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Discussion Starter #1
I have the very first Metris with a blow off valve. I couldn't fight my urges and purchased a piece specifically for the CLA. Since we have the same diverter valve as the M270, I knew it would fit, but would it throw a CEL? Well, it hasn't yet :wink:
It sounds neat and is completely useless, but I had one on my "racecar" and loved the noise. Here's a video:
Metris with a blow off valve
It blows off when I close the throttle, sometimes not even all the way. It hasn't inspired me to drive like an idiot so that's good.

Here's the piece. It bolts on with a single modification: bending a bracket slightly and rotating the intake a few degrees. I'll post more detail if someone needs info about installing.
CLA BOV adapter
 

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I am interested in it not for the noise but to eliminate the hot exhaust gas going into the intake and this is supposed to just bypass the turbo and send the hot gases into the exhaust. Is this correct?

Does it affect the warranty?
 

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What a blow-off valve does, effectively, is de-preasurizing the turbo faster.

A turbo does not inject exhaust gas into the engine (the EGR valve, if the Metris has one, which I assume it does, does that).

What a turbo does is takes the hot, fast moving, high preassure exhaust gas and runs it through a turbine (hence the name) which is sort of like a windmill. The gas, thus, turns an axle rod which is connected to what is basically the turbine in reverse (the vanes point the opposite direction, thus creating inductive force) called an "impeller". The impeller speeds up and thus pressurizes the (external induction) air, to a pressure governed by a wastegate (it opens slightly and reduces preassure if it goes above the desired parameter.

What the turbo does, effectively, is puts more air into the cylinder, which allows you to put more fuel into that cylinder and still have a "stoichiometric" mixture of air and fuel (that is, the ideal mixture to create maximum power and complete combustion). What turbos used to do, with simple fuel injection or a carburetor , single fire spark plugs, simple vane geometry and a purely mechanical waste gate, is create a smaller engine that whenever the turbo is in use (generally by mechanically chaining operation to a certain rev rage), provides the power (and fuel consumption) of a larger engine, but allows to you to get the benefits of the smaller engine when less aggressively driven.

What the combination of direct fuel injection, variable vane turbo technology, and multi-fire spark plugs (especially when combined with variable valve timing and lift), as you find in the Metris, it creates an engine that is effectively multi displacement. It can achieve, by varying the use and pressure of the turbo, and using the direct fuel injection to perfectly meter fuel, stoichiometry at naturally aspirated air pressure for the two-liter four, or it can do it with the heavy pressure and a ton of fuel- which is how the AMG version of the Metris's engine can make 380 bhp effortlessly.

So unlike the cylinder-deactiviation method of roughly doing the same thing, the Metris has the dead weight- and more importantly- reciprocating mass of a 2-liter four, but can provide the combustion to provide the horsepower and torque characteristics of a 1990s Ford 4.6 V8. Whereas trying to cut the power of the Ford V-8 to a 2.3 liter 4-cylinder by shutting down half the cylinders would still leave you with the reciprocating mass and dead weight of the 4.6 V8.

The downside is, of course, that the Metris will always have the inherent imbalance and lack of smoothness of a 2.0 liter 4-cylinder (which Mercedes attempts to partially quell using a Lanchester balancing module), whereas the Ford V8 will still have the more balanced smoothness inherent to having 8 cylinders in motion instead of four.

What a blow-off valve does is, upon the turbo no longer being called upon for use, it immediately dumps the pressurized induction (clean) air. This creates a really cool sound. It doesn't solve any "problems" involving hot exhaust gas (which will continue to go into the exhaust system for treatment, and bypassing such a thing would be extremely illegal in all 50 states). It does have the potential to increase turbo lag (if you lift off the throttle completely, and then stop on it in short order, the turbo, which would otherwise still be at least somewhat pressurized, would have to fully respool again). You will be dumping relatively cool air directly into the engine bay. (don't think it does much if anything). You might hasten wear on the turbo due to changing pressures or temperatures being magnified (not sure about this) which could theoretically be used as a reason to not honor a warranty.

I'm sure if you had a problem they could trace directly to the effects of the blow off valve, you will have some trouble getting the warranty honored. Can't imagine what they would be, but I really doubt the deleterious effects of the valve (and there are some, mostly relating to increased heat/preassure flux and strain wear on the turbo) would be drastic enough that they would show up under the warranty period.
 

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Discussion Starter #4
Yup, that sums it up. Plus, I'm my own warranty administrator. (Not really)
 

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I was questioning the text in Rob's link:

"Mercedes equipped the CLA 250 / C300 with a recirculating style BOV, which allows the charge air to be routed around the turbocharger from the boost side back to the intake side. The downside to this style of system is it recirculates the hot air back into the intake side of the turbo, increasing temperatures. When equipping a vehicle with a spacer like ours, it helps remedy this issue."
 

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Sorta cool, but isn't the sandblaster noise from the uber restrictive exhaust enough noise ;-P Put a free flowing exhaust on it next and you'll actually gain some hp.
 

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Discussion Starter #8
That free flowing exhaust WILL void my warranty. Pandora's Box of CEL will open, gremlins will hatch, etc.
 

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That free flowing exhaust WILL void my warranty. Pandora's Box of CEL will open, gremlins will hatch, etc.
I never really understand how an exhaust will void warranty? The exhaust won't damage the engine will it? It couldn't hurt to make it more free flowing..
 

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That free flowing exhaust WILL void my warranty. Pandora's Box of CEL will open, gremlins will hatch, etc.
I have the very first Metris with a blow off valve. I couldn't fight my urges and purchased a piece specifically for the CLA. Since we have the same diverter valve as the M270, I knew it would fit, but would it throw a CEL? Well, it hasn't yet :wink:
It sounds neat and is completely useless, but I had one on my "racecar" and loved the noise. Here's a video:
Metris with a blow off valve
It blows off when I close the throttle, sometimes not even all the way. It hasn't inspired me to drive like an idiot so that's good.

Here's the piece. It bolts on with a single modification: bending a bracket slightly and rotating the intake a few degrees. I'll post more detail if someone needs info about installing.
CLA BOV adapter
This is so awesome!! I am not sure why the dealer/sales rep told me the Metris engine is the same as the b200 or b250? So it's actually the same as the CLA?
 

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Discussion Starter #11
It's ACTUALLY the same as a W205 C300. It's REALLY similar to the CLA/GLA.

When I talk about the exhaust voiding the warranty, I mean to say the pipe directly off the turbo is the cat. If I cut or weld on that pipe, and my cat goes south, I can't guarantee it will be covered.

Just a little blow off is enough without making a loud racevan out if it.
 

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I have the very first Metris with a blow off valve. I couldn't fight my urges and purchased a piece specifically for the CLA. Since we have the same diverter valve as the M270, I knew it would fit, but would it throw a CEL? Well, it hasn't yet ?
It sounds neat and is completely useless, but I had one on my "racecar" and loved the noise. Here's a video:
Metris with a blow off valve
It blows off when I close the throttle, sometimes not even all the way. It hasn't inspired me to drive like an idiot so that's good.

Here's the piece. It bolts on with a single modification: bending a bracket slightly and rotating the intake a few degrees. I'll post more detail if someone needs info about installing.
CLA BOV adapter
Any problem with the engine performance previous BOV? How about check engine light?
 

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That free flowing exhaust WILL void my warranty. Pandora's Box of CEL will open, gremlins will hatch, etc.
Robb, I know you’re a MB tech but for the rest of us “normal customers” does the BOV void the warranty? Right now I’m thinking just BOV, BMS C300 open element air filter, and Dinan Sport Tuner for my 2018 Metris Passenger. That should give me the little bit of “pep in my step” I’m looking for.

Ultimately I’d like to take it to my local euro tuner (tuned my BMW 750Li into a monster) and have them put a real DME tune on it with catless downpipe (the tune would code out the CEL for the O2 sensors)... but I’m pretty positive THAT will void my warrantee LOL!
 

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Robb, I know you’re a MB tech but for the rest of us “normal customers” does the BOV void the warranty? Right now I’m thinking just BOV, BMS C300 open element air filter, and Dinan Sport Tuner for my 2018 Metris Passenger. That should give me the little bit of “pep in my step” I’m looking for.

Ultimately I’d like to take it to my local euro tuner (tuned my BMW 750Li into a monster) and have them put a real DME tune on it with catless downpipe (the tune would code out the CEL for the O2 sensors)... but I’m pretty positive THAT will void my warrantee LOL!
Robb had quit this forum after the server change, noticed he has recently posted a little, hopefully he replies
 

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Robb, I know you’re a MB tech but for the rest of us “normal customers” does the BOV void the warranty? Right now I’m thinking just BOV, BMS C300 open element air filter, and Dinan Sport Tuner for my 2018 Metris Passenger. That should give me the little bit of “pep in my step” I’m looking for.

Ultimately I’d like to take it to my local euro tuner (tuned my BMW 750Li into a monster) and have them put a real DME tune on it with catless downpipe (the tune would code out the CEL for the O2 sensors)... but I’m pretty positive THAT will void my warrantee LOL!
Why not the Burger JB4 vs the Dinan?
 

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Why not the Burger JB4 vs the Dinan?
I bought the van new and it only has 8k miles on it now, didn't want to do too much during the warrantee period. Figured the Dinan was a single sensor install/removal where as JB4 would require a lot more to remove/install if I ever needed to take it into the dealer for service. Dinan has a free app and BT built in, JB4 requires another $150 module just for that. Also, I got the Dinan for $140 on eBay, so price wise it was an easy decision. I have a tuner in town who would likely tune the Metris for around $600, which I would do before choosing JB4 as well; because it would be an actual ECU flash rather than a piggy back system thats tricking sensors.
 

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Discussion Starter #18
Robb, I know you’re a MB tech but for the rest of us “normal customers” does the BOV void the warranty? Right now I’m thinking just BOV, BMS C300 open element air filter, and Dinan Sport Tuner for my 2018 Metris Passenger. That should give me the little bit of “pep in my step” I’m looking for.

Ultimately I’d like to take it to my local euro tuner (tuned my BMW 750Li into a monster) and have them put a real DME tune on it with catless downpipe (the tune would code out the CEL for the O2 sensors)... but I’m pretty positive THAT will void my warrantee LOL!
I really do hate the new format. Why would a BOV void your warranty? Read into the Magnuss/Carlson act (google it, I might not have even spelled it right) The answer is it won't.
Do the BOV and the sport tuner. Skip the air filter, it'll be useless on our setups. If you find someone that can tune our MEs, let me know. I've only found one and its in Massachusetts or Maine. A tune will only void your warranty if you get caught with it after you blow the engine up. I would also do a tune before the tuner box because the tuner box is just hackery. I hate this new format. I'll see y'all in 5 months when I have to get on my laptop again.
Also: Still no CEL.
 
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