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Discussion Starter #1
Okay, today I bit the bullet and started to install my pre-turbo EGT probe. I decided to document it for the next person who comes along and wants to do the same.

I must give tons of thanks to Wade Husiman and GMCTD for the advice. I just wish it hadn't taken this long to get around to doing the deed.

Here is how I did it, step by step.

1. Remove the passenger side battery (and insulate the positive end)
2. Remove the airbox.
3. Put the passenger side up on a suitable jackstand and remove the wheel.
4. Remove all of the 13mm bolts that hold the inner fender in place.
5. Remove the nuts that hold the passenger side battery tray in place.
6. Remove the small screw that holds the front lower plastic in place.
7. Carefully push the hose retainer plastic prongs through the inner fender.
8. VERY carefully (it's SHARP) rotate the inner fender forward and down while ensuring you have the front clear of the bumper. Did I mention it's sharp? Don't worry.. I'll heal.
9. Wiggle the inner fender down and around until it comes free.

Now, You have TONS of room to work with. I decided to string the hoses out of the way of the turbo inlet to drill and tap the "boss" that is now staring you right in the face.

Get faceshield, drill, center punch, drill set, tap, cutting fluid and gloves together.

10. Centerpunch a starting mark on the exhaust boss.
11. Start the truck (set the brake) and drill the first size hole (I used 1/8")
12. Drill the hole with bigger sizes in steps using lots of cutting fluid and stepping up in size until you reach the size the tap calls out for.
13. Tap the hole (careful, things are getting warm by now out of the exhaust)
14. Shut the truck off.
15. Mount the adapter for the thermocouple.
16. Mount the thermocouple in the adapter.
17. Start the truck and check for leaks.

If no leaks, reverse 1-9 to put the thing back together. Enjoy knowing how your engine is performing.
 

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Good job, good pics, and if you'll notice in the first pic, the 180deg EBP-enhancing foldback in the GM-4 exhaust elbow.

Then, looking at the smooth gradual open curve of the down-pipe, ask yourself - 'but, why?'

However, don't let my opinion sway you, either way..................:cool:
 

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Who you trying to sway?
Only swaying I do is like in a bar..... a sway bar that is on my toy race car;)
 

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Eggs-actly.......:exactly:
 

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Good Pics & good job,

You did remember to break the torque and coat with fresh anti-seize, those studs while you could access them for that GM-4 to 8 swap you are contemplating in the other thread. Looks like a good way to also access the downpipe I wonder if you could slide in a 3.5" one that way, rather than a 3" one that just barely fits in there.
 

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TD from the tests i've done i don't think 3.5" would make much difference if any at all, maybe with a larger turbo it would help some but even then i think the 3" is sufficient being as short as it is.

Nice picks nvm..... good job!

I see you still have your heat sheilds on the glow plugs, since my head rebuild i haven't put mine back on, its been about 15K that way so far, no trouble yet.
 

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Where dieseldummy?? Nice job nvmtnlion :ro)
 

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Discussion Starter #10
TD, oh yeah.. I PBlastered the heck out of em and broke torque.

Everyone. I intend to take pix of the work I do on the truck so that maybe we can add this kinda stuff to the FAQ with helpful pictures.
 

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dieseldummy said:
I somehow wiggled a 3.5" in mine... Nice pics and details.
I wonder if GM-4 has a little more room than GM-8 to allow 3.5" install since they have different outlet elbows, CR I'm still in a quandry why your EBP numbers are so much more different than mine, but I'll sort it out before I'm done, is it possible you have a psia gauge vs psig gauge ??? I can see a little mis match between our readings but I'm dumbfounded on the big number delta.​
 

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nvmtnlion said:
Everyone. I intend to take pix of the work I do on the truck so that maybe we can add this kinda stuff to the FAQ with helpful pictures.
I vote that someone add a link to this thread, as it stands, to the FAQ.
 

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Done
 

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CR I'm still in a quandry why your EBP numbers are so much more different than mine, but I'll sort it out before I'm done, is it possible you have a psia gauge vs psig gauge ???
Autometer Phantom 35 PSI boost gauge, there was about 2-3 PSI difference from my oilfield gauge which was a 300 PSI gauge so there accuracy is pretty good i'd say and the boost gauge was right on with my scanner.

I do not know why mine is so different from yours, well.... maybe a little bit but not the amount were talking about. Take off your turbo, grind out that ridge inside the compressor housing and then take a plain ole flapper sandpaper wheel and smooth the bumps out of the inside of your turndown on the exhaust side of the housing, remove your exhaust manifolds and bevel every inlet on the manifolds to +/- 45 degree's with a dremel, bevel the inlet flange on the bottom of the turbo +/- 45 degree's, oh ya and paint the housing sh*thouse brown then see what you get for EGBP?
:exactly:
 

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Did the turn down a year ago and both sides of the exhaust manifold at the same time and the EGT's on my gm-4 never hit above 800*F with a load going uphill. I'd like to see my EGBP pre-turbine.

I thought the 3" was tight the first time but after pulling it out and back in a few times, I can see a 3.5" easy and a 4" with a little finesse.
 

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Pull your pyro QM and check them out so we can compare #'s if you don't have another spot to put a gauge.
 

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That would be the easiest. What did you use for tubing on the EGBP line?
 

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I used about 1' of stainless hose coupled to another couple of feet of grease gun hose as its the same size and pressure rated to something like 2000 psi so i could see my gauge stuck to the outside of the window the first time. Second time i just took the fitting from my boost line and had an adapter to the stainless hose, plugged the boost hole where it was tapped in the intake and then i could use the boost gauge for EGBP. I had to use the scanner for Boost pressures to compare, but it was always dead on before to the gauge. I thought i might burn up the boost line but it appears 1' of stainless was enough so the temp didn't reach the line.
 

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who sells the bigger ones. i think i could cram a 4" without much work on my gm-8.
 

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Thanks nvmtnlion for the good work, instructions and pics. Installed some used gauges over the weekend and followed your instructions and things went great. Took longer to take things apart than to drill and tap. Keep up the good work !!!!
 
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