| Larry |
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| #1 |
Hi! I came across your pumps while looking for a regulator that can work with a returnless fuel system.
Long story short we have a turbocharged smart car that needs these huge fuel injectors to reach our desired wheel HP. However with the fuel injectors almost twice as large then the stock one, each "pulse width" applied to the fuel injectors gives the car a very rich mixture up until it goes into boost, so easy driving under vacuum would have drivability issues.
Trying to not convert the system into a return fuel system and getting a typical return style fuel pressure regulator... can I use the 5052 and fit it between the fuel pump and the fuel rail and attach the vacuum / boost line to the reference port on the 5052 pump?
I am hoping to be able to decrease pressure when it's at idle and under vacuum... and from my understanding I should adjust it so I'm getting 45 psi (the minimum of the 5052 regulator) at idle without the vacuum line attached.. and then when I do attach it it should decrease my fuel pressure on the fuel rail?
I basically need to lower the pressure i'm getting now from the OEM pump to the fuel rail... I can tune the air fuel mixture with the piggy back ecu I have.. Just need a regulator that I can lower the actual pressure and then have it remove the restriction or bring it back up to full pump capacity under boost.
Is there a real difference between the 5052 and the 5032?... I'm only aiming for 200 wheel horsepower when the stock engine was making 65 wheel horsepower out of a 1 liter 3 cylinder engine.
Thanks for your time!
Larry
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| Howard |
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| #2 |
Larry,
Yes, the 5052 regulator will work in your installation.
The 5052 regulator has a .250" orifice, the 5032 has a .375" orifice. The smaller orifice yields smoother fuel pressure at lower flow rates.
Is the the first Smart hot rod? The power to weight ratio must huge.
Howard Stewart
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| Larry |
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| #3 |
Howard I want to thank you so much for your quick response!
Even though I'm getting to the extreme limits of this very tiny 1 liter engine.. I still doubt I'm flowing enough fuel to warrent the larger 5032 right? If that's the case I'll just stick with the 5052 if that's your recommondation...
I'll share with you everything of this turbocharged smart car when it's finally finished the way how I want it but it has a Garret GT20 turbo, with a much over killed water to air intercooler that keeps the intake air temp down to about 100-120 degrees no matter how much boost I'm running (even up to 19 psi). Before.. it would skyrocket to 250 degrees intake air temp with the air to air intercooler since it's mounted in the engine bay with only 10 psi of boost.
The natural engine compression ratio is 10:1 ! and with 100 octane fuel I was able to run up to 18.5 psi reliabliy with these huge 550 cc R/C Engineering injectors... The reason they are so big is because I'm aiming for 230 engine hp out of only 3 cylinders... heh
Originally I changed out the stock ones for the 270 cc ones from the Nissan 350z and that was well within the SplitSec piggy back ECU to control the injectors to keep a nice 14.7 to 1 A/F ratio under vacuum and 12-13 to 1 A/R ratio under boost but now with the water to air intercooler, much cooler intake charge and volume of air... Needed much larger injectors but the piggy back ECU is maxed out at trying to trim the fuel down as the pulse width is already as short as possible but still getting a mixture that's like 10:1 at idle =P
So I have one question just to calify before I order your fuel regulator... you stated the product can only adjust down to 45 psi.. I don't know what the fuel rate or pressure is set at from factory but lets say for example the factory returnless system's internal fuel pump regulator is set to.. 45 psi currently... From my understanding without the vacuum / boost line attached to the regulator and the adjustment screw maxed out... I would still yield 45 psi and the overall rich condition I'm currently experiencing on the whole idle, vacuum and boost range... BUT... due to the way how the regulator is designed... when I attach the vacuum / boost line to the regulator.. it should drop the pressure at the injectors low enough to the point where I can fine tune the a/f ratio at idle and vacuum in my piggy back ecu Correct?... And then of course as it reaches 0 psi and into boost it would return back to what the factory fuel pump is outputing to the injectors previously right?
Just as a little info, I have no problem with fuel under boost as I actually need to add fuel to the fuel map in the piggy back ecu it's just under idle and vacuum that it's too rich :)
Thanks Again!
Larry
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| Howard |
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| #4 |
Larry,
Yes, the 5052 would be the best choice.
You are correct, 45 PSI is the lowest setting....but the fuel pressure will be reduced under vacuum and increased under boost.
Please keep me up to date on this very interesting project.
Howard Stewart
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| Larry |
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| #5 |
Thanks again Howard!
With the regulator does it come with any fittings or plugs? I only need one inlet and one outlet but I wasn't sure if it came with -8 AN fittings or should I get the fittings for it. If it doesn't come with fittings how about plugs? Do I need to get an extra -8 AN plug to plug up the second outlet?
Also wasn't sure about the -3 AN fitting on the top, that's the boost reference correct? Does it come with a fitting already or should I also find a -3 AN fitting (O-ring or not?) for it?
Cheers!
Larry
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| Howard |
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| #6 |
Larry,
The regulator has one inlet and two outlets.....all -8 AN O-ring ports. The fittings and a plug is you want to use just one outlet is available on the website under "Hose and Fittings".
The boost reference port is -3 AN. This fitting is included.
Howard Stewart
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| Larry |
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| #7 |
Howard,
Woo hoo, I just ordered the regulator from you guys and it should arrive next monday :)
Mean while I totally forgot to order the fittings from your site along with it but I'll get it somewhere else. Since my stock fuel lines are so tiny I'm just going ot use a two -4 AN to -8 AN O-Ring adapter, one for the inlet and one for outlet and one -8 AN Plug.
Do you have any recommendations on how to connect a 1/8" vacuum line to the -3 AN boost reference port? The only way I can think of at the moment is turning that -3 to a -4 AN, then use one of those -4 AN to 1/4" barb fitting and using a 1/4" to 1/8" barb fitting plastic adapter.
I'm also trying to figure out how and where to mount the regulator in this tight engine bay. On the website it says that the regulator mounts flat, I assume those 4 open holes on the regulator body is straight thru open holes used for mounting purposes right? Would you be able to tell me the dimensions of them so I can make a mounting plate this week so I can just mount the regulator when it comes in? :)
Thanks!
Larry
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| Howard |
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| #8 |
The regulator will work in any position.
An 1/8" vacuum line will typically blow off in a boost situation. You really need to go with a the -3 AN stuff. This is the common size for brake lines, so the hose a fittings are readily available.
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