EGT probe location?

[DieselDixon]

Just pickied up a 03 GMC 2500HD with the Duramax and Allison last month. I purchased a Boost and Pyrometer which I want to install now. However, I am hearing mixed stories on whether I should put the probe pre-turbo or post-turbo, anyone have any comments about this? I really hate to have to pull the manifold off to go pre-turbo, but if that is the best spot, I will.

Thanks

Mark

[mackin]

It may not be the easiest to install but pre turbo is the most accurate reading... The majority have installed in this way...

Mac

[jcummins]

I drilled and tapped my manifold with it on the truck. You don't have to remove.

[DieselDixon]

Okay, Pre-turbo it is!

Just worried about running any shavings through the turbo. Did you do anything special to prevent this from happening?

[hoot]

Yes,

Drill and tap while it's running. The chips blow out as they break free. It hardley gets hot. Protect your eyes. See my signature for pictures.

[chuntag95]

I also used a little grease on the bit to catch the chips. I wiped it off and regreased several times. Once you are through, the chips fly at you like a star field in a movie. SAFETY Glasses at a minimum and a shield would be better. Enjoy.

[TST Tech]

Quad1100'
We do a lot of installs on the Duramaxes now and we use a pencil magnet to retrieve the shavings. You can get them at any Sears that sells tools. They are flexible so you can get go different directions with it. To be honest, we hardly ever get any shavings out of the Chevys. We get the most out of the Dodges because we drill going down from the top. Have a great day! Greg

[Kennedy]

I use a step drill, and do it dry with the engine running. Pilot with a std bit and then the step drill will take it from there. Just make sure you can get the correct step drilled without hitting the far side.

Using a step drill makes forsmall size chips and a large single STRAIGHT evacuation path...

[ 05-22-2003: Message edited by: kennedy ]</p>

[DieselDixon]

Gosh, good info guys. Sure am glad I joined this forum. Me being new to Diesels and turbo's I'm sure I will have plenty of questions!

Thanks

[DMAX_Phil]

Quad - I did the install last night, right where Hoot, Mackin and others have - in the pass. side manifold. Total time was about 2.5 hrs. Took me 20 minutes just to remove the fender liner and scope everything out (where to drill the hole in the firewall, where to route the wire, etc.). Most of the rest of the time was spent wiring. If I had to do it again, I could probably cut my time in half! Mackin's and Hoot's pics. helped a lot. Drilling and tapping the manifold was a no brainer. I was tempted to remove the tire but since I started at 8:30 p.m., I was looking to save some time. There was no problem working around the tire. I put the hole in the firewall in the insulation cut-out just above and to the right of the steering linkage (as you stand at the bumper looking at the firewall). There is a corresponding cut-out of the insulation on the inside.

Things I didn't have or have enough of: 1) I had one Mini-fuse add-a-circuit and I needed two (lights and power to gauge; 2) ring terminal to fit the bolts under the fuse box for the ground; 3) the right size (small) wire loom to protect the probe wire as it is routed over and secured to some rough spots.

Other than that, it was really a piece of cake. I only installed the pyro and not the boost gauge (single pod).

Now, I'm ready for that Predator from JK (John, it just arrived today - thanks!)

Good luck,

Phil B.

[Amianthus]

An alternative to drilling with the engine running is to use an air compressor and set the pressure to about 4 psi and attach a nozzle to the tail pipe. I've done several trucks this way and have had great results. Definately wear your eye protection. I usually use a little bit of anti-sieze on the threads too. Saves heartache later.

[DieselDixon]

Okay, after much deliberation between pre and post turbo, pull the manifold off or drill it with it on, it is finally done!

Took me all of about 45 minutes from start to finish and I must admit it was painless.

I know by now you are dieing to know which way I went so I will tell you it was pre-turbo and as you know by how long it took, it was with the manifold attached to the motor and the engine running.

I must say thank you for recommending the glasses, those chips fly out at you, should have put something on my arms though, a few of them were pretty hot.

Thanks to Hoot for the pictures.

I do have a question though, why in the Autometer instructions does it say

[DieselDixon]

Okay, so let me know if these numbers sound right for a stock truck with the pre-turbo EGT.

No load driving:
</font> Driving down the freeway cruise control, about 800 - 900, 5 pounds of boost</font> WOT about 1100 , 19 pounds of boost</font> Totally off the throttle coasting about 450, 2 pounds boost</font>Pulling a 7500# trailer
</font> Cruise control about 70 MPH 1100, 8 - 10 pounds of boost</font> WOT about 1200, 20 pounds of boost</font>
It seems a little high when pulling the trailer on flat ground, hopefully I'm wrong.

I'm taking a trip this Friday and have a couple of good hills to go up, from what I am reading 1300 is the magic number to start letting off.

[huntindog]

DieselDixon
What was the outside air temp. ?
I try to keep under 1200, I have seen 1236 (stock)towing 10,000# up a very steep grade. It would have gone higher, but I backed off.
I am sure it's been higher before I got the gauges.

[DieselDixon]

It was about 80 degrees out.

[David Proske]

DieselDixon, where did you drill the exhaust manifold? I have been looking at install pictures and noticed that my 03 manifold does not have the nice flat spot on it that the 01 and 02 has. The 03 manifolds are more rounded where people have been putting the fitting :confused:

[DieselDixon]

David,

If you look closely at Hoot's pictures (egt3.jpg) is a good close-up of his install. You will notice that it is not flat where he went in and I put mine in the same exact spot. It does not really need to be flat to work anyway, as long as the drill does not walk around when you start the pilot hole, and you don't over tap when you make the 1/8" NPT.

[WOJO 1]

This has me wondering. I have the X-Monitor with post turbo setup. My boost readings are different. Cruising down the road at 55mph it shows boost of "0". The slightest incline and the boost will go up. Unloaded WOT I get around 16. I have the juice removed at this time to get base line numbers. Anyone know why there would be such a difference? :confused:

[DieselDixon]

At 55 on flat ground it reads about 4 pounds and the most I have ever seen on the boost gauge is 20. The gauge is a mechanical Autometer gauge that is mounted in the waste gate hose.

[TBC]

I have the Autometer boost gauge mounted in the wastegate hose and have seen 23 psi boost at WOT and about 1300 deg exhaust temp and about 80 MPH. Did not see tach since it was a rather quick run nad slow down. I was on level 4 with the 4.6 juice.

Tom

[BADMAX]

I HAVE AUTOMETER AS WELL. LEVEL 4 REG JUICE HAS SHOWN 1200F AND 27 POUNDS OF BOOST TEED IN AT WASTGATE HOSE. WHAT A RIDE!!!!!!!!!!

[GMC-2002-Dmax]

Originally posted by BADMAX:
I HAVE AUTOMETER AS WELL. LEVEL 4 REG JUICE HAS SHOWN 1200F AND 27 POUNDS OF BOOST TEED IN AT WASTGATE HOSE. WHAT A RIDE!!!!!!!!!! That sounds about right, add some Predator to it and bury the gauge at 1600 deg. :eek: :eek:

GMC ;)

[hoot]

My SPA 211 boost sender is in the intake tube, post intercooler. It records highest readings. 25 psi is the highest I've seen.

EGT in the exhaust manifold. Hard hills gets it well into 1300's

Boost around town barely gets off zero unless you put some load onto it. That's normal.

[Bullseye54]

Just got my isspro guages from JK yesterday & am putting them in this morning.I was looking at the thermocouple & it's 2.5" long from the threads.The manifold doesn't look 2.5" in dia. Is this the right length thermocouple?

[4x4man]

I have a couple of closeup shots of the thermo mounted in the exhaust manifold on my 03. Click on my truck pics in my signature and it is towards the bottom of the album. There is a section that is flat, at least on mine there was... good luck, and hope the pics help.

Bob

[hoot]

Originally posted by Bullseye54:
Just got my isspro guages from JK yesterday & am putting them in this morning.I was looking at the thermocouple & it's 2.5" long from the threads.The manifold doesn't look 2.5" in dia. Is this the right length thermocouple? Usually you can slide the thermocouple to adjust it's length. I like it about 3/4" into the exhaust stream but you should have specific instructions...

[Bullseye54]

Hoot,I found the compression fitting after I posted.Thanks.