Engine temp rises when I get to cruise speed

[jrvariel48]

I've been trying to cool my car down a little for the past couple of months. When it's 50-60 degrees outside it's not a concern, but as we get into summer here in Jersey things really heat up. It seems that after I installed the radiator the problems started. I had a cheap Ebay aluminum P.O.S. it there last summer and I had no problems

Here's what I've done: This is a rebuilt motor with about 2000 miles on it.

Timing is advanced 7* at idle with a max advance of 18* in at 2200 rpm because of a supercharger. Running 102 octane.

I don't have the lower grille pan installed in the grille and wondered if this could be a problem.
The radiator is getting plenty of airflow.

Hoses are new, no restrictions, no collapsed hoses.

I replaced the sending unit and checked my gauge with a new gauge and it was dead on.

I installed a temp gauge directly in the pass. head and it reads very close to what the electric gauge says.

7Lb. radiator cap with overflow tank.

New Brassworks radiator (Not happy at all. This will be another post).

Changed fan from pusher to puller with shroud.

Change t-stats from 180* to 160*.

Started with 50/50 Propylene glycol and tap water.

Tried 40% Ethylene glycol/60% distilled water.

As of this morning I'm at 20% Propylene glycol and 80% tap just to see what happened.

Outside temperature is 72*
Idled in driveway with fan on for 20 minutes at 180* all good so far.
Get on the road and I watch the temp creep up, which is what I expected. Got onto the highway doing 60 MPH and temp goes to about 205. I'm ok with that but not real happy. Cruising rpm varies from 2500 to 3000 rpm in 4th or 5th gear with air/fuel ratio from 11.3 at WOT to 14.8 cruising on a flat road.
I pull off the exit to the back roads and the temp drops.
Now I'm cruising in 3rd or 4th gear going 30-40 MPH same rpm 2500-3000 and I'm at about 190*
As soon as I go past 45 MPH it starts to heat up again.
I understand motors heat up when driving, but I didn't think 20*-30* was normal.

The next thing I will try is straight reverse osmosis water and No-Rosion. (this is what No-Rosion recommends). I understand the boiling point won't be as high as with anti freeze, but with the 7 pound cap I'd be at about 235*. I could also change the cap to a 13 lb. and get the boiling point to around 250*.
This would only be for the summer.
The car sits in a heated garage and gets driven every weekend as long as there's no snow or salt on the roads

I didn't try removing the stats, but I will if that's what everyone agrees on.

Thanks,
Joe