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Jul 13, 2010 14:26:06 GMT
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 Hi all, anybody got or know of efficiency maps for this weeny charger? Just bought one on the 'bay to fit to my Reliant 850 engine. All I know so far is that it kicks out 393cc per revolution, has internal step-up gearing of 1.93:1 (VW TSI fitting only). I'm going for a draw thru setup using an HIF44 carb, it'll fit about here:  And its going in this:  |
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Jul 13, 2010 14:34:03 GMT
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you sir have a vision!
Make it so!
altho is responce to your questions I have no idea, if for some reason you change about using it let me know. . .
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Jul 13, 2010 14:36:51 GMT
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Get onto the S/C Thunderbird boards. They have all the data on the Eatin' you could ever ask for.
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 Team Blitz Ford Capri parts worldwide: Restoration, Road, or Race. Used, Repro, and NOS, ranging from scabby to perfect. Itching your Capri jones since 1979! Buy, sell, trade. www.teamblitz.com blitz@teamblitz.com |
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ben1
Part of things
Posts: 340
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Jul 13, 2010 15:11:07 GMT
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Very nice bond bug!! , more pics plz , havent seen of one the bugs for along time!
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marksparks999
Part of things
I aim to live forever, or die trying!
Posts: 656
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Jul 13, 2010 15:20:52 GMT
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crikey i can see some 'Clarksonesque' moments coming up in that...
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Retroless at the moment... but on the hunt for something old!
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Jul 13, 2010 18:25:50 GMT
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That should work pretty well on that engine (if properly geared)
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 Click picture for more |
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Jul 13, 2010 19:18:10 GMT
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forgive my ignorance, but is that 850 engine a 4 or 2 stroke?
if its a 4 stroke, then that means it uses 850cc per every 2 revs, so thats 425cc per rev. So if you gear your supercharger 1 to 1 gearing to the crank your sc chucking out 393 cc per rev will pump .92% more than your engine can swallow with no boost.
So as long as you double your fueling and your engine holds together you will get almost double the normal power (after you deduct the power used to drive the charger)
This is all theory from my fuzzy brain
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Last Edit: Jul 13, 2010 19:19:33 GMT by suterman
1985 Bedford CF2 camper 1991 Volvo 240 Turbo |
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MrSpeedy
East Midlands
www.vintagediesels.co.uk
Posts: 4,791 
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Jul 13, 2010 19:25:24 GMT
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I like this man's thinking !
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Jul 13, 2010 20:59:40 GMT
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forgive my ignorance, but is that 850 engine a 4 or 2 stroke? if its a 4 stroke, then that means it uses 850cc per every 2 revs, so thats 425cc per rev. So if you gear your supercharger 1 to 1 gearing to the crank your sc chucking out 393 cc per rev will pump .92% more than your engine can swallow with no boost. So as long as you double your fueling and your engine holds together you will get almost double the normal power (after you deduct the power used to drive the charger) This is all theory from my fuzzy brain Your maths are correct though I'll be underdriving from the crank very slightly to stay at about 10 psi max where I think the charger's still efficient. Still need a map though really before I can buy a pulley (alternator) to attatch to the crank pulley to drive it. |
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Jul 13, 2010 21:06:07 GMT
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Also, if the engine's 4-stroke and 4 cylinder, then surely it induces its volume after four complete revs i.e. 212.5cc per rev?
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"Mechanical Power Subduing Animal Speed" (Robert Trevithick, 1808)
'72 BMW 2000 Touring
'99 TT 180 (mrs)
'72 BMW 2500
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Jul 13, 2010 21:19:53 GMT
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Click picture for more |
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Jul 18, 2010 12:34:22 GMT
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Thanks for the replies, still need an efficiency map like this one for the bigger M45. Any google-fu experts out there?  At least I've found a nice pic of the M24!  |
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Jul 18, 2010 13:06:55 GMT
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You could use an SU HIF44 carb from a Metro Turbo. It will be of a blow through type. They usually have a clamp around the dashpot to stop it being blown off. Or you could use a Renault 5 turbo carb.
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RobinJI
Posted a lot
"Driven by the irony that only being shackled to the road could ever I be free"
Posts: 2,995
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Jul 18, 2010 19:22:40 GMT
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forgive my ignorance, but is that 850 engine a 4 or 2 stroke? if its a 4 stroke, then that means it uses 850cc per every 2 revs, so thats 425cc per rev. So if you gear your supercharger 1 to 1 gearing to the crank your sc chucking out 393 cc per rev will pump .92% more than your engine can swallow with no boost. So as long as you double your fueling and your engine holds together you will get almost double the normal power (after you deduct the power used to drive the charger) This is all theory from my fuzzy brain Unfortunately I'm not sure that's quite right. Think of the engine as a pump, at atmospheric pressure, the engine can possibly draw in 425cc of air every revolution. (The amount of air an engine manages to pump in comparison to this figure is known as volumetric efficiency, and it is completely possible to achieve 100% VE naturally aspirated.) If the supercharger pumps 393cc per revolution, then at a gearing of 1:1, the engine would still be 32cc short of what it could pump naturally aspirated, so the engine would actually be being starved of air, and running at a VE of only around 76%, and the pressure in the inlet of less than atmospheric. In other words, you'll want to gear it up a bit to actually build a pressure higher than atmospheric. Afraid I can't help with an efficiency map. |
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Jul 18, 2010 20:16:32 GMT
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What RobinJI said is correct.
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I will be gearing the charger at just under 1:1 because it's internaly geared at 1.93:1.
So approx 1.9 x 393cc per rev, engine inhales 425cc per rev so about 10psi boost.
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I have an M45 on my 930cc imp, geared at 2:1 with a wastegate to control the boost. It makes 12psi as soon as the throtle is cracked!
I'm no help on the M24 though :/
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