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      01-05-2013, 08:12 PM   #54
Asbjorn
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Drives: Z4 N54 DCT (VTT GC lites)
Join Date: Mar 2012
Location: European in China

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Quote:
Originally Posted by jts1981 View Post
What I meant was that the power band, the way the engine makes power, is very "peaky" on the 35i. Which means that less then 6000 rpm the engine brings up power slowly and then peaks.

For the 35is the power comes quicker and flatter curve. you will feel more power sooner with the 35is.
I respectfully disagree. There is no way that the N54 with or without ESS produces anything other than a tonne of torque at relatively low RPMs. The differences from engine to engine will be no-where near the difference between American V8 and a Honda Civic. If we were comparing the N54 to the boxter or cayman engine I would agree with you much more.

Although the N54 was updated over the years, any differences will probably be within +/-5% on the same car, with the same fuel and on the same day. But there is no way to find out exactly of course.

Now, I will not be surprised if the 35is produces almost the same torque as ESS during overboost, but that is an entirely different discussion. If it does indeed produce ESS torque, but only at a certain lower rev range (to keep peak hp at 335 for whatever reason), then it would indeed produce a more peaky torque-curve like you said. But anyhow, the actual peak torque figure will not be higher than that of ESS at any RPM no-matter 35i or 35is. Remember the engines are essentially the same from a hardware point of view, and there is no way that ESS would lower the boost at any RPM.

AFAIK ESS stage 2 for 35i and ESS stage 1 for 35is are the same ECU flashes applied to the same hardware. Among other things, they increase the turbo pressure to the maximum that these totally identical fellows can run "safely".
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