Mods and Turbo physics

[Jetmek319]

Greetings Fellow Kerosene Sniffers!
I am getting ready to do a couple of upgrades to my '04 F250SD 6.0 and while I was planning out a course of action a couple of question popped into mind. I am going to be installing a MBRP turbo back 4" exhaust (haven't decided on the T304 or T409 SS yet) and an SCT Livewire with the EGT module. Here's where you get to go back to high school physics...

Various fluid and thermodynamic laws state that as the pressure drops so shall the temperature. No problem so far. Using these laws/theories and LOTS of help from my physics major buddy, we calculated that an average temperature drop, through a stock power curve, taken at the pressure wall at the turbine inlet to the turbine outlet was between 2-4 degrees Celsius (35.6 -39.2 F, minimum was 1.4C, max was 13.67C). All reasonable operating condition resulted in less than a 70 degree swing.

With that in mind here's the question... Is it reasonable, and safely accurate enough, to put the EGT probe in the down pipe just downstream of the turbo outlet? I would be much more accessible for maintenance, removal, installation and seem like a much safer installation. I would much rather have the metal shavings blow out the back, instaed of getting sucked through the turbo, and if not done correctly those taps are a bear to get when you break one in the manifold. It's cheaper and less difficult if you need to replace the downpipe after making a mistake!

Just a thought.....

Jetmek319

[alfajay]

I know it very easy to tap the manifold, and tons of ppl do it w/o problems. Don't know for a fact but I have been told its 150-400 deg. F differnt in the downpipe. But I never knew anyone that had 2 pyros to prove it, just hearsay.

[mschn99]

pressure in the Y pipes can be as much as 60PSI....pressure in a strait pipe might be 8.....

Temp differences are too great...ur theory is great..but numbers are not right....on average its a 200-250 degree difference..and i have seen that proven....

[Jetmek319]

I guess that would be the most accurate way to test it. May be experiment worthy... hmmmm.

[Clay Henry]

your downpipe would be much harder to tap for the probe, two thin.
Theres no maintenance needed on it in the future and if for any reason you need to take it out, its very accessible if you put it in the rear corner, driver side y-pipe.

[460+]

If you have seen in semi's all of the probes are in the turbo down pipes and have worked for years. But if you are building some serious hp then i would recomend in manifold. I know some even run 2 one ineach bank.

[cstroke69cpy3]

the tapping is not to difficult.. just take your time..

[jwsland]

i am no mechanic, believe me, i've never even tapped anything before. "maintain" helped me with my install. he told me what to do and it was actually quite simple.