Avernier Posted January 7, 2014 Share Posted January 7, 2014 Let me start with: i've never had anything with a fuel cell before, or an fuel lines. First question: Can i run stainless braided from the surge tank to the fuel rail, which is around 10 feet or something? I've heard that you should run hard lines over long distances, but wasnt sure if stainless braided ptfe lined hose would swell enough to make it shitty. The reason i want to do full ss braided is because the factory feed and return are only 8mm, and im not sure that they can flow enough e85 to make 400 squirrels. My fuel cell has -8 feed and return, so i was going to take advantage of that. Next question, i'm running one of those aluminum drag cells with the little sump in the back. Im going from that, to a walbro 255 inline, to the surge tank, which has a 255 in tank inside. Hoping to avoid a shit storm on the road course or at a drift event. Sound pretty solid? Suggestions? Quote Link to comment Share on other sites More sharing options...
seattlejester Posted January 8, 2014 Share Posted January 8, 2014 (edited) To answer the first question, yes you can run stainless braided hose from the surge tank to the fuel rail if you can use AN fittings on both ends. Depending on who you ask you will get different responses of should you or should you not. As long as you aren't running too much pressure the lines shouldn't swell very much. The SS braid keeps it from swelling the internal rubber to an extent. Granted it is rubber and will compress against the braid so there will be a bit of swelling going on. Whether you can feel it will have to be determined by looking at fuel pressure during a run. I think the general consensus is convenience and money versus time on whether you should do it or not. SS braided lines cost quite a bit more, (30-70$ per hose, I think it cost me 200$ for 4 hoses front to back), but are much easier to route. You can get 25 ft of aluminum hardline for 30$ and the correct conversion fittings for another 10$ or less each from jegs and sit at roughly 70-100$ for front to back and still run AN. The moment one of the braids for the SS line is cut it will start fraying, also, depending on the mounting location, it can also saw through the mounting location over time if left unclamped/isolated. Hardlines will just take a bit of fettling to route and a gentle touch or a tube bender to make sure it doesn't kink, but once it is setup it will be a setup and forget kind of arrangement until you want to upgrade the size. Curious as to the surge tank when you have a sumped fuel cell. Are you worried about overheating the out of tank pump? Or trying to keep the weight down for autocross events by running low amounts of fuel? Or running bigger outlets from the surge tank? Or planning on mounting the tank backwards? Or running an ice bath/coolant around the surge tank? As long as you have a gas gauge and gas in the cell, I think having one pump feeding to the fuel rail is fine. I don't think the surge tank would hurt any, but it is quite an additional cost. Edit: Just saw the E85 part, make sure the hose material inside the braided line is compatible with E85 if you choose to go down that route. Edited January 8, 2014 by seattlejester Quote Link to comment Share on other sites More sharing options...
Avernier Posted January 9, 2014 Author Share Posted January 9, 2014 The hose I would use is ptfe lined and e85 compatible. I can run AN fittings straight to the fuel rail. The fuel cell is a drag style cell woth a very small rear sump. It would not provide much protection in a sustained high g turn or sloshing as experienced in the transition of a drift. the surge tank would simply add stability to the fuel pick up. Sounds like I've decided to run -8 to the surge tank, and -6 to the rail from the surge tank. Contemplating running a c6 corvette fuel pressure regulator so that i can run a return less system. That would cut down on the amount of ss hose I would have to buy and route. Need to research that setup more and find out how capable it is in regards to flowing enough e85. Quote Link to comment Share on other sites More sharing options...
seattlejester Posted January 14, 2014 Share Posted January 14, 2014 Ah, I see, have you considered fuel cell foam? I am all for a surge tank, I think it is a great way to guarantee fuel gets to the engine, just the added cost of double everything is hard to justify (AN lines cost more per line then per foot, i.e. 3 foot line = 40$, 10 ft line = 60$) for me personally. Though if I ever hit fuel starvation, I'll be jumping right on board. Curious, is there a reason you want to run E85? 400hp doesn't seem too far of a stretch for a 2jz, and at least over here you can find 92/93 octane, while e85 is pretty hard to come by. Returnless is out of my knowledge range, so can't help you there. Would you use it just in the surge tank? From what I recall, you have to use a lot more E85 compared to regular gasoline, 6AN was only rated to 450 or so on gasoline, I would think that you would need bigger lines to the fuel rail. Most surge setups I see have bigger outlets then inlets. That's my 0.02, sorry if it doesn't help much, keep us updated on how things turn out, or your decisions and how you came by them. Sure to be useful down the road. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted February 14, 2014 Share Posted February 14, 2014 If anything, you can run smaller line from the in-tank to the swirl pot since it's not pressurized. You need -8 to the front at least. On a swirl pot with a return system (which I recommend), you have feed and return between tank and pot and you have feed and return between pot and engine. The in-tank pump will pump up to the swirl pot and when it fills up, the excess goes back to the tank. This overflow line is obviously at the top of the pot. The fact that the swirl pot is not pressurized (because the overflow lets the rest go out) is why the in-tank pump will push so much fuel; it's essentially open discharge into the swirl pot. The feed into the pot is typically at the bottom. The output from the swirl pot pump is wherever the pump fitment puts it. The return from the engine should be close to the return to the tank so the warm fuel coming back from the engine is preferentially sent back to the fuel tank. Search all this, it's been posted up and linked, etc. E85 requires you to pump 39% more volume to get the same energy input. Granted, turbo cars and knock resistance benefits are going to narrow that gap a little bit, but otherwise 40% is a safe estimate. http://en.wikipedia.org/wiki/Gasoline_gallon_equivalent Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted February 14, 2014 Share Posted February 14, 2014 Here ya go. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted February 14, 2014 Share Posted February 14, 2014 And to illustrate open discharge flow rates... Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted February 14, 2014 Share Posted February 14, 2014 And some previous threads: http://forums.hybridz.org/topic/90172-surge-tank-placement/?hl=%2Bswirl+%2Bpot&do=findComment&comment=855580 http://forums.hybridz.org/topic/104550-fuel-surge-tankswirl-pot/?hl=%2Bswirl+%2Bpot Quote Link to comment Share on other sites More sharing options...
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