4AGE engine tuning discussion

[Morten]

NoHachi Wrote:Sorry Jamie, but you'll have to show me a dynosheet with boostnumbers before I believe those 200hp...0.5bar will net you stockhp*(1+boost)*15% efficiency loss..== 124*(1+0.5)*0.85 = maybe 160hp. And if not, I would be very interested to see the physics if that setup..increasing or consolidating VE with a turbo.

Where do you get the 15% efficiency loss from? I know the conventional idea is that with 0.5bar of boost you get 150% power of NA minus a bit since everyting is not optimal. However I have seen in real life engines beeing converted from NA to turbo that has gotten more than this (with a proper setup). I think one of the reasons is that no NA engine (at least in stock form) really sees the full vakuum. Already if, for example, you have 0.1bar pressure loss through airfilter-afm-throttle-inlet manifold in NA form, and then compare it to 0.5bar boost after putting on a turbo the difference grows, and teoretical new effect would be closer to: 1.5/0.9*124=206.7hp. I have not measured real loss on a stock 4AGE, but I don't think it wold be less than 0.1bar (1.5psi) when completely stock. Remember this is the same reason why you get most of the power difference when converting to ITB's, only magnified due to the boost.

Just my opinion. I am by no means an expert so please feel free to correct me.