Blow Off Valves Explained | Should You Get One?

In this video, Kevin covers anything and everything Blow Off & Bypass Valve. Most, if not, all factory turbocharged cars come with a recirculated air system from the factory which is definitely a good thing! Want to learn more? Check out what Kevin has to say!

Need a BOV for your car?

#bov #blowoffvalve #bypassvalve #turbosystem #tial

[maperformance]

What other car parts would you like us to explain in more detail? Let us know down below!

[samisuhonen]

The "stu-tu-tu-tu" flutter sound is actually caused by a lack of a BOV of any kind. It's caused by the throttle closing, and the pressurized air having no path to escape. So the air is escaping out of the intake, through the turbo the wrong way. And that causes the fluttering sound.

You hear a "PSHHH" from a venting BOV, which vents the pressurized air out of the intake, so it doesn't wear out the turbo parts as it would normally escape out the wrong way through the turbo, putting high stress on the parts.

And most stock turbo cars have a reciprocating BOV. This doesn't vent the air, instead it circulates it back in front of the turbo. The benefit of this system, is that you don't lose as much boost. These ones make only a tiny humming sound that's barely audible. Although a pro tip, is that you could replace often plastic stock intake tubing, with metallic (aluminum) tubing for like 300€, and the sound of the BOV circulating air will be MUCH more noticeable.

Well, also if your car has a MAF sensor (mass airflow sensor), a venting BOV will cause issues with the engine. The sensor calculates air taken in by the intake, and calculates relative fuel amounts for combustion. These calculations will be WAY off, if you vent all the air as you lift off the throttle. The engine will run rich, run bad, may cause a knock, a check engine light, and might even begin to stall every time you lift off the throttle.

A venting BOV is just fine and healthy if your car is tuned for it. Or if it is some kind of a model that has no MAF in the intake. Then you can vent all the air you want for loud hissing sounds. But for the love of god don't buy an Evo or WRX and just replace the perfectly fine silent stock BOV with a loud venting one. You will fuck up the tune. You will fuck up the engine. You will even lose power. All just to arguably make it sound a bit cooler.

[jacobkennedy]

Ex-turbo test tech here - Compressor surge on closed plate is BAD. Will prematurely wear bearing(s) and shaft. If they get too worn your compressor will begin to contact the housing. TLDR: you will be buying another turbo.

Good video, love the content, keep it up, guys!

[PrvOne]

The "stustustu" sound is the turbo still spinning forward and the blades chopping the compressed air. It's going to take a lot more than that to blow your turbo, and spin it backwards (turbos spin at insanely high rpm), it will put more wear on the bearing and such but isn't going to massively impact longevity. Compressor surge that is going to hurt your car badly is when your on boost and it starts doing the flutter sound, since your boosting more than the capabilities of the engine, it literally can't take the air being forced into the engine so the turbo starts surging.

[theignorantcast]

As someone new to car modding, I love that I discovered this channel!!! Easy explanations, nice info, and nice vid flow. Helps that I also know where to buy from after I watch the vid!

[RoadsterAlex]

I love the HKS sound. Always have always will

[bluegun]

Years ago I had a roommate with an EJ20K swapped '00 2 5RS and he loved the turbo flutter sounds. I tried telling him that's air going the wrong direction through the intake pipe when boost is released but he didn't care. Then yesterday I see a video that was uploaded the same day, some guy with a Civic running ebay turbo parts and getting a dyno session done. All flutter lol. Then they start testing launch control settings and by the end of the video he'd busted a wastegate and cracked the manifold lol

[yoltsbp]

lol I upgraded my stock recirculating bov to a hks super ssq4 which is bent to atmosphere like people want. Also the loudness is more directly associated with the amount of boost your pushing. You can here it easily even when recirculating with a high boost pressure but it will be a bit louder if you chose to vent to atmosphere. Hks is the best in my opinion and don’t buy a knock off chances are you won’t hold boost correctly and your tune day will be a waste

[SG-Cichlids]

Blow off valves do three things. They don't kinda save your turbo they do. First they save the bearings from the surge spinning the turbo backwards almost instantly. Second they keep the compressor wheel spinning fast to increase transitional response on boost/off boost/ back on to boost as fast as possible. Third they sound pretty sweet but that's opinion.

[bigjdm]

a great video is a detail understanding why the japanese usually dnt run bov, and how they route everything up.

[streetrookie]

Can you guys do a “speedy density” explained? I’m lost on those whole evo 8 intake thing

[josephtejeda]

I spent most of the video staring at the Supra next to him, I can’t wait to get kw coil overs on mine 😭🔥👌🏻

[Dad-mode-locked-on]

Now explain why VTA with MAF is a bad idea vs using speed density calculations instead of the MAF.

[adamrozman]

Nobody believes me when I tell them the Stututu is their BOV improperly opening 🥴

[Emboltic]

Great video! Been thinking of buying a BoV for my Q50. Just trying to see the good and the bad about getting one. Thanks for the info

[jaimecarmona]

Great video a friend of mine sent it to me when he recognized my car as the cover photo .

[jesusbonales]

Not sure anyone will get back to me but really looking for someone to point me in right directions for upgrades not just from experience but from knowledge as well 🙏🏽

[kevinboeselager]

But the orange SRT4 wasn't even mine😭 It was the camera car lol

[IvanMorales-fg]

I have a chinese copy of turbo smart dual port for 3 years in my car and works nice .

[emacflores]

@1:30 i just got my first turbo engine (ka24det) in a nissan 720 1984 and i love doing just what you said.... Build boost and blow off some pressure tsu tsu tsuuuu 😂 ....never gets