Rice's Performance Acceleration and Boost Controller
Leslie F. Rice's Performance Porsches has developed a vastly improve fuel enrichment system that not only improves the quantity of the fuel injected into all six cylinders, but the up-graded control pressure regulator increases fuel flow as quickly as the accelerator pedal is pushed down.
The 1975-77 3.0 Turbo system enriched fuel during acceleration, but not on boost!
The 1978-94 3.3 & 3.6 Turbos enriched fuel only above a boost pressure of .5 bar!
Add-on enrichment systems use a single fuel nozzle to spray a stream into the throttle area with an uneven distribution going to each cylinder. There is a good electronic system that enriches the fuel volume, but this system only enriches the fuel mixture after boost pressure has already built up.
The Porsche Turbo engine needed a much greater volume of fuel instantly, to increase throttle response and deliver more power, and that is why I developed the Rice's Performance Acceleration and Boost Controller (RPA&BECPR)
The basic operation functions for starting, cold to warm up, cruise, deceleration, and emission control are exactly the same as the original unit.
Installation is the same as the original Control Pressure Regulator, with the addtion of a small fuel pressure damper, clamp, vacuum hose, "T' fitting, and an additional fuel hose to the new RPA&BECPR.
The principal of the original control pressure regulator is to maintain "warm control pressure" after the warm up cycle is completed. Only as boost pressure builds to 0.5 bars and above does additional fuel flow in the engine, about a 15-16% increase. The R.P.A.&B maintains warm control pressure by manifold vacuum and as the throttle is opended and manifold pressure drops (vacuum decrease) the fuel flow is immediately increased. This increase in fuel flow at first application of throttle instantly injects more fuel, (nearly 30% more) into the combustion chamber for more power. A hotter and greater volume of combustion gas forces the turbine to spin sooner and faster, thus the turbo response is quicker and comes on with a most noticeable "kick in the seat of the pants."
During driving tests using a Split second light emitting diode air/fuel ratio monitor sensed by an O2 sensor located at the inlet to the turbo, I observed that while cruising, an A/FR (air/fuel ratio) of 14:1 to 14.7:1 was maintained (yellow LED'S). With slight acceleration the A/FR jumped to 13.2:1 (1st blue LED). During full throttle, off the line from idle, the LED instantly jumped into the 2nd blue with a 12.5:1 A/FR and stayed there up to 1.0 bar+ @6500rpm.
Compare to the stock warm up regulator, that would get into the 12.5:1 ration for an instant, then the led would slowly drop down to the green-yellow LED's, 14.2:1 to 14.6:1 A/FR. This was with a relative rich C.O. setting that had the engine idling so rich it would almost stall when accelerating the engine from idle to high rpm and back to idle. Porsche service technician like to "fatten-up" the A/FR by setting the C.O. to 3% or higher. This has been the normal practice to allow enough fuel to give the Turbo decent response during acceleration.
Now you can set the A/FR to factory emission specifications and know you will have more than enough fuel for maximum throttle response, torque, and power at maximum boost.
When the Turbo Porsche is modified most builders forget fuel enrichment! It is thought that with improving the airflow throughout the engine that more fuel will automatically flow with the increased air volume. It does not. This is why Turbo pistons, cylinders, and heads start to melt when a stock engine increases boost pressure, beyond 1.0 bar boost. Even stock 911 Turbos notice a dramatic increase in power and throttle response with Rice's Peformance Acceleration and Boost Controller.
To contact Lee Rice please call 714/539-1042 or Email Riceturbos@aol.com
If you have any questions or want to talk Turbo, please contact me dtdvo@yahoo.com