pyrometer & boost location with turbo

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

May 29, 2007
Orlando Florida
Rubuilding a 3B on the stand. The engine was in pieces when I got it and it came with a new AXT turbo kit. I figure since its out on the stand now I might was well drill the necisary holes for a pyrometer and boost guage line.

Where should the pyrometer probe go? Also, is there a spot to hook a boost line up to for the boost guage or does a hole need to be drilled for that?

Any recomendations on brands of guages I should be looking at? I have Ispro in my F250 and it seems to be pretty good.


What vehicle is it going in?
I would say the pyro in the manifold. And the boost, put a T between the wastegate actuator and the outlet of the turbine. There should be a tupe in between, cut it and install a T
I did the same as "eleblanc" recommends. I have Isspro in my 'Cruisers and I like them.

You'll get several recommendations on pyro location. Some like me are "pre-turbo" and others are "post-turbo" (sounds like a religious discussion!).
Its going in a 1982 FJ40 landcruiser 5 speed. I hadn't thought of the wast gate hose, that's a great place to tap into.

I always thought post turbo was kinda useless, the temp your reading is not the true cylinder temp. When I installed one in my F250 w/ 7.3 internation diesel I put in in the driver manifold I think between the two center cylinders. Is there an ideal place on the manifold to put it, front, back, between certain cylinders?


Last edited:
Is there an ideal place on the manifold to put it, front, back, between certain cylinders?

All mine are where the cylinders all collect just before entering the turbo.
Sounds like the best place to me, that's what I'll do.

Just thought of one other thing before I find gauges, what ranges do I need? How hight do these AXT turbos boost and what is safe for a stock 3B engine with stock head studs? Also, what kind of exhaust temps are safe and what temps melt the engine? Another words how high should be boost gauge and pyro I buy go to? I know the pistons in my F250 melt around 1450 F, is a 3B the same.


remember, the pyro is to give you an idea of what is going on inside your engine. if you run close to the melting temp then you might have to change your driving style.

think of it like those 'tilt meters', when you go over they tell you at what angle you were sitting at. when the piston melts you can tell us at what temp you are putting out.

preturbo is the best if you the manifold is off anyway... there have been a couple instances of the sensor breaking off and i used to be dead set against putting them pre turbo for this reason but it seems it might have been install error more than poor design...although if you are installing the pyro AFTER the turbo is already installed in the engine then post turbo is safer due to metal filings conecting with the blades
A boost gauge of 15 psi is adequate. My Isspro pyrometer has colored scales and yellow is from about 950 to 1250 and red over 1250 F. I believe that is the recommended scale for a pre-turbo pyrometer.
From driving transport trucks I was told to try and hold speed and rpm on hills until you hit 900F then downshift. This is probably a little conservative but safe??
The gaoges seem to go much higher, but I'm not sure what the engines will take?
At least will know where were at? with a pyrometer and know when the engine rolls over!

Users who are viewing this thread

Top Bottom