Pushing the limits of an I5...

JShadzi at aol.com JShadzi at aol.com
Sun Jul 8 18:29:49 EDT 2001

As some have alluded to, the real weakness in the Audi motors is not the 
motor itself, but the fueling and management of it.  Running any Audi CIS, 
you are pushing it with anything above 250hp, granted, some may say they blew 
a piston at 250hp, but again, most likely a function of poor fueling causing 
excessive detonation, same goes for the headbolts, with proper fueling/timing 
and lack of detonation, the headbolts should not have have too many problems 
either.  Headbolts will stretch easily, however, under detonation when 
cylinder pressures can rocket to over 1500psi.

IME building an engine for my own car, and running a stock MC managed by a 
20v Motronic system for 3 seasons in NASA Unlimited, the practical/functional 
limit for any Audi motor (they are all basically the same) is 400hp with 
proper management, and not more than 7k RPM for the 2v, and 8500 RPM for the 
4v.  None of these motors are designed for high RPM per se, the factory went 
to great lengths to allow the 2v TA motors to rev to 8k, and the IMSA cars 
did not rev over 10k, again with extensive modifications and compromises that 
would be unacceptable for the street.

Basically, don't worry too much about the mechanicals, you will need to 
invest 10x the energy into the management vs engine to create a high hp car, 
see what I have tried to do with esentially a stock motor below, currently I 
estimate 300hp and am limited by injector size...

Javad Shadzi

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