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Re: BENCH RACING: 8-71 V.S. Procharger?
[Re: tilt]
#518099
11/09/09 07:38 PM
11/09/09 07:38 PM
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Joined: Jul 2005
Posts: 8,647
ELYRIA,OH
blownzoom440
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Joined: Jul 2005
Posts: 8,647
ELYRIA,OH
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no but i have a 3 step retarder in the box on the shelf.i put the timing at 30* to help the stock main caps live.
Last edited by METAL STORM; 11/09/09 08:23 PM.
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Re: BENCH RACING: 8-71 V.S. Procharger?
[Re: prochargedhemi]
#518101
11/11/09 06:52 PM
11/11/09 06:52 PM
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Joined: Jan 2005
Posts: 3,635
Oakland, MI
dizuster
master
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master
Joined: Jan 2005
Posts: 3,635
Oakland, MI
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Quote:
so you think that a roots style blower comes off idle with maximum boost? It’s the same concept a procharger uses, the faster it spins the more air that it passes which in turn creates more boost.
With a comment like that, you obviously have no idea how either of these blowers work.
They don't make boost the same way at all.
A roots blower is positive displacement, a procharger is not. That means the roots moves the same amount of air, per revolution, regardless of RPM. A 6-71 blower was originally built for a 6 cylinder diesel, with 71 cubic inches per cylinder. 6 x 71 = 426 cubic inches. So when the rotor turns, it captures 426 cubic inches of air, and moves it from the carb to the intake. Small dynamic efficiency differences aside, it moves the same amount of air at 1,000 RPM as it does at 10,000 per revolution. At one to one, take a 340 motor. Every revolution, the motor uses 340 cubic inches of air (at 100% VE), but the blower is providing 426 cubic inches of air. The difference is seen as boost.
A procharger, simply put, is a fan hooked to a belt. Basically, it's no different then your household fan. Low RPM doesn't move much air. And the higher you spin it, the more air it moves.
It's easy to see then how at low RPM, the procharger doesn't make move the air the roots does.
Quote:
I take it you have never ridden in a procharged car?
Roots style do come off idle at instant boost (for the reasons above). Yes I've ridden in several of both roots and procharged cars, and they don't have near the off idle torque that a roots blower car has.
Quote:
I will let you all argue amongst with "all your roots/procharger knowledge"  but at the end of the day boost=force fed (there all the same) different strokes for different folks.
They're not "all the same" either. Different blowers/turbos at 15psi will make different power because of the compression efficency. 15psi on a roots won't make the same power as 15psi on a procharger...
I'm not arguing with anyone, just trying to share knowledge and experiences.
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Re: BENCH RACING: 8-71 V.S. Procharger?
[Re: Bakaruda432]
#518104
11/12/09 09:13 PM
11/12/09 09:13 PM
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Joined: Jul 2005
Posts: 8,647
ELYRIA,OH
blownzoom440
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Joined: Jul 2005
Posts: 8,647
ELYRIA,OH
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Quote:
I know they say a Roots blower is at most 50-75% efficient and a Centrifugal is more.
Wouldn't E-85's Ethanol component cool down the air charge as much or more than an air to air intercooler,especially when combined with water injection?  
the water inj works great.i just dont trust my install of it.that is why i got the intercooler.i tried a snow kit for 3 races though.
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