WRX's Autometer Boost Gauges are Inaccurate????

**Khryz** · 05-04-2004 06:02 PM

So my friend has a 03 WRX with Turbo XS Stealth-back Exhaust. He also did used to have an AEM CAI and Turbo XS Type H-RFL BOV on his car too, but he took them off when I told him they were hurting his car's performance.

He recently got a Autometer Pro Comp Ultra Light Boost Gauge for his car, so he obviously can read the boost if he wanted to up the boost. However, whenever he goes WOT, the boost gauge spikes to 15 PSI, then it drops to 10 PSI, then it goes back up to 15 PSI, then it goes back down to 10 PSI, then it hits redline. And during this time, it doesn't feel like the car is gaining or losing power, just maybe something is wrong with the gauge.

His set-up looks like there's a line that comes out from under and infront of the intercooler, which loops around and used to just connect to the stock BOV. Now he has a T there, going to the BOV, and then it connecting and continueing through the firewall and into the gauge. This correct?

We played a little with the vacuum sizes, but he said the vacuum size needed to plug into the back of the gauge is so small, that he had to use small vacuum hosing for it.

Also, I tightened down all the clamps around the intercooler, and turbo area that were lose and that might be causing a leak. After I did this, we got in the car and he said his cruising vacuum is much lower. It used to be -14 vacuum ish and now it's -20 in cruising. At idle it's -18 vacuum.

Is there anything else I should try to get this gauge to work? It should hold at 15 PSI or whatever and just hold there right?

I don't know much about WRX's so I can't really help him out unless I ask you guys. Thanks a lot.

- Chris.

**sarcasmo** · 05-04-2004 06:17 PM

I'll chime in before everyone starts ranting 'Autometer is teh suck' and 'JDM is teh bett4r.'

Autometer gauges are known to be a bit inaccurate as they can leak under high boost. This generally results in the boost readings being off by a pound or two - not the behavior that you're seeing. I have an Autometer gauge and, while not the best, it works for me.

It sounds like what you are seeing is close to the normal boost curve of the WRX. On a stock car the boost will make it up to around 14.5 PSI in 3rd gear. As RPMs climb after peak boost the wastegate will open and boost will taper off toward red-line.

I do find it odd that you are seeing the boost drop and then spike again. Before you blame the gauge make sure you tell your friend to keep his foot to the floor all the way to redline. If he lets off at all during the run the boost will drop and then build again.

Once you have everything tight and you run with a consistent throttle position you should find that the boost hits a peak around 14.5 and then tapers off to redline (peak boost will be lower in first and second gears).

**Khryz** · 05-05-2004 06:32 AM

Alright. Well we're going to probably rip apart the gauge again so I can look at how he installed it. Does the smaller vacuum lines effect anything?

Also, I believe he's going WOT this whole time. And also, we kind of heard some air sucking noises in the gauge pod, is that normal too or does that mean he doesn't have a good seal around the lines and the gauge?

**sarcasmo** · 05-05-2004 07:18 AM

The smaller vacuum line shouldn't really hurt anything, but the sucking sound from the gauge pod doesn't sound right - it shouldn't be making any noise. I'd make sure that there is thread sealant on the brass fittings on the back of the gauge and check to make sure there are hose clamps holding the vacuum line onto the fittings.

**djrez4** · 05-05-2004 09:32 AM

Definately check the seal on the lines. It sounds like 15psi is making it leak. If that doesn't solve anything, try this out: http://www.scoobymods.com/forums/showthread.php?t=210

**jaybara** · 05-05-2004 11:39 AM

I also have Autometer gauges - EGT, Oil Temp and Boost. While the temp gauges have been fine for over a year, I have had problems with the boost gauge. Well, boost gauges I should say.

The needle fell off the first one. I got it replaced for free and the replacement gauge readings were all off by like 3 - 5 PSI. So I got another replacement... but the moral of the story is I had the first 2 hooked up using the larger hose that the tutorial on ScoobyMods says. When I installed the 3rd gauge, I ripped out all the lines and used the Boost Gauge Installation Kit from http://www.wrxtra.com. I haven't had any problems since and the readings are all dead on with my Cobb AccessPort. The only parts I used that didn't come with the install kit were some small hose clamps to make sure every connection stays nice and tight.

**sarcasmo** · 05-05-2004 11:42 AM

I have the exact same set-up and also used the kit from WRXtra.com. I would definitely recommend it.

**jaybara** · 05-05-2004 11:58 AM

The nice thing about their kit is the hose is thicker and heavier duty than any vaccum hose you will get at a local auto store, and all the brass fittings you need are already securely fixed into the hoses. For $15 you couldn't possibly make a better install kit yourself.

**benny cregs** · 07-12-2008 05:32 PM

i just installed a autometer in my 07 wrx last night and when i easy the gas up a little it well only take it to 5psi then if i get on it will drop to 0 until i push the clutch in and it will spike to 10 only during the shift then it drops back to 0 till i shift again or easy up on the gas and it will go to 5 so idk anyone have any ideas the only thing i can think of is there is a leak in the back of the gauge