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97 D2 4.2 A8 Turbo?

Old 02-04-2012, 03:33 AM
1st Gear
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Join Date: Jan 2012
Posts: 38
Default 97 D2 4.2 A8 Turbo?

OK if anyone has been following my posts in the D2 forums I recently acquired a fairly decent stock 97 a8. I am currently getting the car back up and running.

I have seen the prices on the 32v motors and one can be had in running condition for about 800 shipped. What my goal is to do is put down draft turbos (nothing huge or grotesque at first) simply to test out the system. I want to build the engine on the bench and I have been trying to source some parts for these motors. I have found some stock S8 cams but I am not sure how well those will run for a turbo application.

So far I have come to the conclusion that a separate dry sump system will be needed to lube and cool the turbos. I am also worried about the transmission, does anyone know how much power the stock auto in these cars can hold? I have also noticed these engines have a few vacuum controlled parts, so something would have to be figured out for that as well.

From what I understand these engines are over 10:1 compression from the factory, so I would have to try and source some kind of low compression pistons, OR head spacers to drop compression. I am also thinking a secondary fuel pump will be needed unless the factory pump can feed around my rough guess would be 450 to 600 HP. I am planning on running fairly low boost (maybe 6 to 8 lbs from each turbo) and stress test it once it is all built up.

So my main concerns

What transmission options are available to be swapped into these cars?

What can be done about the vacuum sensors?

Where can I purchase some head spacer's or low compression pistons?
Old 02-04-2012, 10:33 AM
ImTheDevil's Avatar
Join Date: Jul 2006
Location: Binghamton, NY
Posts: 11,670

The bigger concern is tuning. If you're going to make that much power, you'll need bigger injectors. Also, that much power under boost will require you to pull ignition timing dependent on boost level. All of that needs to be accounted for in the tuning. No off the shelf chip will be out there so that means a lot of time on the dyno. Tranny-wise, talk to Level10. As for oiling, you can probably tap off an existing oiling port (I'd assume there's an oil galley freeze plug on each side, but that's speculation). You can tap returns into the pan and use inline scavenge pumps to draw the oil back to the pan (which would be enough to draw oil through the turbos) and use a Walbro inline boost-a-pump for fueling.

It's doable but it's going to take a LOT of custom fabrication and a lot of swimming in uncharted waters.

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