Ok don't know where to put this, so here we go. I have an Oklahoma Joe Highlander, did all the mods sealed the firebox etc...two things I need to point out, the temp probe that came with it on the lid was way off, by 50 60 degrees higher then at grate level...no surprise everyone knows this, and the temp difference at grate level was 60 degrees higher on the firebox side, again no surprise. So I got a deflector plate from BBQmodders. I did a burn in today to season it in...and there were a few surprises, and I thought I would let you'll know about them.
1) it takes a good 45 mins longer to get up to temp with this plate in. Granted I didn't use a full charcoal load because I just wanted to do a fews hour burn in, but I did use the normal chimney start up, just took a really long time to get it up over 200 degrees.
2) Prior to the deflector I got temps 50 to 70 degrees higher on the firebox side at grate level, too be expected. I thought the deflector would fix that, and it did, but it over did it. I got 20 to 30 degree cooler on the firebox side. Then I tried something radical, I removed the elbow I had on the stack to grate level and went back to stock setup. Oddly this made it only 5 degree difference from firebox side to exhaust side, very happy with this... I used a mav 733 temp probe set 3 inch from the left side in the middle and the other probe 3 inch from the right side (near firebox). lol...why it is a lower temp on the firebox side is a mystery. But the bottom line is if you have a deflector plate, you don't need the elbow on the stack to grate level, just makes things worst.
3) here is the kicker, now my useless stock temp probe, works great, it is within 5 degrees of what my mav at grate level is reading, why...I have no idea.