surfah

I never heard of BOV before and your explanation makes sense to me.

06032

As OP, I'm so sorry I brought this up, guys....

DanVel

Just installed my renntech BOV adapter and took them off within 10 minutes of driving. Performance impact aside... makes it borderline embarrassing to drive in public.

wizee

Old thread I know, but I noticed some recent threads mentioning BOVs, and I was a bit confused why people were installing them.

The stock electronically controlled diverter/bypass valve will redirect pressurized air from the turbo output to the low pressure (turbo input) side. Thus, the turbo input pressure will increase a bit (above the normal atmospheric-ish pressure), and less air would need to flow through the air filter.

More importantly, the electronically controlled stock valve brings the turbo output pressure to near the turbo input pressure. If the input and output sides of the turbo are kept at near equal pressures, there will be minimal resistance, so the turbo will keep spinning for longer.

If you install a BOV, in addition to pissing away pressurized air (a slight loss, as the stock setup will slightly pressurize the turbo input side), the bigger impact is that the BOV will cause the output side of the turbo to remain at an elevated pressure (the BOV pressure needed to overcome its spring). This increased output side pressure when you’re off the throttle (electronically controlled diverter valve open, output redirected to aftermarket mechanical BOV) will actively slow down the turbo, causing turbo lag after shifts or letting off the throttle.

In short, installing a “BOV” on these engines is counterproductive and creates turbo lag.

Orcbolg

But.... Will it help me look cool in the canyons?








In all seriousness, great write-up, I appreciate posts such as this very much.

wizee

If one likes the noise “in da canyons”, and isn’t bothered by the wasted energy and associated increase in lag, they can go ahead, none of my business.

I haven’t looked at the construction of the Renntech BOV. If you connect the “BOV” to the bypass path of the electronic diverter valve, you could get away with a blow off “whistle” instead of a valve, since there’s no need for a spring. In this case, there could be less pressure drop across the whistle than in a true BOV, but there would still be some pressure drop, and still a waste of pressurized air.

BucsFan

I have never understood the appeal of a BOV. There is a lot of engineering effort in making turbo engines behave and sound like NA while overcoming or masking the downsides of turbos. BOVs go in the opposite direction. If you like BOVs, great. I just don't get it.

peejalino

interesting read on this thread. people really just enjoy the sound. let them have at it.

Babis Mavrakis

You are making a silly argument. We all know that AMG detunes its engines to allow for various qualities of petrol and owner stupidity. This part is illegal in Australia where you cannot vent exhaust gasses in the atmosphere so even if it was beneficial AMG would not fit it in its engines.

as far as the technical argument you are making I have absolutely no idea so I have to accept your point. My only comment is that I have read somewhere that any excess boost is fed back to the system to burn off any unburnt fuel for emissions targets but I don’t know how or where that happens.

Xerial

You are SO VERY WRONG and believe you’re right. Think about it, the air box IS CONNECTED TO THE ATMOSPHERE! Therefore, installing the spacer simply vents it to the SAME ATMOSPHERE that the stock recirculating valve vents to. BOV spacer neither harms or benefits performance, IT ONLY ADDS SOUND. The air box in no way holds pressure, as air filters are DESIGNED to be as unrestrictive as possible. Therefore, the extra “air” from the recirculating valve simply escapes out the air filters. AMG designed a recirculating valve instead of venting to atmosphere because NOT EVERYONE LIKES THE SOUND.

4LTwinTurbo

This is what I was thinking back then as well. No longer even have the c63s but I had a chuckle reading this again because the dude was calling me an idiot for just asking questions about it lol

Xerial

Yes reading through the thread just frustrates me, seeing how obviously wrong he is but how he attacks you even though you are right. It simply takes a bit of common sense and understanding of simple engineering principles to figure out the function of the recirculating valve.

TriggrPullrUSMC

FWIW that noise is a bit too boy racer for me.

Bunnycop

so how would one hook up a blow off valve or a "noise maker" to the M278 engine? A rich neighborhood kid approached me and would like to waste some of his daddys money...help...haha

Acta_Non_Verba

Hi,

This is the AMG GTxxx forum and probably not the best place for info on the M278, but there is a forum vendor that probably could help you (or your rich neighbor) out. Try here:

M157 / M278 Meth / BOV Kits - MBWorld.org Forums

Best,

ZAC MOTORSPORT

This is incorrect. The recirculation is purely for eliminating sound.
There is no performance gain to a BOV spacer though, you are right there.

EDIT, become a part of a bit of a gravedig here, sorry.

TriggrPullrUSMC

Disregard sorry...

Skilly

For those of you that have been wondering what this BOV thing is, here is a version of it for your kids bicycle.

axelwphoto

This is funny 😆

user33

Early indicator of a soon-to-be car enthusiast? Seriously, I bet many of us did this as kids. #;-) Personally, I still think BOVs and "crackle tunes" sound silly ... but I respect that others like things I don't.