Author Topic: New Pressure Gauge  (Read 168 times)

Offline Bully

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  • Your Engine: SBF Fontana 388cu
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  • Your Vehicle: 125" 23 T Hard Tail
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New Pressure Gauge
« on: October 06, 2019, 02:05:13 AM »
Ran my car 2 meetings ago 388cui Ford  80a.5 .030 nozzle’s & 58 main no high speed it went 8.24 - 823 -8.23 @161.
I decided to try a high speed for the next meeting, I had read Spuds article on putting one on and used his N/A calculator. So a got a 160psi gauge with memory from Spud, plumbed it into the top of the distribution block and put the high speed on turned around backwards. Went for the first pass to work out out the fuel pressure.
It clocked the gauge past the 160psi probably around to 180 after the pass. Wasn’t expecting that much,I was only expecting around 120 psi.

Offline Rat

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Re: New Pressure Gauge
« Reply #1 on: October 06, 2019, 04:15:16 AM »
You did not mention what RPM you are turning or the conditions.With that set up my calculation show a touch over 200 psi @ 7000 and very rich. What were your plugs like on the previous 8.20's.

Offline Bully

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Re: New Pressure Gauge
« Reply #2 on: October 06, 2019, 03:22:34 PM »
The plugs look good. It crosses the line at 8000. It doesn't miss from to much fuel at the top end, just sounds lazy. I did have an 80 main in it and burnt the plugs.
 Sep 14 8:00 pm
Temp 80 deg
Hum F49%
Un Corected 29.92Hg
Air Density 94.67 %
Den Alti 1864 ft.
 This was the conditions when I ran the 8.20"s

Offline Rat

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Re: New Pressure Gauge
« Reply #3 on: October 06, 2019, 05:17:06 PM »
Have you had the pump flowed, going by your info it is only flowing about 2.9 GPM but pressure no where near what you got.
Do you have a secondary (Idle) bypass fitted.

Offline Bully

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Re: New Pressure Gauge
« Reply #4 on: October 06, 2019, 05:59:11 PM »
That's what i came up with 2.9GPM, I don't have flow figures for the pump, I bought the the whole system brand new . Pump-nozzles-pills 3 way shut of valve,  the barrel valve leak set and main check valve and Idle check set for me with a 90 main pill in. Melted the plugs first time out.
« Last Edit: October 06, 2019, 06:12:07 PM by Bully »

Offline Rat

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  • Your Vehicle: Colthup Bros FED
  • General Location: Australia - East Coast
Re: New Pressure Gauge
« Reply #5 on: October 06, 2019, 09:17:43 PM »
An new 80A-1/2 should flow 5.2, a used 4.94. With those numbers I would have started with the 90 main as shipped or gone super safe with an 80 - 85 which should have been safe. No other bypass/pressure reliefs in the system?

Offline Bully

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Re: New Pressure Gauge
« Reply #6 on: October 06, 2019, 09:25:19 PM »
No, I checked both the idle and the main, they were both around the rite way and free. It runs fine we just thought it was a little fat up top, so we put the gauge on to set up the
 HighSpeed and that's thrown us a bit.
« Last Edit: October 06, 2019, 09:31:30 PM by Bully »

Offline Rat

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  • General Location: Australia - East Coast
Re: New Pressure Gauge
« Reply #7 on: October 06, 2019, 09:51:19 PM »
What brand is the barrel valve and at what point is pressure gauge plumbed in. Sounds like it is picking up a spike when you are coming off the throttle. Did your crew check it, zero it after the burnout.