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      05-05-2009, 09:22 AM   #78
smdandb2
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Quote:
Originally Posted by Prince ///M View Post
If you want to go "semantic" turbos are part of the engine... and their failure can harm also parts of the block, exhaust intake and so on.
You specifically said the safe limits for the engine, not the turbos. Yes, a turbo failure COULD damage the engine, but at the same time it could simply turn into a smoke factory. The engines safe limits are unknown right now, and no stock compressor map is going to tell you where that is. A bad spark plug could damage the engine too, but there is no map for that. One day someone could make 800hp on a big single on the N54, we just don't know yet.

Quote:
BTW the calculations are quite similar to the one I posted...and I agree on the fact that over 13psi at 6500rpm are too much.

I think that calculations over 6500rpm are nonsense under the assuption we can realistically make (and this is the reason why I'm not considering boost to redline). Please consider that at 6500rpm DME starts to close throttle valve, so volumetric efficiency is hugely reduced, no matter the pressure ratio.
Its all assumptions at this point. You assume one way, I assume the other. Even at 6500rpm, its off the charts at a 90% VE. And a 90% VE is probably on the low side for the N54.

Quote:
P.S.
The sound in the video you posted if for sure abnormal... but for "level" not for "kind". The same noise is present (barely noticeable) on several stock cars at turbo spool on light throttle between 1500 and 2500 rpm.
Its bad, especially at that volume. There is no way that is acceptable.

Quote:
P.P.S.
Here on the board turbo failures are very, VERY rare... (maybe two in three years) and not always related to excessive boost.
Seems as if someone else has already chimed in there.

And as someone else said in another thread I was reading... what good would it be for anyone who has had any catastrophic failure to go reporting it here? Makes no sense at all.
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