View Full Version : Where to put "t" fitting for boost gauge

Turbo Trans Am
09-21-2004, 10:44 AM
I’m having problems figuring out where to install the “t” fitting. According to the site's instructions, it is put on the fourth line from front attached to passenger side of throttle body, but the flexible line after the metal line is only about 8 inches long before it plugs into what I believe is the MAP sensor (has one screw securing in place.) The only straight area in this line is as it connects to the MAP. In the instructions, tthe guy installed the “t” 6 inches past the bend in the line towards the firewall, but my line barely longer than 6", so I don't know how I could install the "t" six inches past anything. Instructions also stated, “Snip the somewhat flexible tube (not the coupler) of the boost line.” What is the flexible coupler?? I don't wan to cut the wrong line. Am I looking at the wrong area to install the “t” fitting? Is my line just shorter because I have a TTA? Can anyone send me, keith.gannon@scott.af.mil, a pic of where the “t” fitting is installed on your car? Thank you very much for your time!

09-21-2004, 09:42 PM
You can grab a line from anywhere you like. It does not matter, as long as there is not a check valve before the "t". I would put it in a rubber hose, not a plastic hard line. Also i would not use a line going to your fuel regulator, as a boost reference source.

Scott :seeya:

09-29-2004, 11:36 PM
Personally I prefer to snatch it right off the turbo, either from the wastegate or the wastegate solenoid itself.

09-30-2004, 06:06 AM
That may not be a true reading of boost making it into the motor, but it will be pretty close, ALL intercoolers have some pressure drop. Would this affect boost control? If a leak happened, or a line blew off, the turbo would go to the moon! Those lines are very important! I would not use those!

Scott H.

09-30-2004, 02:34 PM
You do have a point there, however I'll note that the stock T-Type digital boost readout taps that point. Assuming you don't want to agree with the engineers, my next preference would be split it off at one of the hard lines.. Straight off the distribution block atop the intake, find the metal line that goes down and back along/near the fuel rail, and connects to a plastic line..split and use that one..easy to find, straightforward, no previous splits or check valves, and it's out of the way.

10-26-2004, 12:51 AM
Personally I prefer to snatch it right off the turbo, either from the wastegate or the wastegate solenoid itself.
This is not a good place to measure boost,because it does'nt measure the actual boost in the intake. After the pressurised air leaves the compressor it runs into restrictions (intercooler and throttle body) that lower the boost pressure. In order to see 17 lbs.in the intake manifold,on a mostly stock motor with stock I.C.and T.B.,the turbo has to make 20-21 lbs. of boost. One upgrade that all turbo regals should have is a 70 m.m. throttle body,P.T.E. upper plenum,and R.J.C. power plate. Removing the restriction of the stock throttle body will increace the boost by 2 lbs,which is proof of the restriction. Now to see 17 lbs. at the intake,the turbo only has to make 18 or 19 lbs. This means thar the air is heated less,meaning cooler/denser air. 20 h.p. The boost guage should be teed in anywhere in the line going from the map sensor to the steel line on the intake. Mine is hooked very close to the steel line.