RobC

Can your tuner provide plots of stock vs tuned on the same graph? This will be tons more useful than a stand-alone graph of the tuned output.

722maa

here you go

DeerHunter

That's a huge increase in area under the curve. Interesting that the coast-down numbers are difference pre/post-tune.

I don't suppose they datalogged boost levels, did they?

RobC

Eye-balling the chart, the stock numbers are:
440 HP and 413 lb ft.

The tuned numbers are:
~500 HP and ~516 lb ft

for a gain of +60HP and +100 lb-ft for a simple tune.

These gains are really close the gains from the B5S4 with a tune FWIW (absolute numbers, not percentage).

DeerHunter

Other observations:

• The stock torque curve is flat until 5,400 rpm, after which it tapers gradually
• The modified curve drops quite sharply after 4,750, indicating that the stock turbos are reaching their flow limit

I'm going to predict that replacement turbos are going to be the next hot mod (if the DSG limits aren't reached beforehand).

RobC

It depends how it was tuned. If the software is looking for maximum boost all the way to redline, then yes your observation would be correct. It's also possible that the tuner was being conservative and reduced the boost at the top end.

The only way to find out would be to log the requested vs actual boost -- things that will be disseminated in time....

RobC

Thanks. Do you have the same graph vs RPM that you can share?

DeerHunter

If he doesn't have one, do what I did and divide 6,290 by 244.1, then multiply that dividend (25.77) by the speed on the graph. Clunky, but you can get the key rpm points that way.

722maa

507 hp because the k&n filter I have is useless in my country, cause its always hot here and the filter has no cover, so the engine is always breathing hot air, once I put my stock filter back I'll be doing 540-550 hp, I took it back today and he told me he might take it all the way up t 600+ hp, they tuned an s8 to 950hp.. That's just insane, makes me wish just a tiny little bit the s6 came with the 8-speed tiptronic..

Other than that, the car performed extremely well, 0-100km/h was as fast if not faster than stock acceleration with launch control, mid range is excellent, just put your foot down and the car just thrusts forward reaching the horizon faster than you may think, it's more efficient too, 4 cylinder mode is always on when I'm not flooring it, and yeah that's pretty much it. When I get it back today ill update you guys.

RobC

Hard to believe stock S8 turbos have enough headroom to flow the amount of air to get this kind of power. But hey, it's cool that someone's willing to play around to find the weak links .