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Re: Inlet Manifold Design
Posted: Wed Apr 19, 2017 5:26 pm
by Duk
Dual length manifolds so seem more common on engines with fixed camshaft timing.
But Toyota did use interlinked dual plenum chambers on some of its 6 cylinder engines, both straight 6 and V6 without any form of variable cam timing. And there was that Nissan engine I posted a pic at the very beginning of the thread.
Re: Inlet Manifold Design
Posted: Thu Apr 20, 2017 12:52 pm
by Murray
Yeah I still have a weakness for the first Ford Taurus SHO engine engineered by Yamaha.
I had an 89 and it was an early application of variable length intake runners.Worked extremely well.Don't believe there was any camshaft timing trickery involved.
Re: Inlet Manifold Design
Posted: Fri Apr 21, 2017 7:22 pm
by Duk
It seems like the Porsche Varioram is probably the most devoted variable harmonics inlet manifold. It uses 3 different stages of dual length and divided plenum chambers. Long runners/divided plenums, short runners/divided plenums and short runners joined plenums.
Re: Inlet Manifold Design
Posted: Fri Apr 21, 2017 11:46 pm
by 105gta.
The 360 Fezza works the same. Dependent on revs and throttle position.
Re: Inlet Manifold Design
Posted: Sat Apr 22, 2017 8:28 pm
by Duk
The Ferrari F360 manifolds only have 2 different states not 3 like the Porsche system.
Re: Inlet Manifold Design
Posted: Sun Apr 23, 2017 12:31 am
by 105gta.
The 360 has long runners, short runners and a valve between the two plenums that either joins the Two to make 1 large plenum or when closed keeps them separated.