I've been working on an excel doc that does all the work for you. Pop in some info about your engine, desired boost level, etc and it calculates the rest.
It estimates power gains, fuel requirements, compressor density ratio, cfm, etc.
I'm pretty sure it's about as accurate as you can get by numbers alone.
Enjoy.
http://69.13.18.52/~jasen/turbocalc.xls
i got it but dont know what to do.....it could be cuz i dont a s/c or turbo but its cool to mess with the numbers
Looks cool. I'm curious to where you got some of your calculations from.
Otherwise I'm looking forward to testing your spreadsheet out.
<img src="http://www.j-body.org/registry/americanred/deplysig.gif">
i got a problem with intercooled hp not changing with compressor efficiency......
how are you calculating output energy, simply subtracting output enthalpy..... but if total energy input is enthalpy + pv, then, but ....
umm, where is the .238 coming from, shouldn´t that be a factor of efficiency....
i have a problem with any gain in temperature not from inefficiency
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my new favorite quote, up from franklin roosevelt's mistake/modification quote:
"Dan thanks for the entertainment... but I think someone is going to own you.... "
--CarbonFire (i think he's getting a little ticked over this one............)
'03 eco coupe
'02 z24 wheels
buzzwerdz are conjecture, mathematical certainty defines mechanical results.
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gotcha, compressors have a natural increase in temperature due to the pressurization at 100%, any inefficiency simply increases that output temp.
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my new favorite quote, up from franklin roosevelt's mistake/modification quote:
"Dan thanks for the entertainment... but I think someone is going to own you.... "
--CarbonFire (i think he's getting a little ticked over this one............)
'03 eco coupe
'02 z24 wheels
buzzwerdz are conjecture, mathematical certainty defines mechanical results.
---------------------------------------------------------------------------------------------------------------------
Yeap. All that effiency number does is add/subtract heat rise to the formula.
The 0.238 is a standard factor used to determine heat rise in a "perfect" setup. A standard way to determine heat rise under boost is with the formula:
intake temp X ((compressor pressure ration^0.238)+1)
Changing the IC efficiency will alter output a bit, but not a whole lot. There's not much of a difference between 70 and 80%.
Of course, it's all ballpark, because there's no way to take into account everything, like IC pipe lengths, heating/cooling due to other things, etc. It also assumes you have no power loss due to exhaust restrictions, weak spark, etc.
Actually, looking again, you were right. My intercooled temp rise calculation was based on ideal heat rise, not the actual heat rise. I just fixed it, thanks for the heads up.
Ummm, there's something wrong with the altitude/absolute air pressure calculation. Just cause I know I shouldn't make more hp at 10000ft than 500ft. Might want to check that out.
Jasen would you happen to know the values for a T3/T04E turbo? 60 trim 63 a/r stage 2 wheel
LE61T PTE6262 Powered 
BOOSTED QBE wrote:Jasen would you happen to know the values for a T3/T04E turbo? 60 trim 63 a/r stage 2 wheel
Good call, I totally forgot about that.
I've adjusted the final power outputs to take into account a 3% loss for every 1000 feet of altitude.
Updated version uploaded.
Sorry, quoted the wrong post. Previous post was directed at Ben.
Mr QBE... are you looking for a flow map for it or something? I found this:
If you plot your density up the left side, and your cfm across the bottom, where they meet in the chart is where you fall in the map. Where you'd want to be is in the center ring.
Oh, that map is in lbs/min instead of cfm. To convert cfm to lb/m just multiply it by .0765, which is the weight of air at 60 degrees F.
Very interesting. I have done a similar one but with less details.
Inclusive many time ago, I found one sheet done by a guy, that plot calculated boost curves (air flow / pressure ratio) in turbo compressor maps and have some fuel pump curves too.
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ELIOT. Now.....boosted.
Um.... since it's boosted application, I thought altitude do not affect the hp then.
Hey you might be right, but I know something was wrong with the first version cause it gave like 100 extra hp when I changed the altitude from 500 to 10000. I was just pluggin numbers in to see what effect they had, ya know.
firewolf23 wrote:Um.... since it's boosted application, I thought altitude do not affect the hp then.
Yes altitude affects it dramatically, reguardless if its N/A or FI
Just look at some of the stock SRT-4s that run 15s because they live in 10000ft altitude
Ben992200 wrote:Hey you might be right, but I know something was wrong with the first version cause it gave like 100 extra hp when I changed the altitude from 500 to 10000. I was just pluggin numbers in to see what effect they had, ya know.
It does. The higher you go the lower the ambient air pressure. I've forgotten now, whether boost is measured on a static scale (I.E. 14.7 + boost pressure) or a sliding scale (current air pressure + boost pressure), but either way there will be an effect.
If it's measured statically, you can subtract .5 psi for every 1000 ft you go up. This is actually how the compressor pressure ratio is determined. (boost + 14.7)/(14.7 - altitude adjustment) = compressure pressure ratio
If it is measured on a sliding scale, meaning 6psi of boost is 6 psi of boost no matter how high you are, the thinner air will still have an effect as it affects the temperature rise, and also makes the turbo work harder to get that same 6psi.
cool, since I'm up at 5000 ft, I can run 7 psi without fuel upgrades since you guys are running 4 psi without them as what exploited racing sold his kits without intercooler.
