BAR118 Posted August 6, 2011 Share Posted August 6, 2011 Just wondering what you guys reckon about putting boost through an hs4? Should I just use the 4 or should I go to something bigger? I'm only looking to run 4-6psi through my 1380 A-series? Edit : This is in a blow-through set-up. Quote Link to comment Share on other sites More sharing options...
BAR118 Posted August 6, 2011 Author Share Posted August 6, 2011 Also what will I need to do to the carb to run boost through it? Quote Link to comment Share on other sites More sharing options...
jakesae101 Posted August 6, 2011 Share Posted August 6, 2011 you will need a rising rate fuel pressure reg as you will need to keep fuel pressure higher than boost pressure Quote Link to comment Share on other sites More sharing options...
BAR118 Posted August 7, 2011 Author Share Posted August 7, 2011 you will need a rising rate fuel pressure reg as you will need to keep fuel pressure higher than boost pressure Yup i know that. I was wondering what mods I have to do to the carb itself? Quote Link to comment Share on other sites More sharing options...
Testament Posted August 7, 2011 Share Posted August 7, 2011 usually SU's are used in a draw through setup from what I have seen. I don't think I've ever seen one used in a blow through configuration. they are allegedly easy enough to setup for draw through. Quote Link to comment Share on other sites More sharing options...
Adoom Posted August 7, 2011 Share Posted August 7, 2011 See if you can get a hold of an SU from an MG Metro Turbo. They were blow through. Might be hard to sort out a suitable needle though... Or buy David Vizard's "Modify BL's A series engine". It's essential for someone modifying the A series. Quote Link to comment Share on other sites More sharing options...
BAR118 Posted August 7, 2011 Author Share Posted August 7, 2011 I am looking to do a blowthrough set up, probably should've added that. I do have David Vizards 2nd edition book but can't find anything on setting carbs up for blowthrough... Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted August 7, 2011 Share Posted August 7, 2011 there are a few ways to do it one way is to seal the carb in a presurized box/boost pressure but thats a pain in the arse the other way is to select appropriate bike carbs and modify to suit Quote Link to comment Share on other sites More sharing options...
jakesae101 Posted August 7, 2011 Share Posted August 7, 2011 ive heard of side drafts being used in blow through setups Quote Link to comment Share on other sites More sharing options...
BAR118 Posted August 7, 2011 Author Share Posted August 7, 2011 there are a few ways to do itone way is to seal the carb in a presurized box/boost pressure but thats a pain in the arse the other way is to select appropriate bike carbs and modify to suit So am I predy much shit out of luck if I want to use an S.u for blowthrough? Quote Link to comment Share on other sites More sharing options...
keltik Posted August 7, 2011 Share Posted August 7, 2011 From what little i know, you just have to make sure the throttle spindle and float bowl seal well. Then run a line to the float bowl vent. SU's are pretty well sealed anyways and fairly easy to use for blow through. On webers and holleys they usually just slam the whole carb in an airtight container. The MG Maestro turbo had SU carbs from the factory and i believe it was a blow through setup...could be wrong tho. Found this tuning guide when messing around with researching carbs; http://www.turbominis.co.uk/forums/inde ... tid=159683 Might help you? Quote Link to comment Share on other sites More sharing options...
Raizer Posted August 7, 2011 Share Posted August 7, 2011 So am I predy much shit out of luck if I want to use an S.u for blowthrough? MG/Austin/Rover Metro, Montego & Maestro all had blow through SU carbs if you can find one. Quote Link to comment Share on other sites More sharing options...
Borgweiser Posted August 7, 2011 Share Posted August 7, 2011 You need an HIF44 off a metro dude, anything else wont work at all. True story, any Metro will have one, then change needle using the old one as a base then going thinner till you eliminate flatspots. Use one of the many online calculators to eliminate guesswork with needles and it will work a lot better than rolling road plus cheaper. Quote Link to comment Share on other sites More sharing options...
BAR118 Posted August 7, 2011 Author Share Posted August 7, 2011 You need an HIF44 off a metro dude, anything else wont work at all. True story, any Metro will have one, then change needle using the old one as a base then going thinner till you eliminate flatspots. Use one of the many online calculators to eliminate guesswork with needles and it will work a lot better than rolling road plus cheaper. Are all the hif44's suited to boost? Quote Link to comment Share on other sites More sharing options...
JoKer Posted August 7, 2011 Share Posted August 7, 2011 why the hard-on for a blow? suck thru eliminates the issues no? Quote Link to comment Share on other sites More sharing options...
Borgweiser Posted August 7, 2011 Share Posted August 7, 2011 You need an HIF44 off a metro dude, anything else wont work at all. True story, any Metro will have one, then change needle using the old one as a base then going thinner till you eliminate flatspots. Use one of the many online calculators to eliminate guesswork with needles and it will work a lot better than rolling road plus cheaper. Are all the hif44's suited to boost? Yep, generally, there was no difference between standard metro and turbo one but needle profile. Joker, draw through turbos work well, for a while.. Carbon seals and fuel dont mix too well, also blow-through SU is pretty much the simplest way to go + tried and tested Quote Link to comment Share on other sites More sharing options...
BAR118 Posted August 7, 2011 Author Share Posted August 7, 2011 why the hard-on for a blow? suck thru eliminates the issues no? Wanna run i/c, and I don't really like the thought of compressing/spinning all that fuel around... Quote Link to comment Share on other sites More sharing options...
bubblegoose Posted August 7, 2011 Share Posted August 7, 2011 ihi supercharger im guessing? runamuck might know if they like fuel/draw though or not, ive never looked into it but 5psi from that blower on such a small engine would really not need an intercooler Quote Link to comment Share on other sites More sharing options...
BAR118 Posted August 7, 2011 Author Share Posted August 7, 2011 ihi supercharger im guessing?runamuck might know if they like fuel/draw though or not, ive never looked into it but 5psi from that blower on such a small engine would really not need an intercooler I'm thinkning about going for the smaller Eaton m45 ae, the IHI charger is just a fair bit too big to try jam into the engine bay. Quote Link to comment Share on other sites More sharing options...
BAR118 Posted August 7, 2011 Author Share Posted August 7, 2011 ihi supercharger im guessing?runamuck might know if they like fuel/draw though or not, ive never looked into it but 5psi from that blower on such a small engine would really not need an intercooler I'm thinkning about going for the smaller Eaton m45 ae, the IHI charger is just a fair bit too big to try jam into the engine bay. I had a guy on here offer me an m45 for the IHI so I'm just waiting to hear back from him. Quote Link to comment Share on other sites More sharing options...
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