The Audi 4000q sedan is a great handling dependable car with what many describe as a bullet proof drivetrain. It was built around the same floorpan as the famous Ur-Quattro or Turbo Quattro Coupe (TQC) and in fact used the same transmission. It is capable of handling many a mountain road and the torquey 5 cylinder engine allows for effortless city driving. It is, however, not up to the task of propelling the car in the same manner as an Ur-Quattro or a Sport Quattro. Since all the mayor components are there (the quattro drivetrain, the 4-wheel independent suspension) many a quattro fan has asked himself if the TQC engine could be transplanted into the 4kq and make it a 4000tq with all the performance potential of the Ur-Quattro and the q-ship sleeper quality only obtainable with the understated sedan silhouette.
Whenever these individuals would inquire about this possibility, they would be told that it was impossible, or so difficult that it was not even worth the work and expense. This transplant, although not for the person whose idea of a toolbox is a couple of screwdrivers and a hammer, is not nearly as difficult as some may have you believe. In fact, with the right parts it can be done in a weekend! If a very thorough approach is taken, it may take up to two months. The key to a successful turbo engine transplant is planning.
By far, the easiest thing to do is to find a donor TQC and simply transplant everything. It's almost a direct bolt up job. Unfortunately, TQC's are very rare and hard to find. TQC parts can also be a bit more pricier. Also, the engine management on the TQC, although state of the art in its creation in the very early eighties, is somewhat unrefined by modern standards. The not so easy solution, but still a very viable one, is to use the engine off a 5000 turbo or 200 engine. It has an updated engine management system, plus there are tons of spare parts for the big Audis. The following section will present the different issues that have to be addressed when doing the conversion.