L31MaxExpress
I'm Awesome
I recently made a discovery when it comes to thermostats for a Vortec. I had been running a 180F thermostat, that had been keeping my 383 at 185F going down the road. At idle with the AC on it would creep up to 215F. Electric fan, mechanical fan, mechanical with an electric booster fan, it did not matter. I found a 195F high flow thermostat. I put both the old 180F parts house thermostat as well as the new 195F high flow in a pan on the stove and started heating them. Both started opening about where they were rated as they should. That is where the difference showed up. As the temperature of the pan continued to increase toward boiling the highflow 195F thermostat opened much wider than the previous 180F.
I put the 195F unit in the 383 in the van. It now runs consistently 199-203F. It was only 85F today here, but in the same weather I had watched the old 180F heat soak to 215F. After driving it for 30 miles, I let it sit and idle for 20 minutes with the ac cranked up. The highest I saw it climb was 205F. At 11:1 static compression and 9-9.5:1 dynamic compression these aluminum heads still run 32 degrees total timing at WOT and as much as 42 degrees at cruising speeds without detonation on 91 octane. Going down the road the IATs dropped down to ~90F. My long term fuel trims dropped a small amount running the engine hotter. My idle oil pressure dropped 5 psi, but it still carries 30 psi at 725 rpm at hot idle. At hot idle my IAC counts dropped about 5 counts and the engine is pulling about 2 kpa more vacuum. Will be interesting to find out if my next longer road trip breaks 20 mpg.
I put the 195F unit in the 383 in the van. It now runs consistently 199-203F. It was only 85F today here, but in the same weather I had watched the old 180F heat soak to 215F. After driving it for 30 miles, I let it sit and idle for 20 minutes with the ac cranked up. The highest I saw it climb was 205F. At 11:1 static compression and 9-9.5:1 dynamic compression these aluminum heads still run 32 degrees total timing at WOT and as much as 42 degrees at cruising speeds without detonation on 91 octane. Going down the road the IATs dropped down to ~90F. My long term fuel trims dropped a small amount running the engine hotter. My idle oil pressure dropped 5 psi, but it still carries 30 psi at 725 rpm at hot idle. At hot idle my IAC counts dropped about 5 counts and the engine is pulling about 2 kpa more vacuum. Will be interesting to find out if my next longer road trip breaks 20 mpg.