Fuel pressure gauge isolator

I have this gauge and isolator and i keep seeing not to mount it on the firewall (per NHRA and Autometer instructions). However every pic I see that is exactly where it is mounted. So which is right?

I had one of those on a NHRA Stocker. Was mounted on the inner fender by the firewall. Never questioned. On another note, I never liked the gauge it would change pressure with temperature and altitude wasn't very accurate. Autometer makes a digital gauge that is going in my new car.

I mounted mine on the fender.

Never liked isolators. They are VERY slow to react if there is a problem and the aforementioned issues.

So is there a better mouse trap?

The best mouse trap is data logging. I don't want all the crap that goes with it at this point. So I just use a gauge.

Carburated? 4461. Electric with a transducer. Simple.

If you do use a isolator you HAVE to have it FULL
of oil otherwise it will be slow and give a bogus
reading and when I say full I mean ZERO air.. I
used them in the past but now days I use the electric
gauges so I dont need the isolators

I don't think I would use a mechanical gauge for anything anymore except for brake pressure.

Autometer also makes a digital gauge 1600 psi for brake pressure.
I run a stick shift car so only need 100-200 psi to hold on the line. It is so much easier to run wire instead of steel line.

I have not seen the rule but I would think that they don't want the fuel side near the flywheel or converter so it won't get cut in the event of a flywheel or trans explosion. On my big block with a tunnel ram I bolt it to the rear of the engine using the valley cover bolts.

My isolator uses antifreeze not oil. I didn't know they made an isolator that used oil.

And you do have to get ALL the air out of the line. Or it will drive you bonkers.

Basically they make any one with a fluid that
doesnt freeze.. mine are oil( a very thin oil)

I just went thru this a few weeks ago as I moved my fuel pressure gauge from
the cowl to inside the car. I mounted my isolator on the inner fender by the master cylinder. I used 50/50 mix anti- freeze as recommended. It was kind of a pia to get the anti - freeze to the right level to get the gauge to work using a squeeze bottle to add it to the guage and isolator. I also had to bleed the fuel side several times to get it to work. I finally got it right and the car looks better with out the gauge outside we're its been for 35 years.

I dont have inner fenderwells as I have fenderwell headers.



All I use is mechanical gauges. I know they will work no matter what happens unlike data loggers and computers.

I will look into an electrical fuel pressure gauge.

Sent the mechanical one back ordered an electrical one.