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. 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. Much of the excess engine heat will end up soaking the fuel system under the hood. Reviewed in the United States on January 15, 2021. Note also that PURE ethylene glycol is also flammable but also miscible with water. Loosening the regulator locknut and turning the adjustment screw clockwise increases the pressure. fuel pressure in at the top, fuel pressure out on each side. [endif]-->. Adjusting Holley & Demon Mixture Screws; Holley Specs HP Series; Edelbrock Carburetor Specs; Holley Double Pumper 4150 Specs; Carter Competition Series AFB Specs; Company Info. I have no idea - you are in uncharted territory. the cause for your fuel pressure fluxuation is because the fuel pressure is bumping up against the regulator and the extra fuel has no where to go , the quick fix is run a return line . One is a deadhead and one is a by-pass. Carb Part, 14 PSI Fuel Pressure Regulator Set 3/8in NPT Port 12804 for Holley : Amazon.com.au: Automotive This experience ties with that the owner of a very early Twin Six Packard. . Holley part number for the kit is 12-807; Summit sells it for about $6. If you purchased April gas when you take your Antique out of winter storage it is only a month until the switch from 124 deg F to 140 deg F. This might explain a lot of problems in early summer. It works but not as well as some of the off brands like spectre. There is clearance around the needle which I would have thought would be enough to vent the increased pressure but maybe not. Interesting that the writer suggests certain additives can raise boiling point of gas in the first section. Purchased the regulator from Baxter, unit arrived in 4 days.. Holley 12-804 Fuel Pressure Regulator 3/8 pipe thread ports 7/32 restriction Pressure ranges from 1 to 4 PSI Includes mounting bracket Satin finish This regulator is used to adjust to fuel pressure requirements of various carburetors and supplies the proper pressure to the needle and seat valve to prevent flooding or drivability problems. All Holley regulators are pre-set at the factory at 2.8 PSI so there is no guesswork when first installing the regulator. As a single solution, or partnered with products from other Holley companies - Hooker Headers(R), Flowtech(R) Exhaust, NOS(R) Nitrous, Weiand(R), Earl's Performance Plumbing(R), or Diablosport(R)- Holley products can give you the edge you need over the competition. Conversely if you go too high and it knocks - you can bring it down with kerosene or the paint thinner family. There are two kinds and they look the same. Adjustable Fuel Regulation From 1 To 4 PSI.220 Inch 7/32 Inch Restriction. Putting kerosene into gasoline - while both are hydrocarbons - and they will blend - the lighter oil nature of the kerosene to the solvent of gasoline; in an amount of 5% is not enough to change the STP vapor point of the gasoline, but it will weaken the octane rating of the gasoline enough to feel it under acceleration AND under pressure will raise the vapor point enough to perhaps prevent vapor lock depending on the ambient and under hood temperatures of where one is located. Adding heavier weight hydrocarbons WILL raise the vapor point under pressure - usually enough to keep the fuel from vaporizing in the line or boiling off in the carburetor bowl while flowing. For over a century Holley has driven the cutting edge of fuel-system design. Cool. It's easy! A small amount of IMCT in gasoline - depending on whether it is the winter or summer blend - depending on what that is as a fuel where you are - raises the boiling point like kerosene or diesel - but also raises or maintains the octane level slightly as ethyl acetate tends to loosen the hydrogen bonds and lets mixture burn more completely without causing pre-ignition we call "detonation" - which is really simply a slight lowering of the "autoignition temperature". When I got it to down to 30 - then the 0-15 psi reg would not hold anymore and climbed to 15 flooding out the engine. I switched on the electric pump and it instantly picked up and ran for a few seconds then reverted to the classic vapor lock symptoms. . I am not going to quote all you said, but the flooding from the electric pump was caused by too much fuel pressure over coming the needle seat (or whatever kind of seat it has for the bowl) of the carburetor. 1 oz per gallon - not more than 2 is usually in the right "goldie-locks" range. Octane is an actual chemical which would be at the light end of the scale for gas, kerosene would be at the heavy end. 12-804 : Quantity: Share : . . Please try again later. [{"displayPrice":"$58.17","priceAmount":58.17,"currencySymbol":"$","integerValue":"58","decimalSeparator":".","fractionalValue":"17","symbolPosition":"left","hasSpace":false,"showFractionalPartIfEmpty":true,"offerListingId":"UhTnfcw7IZxaNntXlJwDKCZdMn2swwW9Qa8PxzrWBz%2By8RC0ilxVsHIj8toGUO%2FPmmF8b2HD1iNYooZ7n4ER0XuKiQsQQvJG86lgqsni6KYZs%2FdLcIOIE0Ukulbz%2BJYBuUOC820ciUZxU2UEL9sUjtoq8gdk8bOPIZ3QChg8zpgyIZxlTaXQEA%3D%3D","locale":"en-US","buyingOptionType":"NEW"}]. store If this is true, how come adding antifreeze to water raises the boiling point? I remember when I was a teen in the 50's and everyone had a flathead Ford V8 or a Chevy stovebolt 6. Shop Fuel Pressure Regulators at Summit Racing. I still think they sent you the high pressure one. Thus the "lowest boiling point are the cause of vapour lock" is also NOT CORRECT thinking. Applications. Troubleshooting Carburetor Problems and Vaporlock Blues Revisited - Hagerty Lifestyle. ). This ensures that it's set too low. I am intrigued by you statement, "Once these chemicals are blended - the over-all resulting chemical properties - especially boiling point under pressure is changed - they are NO LONGER SEPARATE boiling points in play.". Loosening the regulator locknut and turning the adjustment screw clockwise increases the pressure. That's where the pressure was going. Of course you may already have this setup - that is the first issue. TURNING THE ADJUSTMENT SCREW ALL THE WAY IN WILL RESULT IN EXCESSIVE FUEL PRESSURE . couple more questions, Rusty, what exactly are "heavy ends"? I installed this on my Onan 7000 generator as part of a project to resolve vapor lock issues in hot weather and high altitudes. Holley carburetors have powered every NASCAR(R) Sprint(R) Cup team and nearly every NHRA(R) Pro-Stock champion for four decades. This Holley universal low pressure fuel regulator is factory-set to 2.7 PSI, but is fully adjustable from 1 to 4 PSI. Product very good. (that is this one in the image below) The adjustment spring under the adjustment screw is pushing down on the diaphragm holding the ball off it's . Works, don't use a liquid filled gauge in an engine compartment! the fuel pressure gage needs to be in the line going to carbs. The 12-803 4.5-9 psi spring is plain, (just the gold colored plating) the spring is accessible and replacable The cheap dial units are terrible. It's not the vendor's fault, these things should have been recalled, or the vendors made aware of the issue so that they could be inspected before they're sold. Some cars are much more apparent to vapor locking than others, I"ve never experienced here in NJ with either of my older Packards which see all kind of hot summer driving conditions. 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.Regulator has a 3/8" NPT . Each Holley fuel pressure regulator is fully adjustable so regulating the fuel pressure to your engines needs is a simple task. Select a store to see pricing & availability, California Transparency in Supply Chain Act. Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising. Copyright 2023, Antique Automobile Club of America. Prewar cars have very low compression and will run better on gas that has some kerosene added. Unfortunately, these FPR are now made in Korea and they no longer include an alternate spring. [endif]-->