Does anyone know the fuel flow rates for the X300 fuel injection system, esp at high RPM or WOT?

I'm looking at some auxiliary fuel check valves to possibly place in the tank to augment the pumps' built-in check valves, and want to make sure they don't create a choke point.

Once I know the flow rate, I can drop the manufacture a note to ask what the spec is.

.

 

According to previous posts & google, injectors are LNA1520BA ( Lucas D3165AA) with a static flow rate of 37.27 lb/hr or 380cc/min @ 43.5 PSI

John Herbert

 

Thanks John!

....showing my ignorance here, but using that spec, what would be the total flow rate with the engine running at a given RPM and all six injectors opening in sequence?

The XJR injectors have a slightly higher rate I think too.

.

 

The injectors are different for the N/A ( LHE1520AA ) to the S/C ( LNA1520BA ) as they have a larger orifice so the ECU regulated pulsewidth is different . They have a color band to not put the wrong ones in . XJRengineer would be a good source of information on the total fuel rate as a all 6 sequencing and varying pulsewidth at a given engine load and RPM .

 

One way to calculate the wide open throttle fuel flow rate from a theoretical point is to take the max air flow rate ( Al NZ in New Zealand recently measured it on his XJR ) and the fuel / air ratio for it's stoichiometric target of around 14.7 to stay in it's target of 0.0 % on the short term fuel trim with a positive margin of 5.0 % in overfueling in order to catch the engine up to your throttle request .

I could be wrong , but starts the discussion .

 

Thanks all, it seems that it is academic anyway.

US-Plastics responded that they do not have flow rates for their 410 check valve. So I'll just have to compare it manually.

It's probably a non issue as the check valve in the throat of the fuel pump is tiny, and I suspect this check valve is a lot larger.

.

 

The fuel pressure increases to about 47 on throttle up as the FPR varies it dependent on intake manifold pressure . On your artificially boosted manifold pressure , I'm not sure how that works unless the FPR vacuum tap is before the rotors .

 

Hi Al,

You may be overthinking this. As long as you choose a check valve with an I.D. similar to or greater than the fuel lines in which you mount it (typically in the range of 6mm (1/4 in.) to 8mm (5/16 in.), and also, choose a low opening pressure of 1 psi or less, you won't create a choke point or increase the strain on the fuel pump.

In our '93, I used an inexpensive CV from McMaster-Carr (mcmaster.com) with a fuel-resistant fluoroelastomer seal. They also carry hose barbs that fit the check valves. I used a CV with male threads on both ends and hose barbs with female threads and 5/16 in. barbs to fit 8mm fuel line. Use Teflon tape on the threads of the CV before threading on the hose barbs as you would any pipe joint. Here's an example of a 1/4 inch I.D. CV from McMaster-Carr:

Brass 1/4 NPT to 1/4 NPT Backflow Prevention Valve Fluoroelastomer Seal

Cheers,

Don

 

Heh, I suspect you are correct, and it is something I tend to have a habit of

The following is what I ordered, two of them, one for each pump. In my case I chose the Viton version:

https://www.usplastic.com/catalog/it...5393&catid=940

https://www.usplastic.com/catalog/it...5394&catid=940


5/16" HB x 5/16" HB Series 410 Brass Check Valve with Viton™ Seals - 1 PSI
Item #: 22399

Brass body & piston
Viton™ seals
Beryllium copper retainer
Good for a wide range of air & fluid applications
.203" diameter through hole in ball
Positive seal at very low back pressure or slight vacuum
Cracking pressure: 1 psi
Maximum pressure: 500 psi
Maximum temperature: 375°F
Made in the USA


Another source, with some more information:

https://www.highflowfuel.com/i-23908...-8mm-5-16.html


.

 

Al,

I couldn't get the links to work directly but those specifications look great!

Cheers,

Don

 

Al,
bear in mind the OEM system is specced to provide excess pressure in all but high load WOT conditions (and even then there is a margin for error), with the excess pressure being released by the fuel pressure regulator and returned to the tank. Inadequate fuel flow should not be an issue with clean filter and properly functioning fuel pump(s).

 

The other link to the check valve I had posted was wrong, this is the correct link:

https://www.highflowfuel.com/i-23908...tegory:1208100

.