What's Wrong With My Boost Gauge?

[Big Rizza]

Hey all,

I have an aftermarket boost gauge installed in my car (I didn't do the install). The car is an R32 GTS-T running standard boost. Yet for some reason, the boost gauge shows boost at anywhere between 12 and 14 psi (I saw around 1 bar boost the other day). It's not spiking to that level - it's holding pretty steady to well over 6000rpm. When the car is turned off, the boost gauge reads anywhere between 0psi and 3psi, which seems a little strange, and tells me perhaps it's the gauge itself that's the problem, rather than the engine overboosting. The car pulls like a stocker, doesn't feel like it's running increased boost. Not only that, my dyno printout shows a boost curve is what would be expected from a standard car - completely at odds with what the gauge is telling me!

Edited November 9, 2006 by Big Rizza

[Munkyb0y]

if the gauge is showing 3 psi when the motor is off, then the gauge is faulty. it should show 0.

[mad082]

i call shenanigans!

sounds like the gauge is cactus.

my work car at mold old work (it was a 1954 morris panel van) used to do 15mph when it was parked.

[Big Rizza]

So, the gauge is screwed then. Is there any way to fix it? Or does it need to be replaced?

i call shenanigans!

sounds like the gauge is cactus.

my work car at mold old work (it was a 1954 morris panel van) used to do 15mph when it was parked.

By the speedo, my mates Silvia could reach it's top speed in about 0.25 of a second - it took about 5 minutes of driving around with the speedo reading 0km/h before it miraculously sprung to life and showed the correct speed. If you happened to be doing 180km/h at the time, then the needle would swing from 0km/h to 180km/h in the blink of an eye!

Edited November 9, 2006 by Big Rizza

[Munkyb0y]

i reckon it's stuffed, coz if it was holding it's reading, but just the wrong psi, you moight be able to adjust it, but seeing as it goes wherever it wants, not so sure.

open it and have a go. you got nothing to lose

[wonkynutz]

Now this is interesting because I've got a wonky boost gauge too.I'm sure it's not accurate even though it hasn't been on a dyno. Much like Rizza's my gauge reads up to 15lb on what feels like a stock donk. Unlike Rizza's my gauge shows zero when the car's off and vacuum when you'd expect vacuum (ie. decelerating or cruising off boost),as well as showing transition to boost that matches the expected change in induction/turbo noise. It's plumbed directly off the plenum and is an AutoMeter Pro-Comp Ultra Lite. Once again I didn't do the installation. It was on the car when I bought it. Anyone got any tips or clues for me?

[Munkyb0y]

what does it show when you're idling? at about 700rpm mine shows about 20vac.

[2gceffy]

mine does the same sits on about 2-3 vac when turned off and at idle you tap it and it moves between 15-20 vac.. i can hear a vac leak but only when it wants to leak so who knows whats goin on.. i installed mine myself i used the stock boost readin line from back of plentum cause my ceffy doesnt have a stock boost gauge..

long story short get newy ??

[Munkyb0y]

yeah it shouldnt move 5 psi when you tap it. lol.

i know u can actually adjust them to sit at 0 when off. I've done it to one of mine, but ever since then i dont trust it, so i use another one that hasnt been opened.

[wonkynutz]

what does it show when you're idling? at about 700rpm mine shows about 20vac.

Just checked it. 700rpm idle shows 15lb vac. RB20 not RB25 if that makes any difference.

[Cubes]

The 25 may read a little more vac.. I know the 30 definitely reads more vac than the 20.

wun hung small,

The autometer reading a little higher than you suspect scares me a tad. I was about to lay out a few hundred in autometer guages (oil temp, pressure, exh. temp) Any chance you can confirm it is indeed reading incorrectly?

Whats the stock guage read when the autometer is reading 1bar?

[dead32]

im guessing by your fluctuations its a vacum signaled boost gauge, the one on my car is digital and vacum fed gauge, i never liked how much the autometer gauges bounce around. you want accuracy not a friken wave of boost.

[Munkyb0y]

i've got 2 splitfire boost gauges (not both hooked up at the same time. lol) and they seem to be pretty accurate, straight to the mark, and dont bounce around.

having said that, i've always considered autometer to be a good quality gauge, and it may just be a case of this particular one being damaged.

[Cubes]

hrmm might have a look in to the splitfires.. They are around the $$ I'm looking at spending and also have the oil temp readout in degree's C not F.

[dead32]

like dont get me wroung, not bagging em out, just the electronic fed gauges are extremly precise on/off boost where as the autometer ones bounce around alot from the ones ive seen.

[wonkynutz]

The 25 may read a little more vac.. I know the 30 definitely reads more vac than the 20.

wun hung small,

The autometer reading a little higher than you suspect scares me a tad. I was about to lay out a few hundred in autometer guages (oil temp, pressure, exh. temp) Any chance you can confirm it is indeed reading incorrectly?

Whats the stock guage read when the autometer is reading 1bar?

Hey don't take the piss out of my user name or I'll sulk.I take myself very seriously you know.

I should get a vacuum check done I s'pose but I've been busy so I haven't bothered yet.Must get onto it.

The car is an R32GTS4 so it doesn't have a boost gauge as standard so I can't compare readings.

It's a funny one.If it was a Chinese gauge I'd just chuck it.

[wonkynutz]

like dont get me wroung, not bagging em out, just the electronic fed gauges are extremly precise on/off boost where as the autometer ones bounce around alot from the ones ive seen.

Yep I've noticed mine seems pretty twitchy.

[JVP]

i have an autometer one that reads only 10-11psi when im actually running 14....

[RB20_ZED]

apparantely my car is going 180km/hr in my garage! speedo's been stuffed for a few weeks now.

[Big Rizza]

And here I thought that my problem was a unique one. Seems like I'm not the only one with boost gauge problems then! Mine also happens to be an Autometer - a really nice (and expensive) fluid filled one, too. And it was a birthday present. And if I get rid of it, the person who gave it to me will feel bad that they gave me a faulty gauge. Kinda pissed off that it's not working!

I might borrow a 1" pressure gauge from work overnight and compare it to the Autometer gauge just to be sure before I conclude 100% that the gauge is at fault.

Anyways, I don't feel like getting banned for slanderous comments about Autometer (if I get banned, I want it to be for something that I can afterwards say "it was worth it!" with a smug smile on my face!), so I'll say now that I have only ever heard good things about Autometer before today - we with faulty gauges are a minority, so any potential buyers should not take this threads experiences as reason not to purchase that brand.

*hides from incoming ban*

apparantely my car is going 180km/hr in my garage! speedo's been stuffed for a few weeks now.

A mate of mine did 140km/h in his driveway by his speedo. His speedo was accurate. There miiiiight have been a sliiiiiight amount of wheel slip, though And he proved me wrong - I didn't think his car could do a 3rd gear burnout...

Edited November 10, 2006 by Big Rizza