He asked about issues and thoughts of what causes vapor lock, so it is just answered in more detail and suggested solutions on how to fix vapor lock. $5 Off Your $100 Mobile App Purchase . Holley 12-804 1-4 Psi Carbureted Two Port Fuel Pressure Regulator: Item #: HLY12-804 : Quantity: Price: $53.99 Add to cart . All petroleum distillates have different chemical properties which change depending on what you mix them with. Exclusive, high-quality Global Featured Holley Transmission Kickdown Cable Bracket 20-121; Gold Zinc Steel for 700R4 . 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. 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. Right & left, Customer Reviews, including Product Star Ratings help customers to learn more about the product and decide whether it is the right product for them.Learn more how customers reviews work on Amazon. Then I got this good one, to try to get 1.5 PSI to the Kadrons. The chemistry class experiment you are referring to will yield the approximate boiling (vapor) point at STP - Standard Temperature and Pressure ONLY. Holley 12-804 Holley Fuel Pressure Regulators JEGS 41040 JEGS Fuel Pressure Gauges Now you need fittings. Also in Tools, Shop Equipment & Chemicals, Cataclean - Fuel and Exhaust System Cleaner, Cataclean Diesel - Fuel and Exhaust System Cleaner, Distribution Blocks, Filters, Adapters and Fittings, Microswitch and Solenoid Mounting Brackets, Mr. Gasket Fuel Pressure Gauge - 0-15 PSI - 1-1/2 Inch Diameter, Mr. Gasket Fuel Block with 0-15 PSI Liquid Filled Fuel Pressure Gauge, 25 GPH Holley Mighty Mite Electric Fuel Pump, 1.5-4 PSI, Earl's Fem.1/8" NPT to Male 3/8" NPT Pipe Bushing Reducer. For over a century Holley has driven the cutting edge of fuel-system design. Steve_Mack_CT The Holley 12-804 is a 1 to 4 range PSI regulator. Loosening the regulator locknut and turning the adjustment screw clockwise increases the pressure. The Holley 12-804 is one of the most popular low fuel pressure regulators that works perfectly for setups that require 1 to 4 PSI. These will raise the boiling point of the fuel but reduce the octane. It appears this one needs 40 to 50 minimum. The two will be very close to the same just as would Water and Anti-Freeze boiled in an open pot. With this set up, pressures throughout system varies only very slightly from atmospheric, lower up to the vacuum tank and higher in the gravity feed from the vacuum tank to the carburettor. They use gravity feed from vacuum tank mounted under the hood and directly over the exhaust manifold. I still suspect the flooding was due at least in part to fuel boiling in the carburettor bowl and venting the vapor above the float could assist. 4.25 out of 5 stars. The carb should not flood even with the pump running unless it is putting out enough pressure to over come the float bowl shut off mannerism mechanism of the carb. A by-pass style regulator has the fuel coming in the same side of the check ball as where the fuel comes out to the carb. The fuel pump and fuel line setting top center of the engine was not only in the hottest ambient temp, except for the exhaust manifolds, under the hood they acted as a heat sink transferring heat from the block to the air. GENUINE Holley 12-804 CHROME 1-4 PSI Adjustable Fuel Pressure Regulator Kit $49.99 Free shipping Holley 12-804 Carbureted Fuel Pressure Regulator $37.07 +$14.99 shipping Holley 12-804 Chrome Street Strip Fuel Pressure Regulator 1-4 PSI $54.53 Free shipping Holley Performance 12-804 Fuel Pressure Regulator $54.53 Free shipping Holley 12-804 $55.86 Then I got this good one, to try to get 1.5 PSI to the Kadrons. Holley 26-137 Adjustable Secondary Idle Lever 90127547045 | eBay I have just this Spring started taking temp. I have used kerosene to avoid vapor lock and there is no doubt it helps, the more the better up to 20% in a low compression 1920's car. Holley Fuel Pressure Regulators 12-803 HLY-12-803. I am having problems understanding why you say OD is wrong and Rusty is correct, it seems to me you are all saying much the same and that is that gasoline is made up of many components each having different boiling points and the components with the lowest boiling point are the cause of vapour lock. Holley Carburetor Fuel Pressure Regulator 1 To 4 Psi Bottom Inlet Sides Are Outlets from Pacific Customs Unlimited your best source for Street, Off Road, Sandrail, Dune Buggy, Manx, Rock Crawler, Volksrod, or Mud Buggy VW Parts. The regulator that was shipped to me has an internal spring from a different model of regulator, the spring should be red. Holley HOL 12-804 12-804 Fuel Pressure Regulator But it is not the ethyl acetate alone that causes the effect to raise the vapor temperature point of fuel. Depending what your compression is you could add 5% kerosene up to 25% for cars from the 20s with very low compression, like 5:1 or less. . You can do a Google search for it, though. I prefer to keep things simple but I appreciate the more correct technical approach. A: Fuel pressure regulator includes mounting bracket with 2 each self-tapping screws for regulator to bracket installation purposes and 3 screws for bracket to vehicle installation.Regulatorhas a 3/8" NPT tapped fuel pressure gauge port and requires reducer 617-6157 to install the gauge. Purchased the regulator from Baxter, unit arrived in 4 days.. That work continues today through Holleys EFI products as well as through Holleys family of brands. Q: Exclusive, high-quality Global Featured Holley Transmission Kickdown Each Holley fuel pressure regulator is fully adjustable so regulating the fuel pressure to your engines needs is a simple task. The point is the 0-140 regulators (they are all coming out of China now-a-days) will not regulate lower than about 20 reliably so you need a staged system - and even Holley says so on the 803BP design set up. LASTLY on your first issue of understanding vapor lock and boiling point. Interesting theory. Google ethyl acetate and pay attention to it's "pure" boiling point, and remember IMCT is a blend of a white gas family of a petroleum distillate and ethyl acetate. If yes what size should I, A: Rusty said any heavier hydrocarbon WILL raise the boiling point - and I said Rusty is correct and OD is wrong. Holley recommends applying PTFE paste to the NPT thread of the fittings before installation on these applications. Stay up to date with the latest releases, events, promotions and more. . Fuel Pressure Regulator Holley 12-804 for sale online | eBay [endif]-->