Thread: S55 vs. S65
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      01-04-2014, 07:48 AM   #492
Sedan_Clan
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Quote:
Originally Posted by Boss330
Quote:
Originally Posted by Sedan_Clan View Post
I believe the S55 has ITB's too dude. That much hasn't changed.
The S55 doesn't even have a single throttle body...

Valvetronic takes care of the TB business on modern BMW engines. So, in effect every BMW engine with Valvetronic has what equals ITB, since air flow to each cylinder is controlled by the valve lift on each cylinder.

In fact, probably better than ITB since the intake valves only allow air flow when air flow is needed. On a ITB setup the TB is still open even though the cylinder is not drawing air in (like on the combustion or exhaust stroke).

And some DI engines today don't even have a throttle at all, they run like a diesel (but with a spark plug obviously) with only the amount of fuel injected regulating the power output.

Face palm @ myself. I totally forgot about Valetronic/DI.
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