Quote:
Originally Posted by IT
Have you looked into the BBK engine fitted to my S4?
Very similar (I believe) V8 4.2 to the BFM, but runs on a manual box...
Runs rather very nicely too...  |
I considered the BBK motor, but only briefly. The main issue with the BBK V8 is the multiple chains at the rear. Broken or rattling chains are very labour intensive to rectify.
It does look very similar to the BFM V8 fitted to the D3, at least at first glance. Similar valve covers, and coil packs, down to their wiring conduit. Both engines also share the same exhaust manifold, intake plenum and throttle body. That's where the similarities end though.
The BFM, under its valve and timing covers, and behind its accessory brackets has more in common with the 077-series V8 40V engines found in the D2 and C5 models. It is actually an 077 motor. The BBK motor is an 079-series V8, and the first of the "New Generation" chain-driven V8 engines from Audi. It was followed by detuned a derivative in the C5 Allroad, the FSI variant in the 2005 D3 and later the Q7. The FSI variant went on spawn a high-revving, 420hp unit, and the B7 RS4 and R8 4.2 FSI were born.
Another interesting evolution of the 4.2 BFM V8 is the physical dimensions of the block. It shares this with the C5 RS6, meaning some machining of the rear to mate to an 01E 6-speed is required, which is where I'm at now.
Yes, the BBK will be EASIER to install in a B5 - well, kind of. But the chain issues, and the complex location of the driven accessories, and integration of the harness with the B5, including aircon and ABS means it's not worth the hassle. It will also be frustrating getting a VSS signal to the BBK ECU. B6/7 S4 took the signal from the ABS wheel speed sensors, then to the ABS module via the combination instruments, then sent the modified signal out to the ECU.
Pretty interesting stuff, albeit complex.