Fuel Sampling Valves

[Cglrcng]

I mean to relate this info in the best of ways...I fought with myself for 24 hrs about the post (I hate writing a book when a few sentences will suffice so you can read the short version if you like): "If you see me under my rear bumper of my stocker taking a fuel sample at an event from my Turtle of a Stocker...It is because it is legal by the current NHRA rule set."

Rules sometimes change and many of us are here for decades (some take breaks over the years).
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[Cglrcng]

And here is the long version if you care to read it:

The very last thing I wish to do on this planet is to reach out publicly and correct anyone. Over the years rules change, and they are hard to keep abreast of and adapt to all the changes.

So lets first review the appropriate rule by going first to the current NHRA 2024 Rule book.

General Regulations Section 21, page 5 Skip down to Pumps/Valves: Pumps/Valves: Cars equipped with mechanical non-OEM fuel pumps must have a quick-action fuel-shutoff valve within easy
reach of the driver and located in the main fuel line between the
fuel tank and the carburetor and/or injectors. Fuel recirculation
systems not part of normal fuel/pump system prohibited. All
cars in Stock, Super Stock, Competition, and Pro Stock must
be equipped with a positive-lock drain valve located between
the fuel tank and the carburetor(s) or fuel injector to facilitate
removal of fuel samples for fuel-check purposes.

My note: That last sentence is the key as it will not be found in Section 11, as it is a ?general regulation? dealing with the required specific classes called out above ? Stock, Super Stock, Competition, and Pro Stock.?

My particular slow stocker (EF/S) has had 1 installed under hood (passenger side back by the firewall in the throttle body supply line between the stock steel line and the throttle body (and top hat mounted single TBI Injector), since the early 90's, but there was a very unsafe feeling every single time I pulled a sample as it had to be performed directly above the hot header (and I had to turn the high pressure EFI fuel pump on also to use it and actually fill the required sample cup), when coming off a pass in competition or Q runs.

Recent Updates: (It is another book but bear with me please).

Preparing the car 2 yrs back I decided to upgrade the car to a 5 gal.fuel celll (with the required fabricated upper/lower bulkheads in my particular application), that has a through the floor sump with 2 rear outlets in the sump (one is capped off), the other is the supply line and then goes directly to the positive-lock fuel sample valve installed at the rear of the car on the supply line (between the cell Pre-Filter and electric EFI fuel pump). It is at at the rear of the car (Under and inside of the rear bumper firmly attached to the spare tire well that contains the new fuel cell). But, it also is per the rule ?located between the fuel tank and the carburetor(s) or fuel injector?...

I have only used it so far in competition 3 total times in the last year (all in Mar/April 2024 at 1 National Event and 2 Divisional Events that followed), and all 3 events were conducted at Las Vegas, NV within a few weeks of 1 another, and I certainly felt a lot safer sampling my fuel at the rear of the car without my fuel pump running, and far away from open hot headers under-hood). At the 4 wide National event I was not questioned at all.

But, (Q1) at the first Div. event of a double the next week I squatted down after my first Q1 run and took my sample , so I have no need to even turn on the EFI fuel pump to fill the cup), as an NHRA Tech member walked past me handing out empty sample cups (since I was under the rear bumper and my hood was still closed), he instantly firmly questioned me as I stood up with my filled sample cup, as to ?exactly where I retrieved that sample from? (he was not happy), so I showed him it was directly out of the supply line within 12? of the cell sump on the supply line.

At that point (he told me ?he would report to and discuss it with Pat?). I also immediately told him I have 1 under-hood and if he would prefer, he could dispose of the sample I just drew, and if he would re-issue me a new clean cup, that I would supply a new sample from the under-hood sample valve, as I only prefer but this location as it just feels much safer (as it is not performed directly over the hot header location high pressure pump on). He said he would discuss it with Pat and let me know.
Use the sample I just drew. It passed.

I had to go to the tower anyway (to speak with the Div. 7 Director), as I was in the first pair down the track & they had us all in the computer at sea-level indexes instead of the corrected elevation indexes for Las Vegas, to make sure our Q sheets were correct later. He made the immediate adj. Index corrections necessary to the computer and thanked me for reporting the issue.

While there, I also spoke to Pat, who said he had witnessed the fuel check event discussion first hand but off to the side and was unseen by me there, and he immediately said ?Gary, I saw it when you were questioned, he (the NHRA Tech), discussed it with me while you were having your sample checked, and I am fine with where you received and drew your sample from, as the rule is very basic as the sample valve only needs to be ?located between the fuel tank and the carburetor(s) or fuel injector.? And yours is, so you satisfy the rule...you are good.

Conclusion: I just wanted to clarify (I tested the rule in the name of safety).

The option is not only NHRA Class legal, but has been recently verified by Pat.

An interesting side note: Every class combination is different, and OEM Stock on my particular 1984 Dodge rudimentary High Pressure EFI fuel system is an OEM recirculating single point throttle body (TBI) injected system (a 1 off, 1 single year very weird non-turbo N.A. stepchild), with the Upright Bosch Throttle body and the integrated bolt on pressure regulator is actually installed immediately after the single injector, then sends the excess fuel back to the tank/cell via a smaller return line. So, there is no port on it to facilitate the valve, and it would also violate the rule as currently written if it did, as it would not be between the tank/cell and the Carb./Injector.

Thanks for listening.

[Jeff Stout]

Interesting. Building my wagon I was thinking about where to put valve as it's a small pain to open hood. Should have read rule closer.

[Robin Lawrence]

I had issues with high pressure "splash" as I initiated my sample. I was also concerned about the heat from the headers.

I solved this by installing a 30" hose from the fuel check valve. I now hold the cup outside the engine compartment next to the fender when drawing a sample.

Robin

[rsalemi]

I HAD THE VALVE UNDER THE BED OF THE cOMANCHE FOR YEARS. nEVER A PROBLEM, even when setting a record and TECH was present. Then I sold the truck and the Div Director there told the buyer that he had to have the valve under the hood!
NOT IN THE RULE BOOK! Also no fuel leakage on hot engine!

1051 Q/SA

[MR DERBY CITY]

Over the years I have seen a few racers attempt to take a fuel sample from the rear of the car AND I have seen tech offials tell them to put the sample valve under the hood. I LIKE Uncle Robins idea ….