anglia4 Posted September 27, 2010 Share Posted September 27, 2010 As always i've got wild ideas flying around in my head Does anybody know if there would be any issues putting like up to 10psi up the arse of a set of R1 carbs? Thinking of throwing an SC12 or 14 at the bike carbs i'm going to hang of the little zetec in my anglia Quote Link to comment Share on other sites More sharing options...
Spencer Posted September 27, 2010 Share Posted September 27, 2010 Na they wont like it, even if they did you would possibly be pushing it to get the main jet big enough to fuel it. Quote Link to comment Share on other sites More sharing options...
BobbyBreeze Posted September 27, 2010 Share Posted September 27, 2010 Pretty sure bike carbs love boost. Google is your friend (UK forums most likely). Bubblegoose will be able to confirm. Quote Link to comment Share on other sites More sharing options...
anglia4 Posted September 27, 2010 Author Share Posted September 27, 2010 bugger! it would be fricken awesome if that would work! Whats the best/cost effective/most awesome option for making good power without going injected? Quote Link to comment Share on other sites More sharing options...
Yowzer Posted September 27, 2010 Share Posted September 27, 2010 Suck through supercharged setup, with more carbs. Lots more carbs. Quote Link to comment Share on other sites More sharing options...
Spencer Posted September 27, 2010 Share Posted September 27, 2010 R1's are CV right? they would be sweet if you pressurised the diaphragms and the float bowl too I guess hopefully it would still all seal. Used them on suck through works fine, just need to drill your jets to suit Quote Link to comment Share on other sites More sharing options...
anglia4 Posted September 27, 2010 Author Share Posted September 27, 2010 have just been doing a bit of googling, have seen it mentioned a couple of times about pressurizing the float bowl. will keep searching, would be fricken awesome i reckon if it could work. Quote Link to comment Share on other sites More sharing options...
anglia4 Posted September 27, 2010 Author Share Posted September 27, 2010 found some good info on how to ballance it out: http://www.turbo-bike.net/Pressurize%20carbs.htm Quote Link to comment Share on other sites More sharing options...
anglia4 Posted September 27, 2010 Author Share Posted September 27, 2010 also found this on another site, relates to carbs in general but explains all the fluid dynamics theory: I remember at one point of time I pretty much wrote an essay on this topic, and since then I just avoid it cause all I hear are flames or the same question asked over and over again. I have no idea what ever happend to that post, it think I made it back when we were on ezboard and I'm not about to go through it again. You can find plenty of sites on the internet on the basic principles of carburation so I will try to keep this short. Basically the carb uses diferences in air pressuse between the bore and the bowl to meter the fuel. It uses the ventrui in the bore to lower the pressure of the air passing through it creating a vacuume. The more air the greater the vacuume the more fuel is drawn it. Read on carburators on the internet to see how the diferent jets and emulsion tubes come into play in metering the fuel it doesn't effect what I am talking about. Under normal circumstances when the motor is running without boost the pressure of the air is less then that of the atmosphere and fuel is drawn from the bowl into the bore. When you bring forced induction into the equation then unless you pressurize the fuel bowl (the fuel bowl is always vented to the atmosphere, usually through the chracoal canaster in emissions controled setups) then even though the air pressure will drop as it passes through the ventrui it will still be higher then that of the atmosphere and air will actually flow into the bowl instead of fuel into the bore. To counteract this you need to pressurize the air in the fuel bowl as well. In a sense what you are doing is faking the carb into thinking that the boost pressure is normal atmospheric pressure (as long as the pressure on both sides of the metering assemblies are the same then the carb wont care what the actual pressure is). Usually this is done by building an air tight box around the carb because the gaskets were never desigend to seal under boost. This isn't alwasy true, some carbs like the weber dcoe can withstand moderate boost no problem. Once you have the bowl pressurized then you run into one more problem. The pressure in the fuel line is going to be less than that of the bowl. The bowl works alot like a toilet with a float pushing a valve closed when the fuel rises to a specific level. The pressure needs to stay above the air pressure in the bowl so fuel will flow in, but not to high so the valve can still seal. The solution to this has already discussed, but you need to get a riseing rate fuel pressure regualtor with a ratio of 1:1. Normaly you would get a high volume pump that puts out around 15psi (most blow through turbo carb setups don't excede 10psi because the floats will implode at pressures much beyond that). You will want a return style regualtor and will need to run a return line to make it work. Also don't forget that the more air you let in the more fuel you'll need to let in. Besides rejetting the carb you will also have to install a larger needle valve. Volvo had a turbo carb setup way long ago (I believe that they used su carbs in it). If you can find one then its a good place to get the parts that you need. andy Quote Link to comment Share on other sites More sharing options...
Mike-e Posted September 27, 2010 Share Posted September 27, 2010 thats a mighty paragraph. so mighty infact that I cant read it. im sure others will feel the same way Quote Link to comment Share on other sites More sharing options...
Spencer Posted September 27, 2010 Share Posted September 27, 2010 Yea screw that wall of txt! as Far as I know just pressurise the diaphragm above and below, pressurise float chamber, buy new floats as they will probably will collapse. Get a fuel pump with adjustable pressure, otherwise it wont fill the pressurised bowl. Learn how tune carbs, pray the jets will go big enough, I think they wont go bigger than 2.5mm with a drill but you shouldn't have to go that big. Then hope they hold together under pressure Quote Link to comment Share on other sites More sharing options...
anglia4 Posted September 27, 2010 Author Share Posted September 27, 2010 fixed the wall of txt haha sorry bout that one guys! yeah would be interesting to know if the seals can handle the pressure. As far as the float imploding, i read somewhere on the net tonight, someone had the idea of drilling a hole in the float and filling it with foam to give it strength and then brazing or soldering or whatever to cover the hole back up again. Just another idea to throw into the mix. Quote Link to comment Share on other sites More sharing options...
anglia4 Posted September 27, 2010 Author Share Posted September 27, 2010 found some good info on how to ballance it out:http://www.turbo-bike.net/Pressurize%20carbs.htm had a bit more of a look around this site and found that this bike is running about 14psi boost, so looks like the carbs might well be able to handle the 8-10 that im thinking Quote Link to comment Share on other sites More sharing options...
anglia4 Posted September 27, 2010 Author Share Posted September 27, 2010 some useful info here too, particularly at the bottom relating to fuel pressure and regulation http://unclebobsturbos.com/newbie.html Quote Link to comment Share on other sites More sharing options...
Bombsquad Posted September 27, 2010 Share Posted September 27, 2010 thats a mighty paragraph. so mighty infact that I cant read it. im sure others will feel the same way Cracked me up cos I thought exactly the same thing. It will will work but im unsure on exactly what boost level you can run up to. Quote Link to comment Share on other sites More sharing options...
Simon Posted September 27, 2010 Share Posted September 27, 2010 Found it less daunting as a solid wall tbh. Pretty much says got to have the same pressure in the bowl as what's going down it's throat to ensure a negative pressure on the other side of the venturi. In order to do that the pressure has to be the same on the outside of the bowl too else leaky = build a box round the whole carb. Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted September 27, 2010 Share Posted September 27, 2010 im actualy not even going to read any of ^shit r1 and zx9/12 crabs seem to be the most boost loving of all, r1s infact seem to work better in bewsted situation and can handle jandles of over 15psi the conversion is very simple many r1 websites will give you a step by step jets will likley need to be smaller and a rising rate fuel reg will be in order aswell(and pump to match) Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted September 27, 2010 Share Posted September 27, 2010 box go back to your RB powered aydubs and leave this the the real men Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted September 27, 2010 Share Posted September 27, 2010 Na they wont like it, even if they did you would possibly be pushing it to get the main jet big enough to fuel it. main often doesnt need change/smaller Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted September 27, 2010 Share Posted September 27, 2010 found some good info on how to ballance it out:http://www.turbo-bike.net/Pressurize%20carbs.htm that all you need to know, was going to link you too that Quote Link to comment Share on other sites More sharing options...
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