You could always look here! Verlag Stahlschlssel Wegst GmbH CHS = Circular Hollow Section. But, you could have Googled it yourself!
Andy K's S1 replica puts out about 425bhp and about the same in torque and the only mod to the bottom end is steels rods.
Just to drag this up a bit, on the matter of the 20v being a 16v with an extra pot stuck on the end - The port for the 5th cylinder on the standard exhaust looks like a total afterthought, 1+2 and 3+4 go into a pair of fat pipes, and the 5th is just a piddly one welded into 3+4
Audi were working on a 5valve 5 cylinder engine for rallying purposes, but i think the idea was binned http://www.audistory.24max.de/old1/etallade.htm http://www.audistory.24max.de/old1/html/e25v.htm
Marketing killed it, see post #29. They could not sell 5 cylinder engines against BMW and Merc. straight 6s or Ford and Opel V6s. This was borne out by the poor sales of 7A engined cars, which, although they produced as much power as the 2.8l 6 cyl. BMs, were quickly replaced with V6s producing less power. The average rep., and joe public, thought that 6s gave more bragging rights! Nice find by the way! This marketing policy was not restricted to Audi. Back in the day, when the first GM engined Saabs appeared, GM stopped Saab advertising the Saab engined 2.4 16V Turbos as the 'High Performance Saab'. The bill board posters were quickly replaced, after only a couple of weeks, with ones advertising the GM V6 engined carss.
25V Engine Chain drive cams. Not gear drive as Chris found on the 90 Rally car. Interesting water pump, nothing like the 20V production motors
daved, that water is different as it probably has to work on that engine!! the standard pumps are pants! plus the poor design of the cooling system doesn't help!
Almost deserved of its own thread - lovely! I'm amazed how much VW recycle its ideas across the VAG ranges, even too looking at some of this motorsport stuff we all dig into. What really was the reason why they didn't produce this 5-valver? It seems totally logical they should? Or am I getting mixed up with another unit? Did the Audi 4.2 V8 go 5-valve?
I reckon Audi built that engine as they had a load of old small block water pumps from Polos and Golfs lying in a shed. And obviously someone got the number wrong when ordering the valves too.
Indeed, and probably the thing which swung it was because everyone was upgrading Mk1s to 16v motors [], and hence using up all the small block breathers !
5 Cylinder Aluminium Block - 035 103 011 AM - €3500 from Audi Tradition. Photo's from the wrong side! Alan. Have you got a photo of the aluminium block from the water pump side?
Absolutely agree there Chris. Looks like that 25v block has dropped the IM shaft and gone for a water pump location similar to the 06X blocks. Presumably a chain driven oil pump in the sump too.
I cried, shook, drooled, and nearly fainted a small bit when I saw those pics Dave. You could have warned me. Ps, yes I quoted them all again.
Chris, Audi did do a 40v 4.2 AFAIK, the head a similar (probably the same as a 20v) Dan, the 25v could use the normal 5 cylinder pump whch mount on the front the crank, behind the front pulley. Dave, i have a look see what i have!
