TR7 said:
In reply to throttlegrotto :
Why try to match up the ABZ with the 928 bell, clutch, PP, flywheel? That seems like extra work. Use as much of the ABZ as possible and just adapt the 928 TT and DS to fit. Dont even make a spline adapter, just cut off the splines from the 928 TT and weld on what you need from an ABZ trans input shaft or something.
There never was an ABZ manual trans equipped car in the states. Even ROW, it's a pretty rare bird. Think Audi D2 S8 and the take rate on a manual on those. I think some of the C6 RS6 cars came ABZ equipped too, but not stateside.
And the 928 setup is unique in that it goes in and out of the car from underneath, not pre attached to the flywheel. You can remove a whole 928 clutch setup in a half-hour. The party trick is the 2 piece sliding spline adapter that goes down the torque tube for removal, and then slides into the clutch discs and bolts in place for engagement. The lower bellhousing unbolts as well to allow to access to about 40% of the pressure plate, and gives room for the intermediate plate/2x discs/pressure plate/release arm/ T-O bearing / and guide tube to drop straight down out of the bellhousing. Only the flywheel stays attached to the engine.
the splined shaft that engages the 2x clutch discs
And the coupler that joins it to the torque tube.
So deviating from this setup would take a lot more ingenuity than I have ,and also make engine removal potentially more difficult later.
I feel like a set of cams and a tune on the 928 engine would make a lot of sense here?
Cams and tune....
The nice thing about a 928, its already good. The down side not so easy to improve.
Some have added a supercharger, and there are a few examples of other mods, but not as simple or as cheap as updating some chevy V8.
Something as simple as exhaust headers, normally a cheap and simple update, while headers are available, they are fairly expensive.
The easy update seems like some sort of chevy V8 that could be updated, basically just use the engine block, the rest could be after market improved parts, there is so much available
But I do admire anyone being creative. I wonder what it would be like to put 4 weber carbs on a 928. Instead of sorting out the old fuel injection.
The 928 is a older design, but it doesn't look like a old car, engines have been greatly updated since then. So many other engines could be a update. There seems to be a fair supply of old / fairly cheap 928's to work with, most need a engine.
Not really much in the way of cam options. For the 16v engine about the only option that I'm aware of currently is to get a set of euro cams, which would be a nice upgrade over the stock US sticks, but still we aren't talking about a whole ton of power. Likewise there isn't a whole ton of tuning to be done for more power with the stock L-Jet.
If you could have found a 01-03 S8 that was wrecked it would have been a bit easier. They have 360hp and are pretty rev happy. Only thing is getting the ecm tuned to have the emobilizer removed from it. Sometimes getting the ignition and instrument panel works as well. Thing with those motors is that when they are uncorked they sound like a nascar. Now if that's what you are going for then good luck.
I do have access to a machine shop that could do an adapter plate easily, but not the flywheel.
Some thoughts: The ABZ was a popular swap into older Audis. VW/Audi gear boxes used to use either the 4/6 cylinder bolt pattern, the 5/8 cylinder bolt pattern, or both (this is up until the mid 2000s). I do not know what flywheels were being used. Motorgeek.com has forums that probably have some answers on how those swaps worked.
Here are some flywheel options, you will have to inquire for price.
The real key is whether you can get the engine into the right position by adapting to the 928 bellhousing, of if you'd have to have a new bellhousing made. Clutch clearance inside the bellhousing also effects this, followed by whether there's space in the tunnel. I'd expect the ABZ to have the starter on the engine side, which would make things slightly easier, since it shouldn't require any modification to engage any off the shelf flywheel product for that engine. If it's transmission side, that means modifying or making a new bellhousing I expect.
The other good news is that with the weird coupler adapter to the torque tube shaft, you could conceivable have a new adapter shaft made to whatever length you need. Since the splines are external, they should be able to be cut on a 4th axis mill, though the cutter may have to be ground to get the right profile. This would be easier than having a bellhousing made, and would let you correct for whatever depth adapter plate you end up with. Additionally, it would also let you use whatever clutch disk you want, ideally the one that matches the pressure plate you use, which then has to fit the flywheel and inside the bellhousing.
For the clutch actuation, using an internal slave cylinder is a popular and relatively easy way out if you have the longitudinal space. Flipping and modifiying or making a new clutch fork would be necessary for an external slave. I know flipping and modifying the 944 clutch fork has worked in the past.
