zep Posted July 30, 2007 Share Posted July 30, 2007 obviously this car is changing from a carburetted engine from 1978 to a fuel injected turbo engine. At the momen't I'm still running the standard metal fuel lines under the car... I did, however, have to put in a return line which is 3/8" I think, the fuel send is much smaller... should I replace this too with a larger one or will I be fine keeping it as is? cheers Quote Link to comment Share on other sites More sharing options...
Mike-e Posted July 30, 2007 Share Posted July 30, 2007 depends on what bore your stock line is. I've had issues using stock carby lines with fuel injection that were 6mm NB. 8mm ftw 3/8" = 9.5mm/heaps enough/overkill for a return. re route slightly and use it as the feed and the stock feed as the return? Quote Link to comment Share on other sites More sharing options...
Gaz Posted July 30, 2007 Share Posted July 30, 2007 Think ya can keep as is. Under presure itll force it through alot quicker. Think thats how itll work. Quote Link to comment Share on other sites More sharing options...
zep Posted July 30, 2007 Author Share Posted July 30, 2007 Ok I think I was pulling bore numbers out of my ass. there is no way its 9.5mm... maybe like 4mm at the most. But that is a good idea, will swap the feed and the return around. The thinner diameter return should be fine eh? Quote Link to comment Share on other sites More sharing options...
Mike-e Posted July 30, 2007 Share Posted July 30, 2007 Should be sweet as long as return isnt epicly small like 2mm stz would also pay to hook up fuel pressure gauge and check rail pressure to make sure theres no restriction on return line flow bumping up pressures 39.5 psi ftw Quote Link to comment Share on other sites More sharing options...
Spencer Posted July 31, 2007 Share Posted July 31, 2007 depends on how hungry your engine is but with a turbo car you wouldnt want much smaller than 8mm. Depending on what computer your running it will dump all four injectors at once or in pairs. With small line this can cause massive fuel rail pressure fluctuations which then = running like shit Quote Link to comment Share on other sites More sharing options...
zep Posted July 31, 2007 Author Share Posted July 31, 2007 Talking to guys on OzGemini who have done the same thing I am, they've run the standard lines without any trouble. If it's a major problem, I'll make another one later on. That new style easy to bend pipe make it was easier. Quote Link to comment Share on other sites More sharing options...
kpr Posted July 31, 2007 Share Posted July 31, 2007 i ran a new feed. then used the standard feed for a return on the kp. works sweet as, only a puss n/a 4age tho. cant remeber what size the feed i ran was Quote Link to comment Share on other sites More sharing options...
Ke36 Posted July 31, 2007 Share Posted July 31, 2007 Think ya can keep as is. Under presure itll force it through alot quicker. Think thats how itll work. as pressure increases, flow decreases ive been pondering this same thing with my lancer dont really want to run new lines but if i need to i will mine are feed 6mm I/D and return 4mm I/D ontopic thread hijack ftw Quote Link to comment Share on other sites More sharing options...
eke_zetec_RWD Posted July 31, 2007 Share Posted July 31, 2007 not 100% true, how u figre that? Quote Link to comment Share on other sites More sharing options...
Mike-e Posted August 1, 2007 Share Posted August 1, 2007 as pressure increases, flow decreases ontopic thread hijack ftw not 100% true, how u figre that? not even 25% true boe Quote Link to comment Share on other sites More sharing options...
kpr Posted August 1, 2007 Share Posted August 1, 2007 yeh you'l get alot more fuel thru the same line when running efi. "as pressure increases, flow decreases" , only relates to the fuel pump itself. if it isnt up to the job Quote Link to comment Share on other sites More sharing options...
Mike-e Posted August 1, 2007 Share Posted August 1, 2007 http://en.wikipedia.org/wiki/Cavitation Quote Link to comment Share on other sites More sharing options...
Ke36 Posted August 1, 2007 Share Posted August 1, 2007 fuck there goes my school physics failing me ive always had that in my head thinking i read it sumwhere Quote Link to comment Share on other sites More sharing options...
Ke36 Posted August 17, 2007 Share Posted August 17, 2007 just an update talked to a few peeps and they reckon 8mm outside diameter feed and 6mm outside diameter return is sweet up to around 350hp (which is waht most cars are apparently even wrxs, evos etc) any more hp and you need to upgrade Quote Link to comment Share on other sites More sharing options...
RT Posted August 17, 2007 Share Posted August 17, 2007 8mm ftw. just make sure you get EFi rated hose if you run rubber. I tried to run normal fuel hose once and it split all over the place. Luckily it never broke the inner seal though. But as soon as I noticed the crazy cracks all through the line I put EFi shit in there. Quote Link to comment Share on other sites More sharing options...
sholdowa Posted August 17, 2007 Share Posted August 17, 2007 as pressure increases, flow decreases ontopic thread hijack ftw not 100% true, how u figre that? not even 25% true boe That's Boyles law ( pV = k ). It's true for a closed system, which this is not. Quote Link to comment Share on other sites More sharing options...
Ke36 Posted August 18, 2007 Share Posted August 18, 2007 as pressure increases, flow decreases ontopic thread hijack ftw not 100% true, how u figre that? not even 25% true boe That's Boyles law ( pV = k ). It's true for a closed system, which this is not. nah shit i was thinking bout was bernoullis theroem as the speed of a moving fluid increases, the pressure within the fluid decreases. relates to venturis and shit, is what makes planes fly Quote Link to comment Share on other sites More sharing options...
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