I think I've read that the #4 exhaust is restricted in the manifold. Does that mean it runs hotter than the others? If so, that should be a good place for the TC - or is it enough to worry about? Is there a better place? This time I'm putting the gauges on first so I can see what's happening before mods! TIA! Craig

 

On the 3rd gen's the back two cylinders are supposed to run hotter than the rest, or so I've heard anyway. Not sure why. At any rate, I've got my pyro located on the vertical section a couple of inches above the flange near where the turbo bolts on to, on left side of the manifold wall. Enough meat to drill and tap for a 1/4 npt thread and provides an average temp of the rear cylinders. I put it there as it's easiest to keep the chips out when drilling (drop the turbo an inch and cover up with cardboard) - there are as many others that put it in by #4 cylinder.

 

Your plan sounds good to me. The back cylinders are the farthest from the incoming air - makes sense that they'd run hotter. Craig

 

I have heard the same thing.....that number 6 cylinder runs the hottest.

My probe is right on the manifold in front of number 5 before it goes into the vertical split section.

 

Another thought may be is if its already restricted then putting the probe elswhere might be the thing ot do , I do not know if the restriction is there or not , it would be good to know.

 

This is where I put mine:

 

Instead of starting a NEW THREAD, I figured this thread is where I had a question:

Has anyone ever TESTED to see if the REAR 4-6 cylinders actually RUN HOTTER than the cylinders 1-3?

If so, can you post what the temp differences were?

It is just a PIA if you drill & tap the rear portion of the manifold as most drills will NOT reach back there...

 

I put mine where Edge said to. I thought about it a lot and I ended up with it on the number three just before it drops into the collector. I don't really think it matters which cylinder runs hotter. I think if you look at the manifold you can see that it is running the front four cylinders into one and the rear 5 & 6 into one and then both run into the collector but are still divided. It looks to me like getting the exhaust from the first 4 cylinders all in one vein would likely be the best for EGT but that's just me thinking again.

Here is where Edge wants you to put the thermocouple.

 

How big of a deal is it to drop the turbo down? Is there a gasket that can become FUBAR??

 

I unbolted the drain tube and dropped the turbo a little. I slid sheetmetal in between to catch the chips. The gasket is metal and I reused it with no leakage. Craig

 

If you are carefull when you drill, (lots of grease, lots of stops to clean the bit, and magnetize the bit again just before it pops through, and also just idle for a couple of minutes ) you wont have any problems anyways

Kevin

 

Are COBALT drill bits good for cast iron???

 

Yep, my cobalt bits chew through an exhaust manifold pretty quick, although I think you would also be fine using something less refined.

 

Also, should you use ANTI-SEIZE on the EGT/PYRO fitting?

 

Yes. here is a pic of my pyro's.



Lets see. The one in the rear is always cooler. When the one in the front is 400 degrees, the rear is 350 degrees. When the one in the front is 1600 degrees, then one in the rear is showing 1350 or so. Between 700 and 1100 degrees the rear is 100-200 lower.