Yamaharider1018

So me and my cuz were talking about turbo motors and he seems to think you only need a blow off valve. But in some of the kits I've seen it includes a blow off valve and a waist gate do you need both or just one. Please explain the differnce thanks

ESG-642T

well you don't have to have either....

However I would not advise unless you want to try Campbell's engine soupe.


Wastegate's regulate boost.

You can run without a blow off vavle if you have an automatic (GN style).

Red Turbo Integra

Pretty much need both, unless you don't like your motor or your turbo. If you don't have a waste "GATE", your turbo will make as much boost as it can, which although I know it sounds great, it isn't for many reasons, the main one being is your motor won't be able to handle it.

You need a blow off valve because when you shift and your throttle plate closes, all that air needs somewhere to go or it will go back to the turbo and stop it from spinning which is A) bad for the turbo (compressor surge) and B) takes you longer to recover between shifts because it has to spool back up again.

Yamaharider1018

Ok. Is the gate usally after the turbo near the t/b. And is the bov before the turbo after the headers?

Red Turbo Integra

The wastegate is before the turbo somewhere on your turbo mani. It's job is to regulate and re route exhaust gas away from the turbo when target boost is achieved. The blow off valve is somewhere on your charge pipes, usually somewhere on the pipe before the TB.

FoxGT

Automatic cars have to use throttle plates too.

Some turbos are better at handling without bovs or bypass valves than others (which is why you see some turbos with machined slits, or holes in the compressor housing)
Running a valve is better than not. The bigger the space between your turbo & throttle plate the harder it is on parts, same with the bigger the turbo. I've ran without one with a very small volume, the turbo's compressor was about 12" away from the throttle body & the turbo was a little small. I would never advise it, the only reason I did it was because I had just got it running at the time & was playing around with it.

Placement can go anywhere, It's best to place it as close to the throttle plate as possible for faster response; it will be louder before the intercooler (if equipped)

vgt & vnt turbos don't use wastegates. I would stay away from them until they get all the bugs worked out for gasoline engines. They're not great at handling the higher temps.