Date:         Tue, 26 Oct 1999 12:31:14 -0700
Reply-To:     AL_KNOLL@HP-ROSEVILLE-OM2.OM.HP.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Al Knoll <AL_KNOLL@HP-ROSEVILLE-OM2.OM.HP.COM>
Subject:      Swirl, Cosworth, ACB Lotus etc.
In-Reply-To:  <199910261802.OAA03131@atlrel1.hp.com>

Item Subject: cc:Mail Text

     About these turbulators...

     Cosworth and Lotus and Jaguar long ago realized that full mixing of
     the fuel vapor is very advantageous.  The FORD 105E based Lotus 1.6l
     used these principles.  The BRM F2 motor also 105E based did too.

     Unfortunately the swirl effect works best IN the chamber.  Hence the
     Jaguar design and Chapman's implementation through Cosworth in Lotus
     development.  Swirl before the intake valve is modulated by the valve
     and less effective the farther away it is from the valve seat.

     Revaporization grooving to allow liquid fuel deposited on the
     relatively cool intake walls also help but NOT for FI motors.

     After the airvane and a very loong way from the intake valve greatly
     diminishes the effect.

     The devices are turbulators and designed to make a more turbulent
     airflow so that mixing is enhanced.  Obviously for port timed FI or
     pee on the valve head FI it is of little demonstrated advantage.

     But, hey, if it pings your dongle and you like it, do it.

     I always noticed that Bessie ran much better after she was washed.

     Al