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EGT Probe in Crossover?

T

TurboTahoe

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Hi guys,

I am getting closer to actually putting in gauges. (I know, I'll probably kill the Tahoe before I actually get the gauges in). I really have no idea what the HyperTech chip (installed by previous owner who also threw away the stock chip, so I can't revert to stock) is doing to fuel and boost.

I am thinking that the easiest install would be installing a clamp-in thermocouple on the crossover pipe, just as it is going up to the turbo. However, I haven't come across many people who installed it there.

Do you guys have any advice?

-Rob :)
 
The harness for it probably wont reach to the crossover and you can't lengthen it without affecting the calibaration of the guage. Preturbo is best but need to drill and tap maanifold, post turbo can be done with a clamp on but I drilled and tapped a piece of 1/8 inch steel and then drilled an oversize hole in the downpipe and welded the steel over it.
 
I don't understand. If you can reach the downpipe, certainly you can get to the crossover, can't you?

-Rob :)
 
heaths is drivers xover, b4 i bought his, i drilled and welded a nut onto xover and screwed coupler into it. worked like a champ till upgrade.(super easy to do)
 
It was my first drill/tap job into the collector boss under the turbo via PS fender wheel well. Wasn't hard at all.

If you want to avoid drill/tap for intake, buy the Boost Bolt from the vender Oil Burner here...

I would if i had to do it again. make that boost guage take no time at all.
 
I'm confused, I thought Rob was asking about an EGT probe, not a boost tap....?

Anyway, I've had a clamp-in style probe in the downpipe that I got from Kennedy when I got my gauges back in late '99 or early '00, since, well, 1999 or 2000 :) and it is still working fine...

Don't see why it wouldn't work on the crossover with the right gauge. Only thing I can think of is that the drive pressure is going to be higher pre-turbo and that the clamp-in might be more prone to leak a little boost (and heat, and soot...)
 
Only possible downside is you are getting the average temp of half the engine, instead of the average temp of all 8 cylinders.

Eitherway, your getting the 'jist' of the information you need. When that thing is climbing past 1000 you know to ease up, regardless of where it is mounted (this applies to PRE-TURBO) The post turbo is a few hundred degrees lower before warning.
 
Excellent location would be in the crossover pipe just below the oilfilter-side flange, where EGT has not been cooled by passing thru the crossover to the turbo-side bank - the crossover pipe is down in the road draft, where winter temps would cool the pipe, not even to mention the icy road slush - 'nuther better location would be in the exhaust manifold in that bend B4 the flange - manifold EGT in both banks will be the same - if not, you shouldn't be driving the vehicle - this location would, of course, be pre-turbo

PUCKEDUP017.jpg
 
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As always, appreciate the kudos, Matt - truth is, I'm not only dyslexic, but pc-illiterate, to boot (the former causes the latter) - I just plain fergit how to do that stuff - prollem being, when I do remember that stuff, I fergit other stuff - it's just like Sunshine's monitor: not enuff room on my screen fer everything......................

One point, to prevent confusion - the pic is of the '95 GMC 6.5TD as installed in my '89GMC, which is the '80's-series square-body style with Dana 60 front axle
 
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Most of my vehicles are running Rancho shocks, but, yeah, the big GMC has ~3" lift
 

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gmctd said:
Excellent location would be in the crossover pipe just below the oilfilter-side flange, where EGT has not been cooled by passing thru the crossover to the turbo-side bank - the crossover pipe is down in the road draft, where winter temps would cool the pipe, not even to mention the icy road slush - 'nuther better location would be in the exhaust manifold in that bend B4 the flange - manifold EGT in both banks will be the same - if not, you shouldn't be driving the vehicle - this location would, of course, be pre-turbo

PUCKEDUP017.jpg
Click to expand...

Thanks JD, that's an excellent idea. I can drop the crossover and do a wee bit of drilling on the exhaust manifold, or pop a clamp-in around the same place. Excellent!

Thanks,

Rob :)
 
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