Landracing Forum

Bonneville Salt Flats Discussion => SCTA Rule Questions => Topic started by: JoeBlystfk on October 12, 2012, 08:35:50 PM

Title: Fuel pressure gauge
Post by: JoeBlystfk on October 12, 2012, 08:35:50 PM
Perhaps a dumb question, but how does the rule that says no parts of the fuel system may be in the cockpit affect the installation of a mechanical fuel pressure gauge in the dash ?
Title: Re: Fuel pressure gauge
Post by: Captthundarr on October 12, 2012, 08:42:05 PM
Elecrtic gauge or an isolation adaptor between the line with fuel and the gauge. see Summit, Jegs ect.
Title: Re: Fuel pressure gauge
Post by: Stainless1 on October 12, 2012, 09:41:54 PM
The one in the liner has glycerin in the line between the isolator and gauge
Title: Re: Fuel pressure gauge
Post by: manta22 on October 12, 2012, 09:42:52 PM
That's not a dumb question at all... the purpose of a fuel pressure isolator is to keep a ruptured gauge line from spraying fuel into the cockpit. The isolator itself must be mounted outside the cockpit or the whole purpose is compromised.

Regards, Neil  Tucson, AZ
Title: Re: Fuel pressure gauge
Post by: JoeBlystfk on October 12, 2012, 10:33:53 PM
That's why I love the internet.....thanks
Title: Re: Fuel pressure gauge
Post by: maguromic on October 12, 2012, 10:51:57 PM
You should also use line isolators on your oil line and hydraulic clutch line.  A friend of mine made this up for my vintage race car I road race. It does the fuel, oil and the hydraulic clutch in one small unit (4" x 1 1/2") and mounts to the firewall and has the bleeders on the firewall side. Tony

(http://i273.photobucket.com/albums/jj236/maguromic/isolatore.jpg)
Title: Re: Fuel pressure gauge
Post by: Captthundarr on October 13, 2012, 11:51:36 AM
Tony, you have the coolest stuff,and the avitars are't either. :-D
Title: Re: Fuel pressure gauge
Post by: Dean Los Angeles on October 13, 2012, 12:31:10 PM
The value of a fuel line isolator for safety is obvious.
The value of the gauge . . . I can see that you would want fuel pressure going to the data logger. Why do you need it during a run? I'm thinking you are pretty busy to even look at it.
What is the advantage of a mechanical gauge over an electric gauge?
The isolator adds complexity, cost, and another component that can break. Sure, the electric requires a sending unit that can fail, but wiring to a gauge beats plumbing.
Title: Re: Fuel pressure gauge
Post by: hotrod on October 13, 2012, 09:33:54 PM
The other advantage of an electrical fuel pressure gauge is you can wire up a low fuel pressure warning light in a high visibility location.
That will get the drivers attention with a lot less focused mental effort than trying to watch the gauge during a run.

Then if the light comes on the driver can glance at the gauge to confirm he/she has a real problem and abort if true.

Larry
Title: Re: Fuel pressure gauge
Post by: JoeBlystfk on October 13, 2012, 10:28:54 PM
Well its about a flat head with 97s and a magneto and mechanical fuel pump and an old guy that says we should have a fuel pressure gauge. Data logger......what's that.. :-D
Title: Re: Fuel pressure gauge
Post by: jl222 on October 13, 2012, 11:13:35 PM
Well its about a flat head with 97s and a magneto and mechanical fuel pump and an old guy that says we should have a fuel pressure gauge. Data logger......what's that.. :-D

   :-D  JL222
Title: Re: Fuel pressure gauge
Post by: Milwaukee Midget on October 14, 2012, 11:21:39 AM
Well its about a flat head with 97s and a magneto and mechanical fuel pump and an old guy that says we should have a fuel pressure gauge. Data logger......what's that.. :-D

Ahh, vintage data logger for flat heads - a pencil, a pad of paper, a theodolite and a sun dial.  :wink: 

From what I understand about 97's, you don't want to overpower them with fuel pressure, which I just looked up - 2 1/2-3 psi max - same as a DCOE Weber.  What I wound up doing is putting a fuel pressure gauge under my hood after the regulator so I can check it when tuning.  If you think you need it, I'd plumb in a pressure switch and an idiot light.

 
Title: Re: Fuel pressure gauge
Post by: Tman on October 14, 2012, 11:46:36 AM
Well its about a flat head with 97s and a magneto and mechanical fuel pump and an old guy that says we should have a fuel pressure gauge. Data logger......what's that.. :-D

Ahh, vintage data logger for flat heads - a pencil, a pad of paper, a theodolite and a sun dial.  :wink: 

From what I understand about 97's, you don't want to overpower them with fuel pressure, which I just looked up - 2 1/2-3 psi max - same as a DCOE Weber.  What I wound up doing is putting a fuel pressure gauge under my hood after the regulator so I can check it when tuning.  If you think you need it, I'd plumb in a pressure switch and an idiot light.

 

Thats how we have our setup wih the Y-block. Besides, you WILL KNOW if you lose pressure anyway!
Title: Re: Fuel pressure gauge
Post by: JoeBlystfk on October 14, 2012, 04:02:55 PM
Ok dumb question number two.
Rule 3 k says all vehicles must have a main battery shut off switch. What do you hook it to if you aren't running a battery ?
We are just going to plug in a battery to get the thing started and then it goes in the push truck.
Title: Re: Fuel pressure gauge
Post by: hotrod on October 14, 2012, 05:36:26 PM
I would suspect that would mean you would need a positive method to kill all system electrical power -- kill alternator power (assuming you have an alternator) and to cut off ignition (assuming you have a magneto). In short a positive method to stop the engine.

Larry
Title: Re: Fuel pressure gauge
Post by: Peter Jack on October 14, 2012, 05:53:04 PM
I think you said you were running a magneto. Providing that's the only electrical in the car then just install an external switch to ground the mag.

Pete
Title: Re: Fuel pressure gauge
Post by: JoeBlystfk on October 14, 2012, 05:59:26 PM
Perhaps the rule should say that   :-D
Title: Re: Fuel pressure gauge
Post by: jdincau on October 14, 2012, 07:34:03 PM
The rule says what it means, you must have a battery cut off switch. No battery, no switch required. As has been discussed at length here before the idea is for the first responders be able to cut all electrical power before they start extraction procedures on the driver.
Title: Re: Fuel pressure gauge
Post by: Glen on October 14, 2012, 07:53:52 PM
I think they need a impact switch as well.
Title: Re: Fuel pressure gauge
Post by: Milwaukee Midget on October 14, 2012, 09:32:33 PM
I think they need a impact switch as well.

That would be for an electric fuel pump, but Joe mentioned a mechanical pump. 

I agree with Hotrod - if all you're running for electrical is a magneto with a mechanical fuel pump, there is the potential for a situation where you're unable to shut it down.