Engine/Transmission (1998.5 - 2002) Installing gauges...have questions

[stownsend]

I'm going to be installing the gauges within the next couple of days and I have some questions for you wrench heads.



First off - the instructions for the boost gauge suggest installing on the intake horn. Is this really better than installing on the boost line? (Better in respect to response and accuracy. )



Second - the instructions call for a 1/8 NPT tap. I have in my hot little hand a tap marked 1/8 x 27. Are these the same, or do I need to make a trip to the store? (I'm capable of doing this job... . I just don't deal with this **** every day. )



Third - how do I attach the sensor to the transmission? Is there a drilled/tapped hole?



Thanks in advance for your help.



ROCK ON TDR!!!!!!

 

[Pmaloney]

I'll tell you what I did (right or wrong)

1. I drilled and tapped the intake horn with the thought that it is better to have a metal fitting than the supplied plastic "T" and clamps

2. I believe that the tap you have is correct, it should say "N. P. T" on it or have a "V' shape to it (thinner at the bottom than the top)

I had a 1/4 N. P. T tap and a adapter lying around so I went that route.

3. On a previous auto I had I placed the sender in the side of the pan and applied J. B. Weld around the threads on the inside for security, seemed to work fine.

 

[BarryG]

There are a variety of places to connect the boost sensor for the gauge. You can drill and tap the intake horn, you can purchase a boost bolt from Piers which replaces one of the bolts in the intake horn or you can just go to the hardware store and get a 3/4 to 1/8 npt bushing and remove the 3/4 npt plug in the block and replace it with the bushing and screw your sensor into that. That plug is on the drivers side towards the rear of the block. There are two plugs one is a coolant galley you want the other one. I honestly cant remember which one is furthest back. The one you would want is right above the lift pump. Mine had red/orange loctite visible on the threads.



The transmission gauge you can drill and tap the pan, you can place it in one of the test ports on the trans (one port is better than the rest but not sure which one, just make sure if going this route that your sensor doesn't ride to deep into the port as there is a piston in there that you do not want hitting the sensor, many have used the port with no problem and others have had the piston destroyed as well as the sensor, or you can tap the hot line from the cooler with comp fittings, flair fittings and splice in a port or last but not least you can purchase a new hot line with a port built in it which is what I did (I believe the line is from a 95 that came stock with the sensor port in it and if using this you need to make sure and remove the check ball out of the cooler end of the line).



I am sure there are other ways to do both and others will probably chime in about them.

 

[Tcolesanti]

I believe either tapping the intake horn or using the boost fitting from Piers is the absolute best way to go, so if you have a leak in the intake system it would show up right away on the gauge. Having it on the turbo with that "t" fitting will never show a change if you rip an intercooler boot or something.

And yes 1/8"x27 is the right tap, it should also say "NPT".

 

[Kellydown]

Be careful not to overtorque the boost bolt from either Piers or Genos, the one I got from Geno's had a warning about this, with 12 ft/lbs as a limit, it failed at 10

 

[JHerrlich]

I just relocated where I got my boost from the port at the back of the engine (by the way, it's right behind the fuel filter) to the intake horn. It gets much more stable numbers there. The needle used to vibrate at high boost. Now it's nice and smooth. I wouldn't be afraid of drilling and tapping the intake horn, the casting is pretty easy to drill, I drilled mine right below where the dipstick is for support of the line. Just make sure not to run the tap too deep. Run it deep enough that your fitting will go in a few threads by hand. If it's too deep, the fitting will go in too many threads and may not seal.