More speedo data gathering... shout if I am boring anyone.

First off some ratios. The dash I acquired is from a SD1 2600, the correct speedo transducer (more on this later) for this model has a 23 tooth pinion driven by an 8-tooth worm on the gearbox output (propshaft speed) so it turns at 8/23 times prop speed.
The diff on this model is 3.45 and the tyres are a T3-friendly 195/70/14 (later ones had 205/70/14 and alloys but no other changes afaik)

8/23 x 3.45 = 1.2 transducer revs per wheel rev.

But what goes on inside the transducer? How many pulses does it make per rev? As it turns out, the magic number is 8

http://www.pistonheads.com/gassing/topi ... 2&t=448935" onclick="window.open(this.href);return false;

8 x 1.2 = 9.6 pulses per wheel rev I can't have a trigger wheel with 9.6 teeth! But I can turn 12 into 9 by removing every 4th one. Would it read strangely if the impulses were 1-2-3-skip-1-2-3-skip-1-2-3? Otherwise I can make a 10-tooth easily enough, it's only pressed onto the diff box.

I suppose it boils down to tyre sizes and those few % as to which is needed. More arithmetic needed.

[silverbullet]

The UN1 is so easy to open up
http://i1103.photobucket.com/albums/g47 ... 91s3az.jpg" onclick="window.open(this.href);return false;

The input shaft spline is indeed the same as the VW, but the Renault one is a bit "easy" and has interrupted splines, so I will be needing one from an 094 to go with the superb condition input shaft from syncropatrick

[silverbullet]

Comparing tyre sizes (I had to actually go and check, its been so long) and how it affects the speedo:

The Rover speedo expects to see 9.6 impulses per wheel rev at a tyre 630mm dia. This relates to 812 revs/mile, or 7794 impulses per mile.
My 255/45/17 are more like 660mm dia, 5.1% larger, only doing 775 revs/mile.
So... 7794÷775 = 10.056

So I need to make a 10 tooth trigger

[silverbullet]

To anyone thinking of making their own bellhousing...don't! It's a nightmare and my brain is melting just trying to work out what needs to be kept and what is required to tie it all together. A search o' the interweb turned up nothing available to tie a UN1 onto a VW flat 4, so thankfully my time isn't being wasted.
Unless some one knows of one? I have heard of UN1 going into various Type 1 rail buggies etc, so how do they get around the starter problem?

[Aidan]

To anyone thinking of making their own bellhousing...don't! It's a nightmare and my brain is melting just trying to work out what needs to be kept and what is required to tie it all together. A search o' the interweb turned up nothing available to tie a UN1 onto a VW flat 4, so thankfully my time isn't being wasted.
Unless some one knows of one? I have heard of UN1 going into various Type 1 rail buggies etc, so how do they get around the starter problem?

You and Richard should compare notes some day over beer he's doing scoobyengine porschebox hybridisation all the same issues

[dave friday]

The signal gen box looks good,how good are you at working out the frequency from the display on your oscilloscope ? I bought one of those moby size scopes( gives the frequency with the waveform )
Shame you can't use the alternator pulse output.

[silverbullet]

Aidan. Most of my starter relocation pain stems from the small VW flywheel. The Scooby flywheel is bigger (busprojekte don't need to move the starter for their EJ to UN1 bell)
I guess Richard is using later G-series transaxles?

Dave. I am pretty confident in my pulse calcs for the speedo, keeping to mid 80's tech should mean less headaches...

[silverbullet]

I may have created another potential problem... in conversation last weekend at Mendipity, Lee recalled that Peter William's Carrerabus 440 has uncovered a failing in the T3 aerodynamics (no laughing now) when pushing the envelope.
Get over 130 mph and your passengers will start to scream as the low pressure zone along the sides of the bus tries to suck the windows out! Story goes that his passengers could see the seals climing out of the body apertures...



I dont really want to have to fit window retaining tabs!

Sent from my Vectrex. Awesome!!!!