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View Full Version : Which gauge do I believe?


CajunKenny
02-25-2009, 06:20 PM
I am running the ProfecB SpecII EBC and am setting up the 'Lo' mode.

The problem is that there is about a 3psi difference between my boost gauge and what the EBC reads. Ex: Boost Gauge = 15psi while the EBC = 13psi.

Any idea which one would be more accurate and/or why there is a discrepancy?
eman2289
02-25-2009, 06:22 PM
Where do you have the vac line hooked up to?
IJ.
02-25-2009, 06:32 PM
You could have a 3psi drop across the IC Kenny.
CajunKenny
02-25-2009, 06:32 PM
Both were installed when I got the car so I didn't install them; but, it looks like the EBC T's into the Boost Pressure Sensor and the Gauge T's into the line coming off the back of the intake manifold.

IJ: Given the above setup, would I then go off the EBC for tuning or the gauge? I don't want to go over 13psi until I get my fuel mods installed.
dumbo
02-25-2009, 07:22 PM
I would personally go off the gauge since its basically reading manifold pressure.

When you say "EBC T's into the Boost Pressure Sensor" do you mean the line that gives the stock gauge its reading or the line that goes to your WG actuator?
CajunKenny
02-25-2009, 07:39 PM
It goes in to the boost pressure sensor that is mounted on the Driver's Side Fender right by the Cruise Control.
grimreaper
02-25-2009, 08:03 PM
that line comes off the manifold as well.
Fletch124
02-25-2009, 08:05 PM
I wouldnt trust a factory boost gauge.
CajunKenny
02-25-2009, 08:24 PM
Grimreaper is correct. Both my pillar gauge and my EBC are T'd in to the same line.
IJ.
02-25-2009, 08:25 PM
Do you have access to a compressor and an accurate gauge?
CajunKenny
02-25-2009, 08:29 PM
Maybe. My little compressor isn't accurate at anything below 30psi. My big one may though. I haven't checked it down that low before.

Also, the gauge in question is an AutoMeter ProComp.
IJ.
02-25-2009, 08:39 PM
Turn the reg on the compressor down low hook both the gauge and the EBC into it and increase the pressure and look at what the 3 gauges say.

There are a LOT of pressure spikes going on in a running engine so it's sometimes hard to get an accurate baseline not to mention the gauge might be dampened and the EBC Map sensor not.

I run a 1.5mm restrictor to my Map sensor for this reason (also helps protect it in case of a backfire)
CajunKenny
02-25-2009, 08:56 PM
I'll try that.

On each line going to both the gauge and the EBC Map sensor there is what I thought were just filters. Do these filters double as a filter and a restrictor?

Thanks IJ!
IJ.
02-25-2009, 08:58 PM
More than likely just filters Kenny.
(clear plastic things?)
CajunKenny
02-25-2009, 09:01 PM
Yup. Clear plastic thingy's...
IJ.
02-25-2009, 09:04 PM
Just filters are they have at least a 3mm hole in em.
dumbo
02-25-2009, 09:45 PM
It goes in to the boost pressure sensor that is mounted on the Driver's Side Fender right by the Cruise Control.

Ok, thats what I was thinking. IJ's got it, a third gauge should ballpark witch one is not accurate.
susonet
03-07-2009, 08:43 PM
hi i'm new to this forum and new to the supra world i just rebuilded my car not even a week ago and want to put oil temp, water temp and boost gauges to be safe since the stock ones don't work to well my question is where and how to find wires for the dash light cause that is where the gauges get the back light from i got a 87 7mgte please let me know if this is not the right forum thanks alot