RussB

I don't know the history of the 5cyl 10 valve head. Is there a reason why Audi didn't make its head a cross-flow design?

cuatrokoop

To re-vamp the 10v would have been cost-prehibative for an engine that by 1992, was being totally phased out of all VAG products. The 20v/20vt carried on until 1996/7 because it was much more modern and worth some minor retooling costs. Then emissions killed it I believe. The basic 5cyl architecture lives on in the Lambo Gallardo's V10. Bore, stroke, bore spacing, etc is all 5cyl stuff ;-) VW has a VR5 20v too, but it is totally different than the I5.

RussB

Thanks, Koop.

When did Audi first manufacture the I5 engine? What was the reason for it not being crossflow from the onset?

cuatrokoop

There was no need back in the '70's when it was designed and first manufactured. Also, take a look at the cross-flow heads and intake layouts. With the exception of the KW and AAN engines, all ended up with the airbox on the "hot" side of the engine bay, with hoses/pipes crossing over the EM and head to reach the throttle. They were trying to fit a lot of stuff in a relatively small place.

That is my take on it anyway.

rooster 2

I can remember it caused quite a stir in the automotive world upon introduction. Audi needed a larger displacement motor than what they had in the Audi 100s of the early 1970's to power the new larger 5000 model (type 43.) I seem to remember it was more a matter of engine bay space available, and existing engine tooling to produce the 5 cylinder in lieu of the 4 cylinder. Going to a 5 cylinder lay out was the easy way to gain additional cubic inches, horsepower, and smoothness. In those days, I wouldn't be surprised if Audi/VW 4 cylinder pistons, and valves were interchangeable with the Audi 5 cylinder motors.

For the record, Mercedes, introduced their 5 cylinder motor in diesel form (model 300D)in the mid 70's before Audi introduced their inline 5 in 1978. So it looks like Audi copied a page from Mercedes with 5 cylinder engine production.

Since the Audi 5 cylinder was derived from existing and older 4 cylinder engineering motor, Audi saved money, and did not redesign to create a cross flow head design. Again, existing manufacturing tooling could be cheaply modified to produce either 4 cylinder or 5 cylinder heads.

Performance was not a hot topic with Audi in 1978, so the car was not a high performance model. Quattro and turbo models performance started appearing by the mid 80's with the type 44, and that's when the cars became a lot more interesting and desirable............Rooster

5kcstq

Originally having the IM over the EM was good for the carburetion, I hear.

cuatrokoop

Carb'd 4cyl motors in the 1.5-2.0L range. They still made a carb'd engine all the way until I think 1995 or so?