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Your candidness about this is very refreshing......... 

This is quite a subject and not one which is discussed or considered very often.

Going to extreme tunes people forget that high hp engines tend to be knarly beasts and even with today's ECUs can have real characters which are not particularly pleasant for a daily driver.

Some examples I have experienced.... My Ruf CTR (Yellowbird) - an awesome machine in many respects but the combination of engine lumpyness, exhaust frequencies and a constant "pulsing" made it a no no for anything but one off "fun" drives.

A pal had a real 600hp single turbo engine built and tuned on the Judd engine dyno so it was pukka power. When we met up at the airstrip my RS engine with 600hp was relatively purring like a limo engine and this pal's was hunting and spitting, I remember then it striking me how smooth mine was and that this issue was alive and kicking.

Someone posted on 6 speed about hearing the 231mph EVO engine and it sounding like a cement mixer (or something similar) - of course all the egos took over and this was buried but I would guess that a 3.6/3.8 turbo engine to be that powerful must have uber radical cam timing and exhaust solutions which by their nature would make the engine a complet beast and not dd friendly in the least..

During my last 3.8 build on the 993tt RS said they were planning to use an development of the racing EVO camshaft and specifically pointed out to me that it would change the character of the engine and it may be jerky as one slowed to a halt in gear.... As it turned out it did change the character but it was still tuned to be perfectly acceptable as a dd. My 993tt went from standard cams to 3.8RS (hydraulic) cams to these EVO cams and the character changed noticably each time and it is only really noticable if you got in a stock car back to back, it felt so smooth.....

So back to your ECU tune - I don't have much knowledge of what they do to these modern ECUs but I would guess they play with the variocam which probably has a similar effect as a cam change, this combined with exhaust, then all the other more aggressive parameter changes has obviously caused what you have - It sounds like you are a little unlucky with your combinations of components causing this as there must be many others with this ECU which don't have the problem....

I will make a note to ask RS (when I see them later this month) if they specifically think about this when they sign off a tune ?


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2009 997 GT2 RS Tuning 542PS/736NM