B6 S4 (already remapped) up to 400 BHP...

[BillTheButcher]

My B6 S4 is currently running about 370 BHP with catback, high-flow cats and remap.

I'm very happy with it but I've been wondering what it would take (or if it's even possible) to get it up to 400 BHP? I don't want to de-cat, go FI or sacrifice the reliability of the engine.

:thumbsup:

 

[aragorn]

The basic premise is you need to get the air in faster, and out faster.

So your looking at things like ported and flowed cylinder heads, bigger valves, different camshafts, individual throttle bodies etc.

You'd also want to fit a decent exhaust manifold, with properly designed tubular runners.

400hp isnt going to be particularly hard to achieve, decent exhaust (ie including the manifold) and some cams will likely see you there, but its not going to be cheap, because tuning N/A engines never is, plus the parts will all probably have to be custom made, as unlike something like a Ford Zetec or Vauxhall XE, theres probably very little in the way of real tuning parts off the shelf for these engines.

Once you go much past that point, you start needing to equip the engine to rev higher, as a general result of tuning a N/A engine is the power moves up the revs. This is why highly tuned factory motors like the honda vtecs (and the audi RS4 engine) rev to over 8k in standard trim.

 

[BillTheButcher]

Thanks a lot.

Sounds like it's going to need a fair amount of money to get it much higher without going FI.