Calculating A/Rs on turbo
#1
Calculating A/Rs on turbo
Id really like to know the A/Rs on my Mitsubishi turbo (TD-07 25A) used on my Panspeed turbo kit. If this is possible to do just from the measurements, and anyone knows how and wouldnt mind, Id appreciate it. Id just like to know what to expect from this. Here are the measurements I took:
Compressor Inlet: 66.5mm
Compressor Outlet: 54mm
Exhaust Outlet: 73mm
Thanks alot.
Compressor Inlet: 66.5mm
Compressor Outlet: 54mm
Exhaust Outlet: 73mm
Thanks alot.
#3
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My guess is it's the ratio of input area (rectangle circumscribed by two fins, housing, and turbine base) divided by exit area, to give compression ratio. It may be hard to do if the fins are curved on the inlet. That would require cutting.
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The "A" in an A/R ratio is the cross-sectional area of the smallest intake passage in the turbine housing before the passage spreads around the circumferential volute that leads to the turbine wheel. The "R" in the ratio is the distance from the center of the "A" to the center of the turbine wheel. The MHI "6cm2" designation is just the "A" in the A/R ratio, that is, it is just the cross-sectional area. Like A/R, the smaller the size of the "cm2" number, the faster the exhaust gases will discharge onto the turbine wheel, and so the faster the spool up will be (less "lag"). The size of the "cm2" number or the A/R ratio also determines the amount of exhaust gas backpressure and, thus, reversion into the combustion chamber. A larger "cm2" number (or larger A/R) means less backpressure at high exhaust flow. Extreme Turbo says that the TD05H-7cm2 housing is equivalent to a 0.50 A/R. I would guess the TD04-6cm2 would be equivalent to an A/R of close to or a little less than 0.50.
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#8
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The thing is, A/R is very relative, the stock TII turbo is a 1.00 (S5) or very close too, but I think we can all agree a turbo with a Ptrim exhaust wheel and a .96 A/R will flow a WHOLE lot more. Since you have a TD07H exhaust wheel it'll be very hard to compare with Garrett turbo A/R because since its a ratio even though 2 numbers may be the same they describe a very different situation.
#11
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Originally Posted by Rxmfn7
Yea, I was trying to get a idea of size to compare to Garret A/Rs, being they are more common and would give me a good idea of what to expect, I guess I didnt think it would be that difficult.
#12
Thanks Evil, guess Ill just have to try it out and see what it does.I thought that by finding the A/R I could at least have an idea of what turbo it would be comparable to, being very few people use the Mitsu turbos, and I could judge from a similar garret setup, but I see now that it doesnt really work that way.
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Originally Posted by Rxmfn7
Thanks Evil, guess Ill just have to try it out and see what it does.