I have a 1994 XJ that is RHD and my floorboards are so hot. Unbearably hot. I don’t have carpet in it, just the standard one layer floor and I’m looking for the best options to reduce/ eliminate the amount of heat I’m getting from my floor. It will literally melt the bottom of your shoe. I want to put carpet in it but want to know the best layering process or products/ companies to get aftermarket stuff from to fix it before it gets too hot this summer! I was going to get carpet with the mass backing but want to know if that will be enough. Keep in mind it is right hand drive so my drivers side is much worse due to my muffler and exhaust being directly under me.

There's a heat shield attached to the upper side of the stock cat on mine. If yours doesn't have one you might look into getting or making one, that'll help. The mass insulated carpet you're looking at will help and be an upgrade too.

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I installed heat shields over my exhaust from the passenger footwell to the muffler, and also put down foamboard on my floor for insulation. Look at my build thread for pictures and specifics.

Don't use sound deadener thinking it will help with heat. You need something with a decent R-value. Factory jute-backed carpet will help significantly if you want to go that route.

When was the last time you renewed the transmission fluid? My floor temp, specifically the area between the front seats leg areas became significantly cooler after I renewed all my ATF.
Just a thought.

I used baking sheets to create heat shield for the floor pan. Bolts are ran down from inside the cab, with two nuts holding them tight and spacing out the heat shield, then another nut to hold them ok on.

The adhesive-lined heat shield material I got from Summit probably would have worked just fine without the baking sheets, but I didn't want the shields trapping water and causing rust, so I used the baking sheets...

-7% LTFT means that the fuel system is running inherently rich. This almost certainly due to the 4-hole injectors you mentioned. These are likely flowing ~7% higher than factory injectors. With that said, I don't think this is the cause of the toasty floor because the fuel control system is able to compensate and reach target AFRs.

In the summer, my XJ also gets a pretty warm floor from the firewall to the back of the vehicle. 100% stock motor and exhaust. The 4L motor and AW4 transmission simply throw off a ton of waste heat, and that in combination with your muffler and cat being much closer to the floor is likely the problem.

If you don't want to move the muffler and cat further away from the underbody, then I think its necessary to beef up the heat shielding and insulation.

Heat shields primarily reflect radiant IR. They need to be shiny. But it also will help if they are low thermal conductivity. If you want to get creative, build a bigger heat shield, and maybe make it a layered structure. One suggestion is a 2-layer system where the exhaust-facing layer is shiny metal, and the second layer could be a sheet of metal wrapped in exhaust wrap. Also choice of metal matters greatly. Cookie sheets are made of aluminum which has excellent thermal conductivity. Considering making your heat shield out of 304 stainless steel (preferably polished) which has almost 20x lower thermal conductivity than aluminum. In this scenario, a second layer covered with exhaust wrap wouldn't likely be needed.

Consider shaping the heat shield so that it deflects the hot engine/trans air away from the body.

Lastly, consider plastering portions of the underbody with insulation/heatshield. This is better than doing it from the inside of the vehicle. For the temperatures you mention, I'm not sure what insulation I'd recommend. Some butyl or rubber foam insulation with foil covering can handle perhaps 250F, but for higher temperatures than that, silicone foam or a fiber base is needed.

DEI sells a variety of products, some of which are more expensive than seem justified for putting on a XJ.

I believe this reply is misplaced and was meant for XJlimitedx99 thread... https://www.cherokeeforum.com/f2/mit...normal-275227/

Yep, looks like it was. I did the same thing, scrolling right from one thread into this one. I'm going to copy and paste this in the other thread to keep the info over there.

Oops. I didn't even realize that there are two threads.