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Quote </td></tr><tr><td id="QUOTE">Well, you forgot to put the efficiency in the equation I got 254 and used .85 efficiency and 7000 rpm.
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I used .85 for the VE and an rpm of 6500...the rpm was the difference. I forgot the KA24DE has a rev limit at 6900...sorry.
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Quote </td></tr><tr><td id="QUOTE">Well, i just got my book back and went into reading. It said that if i'm not running the i/c, my compressor efficiency got to be above 60%. With the t3 "60" i'm gonna be in the 70% area, so i guess i'm fine. From what i calculated at 70% efficiency i'll be providing air of about 165*F to the intake manifold at 4 psi. Is that fine/reasonable?
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That doesn't sound too bad. But why not just get a Starion IC or something? If you're having piping made, plumbing that in won't be that hard. Or get an SMIC from someone with an SR (like me <img src="#/f/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt='
'> ).
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Quote </td></tr><tr><td id="QUOTE">Now i've gone back to calculate where will i hit full boost. I assumed about 3000rpm and it came out that i will need 107CFM (7.38lbs/min) of flow. Plotting that against the graph - still in the 70% area. So i guess i'm set. I'll be out of the 70% efficiency area only at 14lbs/min => 203CFM => ~5653RPM. And thats about 100-200 rpm after most people shift.
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Sounds like you've got a nice match there.
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Quote </td></tr><tr><td id="QUOTE">Also, what does the lower bound of the compressor map mean. Suppose, i run like 2psi of boost - 1.13 ratio. That is below the compressor map completely. What will happen? Will the turbo just never spin up to produce any valuable boost?</td></tr></table><span id='postcolor'>
I'm not sure about that. You're probably right that it would never make boost. Check out this website:
turbo site <img src="#/f/iB_html/non-cgi/emoticons/crazy.gif" border="0" valign="absmiddle" alt=':crazy:'> <img src="#/f/iB_html/non-cgi/emoticons/crazy.gif" border="0" valign="absmiddle" alt=':crazy:'>
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Quote </td></tr><tr><td id="QUOTE">Also, the numbers on the compressor maps (t3 "60" in this case) - like 56,400 , 78,800 etc - are these the rpms of the turbo? If so, that means that the turbo won't be boosting till it spools to 56400 right?
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Yes, those are impeller rpm numbers. I would assume that until it reaches this point, you will not build boost. But, again, not sure...
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Quote </td></tr><tr><td id="QUOTE">Another question - the compressor efficiency means (ideal temp rise)/(actual temp rise). Suppose now the pressure ratio of 1.6 on a t3 "60" compressor map. How come the tempreture while flowing 7lbs/min is hotter than when flowing 15CFM when the turbo is supposed to spin faster. How does this work?
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Well, if you just take a quick look at the map, you'll see that this is outside the prime efficiency range of this turbo. It's create unnecessary backpressure and not working where it wants to work. Sort of like that unhappy sound your engine makes when you lug it in 5th at 1500rpm. <img src="#/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt='
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Quote </td></tr><tr><td id="QUOTE">Finally, what does the trim stand for? Like what is "60" trim? Is this the a/r ratio? Like .60 => "60" trim or something? If not, is there a way to determine trim from the a/r ratio?</td></tr></table><span id='postcolor'>
Trim is the ratio of the inducer to the exducer (small to big radius of the impeller). A/R relates to the area of the housing. Umm...I think. Don't quote me on that.
I'm still learning too.
Eric