The goes-way-too-f#$king-fast-mobile

[4g63mightymax]

So..... Are you welding bungs to the holes? What happens next? You've lost me.

[300D50]

The holes to the pump cavity will get milled round (threads removed), then the whole thing will bolt to an intermediate plate with o-rings sealing to the milled surface.

The intermediate plate will bolt onto the main sump plate with screen between it, and o-ring seals. Seems to be the easiest option for this.

[300D50]

Saturday was the pail sale at the best of the two local pick-and-pull auto yards, so I got some goodies to play with.

As for how that relates to this unholy and involuntary collection of parts and pipe dreams,
I managed to extract a Pierburg CWA200 waterpump from a BMW 328xi.

It's a little 200 watt electric pump with a rather simple control interface

I've also found a source for an air conditioning compressor that runs off of 12V DC with built in control, and should suit cooling needs for the car if/when the time comes.
I haven't ordered it in yet, because it's rather expensive and I don't see it as main priority.

Altogether, this means I'm down to two required things running off the front pulley of the engine; the alternator and the dry sump pump.

I've got a 2008 Audi Q7 190A alternator on the way from fleabay, should be here by middle of next week.

Should be relatively compact, and it's liquid cooled so no worry about road glop destroying it.

It's going to live either at the top of the engine where the original fits, or on the side where the A/C would bolt in normally. Depends how much clearance I have with the intake manifold, and what makes more sense packaging wise.

The added bonus of switching to one pulley instead of two frees up more longitudinal space at the front of the engine, which I dearly need to meet my track width specifications...

[4g63mightymax]

What is preventing you from running a Mazda rx7 alternator? Also - can the Q7 alternator handle the RPM's that the rotary can throw at it?

[300D50]

Nothing really, but the Mazda alternator is only 100A.
My thinking is it's going to be a bit anemic for the added electrical load of the waterpump and electric brake booster, and eventually electric A/C.

As far as RPM, I'll probably have to change the pulley ratio to keep it from self-destructing.

[knuckshaft]

Any recent pics of this?

[300D50]

Nothing really recent, but there's stuff in the works.

I'm trying to get down to the shop after work every day to push forward.

[300D50]

Nothing much new, winter and the time change/darker evenings hit like a dang mule and derailed my efforts a bit.

I'm going with a gilmer drive for the alternator and sump pump, I ordered in a cheap kit a few days after the alternator came in.
The ratios work out close to what I need, and the sump pump needs a gilmer anyways.

The original OAD (over-run clutch) on the alternator is getting turned down (Well, a new one is, but semantics) and press-fit into the bored out pulley from the kit.

One little "issue" is the Q7 alternator does not have computerized field control, so the ECU can't disengage it like the factory one.

I'm going to look into doing some surgery to the Q7 alt to breakout the field wiring and run a Mazda regulator.
Or just live with it the way it is.
The joy of custom stuff.

Still have yet to decide where I want to mount the alternator, but I'm leaning towards the existing top mount more and more.

A recent addition to my toolset is a bare bones china 3D printer, for those times when I want to turn 5+ hours into a plastic test part.

[4g63mightymax]

Cool stuff. I'd love to mess with one of those 3D printers at some point. I'm too cheap to spend the money at the moment though. I need to recover from this garage build before burning any more cash! I'm looking forward to seeing some pictures/video of the printer in action!

[300D50]

Progress was made.

I had switched from the 1990 front cover to the 2004 RX-8 one for a multitude of reasons a while back
One among them to get rid of the CAS and go to trigger wheel , engine control, and all that lovely jazz from a 06 RX-8.

One of the sticking points is the RX-8 front hub was slightly shorter than the S5 one, so the e-shaft stuck out about 3mm.

That means the front bolt won't tighten, torrington bearings wouldn't get pre-loaded, bad times would be had by all.
I could have stuffed a spacer on and called it a day, but in the end I couldn't really see how I could do that and still seal the e-shaft safely.

The other option was to machine the S5 front hub to take the trigger wheel on the back side, to keep it in alignment with the sensor.

I didn't end up getting photos of the hub being machined, mainly because it's cast iron and made an absolute mess.

The back side had to OD brought down to match the front, up to the back face of the pulley flange.

The flange got shaved down from 12mm to 8mm thick off the front face, so the gilmer pulley could slip back a bit further. I couldn't machine further material off the flange without hitting the balance dimples.

I did start snapping photos as I bored the gilmer drive pulley back 0.05" to get a little bit more recess.


Test-fit, seeing if I had a good seat.


Trigger wheel bolted to the flange from the back side, using OE RX-8 pulley bolts.
Slipped into the pulley to verify that everything lines up.




There's roughly 3mm gap between the trigger wheel and the edge of the pulley.


Side-by-side, modified S5 front hub on the left, stock RX-8 on the right.
The trigger wheel is slightly lower, but that shouldn't cause any issues. I couldn't machine the flange to keep it flush without hitting the dimples andrisking the balance being off.




The reduction in protrusion wasn't as much as I was hoping, being only 9mm shorter, but I now don't have to worry about belt slip, and can drive the dry sump pump.


The threaded holes need to be chased, and then I can get longer flange bolts so I can hold the pulley on with nuts.

[300D50]

Also completed the alternator pulley on Monday, but work on it actually started back in October 2019, so some photos and steps were done out-of-order.
I've arranged them to best tell the narrative as if I was doing everything all in one shot.

2007/2008 Audi Q7 190A liquid cooled alternator with the OAD pulley removed.



Back of same alternator.


OAD chucked in the lathe, getting the serpentine ribs removed.


Machined down to 48mm (1.890").
Not shown is flipping and bringing down the other side.


Trimmed the back of the gilmer pulley to release the guide flange.


The pulley was bored out to 1.888" (~47.95mm)




Gilmer pulley went into the toaster oven on max broil convection for an hour, which is roughly 500°F
OAD went into a 3°F freezer for the same time.
I had two smaller sections of aluminum plate that I sat on top of the gilmer pulley in the oven, to get a little more thermal mass.
Likewise with the larger plate below, that was out in 30° weather before it came in.

Slid in like a dream, just had to lean on it slightly to get it cozy.






I went flush because I can vary the spacing by machining down the spacer ring that slips over the alternator shaft.
That needs to be done anyways to account for belt alignment, so might as well allow for the maximum adjustment.

Now to get the front cover trimmed down to fit the alternator.

[4g63mightymax]

Damn, that's some badass stuff. So am I understanding that the alternator will have a cogged belt running it?

[300D50]

Yeppers, cog belt goodness.

[300D50]

[4g63mightymax]

You're getting close!