Quote:
Originally Posted by FOMOGO
Bill, good things to hear.
I may be late to the game, but its nice to know I have still arrived at the right sport. 
I am very interested in the idea on more plenum volume. I need to get my hands on an intake manifold so I can look into joining the separate the existing plenums for greater volume and to allow each bank to draw from both throttle plates.
Jim |
Jim,
There is already provision for the two plenums to be cross linked by means of the induction control valve and the associated variable intake system.
I have previously suggested that experiments should be carried out with the valve held constantly open, or removed so as to increase the cross section of the interconnection, but as far as I know this has never been done.
The existing set up allows the frequency of incoming pressure to match RPM, thus assisting the filling cylinders, and improved breathing efficiency. The frequency depends on the cross-sectional area of the interconnection and an increase here will raise the point of assistance in respect of RPM.
Going by the data published in the manuals, it would appear that this would result in a reduction in efficiency around 3600 RPM. However the upwards curve would be constant, rather than peaking at this point, as is the result of the ECU controlled variable set up. Clearly there could be advantages in respect of a performance engine, where a cruising mode is not important.
Trevor.