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| Engine horsepower calculator, slant specific variables? https://www.slantsix.org/forum/viewtopic.php?t=66305 |
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| Author: | MazdaRX8/6 [ Sun Nov 21, 2021 9:34 am ] |
| Post subject: | Engine horsepower calculator, slant specific variables? |
I found this http://hpwizard.com/engine-horsepower-calculator.html What variables do I need to put in specific to the slant-outside of the obvious bore, stroke, etc? It gives a constant for volumetric flow rate of 364 that it allows you to change. |
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| Author: | MazdaRX8/6 [ Sun Nov 21, 2021 10:39 am ] |
| Post subject: | Re: Engine horsepower calculator, slant specific variables? |
The calculator uses 90% volumetric efficiency, which it allows you to change. |
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| Author: | Jase [ Sun Nov 21, 2021 11:16 am ] |
| Post subject: | Re: Engine horsepower calculator, slant specific variables? |
Quote: The calculator uses 90% volumetric efficiency, which it allows you to change.
I've not played with calculators, but understand they can be a bit optimistic. Useful for trends, but not real useful for reality.. Anyhow why not reverse engineer the numbers until you come up with what a stock slant puts out, and go from there... I'm quite sure 90% VE is a tad inflated for anything with two valves per cylinder.
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| Author: | MazdaRX8/6 [ Mon Nov 22, 2021 5:14 am ] |
| Post subject: | Re: Engine horsepower calculator, slant specific variables? |
I found this helpful. http://www.epi-eng.com/piston_engine_te ... ciency.htm The HP calculator uses a 14.7 air/fuel ratio as default. The article above stated that 12.6 was ideal for HP. With 85% VE, 12.6 air/fuel, and 6000 RPM, I get 241 lb/ft and 271 HP. Reasonable? I am planning on building a long rod engine with 2.2 turbo pistons and Molner rods. |
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| Author: | Dart270 [ Mon Nov 22, 2021 7:26 am ] |
| Post subject: | Re: Engine horsepower calculator, slant specific variables? |
That HP level naturally aspirated (on pump premium gas) requires a very well ported head, 10+:1 compression and a big cam...and careful tuning. Calculators might be fun, but I would wager that using the experience on this site will prove way more useful. If you want that kind of HP (or a bit more), it is easier to use a mildly ported head, 9:1 or less compression, and 5-7 PSI of boost. No fancy internals needed, just stock pistons, rods, etc. Having port EFI makes tuning a turbo or supercharger pretty simple. Lou |
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| Author: | Rick Covalt [ Mon Nov 22, 2021 2:07 pm ] |
| Post subject: | Re: Engine horsepower calculator, slant specific variables? |
I know nothing about calculators, other than they give you a number!  270 HP from any Slant 6 is a very strong engine.I just punched in my 12.80 ET in my 2775# race car and only get 267 HP. That is with a Jeffrey head, .566 lift cam, 11.5 CR and 3 Webers. Just some real world info. |
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| Author: | MazdaRX8/6 [ Mon Nov 22, 2021 7:17 pm ] |
| Post subject: | Re: Engine horsepower calculator, slant specific variables? |
Thanks guys. I don't want the complexity of a turbo. I don't really need the power. I plan on having my head professionally done. I hope to get 230 HP and 6,000 RPM. I've been trying to find 7.005 rods for a cast crank. |
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