I am that guy^
Just returned a couple of hours ago from a 3000 mile trip from the SF Bay area to southern Arizona (looking to re-locate for refuge from the horrors of California).
Needless to say the MOD unit got a workout as the temps reached 105F.
Here's what I got:
1989 ROW 110 RHD 200tdi (Discovery)
Tinted windows all around, sunroof fully blocked off with a thick black plastic sheet, seatbox and trans tunnel insulated, firewall insulated, brand new OEM door seals (4).
Cowl vents leak free.
Air intake at footwell clear of obstruction.
16" puller fan, 7" pusher, both always on when AC is on.
AC system leak tested and charged one month ago.
Tweak #1
Duct work in lower dash.
Prevents the cold air from cooling down the inside of the lower dash or absorbing heat from the firewall.
Notice the insulation around the duct work.
I didn't measure volume or velocity of air between before and after, didn't seem to change much.
View attachment 15537
Tweak #2
Aluminum shielding with 3/4" hood liner insulation around HVAC box, shields held on by magnets.
I thought this was going to be the holy grail of tweaks as the HVAC box sits so close the the exhaust manifold and turbo, it helped
but nothing drastic. After a long drive the aluminum is almost too hot to hold but pulling it away from the HVAC unit the box itself is
quite cool.
Note the heater hoses have been disconnected and looped together.
Also note the high and low pressure hoses that pass over the engine have been insulated.
View attachment 15538
Gauges used:
Blue Sea temp gauge with sensor mounted well aft to avoid engine bay heat.
Typical meat thermometer in vent; always stayed in this spot, never moved.
View attachment 15540
When in southern Arizona I would turn the AC on at 85F ambient, vent temp would be 42F, then driving all day long, mostly 65-70 mph highway driving, when ambient temp hit 90F vent would be 50F at 100F ambient vent temps would be 60F and at 105F ambient (highest temp I saw) vent 62F. To simplify: approximately 1 degree rise in ambient raised vent temp by one degree.
At 100F ambient 60F coming out of the vent was better than nothing but not by much, it at least eliminated the wind buffeting and noise if the windows were down, which I sometimes did out of disappointment and frustration.
I really hope I've done something wrong or I have a defective component as I think this is a brilliant design and I'm really going to need it if I relocate to southern Arizona!
I apologize for the unflattering review and I hope those who install this unit have better results.