I bought my FD stock and worked diligently to get the temps down. My issues were similar to yours but my temps have greatly improved. Main differences in our setups right now are:

Fan switch
Radiator ducting
Ducting around oil cooler ducting
Pill in the AST line
Airbox intakes

The first two have been mentioned with good reason as they are must haves IMO and would give the most benefit while low speed driving or sitting. Benefits of the fan sw are obvious but the radiator ducting will help much also.

Ducting around the oil cooler ducting(see pic). I had some gap around the sides of my OE oil cooler ducts as well as the fins on the OE coolers stop short on the sides. I made some extra side ducting out of silicone gasket material and fastened it to the OE ducts with pop rivets and small washers to spread out the load of the rivets. Won't help while sitting still but will with low speed driving.

Pill in lower AST line. I stumbled onto this while reading on this site. There is a restriction in the OE AST lower line nipple. You loose that with a different AST and while I was having cooling issues it was anathema to me to have any significant amount of hot coolant bypassing the rad. I put a pill in the lower line made of a short length of, IIRC, 3/8" diameter aluminum rod with a hole drilled in the center of not more than say 1/8" diameter and the ends of this pill smoothed out with a file. I put a worm clamp on it and another below it so it wouldn't migrate down toward the rad with the water flow.

Definitely do the fan sw and the ducting first but you could try these others also if you still want to do more.

I have closed the engine air intake hole in the ic duct and made the lower airbox mod with a cool air duct along the frame rail but these should be of benefit mostly during hard pulls.

 

I forgot to include that I do have the DP wrapped up with DEI titanium stuff.

I called Atkins rotary today and one of their employees brought me a FC thermo switch. He apparently lives down the street. I threw it in a pot of water and with 2 multimeters 1 with a thermocouple I was able to find that it activates at 205F and deactivates around 194F. That went into the car this evening. I'll see what that will do for me in tomorrows heat!

@CrimsonPride, The idea for the pill in the AST path makes total sense. I may put it in the hose just as it's leaving the filler though. I don't want to introduce any pressure into that "mini-system" before the pill...and I'm too lazy to take all that stuff apart anyway.

Now as for the ducting you're all talking about? Is the stock under tray inadequate? Or is your focus directed at the oil coolers?

 

stock car with all stock plastics installed besides alum rad

never see over 86c sitting in traffic in 100* temp.

maybe try a coolant flush? is your water pump pulley good? (still has grooves on it)

 

I'm running fresh distilled water with half a gallon of antifreeze. I did a system flush before the summer started.

Here's some new info for you guys.
https://www.rx7club.com/3rd-generati.../#post11778168

 

I would think the pill would work just as well in either place but the stock system puts it in the lower so I put it there also. I just didn't put much thought into it beyond that.

Everyone was talking about the ducting as being radiator ducting. The extra oil cooler ducting is something that I did also. I haven't seen anyone else do that with the oil coolers but I think it should be of some benefit. I've never heard anything about the stock undertray being inadequate. But, foam pieces, "ducting," is needed on both sides of the radiator so you won't lose airflow there. The undertray just takes care of underneath.

For ducting most people just cut some foam pieces to seal between the sides of the radiator and frame rail. As you go further down the side of the radiator the ducting will seal between the side of the radiator and the side of the undertray where the undertray turns upward to attach to the frame.

Good screen name BTW.

 

There is in reality 4 speeds ... one comes from the thermoswitch which turns on at 108C , the other is the AC which turns on when the AC is pressed ,

THen 2 switches which are controlled by the ECU I dont know what temps they turn on because I never had OEM ECU in my car .

But if one of the relays are bad then one of the speeds arent working ,

When I only have 1 speed my temps raise slowly . , When I have 2 fan speeds depending they will either stay or go down .