Hp Calculator, boost, IC, water inj'n
http://not2fast.wryday.com/turbo/glo...rbo_calc.shtml
This program seems to be well done, and includes effects of water injection (Ken). Notes: 1) use 94mm bore and stroke, 4 cyl, for 1.3L rotary simulation. Argue someplace else. 2) use sfc of about .65 and a/f of 10:1 for starts, but these 2 variables are related. Running leaner makes more hp more efficiently, and the sfc must be increased to properly reflect the power increase. Best to just leave these alone, and vary other parameters. 3) 255 hp stock? 10:1 a/f .65 sfc 10 psi 21C ambient 75% compr eff 60% IC 6500 rpm 80% VE 1 psi IC drop |
Re: Hp Calculator, boost, IC, water inj'n
Originally posted by KevinK2 http://not2fast.wryday.com/turbo/glo...rbo_calc.shtmlThis program seems to be well done, and includes effects of water injection (Ken).Notes: 1) use 94mm bore and stroke, 4 cyl, for 1.3L rotary simulation. Argue someplace else. 2) use sfc of about .65 and a/f of 10:1 for starts, but these 2 variables are related. Running leaner makes more hp more efficiently, and the sfc must be increased to properly reflect the power increase. Best to just leave these alone, and vary other parameters. 3) 255 hp stock?10:1 a/f.65 sfc10 psi21C ambient75% compr eff60% IC6500 rpm80% VE1 psi IC drop Just what I was looking for. Ken |
Yup fantastic program. I use it often :)
Checks out with other formule & spread sheets I use. Infact I find it easier to use as its all rolled into one sheet (very handy). Still only as good as the data you have though ;) |
good site guys :D
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Thanks !
What bore and stroke should i use for a 12A ? Karis |
Re: Hp Calculator, boost, IC, water inj'n
Originally posted by KevinK2 1) use 94mm bore and stroke, 4 cyl, for 1.3L rotary simulation. Argue someplace else. |
Re: Re: Hp Calculator, boost, IC, water inj'n
Originally posted by Evil Aviator So you techno types have found that a rotary engine is comparable to a "square" piston engine as far as number-crunching is concerned? (Not an arguement, just a clarification which would also help answer the question above about the 12A). The calcs do not determine anything bare the displacement fromt he bore/stroke fields, the rest is info you need such as BSFC & Ve from either another source or testing of your own. |
Re: Re: Re: Hp Calculator, boost, IC, water inj'n
Originally posted by RICE RACING Its not applicable to the formula, just input in a number into the bore or the stroke field untill you get the 4 stroke equivalent displacement for your rotary engine of choice. The calcs do not determine anything bare the displacement fromt he bore/stroke fields, the rest is info you need such as BSFC & Ve from either another source or testing of your own. |
dumb question, in the calculation i can get like 200more hp by making the afr 1:1, but in real life it wouldnt even run that rich, what am i missing?
mike |
Originally posted by j9fd3s dumb question, in the calculation i can get like 200more hp by making the afr 1:1, but in real life it wouldnt even run that rich, what am i missing? mike There is probably no limit on the AFR so that the calculator works with any type of fuel (pump gas, race gas, methanol, nitro, etc.). Also, in reality the BSFC will change with changes in the AFR, rpm, load, and other conditions. |
Originally posted by Evil Aviator The program probably just computes the HP by dividing out the mass airflow by the AFR to calculate the fuel flow, and then multiplying by the BSFC. This is my personal lazy method with my sophisticated Windows calculator, lol. You can check this by seeing if a 10:1 AFR results in twice the horsepower of a 20:1 AFR with everything else remaining the same. There is probably no limit on the AFR so that the calculator works with any type of fuel (pump gas, race gas, methanol, nitro, etc.). Also, in reality the BSFC will change with changes in the AFR, rpm, load, and other conditions. mike |
I'm using the program to see the relative increases in power for things like cold air intake, better IC, water injection flow increases and where to inject water and water spray and electric fan on IC. In other words the colder the air intake the more power.
It's kinda of a calculator to see the effects of different mods for me. |
Originally posted by j9fd3s dumb question, in the calculation i can get like 200more hp by making the afr 1:1, but in real life it wouldnt even run that rich, what am i missing? mike These are the real life or factual data you will need to use that "part" of the program to be "realistic" ALL else can be used pretty well :D Good questions, and again bloody great program mate ;) |
Originally posted by j9fd3s dumb question, in the calculation i can get like 200more hp by making the afr 1:1, but in real life it wouldnt even run that rich, what am i missing? mike 2) use sfc of about .65 and a/f of 10:1 for starts, but these 2 variables are related. Running leaner makes more hp more efficiently, and the sfc must be X(increased)X to properly reflect the power increase. Best to just leave these alone, and vary other parameters. but I should have said "... sfc must be DECREASED to properly reflect the power increase. " (with leaner a/f input). |
Re: Re: Re: Re: Hp Calculator, boost, IC, water inj'n
Originally posted by Evil Aviator OK, I guess that website doesn't compensate for bore/stroke differences for a given displacement. However, some calculations do, because I have used such correction factors on aviation piston engine equations. However, it was over 10 years ago, and I can't remember exactly what was affected. I was just wondering how the rotary engine compared to the various bore/stroke ratio of piston engines in this respect. Knowing the eccentric shaft offset is only .59", and power cycles are 270 deg vs 180 deg for piston engine, I say a starting place for comparison is a 6 cyl 2.6L with 5.35" pistons, 1.18" stroke. More oversquare than an F1 engine. |
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