FrontEngineDragsters.Org Forum
Technical => Spud Miller's Cave => Topic started by: BK on January 26, 2015, 07:25:48 PM
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If I run my return line on the top rail of my car it would need to rise up a couple inch's to go in the top of the tank. I'm thinking that's not good. It would still be lower than the pump and check valve.
I could put a bung in the back of the tank and keep the line pitched down all the way. The pump and check would be a few inch's above the top fuel level. But the return line would be below the fuel level most of the time.
The other choice would be to return it to the feed line to the pump.
Thoughts on the best scenario or other ideas.
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I had a manifold with one return going into tank. Fitting was higher than the pump.
I have since made a manifold that goes into the feed line to the pump that all the returns feed into...its below the pump.
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No need to worry about keeping things running downhill. Pressure will get it all there. When pressure/flow stops, the check valve closes (it's supposed to anyway) and it's like putting your finger over one end of a straw. The fuel will likely stay in the line behind the check valve even if it is downhill to the tank.
If it's your main check valve (with a pill inside), it might be nice to have it a bit higher than the level of the fuel just because you won't spill as much when you change the main pill.
Returning fuel to the pump inlet is perfectly acceptable and can save you a bunch of hose. Sometimes the need to purchase fittings with return ports can cancel out any hose savings however.
Spud
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I have been running all returns into the inlet for years, never had any issue doing it that way
and the fitting to do that is only around $40
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My fuel returns are connected back to the main fuel line. I have not run my car yet but I know that the two fastest J/F guys on the planet have been doing this with zero problems.
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My fuel returns are connected back to the main fuel line. I have not run my car yet but I know that the two fastest J/F guys on the planet have been doing this with zero problems.
What size is the hard line ? I 'm guessing it's #12 braided line? I am going to something similar on ours. It's the connection to the tank that may take some fabrication. I will probably use .035 SS. Thanks. George
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George, you are correct. The hard line is 1" and it is broken up into several segments joined together by rubber hose. The braided hose portion of the main fuel line is #12. The returns are #6. Hope that helps. Chuck
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George, you are correct. The hard line is 1" and it is broken up into several segments joined together by rubber hose. The braided hose portion of the main fuel line is #12. The returns are #6. Hope that helps. Chuck
Thank you Chuck. I ordered 1" .035 wall 316 SS . What kind of hose and clamps did you use? I run a filter with a shutoff and will return to one end of it with # 6. Your ride is looking good. Please keep us posted. Thanks again. George
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George I can get pics of mine tomorrow if it will help. I came off the tank with a -16 into the manifold which is just about a foot long. Another piece of hose mounts goes to the pump from there. If your tank has a hose bung, you can adapt to AN flare for ease if needed.
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George I can get pics of mine tomorrow if it will help. I came off the tank with a -16 into the manifold which is just about a foot long. Another piece of hose mounts goes to the pump from there. If your tank has a hose bung, you can adapt to AN flare for ease if needed.
Thanks Troy, on our FED we will have 6' of hard line from the tank to a large filter/shutoff. It will take some custom fabrication to connect the two and that is not a problem as Doug (driver) can make almost anything. I am concerned about the hose material needed at both ends Also I want to use something better than hose clamps to attach the hose. Thanks. George
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George, I'll check out the hose and clamp type for you tonight ... or tomorrow at the latest. Work is presently getting in my way! I can tell you that the rubber hose and clamps were originally put on the car at N&P.
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Radiator hose from the auto parts store works great. Many foreign cars use 1 1/4" and other sizes and have molded in bends that you can cut out and leverage. They're methanol and nitro proof but not gas proof. Some of the parts store hoses come with a spring molded in to prevent collapsing too.
If you use worm-gear type clamps, it'll chew your hose up and eat into it. Using the smooth hose clamps (like some folks use for motor mounts on a dragster) work great. Hose shops usually have those in a bunch of sizes.
Spud
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Hey, thanks guys. George
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George, The hard line on my car is a little over 10 feet long. It is broken up into 4 segments. The segments are connected together by rubber hose that looks to me like it is radiator hose. The only marking I could find on the hose was "25.4 mm ID" and the clamps are regular hose type. Chuck
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Ive saw the radiator hose used as well as the stuff the pro teams used...Spuds correct as both will work but I would spring for the aircraft clamps.
Heres mine..
(http://i62.photobucket.com/albums/h94/sandstreet/914EC0C7-34D8-4569-994B-D6D30131330F_zpsinzllny0.jpg)
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GREAT! Thanks for posting the pictures. I bought a 6' piece of 316 stainless from Grainger and picked it up on my way thru Peoria today. Thank you! George
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Totally T. that log would be a lot better if the returns are angled to the pump instead of at a 90*. Reason being is to prevent cavitation of fuel going to the pump. Remember, while the engine is running the returns are under pressure, not atmosphere.
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They do offer special tube/hose clamps for soft materials, some have liners, some have rolled edges, some have both, price varies as to size but expect to get a package of 10 for around $12-$14. T-bolt/Marmon type clamps are a bit much,3-4 times the cost, and do not do the job any better, all it has going for it is the COOL factor.
Check out McMaster-Carr as they offer many styles
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Well I do something a little different on my NA alky SBC, we just loop a hose right into the intake of the pump. The same way Bob McKray, engine builder and tuner for the last 3 years Heritage JF champion Don Enriquez. Gene Adams plumbed the JF car he worked the same way. They both worked at Hilborn, before starting their own shops.
When I dynoed one of my SBC's another team said we shouldn't plumb it that way because when the high speed opens it puts air into the inlet, well we have been running it for 13 years, but I thought well let's hook it up that way on another dyno pull and see. But there was no difference in fuel pressure or fuel flow. It is simpler/ cleaner/ lighter. All this might be just what you like.
In 2009 I sold one of my iron RR SBC to a new racer in PA, and he ran some 7.27-7.30's right away but has had some problems since, including real high EGT, and burning up valve seats running the same tune-up we were running 7.18-7.20. He hurt it bad enough to have to replace the pistons. Finally he just sent me his lap top so I could look at his RacePak run info. What I found was every once in while his fuel pressure dropped a bunch and at different parts of the run. What we think is problem is braided AN fitted fuel line is collapsing, he even went from our return line loop into the inlet to moving the return lines to the tank , still big fuel pressure problems, even after changing the fuel pump manufacture and going to an adjustable hi-speed. So I knew it had to be something in his race car set-up. I had him look inside the inlet fuel line for a flapper piece in the line, and that's where he found a soft spot in the line, so maybe the pump is collapsing the line. I suggested he build a inlet line like what we run, hard line from the tank and braided flex to the pump.
Here is a picture of our return line loop.
I hope this helps !
Jon
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^^^^^^^ This guy is one of the smartese racers I have ever encountered!! And Jon will ALWAYS help if you just ask!! Thanks, Jon
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Well I do something a little different on my NA alky SBC, we just loop a hose right into the intake of the pump. The same way Bob McKray, engine builder and tuner for the last 3 years Heritage JF champion Don Enriquez. Gene Adams plumbed the JF car he worked the same way. They both worked at Hilborn, before starting their own shops.
When I dynoed one of my SBC's another team said we shouldn't plumb it that way because when the high speed opens it puts air into the inlet, well we have been running it for 13 years, but I thought well let's hook it up that way on another dyno pull and see. But there was no difference in fuel pressure or fuel flow. It is simpler/ cleaner/ lighter. All this might be just what you like.
In 2009 I sold one of my iron RR SBC to a new racer in PA, and he ran some 7.27-7.30's right away but has had some problems since, including real high EGT, and burning up valve seats running the same tune-up we were running 7.18-7.20. He hurt it bad enough to have to replace the pistons. Finally he just sent me his lap top so I could look at his RacePak run info. What I found was every once in while his fuel pressure dropped a bunch and at different parts of the run. What we think is problem is braided AN fitted fuel line is collapsing, he even went from our return line loop into the inlet to moving the return lines to the tank , still big fuel pressure problems, even after changing the fuel pump manufacture and going to an adjustable hi-speed. So I knew it had to be something in his race car set-up. I had him look inside the inlet fuel line for a flapper piece in the line, and that's where he found a soft spot in the line, so maybe the pump is collapsing the line. I suggested he build a inlet line like what we run, hard line from the tank and braided flex to the pump.
Here is a picture of our return line loop.
I hope this helps !
Jon
Jon was it Walt Conway ? i met walt last year at the Dutch classic super good guy with a really nice fed !