Pyrometer Guage Debate!

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Feb 10, 2006 | 08:39 AM

fei1

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Mountain Pass

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Pyrometer Guage Debate!

Hey all you guys running the pyrometer guages, where did you mount the sensor? I was talkining to a few people and some said they used the manifold and others said that was no good because the hottest exhaust temperatures come after the turbo going into the downpipe. What is your take on the issue and where do the big rigs usually mount the pyro.

Thanks for your input. I appreciate it.

fei1

Feb 10, 2006 | 08:46 AM

Orezona

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This is the result from the last time that question was posted. And I vote for pre-turbo.

https://www.ford-trucks.com/forums/s...ight=pyrometer

Feb 10, 2006 | 09:16 AM

kilapapipa

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From: Central Wyoming

I've had both Post and Pre turbo and there is a huge difference. Post Turbo temps did not rise above 900* and Pre Turbo hits 1350* at WOT sometimes when I am having fun. I believe you need to know what temps are going into the turbo and not what is coming out.

Feb 10, 2006 | 09:31 AM

arninetyes

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Quote:

Originally Posted by fei1

Thanks for your input. I appreciate it.

fei1

Sorry. I'm no expert, but that is dead wrong. The experts will chime in soon.

The energy of the exhaust drives the turbine, the turbine drives the compressor, the compressor uses that energy to compress the incoming charge.

When the energy of the exhaust goes into the exhaust turbine, it reduces the energy in the exhaust, thus reducing the temperature. It seems to me there is about a 300 degree drop after the turbo - and that drop is precisely because the turbo is using that energy to accomplish work - otherwise, all that energy simply goes out the exhaust pipe.

If you want to monitor exhaust temperature, it is best to put it before the turbo, either in the manifold or in an up-pipe.

Banks sells their pipes with pyro plug-ins in the downpipe. They do it for simplicity and ease of installation. But you will find that a post-turbo temp should stay below about 900, give or take, while a pre-turbo temp should be kept below 1250.

Pre is more accurate.

Feb 10, 2006 | 10:03 AM

jtharvey

Lead Driver

Joined: Oct 2004

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From: Columbia, MO

Pre-turbo is what you want. The main reason for the EGT guage is to watch the temps coming out of the engine. Get too high with those temps, and you could melt a piston. So, the closer you get to the exhaust directly out of the cylinder, the more accurately you'll know what the temps are. The post turbo is definately cooler than the pre turbo. Mine right now is post turbo, since the exhaust came with a port to mount the probe, so it was just easier for me to mount it there. But, I do have plans to install a pre-turbo guage sometime in the coming months. I've heard most of the big rigs have theirs mounted in the downpipe, but for conflicting reasons. One was the obvious--it's easier, the second was a claim that if the probe breaks they don't want it going through the turbo. However, I've never heard of a PSD that had broken a pre-turbo probe off, so I don't think it's a concern. And there are plenty of guys that have their probes mounted pre turbo.

Feb 10, 2006 | 11:15 AM

RedBoat

Rather Be Floatin

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From: Marble Falls, Tx.

Is th pre turbo where you get under the truck and drill into the exhaust manifold seems as though that would be post turbo of is post turbo in the downpipe??? Sorry just dazed and confused. typical

Feb 10, 2006 | 11:27 AM

fei1

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Mountain Pass

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That's what I was thinking. Post turbo should be cooler than the pre-turbo because thats where the feul is going to combusting no? Thanks for the advice now I can shut this guy up and I will print a few posts out to give him proof.