kamikaZeS30 Posted April 8, 2011 Share Posted April 8, 2011 (edited) Okay, something about my set-up: I'm running a 383 with a dual-plane intake (not super high RPM), aluminum heads (190cc/64cc), shorty-block huggers, and forged bottom-end (crank, rods, pistons), 240 @.050" (both sides, I don't recall my LSA) and .466" gross lift (with 1.5 ratio rockers) and Edelbrock 1406 carb (I don't plan on racing, at least, not in the very near future). I got the car back from the shop after they supposedly "finished" the swap. They didn't. One of the big ticket items I am trying to fix right now is my fuel delivery. I'm running a generic aftermarket fuel-pump rated at 115GPH and 7 PSI. I didn't realize it previously, but the shop had just run the fuel through the stock hard-line, through 5/16" hose straight to the carb inlet. Needless to say the carb/engine would flood itself if I wasn't laying into it while cranking and then not letting the RPM drop much below 1500. Oh, and they neglected to do anything with the return line, which I discovered when I tried to fill up my tank, started a fire at the gas-station (I thought I was going to die that night). So, today, I received my Holley bypass ("return-style" P/N 12-803BP) regulator in the mail. I mounted it on the fire-wall, since I noticed the stock hard-lines are ridiculously close to my headers and I began re-routing them (carefully, so as not to crack or kink them, I used a tube bender). My question is, will the stock hard lines (I am assuming the feed line is big enough, as it successfully flooded the engine once already) provide enough flow for the return side? I am mainly concerned whether or not I will 1) be able to flow enough fuel to feed the engine (I don't plan on racing, but I don't think it'd be a good idea to run a huge risk of starvation at any rate) and 2) can I dial the pressure to the carb down enough to avoid flooding with the stock return line? I thought the stock return was 1/4" but 1/4" hose is a tad loose. I want to go AN, eventually, but this project is nickel-and-dime-ing me right now just getting it running. I was thinking AN -6 and maybe AN -4 for return? Edited April 8, 2011 by kamikaZeS30 Quote Link to comment Share on other sites More sharing options...
kamikaZeS30 Posted April 11, 2011 Author Share Posted April 11, 2011 Well, I went to Industrial Metal Supply and got some stainless tubing, 1/4" and 3/8". I installed the Holley FPR on the stock hard-lines and the return line was too small to bleed enough pressure, so the 1/4" and 3/8" should do the trick. So far I have the stainless tubing routed and bent into the shape it needs to be, I also got some earl's compression fittings to help me with the job. Since I am unable to remove the old lines (trans, exhaust, drive-shaft, etc. are in the way), I ended up routing it next to the in-board side of the passenger's side frame-rail (I have the bad dog full-length rails). Shooting for 5-6 PSI on this set-up. I'll have pictures once it is completed. Quote Link to comment Share on other sites More sharing options...
Neverdone Posted April 11, 2011 Share Posted April 11, 2011 Arn't you worried about rocks and other debris flying up and hitting your fuel line? Quote Link to comment Share on other sites More sharing options...
kamikaZeS30 Posted April 11, 2011 Author Share Posted April 11, 2011 Yeah, that's why I went with a heavy wall-thickness stainless tubing and I tried tucking it as much as possible. Eventually, I think I will make a sheet-steel shield to protect it. The biggest problem I had was routing it so it didn't interfere with the rear suspension. Quote Link to comment Share on other sites More sharing options...
kamikaZeS30 Posted April 13, 2011 Author Share Posted April 13, 2011 Okay, so, after all the hassle of running new stainless lines, installing a return bypass fuel pressure regulator and everything, I have come to realize the wrong fuel pump was installed. 14PSI pump on an application that requires no more than 6 PSI at the carb. FML. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted April 15, 2011 Share Posted April 15, 2011 theres a great deal of info in these links that may prove useful http://forum.grumpysperformance.com/viewtopic.php?f=55&t=211 http://forum.grumpysperformance.com/viewtopic.php?f=55&t=635 http://forum.grumpysperformance.com/viewtopic.php?f=55&t=109 Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted April 15, 2011 Share Posted April 15, 2011 Just curious as to why you think a 14psi pump is wrong for your application? Several of the electric pumps I had looked at for carburetion were 14psi max. That is why you are running the bypass regulator to dial it down to 5.5 or so before the carb. Quote Link to comment Share on other sites More sharing options...
kamikaZeS30 Posted April 16, 2011 Author Share Posted April 16, 2011 (edited) I ran the bypass regulator on the 14 PSI pump and the most reduction I could get was down to 9 PSI. I even upped the size of my return line. The pump did not have a built in pressure relief to dial its own out-put down. So, I went with a Holley "Red" pump, I finished the install today and tested it. Absolutely perfect 5.5 PSI, steady. The Holley pump is also much quieter than the one I had in there before, it's more like the mellow "hum" of an aquarium pump than like the almost "weed-whacker" noise that came out of the other one. Grumpy, I read your posts about the topic before, they've been very helpful. I feel enlightened everytime I read one your posts here. My fuel system layout is exactly like the diagram you have there and it works beautifully now. Exact details of my set-up (in order from tank to carb): Stock 240Z fuel tank Duralast brand 3/8" inline filter (for the big stuff) Holley "red" fuel pump (97 GPH 7 PSI) 1/4" stainless steel return hard line (runs between tank and bottom of regulator with roughly 12" of rubber hose on each end) 3/8" stainless main feed hard line (runs between fuel pump and regulator, 18" of hose on engine bay side before regulator, 6" from pump side) Earl's compression fittings at all junctions of the hard lines Earl's 10 micron performance filter 3/8" hose barbs, before regulator Holley 12-803BP "Bypass" regulator (4.5~9PSI) w/ Earl's 3/8" NPT to 3/8" and 1/4" hose barbs (on feed and return side) Earl's 3/8" NPT adapter to 3/8" hose barb with topside 1/8" npt fitting where resides a Earl's fuel pressure gauge (3~18 PSI) Then to carb via a 12" rubber 3/8" hose I do want to back eventually and replace all of the rubber hose with AN line, but that may have to wait until I get the clutch working and win the lottery-- because AN is really expensive. What would be even spiffier, is if I can find someone that is trying to get rid of their stock tank, pay a radiator shop to make some modifications to the stock tank (like add a sump with 1/2" fitting both in and out) and then run bigger diameter lines. I wanted to use 3/8" return and feed, but the stock return on the tank was 1/4". Edited April 16, 2011 by kamikaZeS30 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.