Adjusting Holley & Demon Mixture Screws; Holley Specs HP Series; Edelbrock Carburetor Specs; Holley Double Pumper 4150 Specs; Carter Competition Series AFB Specs; Company Info. Each Holley fuel pressure regulator is fully adjustable so regulating the fuel pressure to your engines needs is a simple task. Q: September 21, 2010 in Technical. Unfortunately, these FPR are now made in Korea and they no longer include an alternate spring. wrapped around the fuel lines. May God's grace bless you in the Lord Jesus Christ. To minimize exposure, avoid breathing exhaust, do not idle the engine except as necessary, service your vehicle in a well-ventilated area and wear gloves or wash your hands frequently when servicing your vehicle. This will keep your pressure steady and have instant pressure change when adjusting. Holley 12-804 Chrome Carbureted Fuel Pressure Regulator If I could get 75-85 octane, non-ethanol, Regular gasoline that vaporized at above 180 deg F, I think my car would run fine all the time. The reliable, albiet slower, stovebolts never suffered vapor lock because the fuel pump and lines were up front in the airstream of the engine fan. It's unlikely that anything's stuck. In some areas, according to the map, RVP can vary from about 7.0 to 9.0 in some of the fuels. If the carbs are drawing fuel and you lower the pressure at the reg, it should show on the gauge. Then I got this good one, to try to get 1.5 PSI to the Kadrons. The issue is boiling points UNDER PRESSURE we are talking about here - though the BP article speaks to other issues of engine and carburetor design contributing to the vapor lock problem. Too much anti-freeze - (typically ethylene glycol) causes the opposite effect even under pressure of the cooling system. This Holley FPR (12-804) use to be a perfect choice to solve the "too much fuel pressure" produced by the aftermarket fuel pumps on vintage VW. , . Most certainly it will be my plan to fully explore the possibility of "treating the Fuel", with hopes that diesel fuel will make just enough difference to avoid any re-engineering. Otherwise it's good. Auto Parts v 6c02f45cd (2fvgn) cv1440. Needs you to make/tap your own threads for screws, Reviewed in the United States on February 4, 2023. Gasoline at the pump is a blend of different chemicals. Going to check my VW bus fuel pump pressure. Use with standard pump only - not recommended for maximum pressure pumps. Q: I can only say acetone will lower flash point (light easier) but also lower auto-ignition temperature and thus create knock into too much of a quantity - while a very little bit will raise octane but not lower auto-ignition - so if you go TOO low with kerosene or diesel you can bring back some kick to the fuel with SMALL amounts of acetone. Fuel Pressure Regulators Instruction Sheet (42712804), Designed to be used with standard pump only, Measures 2-1/2" wide and 1-1/2" tall and deep, This low pressure fuel regulator is factory-set to 2.7 PSI, but is fully adjustable from 1 to 4 PSI, It includes mounting bracket with 2 each self-tapping screws for regulator to bracket installation purposes and 3 screws for bracket to vehicle installation, 1-3/4" hole spacing to mount the regulator to the bracket. In fractional distillation (the refining of oil) - what we call "mineral spirits", "paint thinner", "kerosene" and "diesel fuel" all ALL "heavier" hydrocarbons (pretty much in that order) than what we call gasoline - in that they occur lower in the distillation tower and condense at lower temperatures back into liquid before what we call "gasoline" does. Then, we got what was loosely described as winter gas, all year round, with RFG. Each Holley fuel pressure regulator is fully adjustable so regulating the fuel pressure to your engines needs is a simple task. Why does this occur only under increased pressure? Q: Does this need to be mounted upright or is it ok on its side? I realize this is an old post - but when people write things that are WRONG - it leaves the next Joe who comes along thinking that is the correct answer when especially in this case - it is NOT. P/N 12-803, 12-501, 12-804, 12-500, & 15812NOS Installation Instructions WARNING! On the Holley 12-804 fuel pressure regulator, the factory preset is supposed to be 2.8 pounds - can anyone say is Holley usually pretty accurate on these presets? Applications. It will meet your needs and deliver great quality at an affordable cost. Fuel pump regulator has 3/8" NPT inlet/outlet ports. In fact I can completely remove the adjusting screw and it still does not go down to 3psi. The reg takes 3/8" fittings and the gauge takes 1/8" fittings. This satin finish regulator feature 3/8 pipe thread .