Okay, we have movement, finally!
We now have a baseline flow chart for the UCE head with standard valves in it, just like is in all your bikes. That's the good news.
The bad news is that it flows pretty much exactly like the Iron Barrel head does, except the UCE has smaller valves.
Basically, the flow differences could almost be considered small enough to call it about the same as the stock Iron Barrel head in terms of actual supply to the engine. There are some design differences, but the outcome is about the same, which we suspected. Some notable observations are that the UCE head definitely flows better at the very low valve lifts, but not quite as good at .300" lift, which is about the lift height for both stock engines on the intake.
For reference purposes, the Iron Barrel max flow at .300" lift is 143 cfm, and the UCE max flow in the same conditions is 136 cfm. Pretty close. The flow at just .050" valve lift, just as it's opening up, is 28.7 cfm for the stock Iron Barrel, and 35 cfm for the UCE, which is a good bit better(percentage-wise) at the lowest lift. But not much flow takes place at such a low lift, so it isn't really giving it much of a boost there, but every little bit helps some.
In terms of average flow over the entire lift range, the stock UCE flows 94 cfm average, and the stock Iron Barrel flows 92.1 cfm average. For all intents and purposes, a virtual tie.
So, the next step was to make a try at improving what was already there, with the same valves and lifts. This yielded some improvement of about 17% in max flow. Now, the intake flows 159 cfm at .300" lift. Average flow goes up a couple of percent. This is still not great. But it's better. And if somebody wanted just that alone, we could give them that right now.
There are some issues with the port bowl shape which need to be addressed to get better flow. I will be discussing this with them tonight.
The goals that I have in mind are to get the UCE intake flowing as close to the Fireball head as I can. And I want to treat the UCE exhaust as its own special case, because it has some potential to get some exhaust results that we just couldn't get with the large exhaust port in the Fireball.
The Fireball head flows 182.4 cfm at .300" lift. I'm using .300" lift as the reference height because that's what the UCE intake valve lift is with the stock system. To increase lift higher would mean cams or rockers, and possibly a piston to match, so that there is clearance on the piston for the increased valve lift at TDC. I plan to seriously try to get into doing that too, but this initial discussion is comparing things to the stock arrangement. With higher lift, we could substantially increase the max flow AND the average flow, so we'd like to go there to the extent that it is feasible to do.
So, we have a basic initial look at what we have to work with, and how it compares against a stock Iron Barrel head, and a goal of trying to come as close to the Fireball head as we can.
The heads are fairly similar in layout, and a lot of the things we do with the Fireball can work on these UCE heads.