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Okay, I'll try and put some of my spin on some of the subjects you mentioned.
>Did you get any Chance at
>looking at the formulas I
>was using to figure out
>our stock CFM versus our
>car pushing 6psi?
Yes, I did. I did say a couple of things about it there and it was a good discussion, so it's definitely worth talking about more now to gain a better understanding. This topic is especially helpful in understanding how much fuel do we really need for each corresponding turbo.
>
>In my own mind, flow should
>be the same running 6psi
>with either the 16g or
>the t04E/t3. The only difference
>seems to be how much
>our engines consume faster, ie
>knife edged crank, light weight
>pistons etc. But, all things
>being equal they should be
>the same, right?
I'm really going the other direction with this one. This is my thinking. Let's say you have a T-25, or a really small factory turbo. Then you want to upgrade to a bigger one such as the 16g. When you do that, it's highly recommended to upgrade your fuel pump, injectors, and do a fuel pump rewire. All of these things are asking for more fuel to compensate for the additional air flow(CFM's) which as a end result, of course, mean more fuel. That all means I think each different turbo requires a different fuel ratio. Now, I haven't seen a Super16g next to a T04/03(b) or (e), but I would at least think, if they are different in size at all, they would require different amounts of fuel ratio. This might sound like a lot of hard work in figuring out how much fuel ratio each turbo requires, but when you have an adjustable fuel pressure regulator, a fuel pressure guage, a/f meter, and MOST importantly, an EGT guage, you could tune your car to meet it's important fuel ratio.
Sure, HRC has done the work for some of us in telling us where we should set our fuel ratio for the Super 16g, but it is very clear, at least in my mind that the STAR turbos also need a turbo-specific fuel ratio.
>Another thing that might change you
>CFM would be turbine back
>pressure. As you have also
>probably read, smaller turbine wheels
>create more backpressure, thus lowering
>air flow through our engines.
>More backpressure means quicker spool
>up but also lower boost
>threshold. I think the 16g
>is a much better turbo
>for low end quick spool
>up. The t3/t4 seems to
>be more toard the top
>end.
>What do you think. am I
>making any sense?
Somewhat. I think perhaps that backpressure is an outdated term. Maybe, as many DSMers now use, is "exhaust gas velocity." With that, I think the Super 16g, as a presumably smaller turbo requires less of the exhaust gas velocity to turn the turbine wheel than does the bigger garrett turbos, thusly enabling a quicker spool. Same concept as turning a merry-go-round. If I'm turning a smaller one, it'll get going faster than a bigger one, in a shorter amount of time, applying the same amount of force. However, once that bigger merry-go-round gets moving, it has more inertial power eminating from it than the smaller one, until you get one so large that the constant force you are applying to it is not enough to extricate the maximum amoutn of inertial force. I think many of these same principles are somewhat applied from a reverse energy-saving concept like the lighter and smaller underdrive pulleys.
So that's my .02.
Jason
98' Eagle Talon ESi-T
Mitsu Super 16g Turbo(HRC)
http://springfielddsm.homestead.com/JasonsPics.html
_____________________________________
Jason ESi-T
04' BMW 325Ci
91' Nissan 240SX
98' Eagle Talon ESi (sold)
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