First a disclaimer. I am still learning on nitrous, I'm far from an expert, so anything I say is just my opinion, so use common sense. I had an old plate system on the shelf, and tried it on the manifold on the bench. When I triggered the nitrous, the distribution was terrible. Cyls 1&6 got a lot, 3&4 got very little, 2&5 were in between. By rotating the plate 90* 1&6 got very little, 3&4 got a lot, and 2&5 stayed about the same. I feel a cross bar plate would have cured the problem, but felt the port system was more tunable. Also the fogger system was only about $100 more than having the plate system built and flowed.
You are correct about the cooling effect, it increases the air density, which means more oxygen. The nitrous carries is own oxygen, so I can inject more oxygen than the engine can handle. My injectors spray at the port. As a side note, I have noticed some engines with a lot of spray, have cracked heads and/or valves. I wonder if this could be caused by thermal shock from the nitrous in the combustion chamber. If that is the case, it might help to move the nitrous injectors further up the intake manifold away from the valve. Just a thought, haven't gotten that far yet. Up to now I have had no failures. However I run the "Slant Six Racing News" racing series, Since I am still playing, I did not use the nitrous during competition. I have just used it during time trials and test and tune sessions. Sorry to be so long, but wanted to answer as completely as possible. Any other questions, just ask.
P.S. here is a link to pics of my other engine
http://www.1962to1965mopar.ornocar.com/schmid.html ------------------
Charlie
65 Valiant 170 /6 turbo
66 Cuda 170 /6 Nitroused
[This message has been edited by Charrlie_S (edited 01-02-2002).]