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Jul 12, 2006 18:37:57 GMT
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Its got me thinking - The Bug has a nice exposed pulley system, an 8:1 or so compression ratio (Maybe a bit lower) and a bit of room... How well does blow-through work with supercharger setups? More importantly, if you had the ability to have an inlet made that split the charge to a set of twin 40's, would you do that rather than a single carb setup? Hummm scrapyard modding session plans rule
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Jul 12, 2006 18:47:58 GMT
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40's are a pain with blow through setup's as far as i know, SU's rule the roost The only other thing is that aircooled engines do have heat management issues with forced induction, good oilcooler, and good airfole are essential. J
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Jul 12, 2006 19:33:19 GMT
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SUs and SU-type carbs (read: bike carbs ) are constant-velocity sealed units if memory serves me correctly meaning that they can be used in a blow-through application. Dan - I was thinking about blown Type1 motors earlier (whilst idly assembling the girlfriend's latest IKEA purchase... :/ ) and thought that a 2" SU in a suck-through setup would be nice. You should be able to split the blower output into two without issue... ...The other idea is a set of four bike carbs, split and arranged in a '4-barrell' style arrangement in the centre, the blower feeding all four carbs and each carb feeding a cylinder. Or the carbs in pairs right on the heads being fed by an airbox arrangement...itself fed by the blower... *n
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Top grammar tips! Bought = purchased. Brought = relocated Lose = misplace/opposite of win. Loose = your mum
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Jul 12, 2006 19:55:59 GMT
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Good info - Damn this place giving me ideas This one's twin turbo on bike carbs, but it kind of gives me an idea - The copper piping is an intercooler idea that apparently works, gets rid of part of the cooling problem
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Jul 12, 2006 20:51:53 GMT
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Yup I saw that - dunno how effective it would be compared to a 'proper' intercooler though...
*n
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Top grammar tips! Bought = purchased. Brought = relocated Lose = misplace/opposite of win. Loose = your mum
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Jul 12, 2006 22:02:58 GMT
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well hes cooling a fuel laden charge, so the mixture will condense on the inside of the pipes. not good!
The thing with intercoolers is that a lot of them don't usually use the ambient air to cool them, they work by absorbing the heat produced by compressing the air, into the metal. This heat is then reintroduced back into the air flow under low load conditions.
So the mass of an intercooler has a large bearing on its efficiency to cool the air, this is why charge cooling works so well, that and the fact water is 7 times more effective at transferring heat than air!
This principle only really works on road cars as they are at full throttle only around 5% of the time driven, track cars are driven on boost most of the time and so have to have whacking great air to air units to cool the air enough.
J
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Jul 13, 2006 19:19:27 GMT
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So it's best to cool the charge before the fuel - Mad drawing skillzzzz time. So with a carb being like a big AFM, the fueling wouldn't be too bad to sort out - A relief valve of sorts on the T-Piece that splits the charge, and thunderbirds are go? I was milling over the idea of rebuilding this engine anyway, could be a good excuse to try grenading it
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Jul 13, 2006 19:50:00 GMT
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Lots of you are missing the point its not a Turbo you do not want lots of boost therefore you are not heating the charge, therefore you don't need to cool it FFS how many times does it need to be said KEEP IT SIMPLE Suck through carb set up Chargers well matched to engine size 6-7psi Max boost you don't need hideous pipe runs and BFO intercoolers, thats turbo teritory and totally the opposite of what you are trying to acheive If you want loads of lag and loads of boost then just turbo it to start with. I think a lot of people still need to grasp the basics before designing systems.... especially the basic fundamental differences Otherwise you`ll all be running smaller pulleys, more boost and wondering why you are producing less power than you would have with an SU and straight to manifold system If you don't understand then go away and do some research, if you still don't understand or want clarification on anything then ask Sorry if this offends anyone but I design this sh1t for a living and get fed up with people just coming back and saying supercharging is sh1t compared to turbos etc when in reality they don't know the first thing about either system except what they heard from their mate or read on the net They drive differently, have different power and torque characteristics and guess what.... Totally different requirements to get them to work at their best A good SC set up will pulll from nothing with no lag and give excellent driveability and even return decent economy if you want A turbo motor can be designed to do a similar thing but you wont get the drive off idle or the economy Big turbos will make more power, normally with an "Ooh ya Fooker" power delivery and a lot of everything very quickly (Heat, noise,Revs, Opposite lock etc) if thats your bag then great, but I bet you that the properly sorted Supercharger installation will be quicker and easier and nicer to drive on the road ;D Rant over
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