J666AYP
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| posted on 23/12/22 at 03:53 PM |
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Fuel pressure regulator location
Hi all,
Just going over the plans for the fuel system on the project. As I'm paying close attention to weight distribution I'm thinking about
mounting my fuel pressure regulator in the back with the pump and filter. Usually FPR's are mounted close to the fuel rail, is there a reason for
this and would mounting it in the rear of the car cause issues?
Thanks in advance,
Jay
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obfripper
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| posted on 23/12/22 at 10:43 PM |
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A returnless system is the normal approach on most modern vehicles, with a fixed regulator installed either with the fuel pump or as part of the
filter, sometimes combined with a pwm controlled pump to keep the power useage low.
If you're looking for every last bhp then this is not as efficient, as the fuel in the rail will be as hot as the engine at idle but cooler at
wot, whereas with a circulated system the fuel temperature at the rail will be lower and more constant, giving you denser fuel at the point of
delivery all the time.
You could run a circulated system with the regulator at the tank return, i've not seen it done but it should work similarly to any other
circulated system, the only thing that might be an issue is if you get pressure resonance due to the longer circuit before the regulator. I have a
feeling that it will still be less than a returnless system as a returnless system will experience a similar effect to water hammer due to the fuel in
the system only moving when an injector is opened.
Some OE fuels systems have dampers in the fuel circuit tuned to defeat pressure resonance, there are aftermarket versions if this is an issue, but the
only way to know is with an electronic fuel pressure sensor that has a decent data rate as the resonance is likely to be a figure related to the rpm
ie 15 or 30hz at idle, and unlikely to be spotted on a mechanical gauge. It would likely show up when trying to tune the engine, with parts of the map
being unstable with no visible reason.
The only other issue i can see is if you need a referenced pressure regulator, then you will need to run a reference map line to the rear to operate
the regulator, depending on how much boost you are going to run, and how fine your injector control is; ie if you only have 1 bar boost, then you
could get away with a continuous 4 bar rail pressure and counteract the relative fuel pressure that is delivered with your mapping, but go much higher
than that and the relative pressure will change too much to accurately compensate in the mapping, and you would need a referenced regulator.
This does very much depend on your engine and ecu setup.
Dave
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snapper
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| posted on 24/12/22 at 08:49 AM |
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I think that the weight of the fuel pressure regulator is so low that moving it to a sub-optimal position is not very imaginative and that there are
other things you could do achieve you required weight distribution.
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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J666AYP
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| posted on 8/1/23 at 06:32 PM |
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Author:Subject: Fuel pressure regulator locationJ666AYP
Contributor
Posts 294
Registered 27/7/17
Member Is Online
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Building: Supercharged locost
posted on 23/12/22 at 03:53 PM Fuel pressure regulator location
Hi all,
Just going over the plans for the fuel system on the project. As I'm paying close attention to weight distribution I'm thinking about
mounting my fuel pressure regulator in the back with the pump and filter. Usually FPR's are mounted close to the fuel rail, is there a reason for
this and would mounting it in the rear of the car cause issues?
Thanks in advance,
Jay
obfripper, thanks for that. Given me alot to think about, quite abit I didn't even contemplate.
Jay
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J666AYP
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| posted on 8/1/23 at 06:35 PM |
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Snapper, I get where you are coming from but at the same time moving 0.7kgs to a lighter area of the car and moving all of the fueling system into one
area made sense to me. Well atleast in my mind it did
J
[Edited on 8/1/23 by J666AYP]
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