I see on YouTube some people running their cars without a blow off valve. What's the pros and cons?

you pretty much have to have the blow off valve. If not you would have compressor surge like fck and it would kill your turbo.

It can and has been done, even on factory cars like early Toyotas.

The benefits of keeping one far out-weigh reasons to remove it, and the positives of running without one is speculative at best.

It's a safety piece. Would you run your oil pump with no bypass system on it? How about your fuel system with no regulator? It's a similar system for the BOV/BPV, it protects the turbo from overpressure once the throttle closes. You might be able to get away with a low CFM, low boost/stock style setup with some cars, but once you get to the high boost, big turbo game, you're going to want one so you don't destroy a turbo, throttle plate, intercooler or intake manifold.

Bottom line: there's no deficit to having one that's set up properly, and many issues probable without one.

Both guys have pointed out the reason you need to keep it, safety.
Just think of 40 lbs of boost, flowing 60+ lbs/min all of a sudden hitting a brick wall as I close my throttle plates from a full pull. That boost HAS to go somewhere, the BOV lets it escape.

100% its needed
Will cause so many issues/damage without it!
cost of a good bov setup vs potential damage and repairs....

Replace that pos plastic 2g one and get something better. I bet you wouldn't be asking this question if you had a nicer one already.

To elaborate on thunder clouds post.
I believe it was the toyota celica alltrack. It did come factory with no blow off/ diverter valve. I think it was running running like 5 lbs of boost, I dont know what turbo but I'm sure it was tiny.

The starion never had a blowoff valve either.

To the original poster: run a blow off valve.

Bud92gsx said:

To elaborate on thunder clouds post.
I believe it was the toyota celica alltrack. It did come factory with no blow off/ diverter valve. I think it was running running like 5 lbs of boost, I dont know what turbo but I'm sure it was tiny.

Click to expand...

^^

But yes I believe you're correct it was the Celica alltrac, iirc they had a ct26. I don't recall of the ct20 was ever used.