ran no bov on a few of my rx7s for quite some time and on a 1J motor and had noticebly faster spool on all , no problems arose, deciding if i want to run no bov on my new setup (S475)

Ran 24psi on my new setup with no issues..... My turbo did fail 3 days later. Smoke on startup and shot bearings. HOWEVER, it was super baked for around 30 minutes when I unknowingly left the timing locked after I first got it running. Upon tear down, it was revealed that heat killed it and my little stint with the timing was the cause.

Starting again with a fresh CHRA and billet wheel. Still planning to run no BOV so we will see where she goes.

The tech literature even says that the recirculation valves are to reduce noise. Nothing about turbo life, nothing about response.

Turbo life increased dramatically when watercooling became common. The old turbos died from oil coking because the bearings would run 300-400-500F (going UP after shutoff) while watercooled housings rarely if ever get significantly over coolant temp, even after engine shutoff. No oil coking = turbos don't puke the bearings after 50k like was practically expected in the 80s.

Been running my GTX4202R on my 20b without a blow-off valve all season. At least 8-9 events without issue.

thewird

jesus more idiots than i remembered in here, almost worse than Tech

if you honestly think the thrust bearing on a journal bearing turbo doesn't see any ill from the stalling you are on crack

the thrust is loaded pushing towards the compressor under normal conditions, let it bark and the thrust vibrates loading one side of the thrust then to the other

plus the radial load placed on the shaft

How many cubic feet of air do you figure your intake system from the turbo to the throttle body holds compressed at however much psi you're boosting?

Dodge used water cooled garret and Mitsubishi turbos from the factory from 84-92/3 with a factory bypass valve. Never any premature failures besides the occasional case.

Mitsubishi used their own turbos, water cooled, no bypass/bov, those turbos never saw over 50k less the car was not boosted its entire life. Usually automatic cars.

Mitsubishi Colts from the late 70s early 80s used water cooled turbos with no bov. Very high failure rate.

The DSMs came out with the use of a factory bpv, suddenly 100k was possible out of the same turbos used on the cars before them.

Skylines have always used Mitsubishi turbos, with a factory bpv, no issues there's.


I'm sensing a common theme. The late 70s early 80s was an experimental time for turbos on factory cars. Mistakes were made, lessons were learned.


But engineers getting paid tons of money to figure this stuff out have no idea what they're talking about.