Can somebody explain how the Dual Induction system works on the TL Type-S?

 

The dual induction system uses a principal called "Helmholz" resonance.

Both banks of opposing three cylinders share the intake plenum (it does NOT change total volume). At low speeds the IMRC (the infamous/famous actuator) leaves a double set of butterfly plates CLOSED to prevent pulses from opposite banks from inter-mingling. The area available to both banks is always the same... When 3800-4150 RPM is reached, the IMRC (actuator) opens the butterflies to allow all 6-cylinders to "share" the intake "plenum". This allows all 6 cylinders to "share" the pulses from all other cylinders,

So, at low speeds each bank of 3 cylinders only grabs air through separate paths, while at higher speeds both banks can get their air though either bank. (A picture would be nice – see the Helms manual…)

When a cylinder "gulps" down a "chunk" of air, it creates a pulse of air -- if a cleaver designer can design an intake to take advantage of the pulses to create a "supercharging" effect (or assist air flow), so much the better. One of the problems with a "static" design -- no dual intake, is that the speed/timing of the pulses changes with RPM, so what may be a good configuration at one set of speeds (low-rpm band) may not be the best for higher (or different/higher) rpms. Porsche has a system that actually uses three different modes!!!

 

Thanks for the explaination EricL. One more question...Is it worth it to install an AEM CAI on the Type-S? What kind of performance is achieved by adding a CAI?

 

You will get more noise at WOT (at full-throttle). The dynos from AEM are an average of a bunch of cars and show more than 10 PEAK/MAX HP.

The best that has been dyno'd over on the other forum is around 6-10 HP (for a CLS) with headers. The 6-10 HP is to the front wheels.

IMO -- you get more punch with the headers kicking in -- at 5-7K the thing screems like a race car (It does test to disturb marginal drivers).

A number of people report better gas mileage if they don't lead-foot the car...

 

You the man!!!! First explanation of the dual induction system I read that actually explains how it work's! I have read almost everything on the car (picking it up Thurday) and they all talked about it but didn't explain it like you, thanks!!