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Location:
Brisbane
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Thu, 02 October 2003 11:58
 
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| Mr 20Valve wrote on Thu, 02 October 2003 16:41 |
so it wont damage the s/c too quickly (or blow my inlet manifold off the side of the head) if i leave the s/c constantly engaged?
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These superchargers aren't designed to run constantly so you'd have to expect a shortened lifespan. I don't know how much shorter though - this is only what I've heard. Having said that, I can't think of any simple way to disengage the supercharger since you're running fuel through it, not just air. I guess this is a compromise you'll have to make if you want to do it cheap and dodgy!
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also, how do i determine how much boost the supercharger is putting out? (the lower the better, i figure) is there some equation for working out boost pressure in relation to crank pulley size etc ???
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Both the supercharger and the engine are positive displacement pumps, so if you assume 100% volumetric efficiency for both it's pretty easy to determine the pulley ratio for a given boost pressure. Of course neither of them are 100% efficient so this is only a rough guide, but it's a good starting point.
Anyway, the SC12 pumps 1.2 litres of air per revolution. The 3T consumes 1.8 litres of air per 4-stroke cycle (2 revolutions), or 0.9 litres per revolution. So if you wanted to cram twice as much air down the 3T's throat (1 bar boost), you have to gear the blower so it pumps 1.8 litres of air per revolution of the crank. That's 1.5 times the displacement of the SC12, so you have to overdrive the blower 150%. Simple!
Of course these are very rough measurements, and actual boost is determined by many variables - adiabatic efficiency, thermal efficiency, inlet restrictions, cam timing, etc. I might add that 1 bar boost is way more than you should be aiming for if you want the engine to last more than 10 minutes!
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| | Subject | Poster | Date |
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Supercharging a carby 3T-C
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Mr 20Valve | Thu, 02 October 2003 01:53 |
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Re: Supercharging a carby 3T-C
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roger | Thu, 02 October 2003 02:03 |
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Re: Supercharging a carby 3T-C
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Norbie | Thu, 02 October 2003 02:26 |
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Re: Supercharging a carby 3T-C
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roger | Thu, 02 October 2003 23:56 |
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Re: Supercharging a carby 3T-C
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Mr 20Valve | Thu, 02 October 2003 04:12 |
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Re: Supercharging a carby 3T-C
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Norbie | Thu, 02 October 2003 04:23 |
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Re: Supercharging a carby 3T-C
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Mr 20Valve | Thu, 02 October 2003 05:27 |
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Re: Supercharging a carby 3T-C
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Mr 20Valve | Thu, 02 October 2003 05:31 |
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Re: Supercharging a carby 3T-C
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Norbie | Thu, 02 October 2003 06:11 |
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Re: Supercharging a carby 3T-C
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Mr 20Valve | Thu, 02 October 2003 06:41 |
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Re: Supercharging a carby 3T-C
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Classique71 | Thu, 02 October 2003 08:32 |
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Re: Supercharging a carby 3T-C
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Norbie | Thu, 02 October 2003 11:58 |
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Re: Supercharging a carby 3T-C
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Norbie | Fri, 03 October 2003 00:05 |
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Re: Supercharging a carby 3T-C
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Mr 20Valve | Fri, 03 October 2003 01:44 |
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Re: Supercharging a carby 3T-C
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Norbie | Fri, 03 October 2003 01:52 |
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Re: Supercharging a carby 3T-C
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Mr 20Valve | Fri, 03 October 2003 02:57 |
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Re: Supercharging a carby 3T-C
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Norbie | Fri, 03 October 2003 06:36 |
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Re: Supercharging a carby 3T-C
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roger | Fri, 03 October 2003 06:50 |
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Re: Supercharging a carby 3T-C
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raw_2t_power | Fri, 03 October 2003 09:20 |
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Re: Supercharging a carby 3T-C
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Mr 20Valve | Sun, 05 October 2003 22:55 |
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Re: Supercharging a carby 3T-C
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roger | Sun, 05 October 2003 23:53 |
