I had a hard time finding the info on what psi to sel my relief valve at for my DIY coolant bypass. So i bought the necessary fittings and gauge to see what exactly the pressure is at that 1/2" npt #6 coolant port where most bypass kits relieve pressure from. I took a few videos of the gauge readings, coolant temp, ambient temp, and rpm of the engine.Hope somebody finds this info useful!
-I saw no difference in pressure when i varied the engine load by going uphill but keeping the rpms constant. However im sure if you were racing it and creating substantially more heat the pressure would no doubt increase, but that information is irrelevant when it comes to choosing relief pressure for the valve.
-I noticed a slightly higher pressure at idle once the coolant was at operating temp above 190'. Which is understandable, but again not necessary info needed to select a valve relief preesure.
-UPDATE--Im not telling anyone what to set their pressures at, you can make your own conclusions from the video if you like. I chose to go with an Aquatrol Series 55 valve with chrome plating, set at roughly 35 psi cracking pressure.
**SUMMARY OF RESULTS**
-3k rpm ~ 50psi
-3500rpm ~ 65-68psi
-4k rpm ~ 80+ psi
-engine load was pretty irrelevant, all recordings were at operating temp of 190' coolant
