PetriK more or less caused me to have an interest in better understanding what Suzuki had in mind when they designed the 1300. I created an EAP file for the 1300 using all the stock data I could get my hands on and ran a number of simulations.
Then I focused upon intake tract length as this has been a subject of much discussion. The port itself has a length of 4.7" and the balance of the runner, including short stacks, is around 5.6" which makes for a total of 10.3". To eliminate some of the acoustical effects introduced by the radius of the stack, a friend suggested reducing the runner length .5"............making the stock effective runner length 5.1".
After playing with it a bit longer, it became immediately apparent that the broader the RPM range under consideration the more the engine will like longer runners; conversely, the more you focus upon higher RPM's the more the engine will favor shorter runners. EAP allows you to filter simulations using any number of engine performance parameters and I used average horsepower........not peak. Peak will always favor shorter runners.
The image below is pretty self explanatory and seems to support the thesis that
Suzuki wanted to optimize average horsepower over a fairly broad range when designing the Hayabusa. The "chains" shown below are ranked according to average horspower over the indicated RPM range.
I must say I'm impressed with ability of EAP to pinpoint the length of the runner and anticipate the location of peak power. Based upon this exercise, PetriK should be able to realize gains from 8800 RPM and up.
Don't get to hung up on the power estimate themselves as they are crank numbers and reflect some other items, including fuel, that would inflate stock/factory results.
