400hp with some creative coast down calculations, or 350hp measured properly on an industry standard bench tester.
...Unless a good, tfsi knowledgeable tuner tunes it to 400bhp. Then it will be 400bhp on the bench tester.
Would you put a tenner on that? I can guarantee an engine showing 400hp on a rolling road would not measure even close to that on VW's factory bench tester.
Fair play. Not going to disagree - just didnt know whether you were including claims of 400 by good tuners in the statement. So presumably your day in day out stage 2+ 350/350 (not pushed to the absolute limit) is actually nowhere near that either?
Also that statement leads to the assumption that the inaccuracy is exponential as you go up, as stock cars on the dyno make stock figures.
I just go by science and experience mate. It's not an attempt to discredit tuners. You can only do so much with the standard engine configuration.
To make a genuine 400hp at the standard rev limit, you would have to shove about 2.4-2.6 bar of boost into it from a KO4 sized turbo. A KO4 cannot make 2.6 bar for long without grenading itself. Even pushing it to the usual 1.8 - 2 bar Stage 2+ pressure levels, it's waaaaaaay out of it's efficiency zone and merely super heating the intercooler. Hence why even with an S3 intercooler, after 4 hard WOT pulls the timing starts getting backed off. It's not a crap intercooler, it's the turbo. It's too small.
A genuine 400hp might be achievable if you hogged out the head ports, ported the manifolds, fitted bigger valves, wilder cams and revved it to 8000rpm.....but even then, the more times you run it flat out, the power will start to reduce. And the balancer shafts will sh*t themselves.
Consistency is the name of the game, not an arbitrary peak number which is entirely questionable in the first place.
400hp with a big turbo, then absolutely. With a K04, no way.
Direct injection does have some power advantages, but not to THAT degree. Not even the Focus RS can comfortably do 400hp with it's 300cc bigger engine, and they are cracking blocks and blowing gaskets at standard power, let alone tuned, so you have to use common sense really. VW did not build 400hp worth of headroom into the EA113. There is zero financial incentive for them to over build and engine to that degree. I mean, look what they did to the BYD/S3 engine to run just 30-60hp more than the AXX. That's a lot of mechanical changes for a small increase.
350 is a sensible and realistic expectation from a KO4 with all the bolt ons running 2 bar peak, holding 1.5. You could potentially get a moment of greatness with a whopping great 2.2-2.3 bar 400lbft boost spike, but as you say, that amount of cylinder pressure can and does indeed smash people's pistons. Loads of evidence of that on the facebook group.