FYI - pyro in stock 3B

[Green Lantern]

I haven't wheeled with it, but here is the driving results for my VDO pyrometer installation. The thermocouple is installed on top of the exhaust manifold, in a flat spot between number three and number four exhaust ports (counting from front to back). The outlet pipe is attached to the manifold from below at the number four port.

1981 BJ42, stock with 3B motor, approximately 75,000 miles since receiving a 3B motor from a BJ60. Neither Rob nor I know the complete motor history. No turbo. 4.11 gears and 33x9.5 tires. The speedo is accurate. No tachometer though. I live in Texas. It's flat. We don't have mountains, only overpasses. Most grades are 3% or less and can last for miles.

Driving around the neighborhood, the pryo shows 350 to 450 degrees F. Driving 60 mph on the highway, the pyro sits at 650. Climbing a long grade it will go as high as 850. I got the pyro up to 950 passing someone around 70 mph. Under load the needle moves quickly. Thankfully, the needle drops quickly if I get off the accelerator.

This is old news to most of you. Hope it helps other noobs like me.
Happy Trails! N

 

[Gold Boy]

sounds about right - egt's a lttle on the cool side.

 

[brownbear]

Sounds like good numbers. If you want to push it a little higher you can. Dial up the fuel till the temp is max hitting 1100 or so. Then if you drive on a big hill you might hit 1250. BIG hill.

If you do dial up the fuel you have to be careful with going over 1250. Then you drive a liittle to the pyro. But the engine is way more peppy. I liked it the feel when I did it.

 

[Green Lantern]

Thanks!

I'll look at changing things after I get used to driving the pyro. This is way more interesting than a tachometer. You can feel & hear changes in rpms, but the EGT changes dramactically without any outward sign. Well... until you break something.

Having fun! N

 

[cruiser_guy]

I'd wait till you have a decent hill to check it out on. Dropped pre-combustion chambers are NOT fun. My truck has a turbo but I did not adjust the factory fuel setting (the factory wire is still there) and can hit 1250 on a good hill working the truck hard.
Those readings are pre-turbo and would be dramatically higher without a turbo.