ran anther calc from performance specialties, it doesn't use as many variables as the calc's I have done. The formula I used was ((476 * 0.25 * 1300 * 2)/(7000 * 3)) - 1.4 = 13.3 inches don't really know who has the best idea here but there is quite a lot of variation another (www.exx.se) said either 46cm or 23 cm... ahh... yeah I have, and I recently bought the Nissan SAE article that the autospeed article was based off of too. It had some really good tech in it including a side by side comparison with different runner lengths. the article compares shorter runner lengths (36cm) compared to 48 cm which is what we ended up with. inlet efficiency peaked at 4,400 RPM with 36mm and 3600 RPM for 48. that's all well and good I just don't know how relevant that is after you change literally everything inside and outside the engine like I have. I did find one error in my inputs; runner area. 2.8"^2. average around the place seems to be 13-14" any more thoughts?
The JUN Bonneville Z32 was fitted with a manifold that you are attempting to design. Some pics towards the bottom of the page: http://forums.nicoclub.com/imsa-300zx-race-car-pictures-t197523.html http://s1317.photobucket.com/user/anti-engineered/media/jun 2_zpsauecq7ko.jpg.html
