Fuel Pressure readings

I suspect something is amiss with my fuel pressure reading.
Earlier this year, i added a fuel pressure gauge with a check valve on it.



According to my tune up chart, i should have way more pressure than this little dude is showing me. It is consistently around 50psi (on a full pass, 8100 in the lights)

Tune up:
8 x .055 hat nozzles
.075 main

Highspeed that cracks at 72psi with a .070 jet.

Plugs look great, car runs very consistent.

Does anyone see an issue with this gauge set up? I've had two different gauges, both read the same pressure.

 

The high speed is up there just for a couple MPH gain. I race NE/1 (index class), so it runs the number good.

The pump is an 80A-1

Nothing wrong with how that gauge is plumbed, correct? I'll move it to in front of the BV for next weekend to see what the pump is doing.

 

Will do Mike.

 

I've moved the gauge to in front of the barrel valve and will watch it on the warm up to see if the numbers are the same as behind the barrel valve. I know it'll peg it when i close the blades after a pass though.

Tonight i verified the pump saver is 135psi, the high speed is 70psi, and the idle is 7psi

Anyone want to check my math and see what they come up with for fuel system pressure?

pump flows 6.3
8 x .055
1 x .075 main

 

I get 86.28 lbs press at 8,000 ?

 

If it pegs the gauge it will ruin it -----------------

 

how big what kind of motor how much boost

 

376 SBC
6/71, 21psi
8200 in the lights

 

i'll only have the gauge in front of the k valve for the warm up and converter test. i'll pull it before the run. don't need to ruin a brand new gauge.

 

I see the line from the BV to the distribution block that has the gauge in line ---- what are you running out of the top of the block ?

Also have you checked the high speed in a bucket of water to make sure it's not leaking and not allowing more than 50 psi ?

 

That's the pump saver line, (top port on my k-valve) it cracks at 135psi.

Tested the high speed last night, it barely bubbles until it cracks. i can lap the valve in but it is sealing pretty well.

 

i've used a couple different calcs and it appears i'm lost on my jet area. both are saying 45psi. Not sure how that happened.

Looks like some testing will be done this off season. I'm not touching it until after CHRR.

 

I would suspect the check valve next ----------------- from my notes you should be at 100 psi --------------

 

The line you have coming out of the dist block has a pump saver poppet in line and headed back to the tank ?

The pump saver poppet should be screwed in to the top port of the K Valve and then plumbed back to the tank -

The way you are plumbed the pump saver does nothing , ever -------

The pressure you build up when closing the throttle at 8000 rpm's is in front of the spool , not behind it ---

 

go pro to the rescue

hey, maybe put one of those cool go pro cameras you use to watch the gauge during the run, see if its turning like a tach?

 

Yup, going to have gopro pointed forward next pass to see how gauge moves.

Mark, the poppet is on the top port of the KValve, and that line connects to the poppet. When i close the blades, it takes the fuel from the pump saver and puts it in the blower to cool/lube the blower in the shut down.

I was told to plumb it that way 10 years ago, and it's always been like that. I highly doubt much fuel passes thru it, but what does go thru it, goes thru the blower.

Here's a picture.

 

I ran about same combo years ago 362 ci 6-71 25 psi had hilborn -1 pump 7.3 gpm 8 .050 hat nozzles .040 to .060 main no hi speed ran around 100 psi