GLC 63 Weistec BOV -installation?
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Senior Member
Joined: Apr 2012
Posts: 468
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From: Denver, CO
2015 S550 coupe, 2024 GLC43
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Thread Starter
Senior Member
Joined: Apr 2012
Posts: 468
Likes: 9
From: Denver, CO
2015 S550 coupe, 2024 GLC43
Installed in 40 minutes myself! Quite easy actually? Removed plastic covers upfront, remove stock electronic valves, put Weistec valves and mount back stock ones using longer bolts provided. Put plastic covers back and you're done.
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AMG GLC 63s Coupe
Do you only need 1 if you have the bi turbo!
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Joined: Aug 2019
Posts: 881
Likes: 300
AMG GLC 63s Coupe
Do you have it? I think I am going to skip it based on researching various articles. Here is a pretty good summary of what I have been finding. Thoughts on your end?
This mod is total nonsense. The valve in question is not a blow-off valve. It is a priority valve (or compressor by-pass) that prevents turbo lag. Besides making more noise, letting that air escape to atmosphere increases turbo lag and deadens throttle response, because it defeats the action of the stock design.
Priority valves were first fitted to the Porsche 944 Turbo in 1988. Prior to that everyone used blow-off valves, where needed. Any company since, that made a good turbo system, used the priority valve setup. Audi, Porsche and Subaru are legendary examples. Priority valves are so important I actually welded fittings to my 1988 Celica GT-4 intercooler and intake box to adapt the clever Porsche 944/Audi part! Much improved the throttle response.
Now, racing turbo systems over about 2.5 bar do require a blow-off valve in addition to the priority valve function. Otherwise, the over-pressure in the intake risks splitting intercooler seams or blowing off hoses. The C-Class turbo systems are nowhere near requiring this mechanical pressure relief. The opposite is true. We want to keep that pressurized air working for us, not just **** it away.
Installing an aftermarket 'blow-off valve' defeats the clever function of the stock priority valve. The priority valve is there to remove turbo lag. It does this by recirculating the compressed air back into the atmospheric side. This keeps the compressor from stalling, so when you tip back into the throttle, it makes boost instantly. This is just as true at part throttle as full throttle. It works all the time.
There is also a very clever, simple delay spring built into the system, such that this factory priority valve system, once pulled open by manifold vacuum, resists closing for ~.1 to .3 seconds due to the resistance of this spring. This delay allows the turbocharger to spin up freely (no load) for an instant. As the valve comes completely closed, the turbine is now almost up to full rotational speed, so there is more boost available, much more when opening the throttle that without it.
If you want to understand this theory, put your hand over the suction of a household vacuum cleaner. The speed of the motor rises dramatically because, although still pulling a vacuum, it is doing no work (no air is moving). That is what the priority valve does for the turbocharger, specifically by adding pressure to the atmospheric side of the compressor wheel. It lets it freewheel momentarily and not loose rotational speed. Most important is the spring delay speeds up the turbine wheel further by there being no load on the compressor side.
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Joined: Nov 2018
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GLC 63 AMG, Trackhawk, X3M
Yes I put it on for other reasons. I am pushing twice as much boost and I actually blew off my outlet gasket from turbo to intake manifold. I needed a way to release the back pressure from the turbo more quickly. If I was a stock setup with basic tune there is no point in having it besides the noise. I have not noticed any sort of turbo lag.
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Joined: Aug 2019
Posts: 881
Likes: 300
AMG GLC 63s Coupe
Yes I put it on for other reasons. I am pushing twice as much boost and I actually blew off my outlet gasket from turbo to intake manifold. I needed a way to release the back pressure from the turbo more quickly. If I was a stock setup with basic tune there is no point in having it besides the noise. I have not noticed any sort of turbo lag.
After looking at what it truly is...isn't it just a fancier outlet? Wouldn't it be the exact same thing if you just plugged the intake hose and removed the outlet pipe and hose? Or, you could likely leave the outlet pipe.
Senior Member
Joined: Nov 2018
Posts: 338
Likes: 73
GLC 63 AMG, Trackhawk, X3M
I know you need it, with all your,the stock system won't keep up with your pressures.
After looking at what it truly is...isn't it just a fancier outlet? Wouldn't it be the exact same thing if you just plugged the intake hose and removed the outlet pipe and hose? Or, you could likely leave the outlet pipe.
After looking at what it truly is...isn't it just a fancier outlet? Wouldn't it be the exact same thing if you just plugged the intake hose and removed the outlet pipe and hose? Or, you could likely leave the outlet pipe.
Senior Member
Joined: Jul 2016
Posts: 279
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From: CA Bay Area
2019 GLC 63 SUV, 2013 SLK55
Do you have it? I think I am going to skip it based on researching various articles. Here is a pretty good summary of what I have been finding. Thoughts on your end?
This mod is total nonsense. The valve in question is not a blow-off valve. It is a priority valve (or compressor by-pass) that prevents turbo lag. Besides making more noise, letting that air escape to atmosphere increases turbo lag and deadens throttle response, because it defeats the action of the stock design.
...
This mod is total nonsense. The valve in question is not a blow-off valve. It is a priority valve (or compressor by-pass) that prevents turbo lag. Besides making more noise, letting that air escape to atmosphere increases turbo lag and deadens throttle response, because it defeats the action of the stock design.
...
Senior Member
Joined: Nov 2018
Posts: 338
Likes: 73
GLC 63 AMG, Trackhawk, X3M
I know you need it, with all your,the stock system won't keep up with your pressures.
After looking at what it truly is...isn't it just a fancier outlet? Wouldn't it be the exact same thing if you just plugged the intake hose and removed the outlet pipe and hose? Or, you could likely leave the outlet pipe.
After looking at what it truly is...isn't it just a fancier outlet? Wouldn't it be the exact same thing if you just plugged the intake hose and removed the outlet pipe and hose? Or, you could likely leave the outlet pipe.
Super Member
Joined: Aug 2019
Posts: 881
Likes: 300
AMG GLC 63s Coupe
Yes I put it on for other reasons. I am pushing twice as much boost and I actually blew off my outlet gasket from turbo to intake manifold. I needed a way to release the back pressure from the turbo more quickly. If I was a stock setup with basic tune there is no point in having it besides the noise. I have not noticed any sort of turbo lag.
Thanks for the offer though.
Last edited by ParadigmDawg; Oct 2, 2019 at 02:01 PM.
