do you leave your FP gauge installed?

[weith1111]

I recently installed the Buschur AFPR (awesome, and 5 minute install), and in the box they included a piece of paper with like 80 pt font saying "DO NOT LEAVE THE GAUGE INSTALLED" or something to that effect. As in, put it on, set your pressure, take it back off. So I did. But now I want to check the pressure, and am thinking, why am I going to put it back on and take it back off over and over. Is there some reason the gauge can't or shouldn't stay installed?

 

[SleeperG]

mechanical gauges and most electric senders can be damaged from the vibrations of the engine.
this will of course effect their accuracy.
i run an oil filled gauge for fp. the oil is supposed to help reduce vibration and allow it to last longer under vibration, but i don't know how well.

i definitely wouldn't trust an air filled Gauge to the vibrations of a modified motor.
but it is indeed a pain in the ass to remove them all the time.

now if your fpr and gauge are mounted to the firewall, then its not as big of an issue.
mine is mounted to a spot my intake manifold via a custom bracket.
I'm sure mine sees more vibration than it should.

 

[weith1111]

I figured the concern was calibration or leaking. Mine's mounted on top of the fuel filter, so it's not vibrating with the motor, but the cams do shake the whole car. Waiting for more opinions but thinking it's going on and then coming off...

 

[99gst_racer]

I leave my gauge installed on my AFPR. I don't understand why Buschur recommends against it.

I have a dry type gauge and it has been on my AFPR for 2 years now. It still works fine.

I would say leave it on there. But I would recommend getting a liquid filled gauge. Typically the engine vibration mostly affects the needle (pointer) in the gauge. I've seen numerous dry gauges that are returned for warranty because the needle broke off. The glycerin that they fill the gauges with, help suppress that vibration that the needle sees, thereby extending the longevity and life of the gauge.

 

[Echo5Zulu]

Mines mounted on top of the fuel filter on the fire wall. Its been there a couple years and I havent had any problems with it. I have solid motor mounts so the car really rumbles at idle. Feels like a friggin v8 under the hood. Kind of cool though really impresses people.

 

[weith1111]

I don't understand why Buschur recommends against it.

Typically the engine vibration mostly affects the needle (pointer) in the gauge. I've seen numerous dry gauges that are returned for warranty because the needle broke off.

Reason=cheap B&M gauge I suppose.

 

[steve]

The liquid filled ones can drift due to the pressure of the fluid expanding inside as they get hot.

Steve

 

[daren_p]

I have my gauge mounted to fpr attached to the firewall. It isn't liquid filled. I don't think there is a big issure with vibration with this style of setup and think its fine to leave the gauge installed, maybe if the fpr was mounted to the fuel rail you would have more vibrations. My pointer stays solid in the same spot with the car running, if vibration was an issue the pointer would be jumping around and yes if you do have alot of vibrations it will throw the calibration of the gauge out. A liquid filled gauge will help to prevent the effects of vibration but you have to remember to vent the rubber plug from time to time as pressure will build up inside the gauge with changes in temperature giving you inaccurate readings. You can easily see a couple psi change with internal case pressure. Add this to the fact that most of the gauges they use are only accurate to a couple psi to start with and the pressure you think your running could be quite abit different then what you really are.

 

[kgtalon95]

I've had my b&m gauge mounted to my rail for the past year, still works fine and doesn't seem to be off. It has gotten a tad foggy but hey.....the base is set so it has served its purpose Someday i'll get to worry about inaccurate gauges, in the mean time i'll deal with my crappy shifting................I HATE 1g trannys

 

[SleeperG]

the tricky thing about gauges is they can be totally off, but appear to be functioning fine.
it seems to me that i've heard more stories about defective mechanical pressure gauges than any other type (i.e. temp, speed, voltage,etc) this is not a plea for electronic gauges at all.

the thing is you can set your fp to 38 psi via gauge readings. and it might not actually be 38 psi that is being regulated.
then you can leave the settings the same. throw on a brand new gauge, and find that your settings were off by 5 psi. I've had this happen, and i think i recall keydiver describing a similar occurence on his vr4.
i've also seen the oil pressure gauges be off on a few bikes in my day.

the only way you can really check accuracy is with another "known good" gauge.
but first and formost, always buy a gauge thats manufactured by a reputable name, built on precision.

 

[GPTourer]

Interesting. Hey great, thanks guys, now I have something new to worry about.

 

[ChvyKc]

Interesting. Hey great, thanks guys, now I have something new to worry about.

Never thought about the vibrations messing with my gauge, I'm not going to worry about it to much though, mine is mounted on the fuel filter as well.

 

[daren_p]

the tricky thing about gauges is they can be totally off, but appear to be functioning fine.
it seems to me that i've heard more stories about defective mechanical pressure gauges than any other type (i.e. temp, speed, voltage,etc) this is not a plea for electronic gauges at all.

the thing is you can set your fp to 38 psi via gauge readings. and it might not actually be 38 psi that is being regulated.
then you can leave the settings the same. throw on a brand new gauge, and find that your settings were off by 5 psi. I've had this happen, and i think i recall keydiver describing a similar occurence on his vr4.
i've also seen the oil pressure gauges be off on a few bikes in my day.

the only way you can really check accuracy is with another "known good" gauge.
but first and formost, always buy a gauge thats manufactured by a reputable name, built on precision.

Yes the automotive gauges they sell aren't that great. Since their such a small gauge their accuracy is basically crap, but this is standard for most gauges of that size. Usually they are stated to be 2 or 3% of full scale meaning a couple psi off is still in spec & you can get them brand new like this. With time, use, vibration etc, it will throw them off even more. One of our products we sell at my work is pressure gauges. The one that I used for my fpr is the normal 1.5" size all stainless. I have the ability to check the gauges at work and I went thought about 5 until I got one that read correct between 40-50 psi, the other were out 2-3 psi. Our cost on this gauge is $32 and the selling price is $58. Im almost positive we have alot less mark up the the automotive aftermarket so you can imagine how good those gauges are that cost $20-30.

These gauges are probably the main reason why alot of guys have problems with their injectors not flowing what they are rated at or tested to flow.

 

[Generation X]

Here's my Fullthrottle afpr with a liquid filled gauge.

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