Finally got around to installing my pre turbo pyro this morning. I was a little freaked out at the actual differences between pre & post!!

I've always had my pyro installed post turbo. It's installed in the elbow of my BD exhaust brake. I did the usual and added 300 degrees to my running temps when getting into the pedal and climbing hills and such. Never really thought much else about it. I have the "rainbow" ISSPRO pyro guage, so adding on the fly was a no brainer and I drove accordingly.

Well, in addition to my post pyro, I now have a pre pyro as well. It's the same "rainbow" guage only color coded for pre turbo. Being able to watch 2 guages at the same time doing the same job just got a little freaky.

Idle, cruise, roaming around town, both needles swing in unison like they were hooked together. Stand on it climbing a hill or accelerating into traffic and the pre pyro goes nuclear with the needle screaming it's way around the guage heading for the red zone. The post pyro just slowly climbs it's way around the guage.

On one particular hill where I can climb it easily in 6th at 60 mph, I read 800 post and 1300 pre turbo!! That's a 500 degree difference!!!! Same hill, same speed in 5th which I usually do....700 post and 1150 pre. Still beyond the add an average 300 difference in readings.

Level ground and such, both pyro's read usually the same temps give or take 50 degrees or so.


It's amazing how much heat the exhaust side of the turbo differs in temp from the inlet to the outlet of the turbine side. My pyros are only about 7 inches apart.

Just had my eyes opened today and thought I'd pass it along.

 

Awhile back someone posted a explaintion on how a turbo works.

Basically when your pounded down the skinny pedal the turbo is converting that heat & pressure energy (about 33% of it) into boost. That's why the temp difference. So when you just cruising around and not needing the power it dumped in the exhaust as heat. This will get a bigger gap (pre / post pyro) as you get highier in to the HP and TQ numbers.

This is the main reason for going PRE TURBO on the PYRO PROBES!

 

Ohh come on jeff only 1300 degrees you need bigger injectors!

Jason

 

Excellent post. Can't be restated too often. Too many people, experts included, using the 300* difference as a rule of thumb. Only safe general rule is 500* difference...when the engine is working...even mildly hard.
Many cooked engines out there that learned this the hard way!

RJ