emeraldlion Posted April 18, 2011 Share Posted April 18, 2011 So why is it that on most of the applications I am seeing here, the regulator is mounted in the engine bay. Why don't more people mount the regulator near the tank and just run the feed line forward to the compartment to clean things up? Quote Link to comment Share on other sites More sharing options...
dexter72 Posted April 18, 2011 Share Posted April 18, 2011 Since I have an adjustable fuel pressure regulator, I would much rather be able to look at my pressure gauge and adjust my fuel pressure at the same time. Then try to adjust it from the rear of the car, then walk up front or inside the car to check the pressure. Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted April 18, 2011 Author Share Posted April 18, 2011 Ok. So ease of adjustment I understand. So if I am running two regulators, one return style and one non-return could I mount the return style at the rear naer the pump and reduce the hardline requirement from running return all the way to front? Then just run the feed line forward to the non-return regulator in the bay? Am I overthinking this? I'm planning on running new hard lines in 3/8 minimum and just trying to think through options. Quote Link to comment Share on other sites More sharing options...
BLOZ UP Posted April 18, 2011 Share Posted April 18, 2011 You'd just have to run a vacuum reference line all the way to the back, and like he said above, it's easier to work with in the engine bay. Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted April 18, 2011 Author Share Posted April 18, 2011 No vacuum reference. Carb setup Quote Link to comment Share on other sites More sharing options...
kamikaZeS30 Posted April 19, 2011 Share Posted April 19, 2011 Why are you running a dead-head and a bypass? I went with a bypass to eliminate fuel surges. Wouldn't putting a dead-head regulator after the bypass regulator bias the bypass by causing pressure build-ups in the line between the dead-head and the bypass on the feed side? I'm relatively new to these types of fuel systems, but if you have to run two regulators you might want to look at changing your pump. For most applications (unless you're going to run a mix of fuels) I would think you'd want a low-pressure, high-volume pump? Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted April 19, 2011 Author Share Posted April 19, 2011 I've been trying to build this fuel setup around my stock pump, and the holley 803bp regulator I bought. I was supposed to check it again Sunday with the new regulator. I had posted on another thread about that. My main question here is about the placement of the regulator. If not require a vacuum reference, is there any real reason to NOT mount the regulator further back near the tank. I decided I might as well run new lines, and I ordered 3/8 lines from summit. Was just thinking about eliminating extra length of return line. Quote Link to comment Share on other sites More sharing options...
kamikaZeS30 Posted April 19, 2011 Share Posted April 19, 2011 There's nothing that says you can't, I would just think for maintenance and adjustment purposes it'd be easier to mount it in the engine bay. How are you going to make the 3/8" return work with the fuel tank, or did you get a fuel cell or modify your stock tank? Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted April 19, 2011 Author Share Posted April 19, 2011 (edited) Not sure yet. Not sure if I want to modify the stock tank or run a return line to one of the larger vent lines already on the tank. I think one of the vent lines is 1/2 inch or something close, in which case I would be ordering some new line. Once I recheck the regulator with the stock lines currently in place I will know a little more. I figured mounting the regulator close to the tank and pump, I might not have to run hardline for the return if I did decide to use one of the vent lines(which are currently plugged off). Edited April 19, 2011 by emeraldlion Quote Link to comment Share on other sites More sharing options...
(goldfish) Posted April 20, 2011 Share Posted April 20, 2011 The closer to the delivery point, the more accurate it is. You don't have to compensate for any pressure drop across the feed line from the tank. Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted April 20, 2011 Author Share Posted April 20, 2011 feed line is coming from the regulator, shouldn't the pressure theoretically be the same at the regulator as at the carb. And if my pressure guage is at the carb and reading appropriate pressure then the placement of the regulator shouldn't really matter correct? Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted April 20, 2011 Share Posted April 20, 2011 these links should help http://forum.grumpysperformance.com/viewtopic.php?f=55&t=635 http://forum.grumpysperformance.com/viewtopic.php?f=55&t=211 Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted April 21, 2011 Author Share Posted April 21, 2011 I still am not understanding why it would be detrimental to mount the regulator closer to the rear of the car and reduce the length of return line. I do understand the need for the guage to be at the carb so you know what your pressures are going into your carb. I do understand that the bypass is much better and that fittings and lines are very important(thank you Grumpy, those are great posts for creating efficient system). I am just thinking that pressure coming out of the bypass regulator on the feed line should be the same near the regulator, as near the carb, and if the guage you are reading(and adjusting for) is at the carburetor, then why is it best to run equal length return and feed lines with regulator in engine bay. (moderators if this is too fuel related I apologize and understand if it is moved to more appropriate sub forum). This is related to my v8 swap, that is why I initially started here. Quote Link to comment Share on other sites More sharing options...
rsicard Posted April 21, 2011 Share Posted April 21, 2011 I still am not understanding why it would be detrimental to mount the regulator closer to the rear of the car and reduce the length of return line. I do understand the need for the guage to be at the carb so you know what your pressures are going into your carb. I do understand that the bypass is much better and that fittings and lines are very important(thank you Grumpy, those are great posts for creating efficient system). I am just thinking that pressure coming out of the bypass regulator on the feed line should be the same near the regulator, as near the carb, and if the guage you are reading(and adjusting for) is at the carburetor, then why is it best to run equal length return and feed lines with regulator in engine bay. (moderators if this is too fuel related I apologize and understand if it is moved to more appropriate sub forum). This is related to my v8 swap, that is why I initially started here. The friction and restriction of the fuel line between the rear mounted regulator and carb is NEVER ZERO. There is ALWAYS a drop in the feed line. Put the regulator and return near the tank and adjust the regulator for the proper pressure at the carb. Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted April 21, 2011 Author Share Posted April 21, 2011 (edited) Ok so friction causes pressure drop(thank you for clearing that part for me RSI), but that is why the GAUGE is at the carb and not in the rear. So that the pressure you are reading is most definitely what the carb is receiving, and you adjust your regulator so that gauge reads appropriate pressure for your carb. Grumpy's post did have one entry that said mount regulator close to carb and run return line back to tank, but as of yet no one has explained why it needs to be that way other than ease of adjustment. I'm not trying to contradict everyone but looking for a good reason as well as understanding. Edited April 21, 2011 by emeraldlion Quote Link to comment Share on other sites More sharing options...
kamikaZeS30 Posted April 21, 2011 Share Posted April 21, 2011 (edited) Well, one reason I would think you'd want a longer return line is to help cool it off a little before it heads back to the tank. Especially if your pump is having to work hard, the fuel will absorb some heat as it gets pushed through the pump. Edited April 21, 2011 by kamikaZeS30 Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted April 21, 2011 Author Share Posted April 21, 2011 That does make sense, especially if you are running small tank, low fuel levels, or hard racing. In my application though, utilizing stock tank, street driving, keeping fuel levels above half tank, would the remaining fuel in tank not be sufficient to cool the returned fuel? Especially if the pump you are using is not operating at full capacity( efi pump operating at carb pressures with appropriate bypass regulator and large return lines offering no resistance). Quote Link to comment Share on other sites More sharing options...
johnc Posted April 21, 2011 Share Posted April 21, 2011 You will also reduce the chance of vapor lock by keeping the line from tank to regulator at a higher pressure while keeping the low pressure fuel line a short as possible. My guess though is that you really, really want to run the FPR at the tank and are just looking for some validation of your plan. Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted April 21, 2011 Author Share Posted April 21, 2011 (edited) You got me John, but your reasoning for the fuel lock does make sense. I have to assume that if there are at least 2 decent reasons then there have to be more. It's not that I want to half-A** the job, although I did want to run less line. Potential Heat issues and avoiding vapor lock are two decent enough reasons for me though. EDIT- I would like to add I appreciate everyone being constructive and being my sounding board. Edited April 21, 2011 by emeraldlion Quote Link to comment Share on other sites More sharing options...
kamikaZeS30 Posted April 21, 2011 Share Posted April 21, 2011 Routing the hard lines is easier than it sounds, especially if you haven't done a final install on your motor/drive train. I used some stainless steel tubing I bought at the local metal supply, it was like $20 for 12 ft. of 1/4" and 12 ft. of 3/8". The expense came when I had to get Earl's compression fittings to put it all together (for all the fittings was like $60). I used a cheap $6 tubing bender I bought at autozone ("OEM" brand) and a $9 flare tool (Also, "OEM"). It took about 3 hours total and that's because I had to do it the hard way (had to route differently than stock because my entire drive-train was already assembled). I really want to go back and do away with all of the rubber hoses in my engine compartment, but I'm looking at like $600 worth of AN stuff, at least. Quote Link to comment Share on other sites More sharing options...
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