AIR BYPASS VALVE ACTUATOR
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Former Vendor of MBWorld
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From: Glendale Arizona
C55,SL55,C63
AIR BYPASS VALVE ACTUATOR
Sorry for the caplocks in the title it was a copy paste thing.
Question:
What would happen if I didnt have this part?
Question:
What would happen if I didnt have this part?
Last edited by hooleyboy; Apr 29, 2009 at 11:28 PM.
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Joined: Jul 2006
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From: Orange County, CA
GMC - Miata - Trek - P-Car
If your hybrid ECU is modified to not recognize it, only good things.
The early SL55’s didn’t have one – or any SLR.
They’re used to limit WOT boost in order to ‘manage’ torque and reduce pumping losses (improve fuel consumption) during part-throttle operation. Isn’t yours blocked off?
The C32 doesn’t have one, and can therefore generate 18 PSI - or more - with pulley upgrades.
Still slower than yours, though. =)
Finny’s info…https://mbworld.org/forums/2195279-post66.html
image credit Marcus Frost
The early SL55’s didn’t have one – or any SLR.
They’re used to limit WOT boost in order to ‘manage’ torque and reduce pumping losses (improve fuel consumption) during part-throttle operation. Isn’t yours blocked off?
The C32 doesn’t have one, and can therefore generate 18 PSI - or more - with pulley upgrades.
Still slower than yours, though. =)
Finny’s info…https://mbworld.org/forums/2195279-post66.html
image credit Marcus Frost
Thread Starter
Former Vendor of MBWorld
Joined: Jan 2007
Posts: 3,193
Likes: 3
From: Glendale Arizona
C55,SL55,C63
If your hybrid ECU is modified to not recognize it, only good things.
The early SL55’s didn’t have one – or any SLR.
They’re used to limit WOT boost in order to ‘manage’ torque and reduce pumping losses (improve fuel consumption) during part-throttle operation. Isn’t yours blocked off?
The C32 doesn’t have one, and can therefore generate 18 PSI - or more - with pulley upgrades.
Still slower than yours, though. =)
Finny’s info…https://mbworld.org/forums/2195279-post66.html
image credit Marcus Frost
The early SL55’s didn’t have one – or any SLR.
They’re used to limit WOT boost in order to ‘manage’ torque and reduce pumping losses (improve fuel consumption) during part-throttle operation. Isn’t yours blocked off?
The C32 doesn’t have one, and can therefore generate 18 PSI - or more - with pulley upgrades.
Still slower than yours, though. =)
Finny’s info…https://mbworld.org/forums/2195279-post66.html
image credit Marcus Frost
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Joined: Jul 2006
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Likes: 12
From: Orange County, CA
GMC - Miata - Trek - P-Car
The aforementioned variants didn’t suffer from inordinate supercharger failures. During drop-throttle deceleration from high revs on mine, intake manifold vacuum (negative pressure) will approach 25 inches of mercury (Hg). It’s still spinning and pumping strong after ~72k miles. Regardless of whether a bypass is fitted or not, the throttle valve ultimately controls the air admitted into the intake tract upstream of the supercharger.
I’m as anxious as you (almost!) to pinpoint the source of your supercharger’s failure. Judging by the pictures, it seems as if some foreign object wedged itself between the impellers to force their bearings to become inordinately overloaded. Pure speculation on my part, of course.
edit: the C32’s supercharger continues to be driven at high engine speeds irrespective of throttle position.
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From: Scottsdale, AZ
Mercedes
hey hooleyboy,
I remember a while back that jakpro bought a clk dtm intercooler, which does not have a bypass valve, and there was a reason he couldn't install it, I think it was something similar to the problem you are having(dont quote me on this).... I cant recall right now, but if you PM him, I'm sure he will know!
I remember a while back that jakpro bought a clk dtm intercooler, which does not have a bypass valve, and there was a reason he couldn't install it, I think it was something similar to the problem you are having(dont quote me on this).... I cant recall right now, but if you PM him, I'm sure he will know!
Thread Starter
Former Vendor of MBWorld
Joined: Jan 2007
Posts: 3,193
Likes: 3
From: Glendale Arizona
C55,SL55,C63
hey hooleyboy,
I remember a while back that jakpro bought a clk dtm intercooler, which does not have a bypass valve, and there was a reason he couldn't install it, I think it was something similar to the problem you are having(dont quote me on this).... I cant recall right now, but if you PM him, I'm sure he will know!
I remember a while back that jakpro bought a clk dtm intercooler, which does not have a bypass valve, and there was a reason he couldn't install it, I think it was something similar to the problem you are having(dont quote me on this).... I cant recall right now, but if you PM him, I'm sure he will know!
I have the ABVA (Air bypass valve actuator) installed on my car just to serve as a block off for the intercooler. Along with a custom made block off plate in the pipe line. So really the ABVA on my car is just sitting there doing nothing but stopping boost from leaking out of the IC. From what I've read online is the only way to stop a Lysholm supercharger from making boost is to stop the rotors from spinning. Mercedes does this with a clutch. My clutch is on all the time so I'm always boosting. So my plan of attack is to install a vacuum based diverter valve from the intercooler and shoot the air back into the pipe line when the throttle body closes. In other word when i lift off the gas and the TB closes the retrofitted valve will open and divert the air back into the "pipe line"
For those who dont know.. The "Pipe Line" is what Mercedes calls the thing your throttle body sits on.
Last edited by hooleyboy; Apr 30, 2009 at 03:27 AM.
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From: seattle
1990 300ce supercharged and intercooled
The only functions of the bypass is to limit boost and fuel efficiency. Lots of positive displacement blowers use a bypass that is vacuum activated for fuel efficiency on part throttle. Not having one can not hurt the supercharger in the slightest. Boost does not go up when you lift the throttle on your set up. The throttle actuator restricts air flow to the supercharger. If the throttle actuator was down stream of the blower then yes you would have a massive pressure spike that would simply blow things apart. You would need a turbo style bypass valve in order to dump the boost. With the throttle before the supercharger there is no restriction between the supercharger outlet and the engine.
I would think that there is really only two options for the failure of the first blower. One that it was defective and the other that something got in it. If the bearings failed then the rotors simply beat themselves to pieces very quickly.
I have had several blowers do the same thing but only after many years of service or if I was spinning them way to fast, which you are not.
Good luck on making more power and my two cents is bigger intercoolers.
I would think that there is really only two options for the failure of the first blower. One that it was defective and the other that something got in it. If the bearings failed then the rotors simply beat themselves to pieces very quickly.
I have had several blowers do the same thing but only after many years of service or if I was spinning them way to fast, which you are not.
Good luck on making more power and my two cents is bigger intercoolers.
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Hooley-thats the same set up that most manufacturers are running on turbo cars (recirc rather then vent to atmosphere)-I would def agree that even at 7psi (sure you are....I bet its 10 
) you will want the boost to go somewhere other then press against the internals of the SC-most places divert the air back into the intake pipe-after the MAF, this air has already been measured for fuel purposes-and use a BOV/BPV to regulate when it opens and closes (most AM BOV's have an internal spring that you can adj to a spec open and close to not get flutter at partial thrtl or let off-takes some adjusting on specific cars, but in the end is well worth it)-I think the idea of tapping the IC and routing that boost to the intake is great-there should be enough vacuum to open a valve-is there anywhere post SC that would work other then the IC? GL on the mod-I also agree that the damage was NOT a result of boost in the SC-it looks like something got in there and got puree'd on the blades!
) you will want the boost to go somewhere other then press against the internals of the SC-most places divert the air back into the intake pipe-after the MAF, this air has already been measured for fuel purposes-and use a BOV/BPV to regulate when it opens and closes (most AM BOV's have an internal spring that you can adj to a spec open and close to not get flutter at partial thrtl or let off-takes some adjusting on specific cars, but in the end is well worth it)-I think the idea of tapping the IC and routing that boost to the intake is great-there should be enough vacuum to open a valve-is there anywhere post SC that would work other then the IC? GL on the mod-I also agree that the damage was NOT a result of boost in the SC-it looks like something got in there and got puree'd on the blades!
Thread Starter
Former Vendor of MBWorld
Joined: Jan 2007
Posts: 3,193
Likes: 3
From: Glendale Arizona
C55,SL55,C63
The only functions of the bypass is to limit boost and fuel efficiency. Lots of positive displacement blowers use a bypass that is vacuum activated for fuel efficiency on part throttle. Not having one can not hurt the supercharger in the slightest. Boost does not go up when you lift the throttle on your set up. The throttle actuator restricts air flow to the supercharger. If the throttle actuator was down stream of the blower then yes you would have a massive pressure spike that would simply blow things apart. You would need a turbo style bypass valve in order to dump the boost. With the throttle before the supercharger there is no restriction between the supercharger outlet and the engine.
I would think that there is really only two options for the failure of the first blower. One that it was defective and the other that something got in it. If the bearings failed then the rotors simply beat themselves to pieces very quickly.
I have had several blowers do the same thing but only after many years of service or if I was spinning them way to fast, which you are not.
Good luck on making more power and my two cents is bigger intercoolers.
I would think that there is really only two options for the failure of the first blower. One that it was defective and the other that something got in it. If the bearings failed then the rotors simply beat themselves to pieces very quickly.
I have had several blowers do the same thing but only after many years of service or if I was spinning them way to fast, which you are not.
Good luck on making more power and my two cents is bigger intercoolers.
I guess I'm just worried about this happening again. So you would say there is no need to have a bypass valve on my car? If my clutch on the SC is on all the time when the TB closes will this present a boost problem?
Thread Starter
Former Vendor of MBWorld
Joined: Jan 2007
Posts: 3,193
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From: Glendale Arizona
C55,SL55,C63
Hooley-thats the same set up that most manufacturers are running on turbo cars (recirc rather then vent to atmosphere)-I would def agree that even at 7psi (sure you are....I bet its 10 ) you will want the boost to go somewhere other then press against the internals of the SC-most places divert the air back into the intake pipe-after the MAF, this air has already been measured for fuel purposes-and use a BOV/BPV to regulate when it opens and closes (most AM BOV's have an internal spring that you can adj to a spec open and close to not get flutter at partial thrtl or let off-takes some adjusting on specific cars, but in the end is well worth it)-I think the idea of tapping the IC and routing that boost to the intake is great-there should be enough vacuum to open a valve-is there anywhere post SC that would work other then the IC? GL on the mod-I also agree that the damage was NOT a result of boost in the SC-it looks like something got in there and got puree'd on the blades!
) you will want the boost to go somewhere other then press against the internals of the SC-most places divert the air back into the intake pipe-after the MAF, this air has already been measured for fuel purposes-and use a BOV/BPV to regulate when it opens and closes (most AM BOV's have an internal spring that you can adj to a spec open and close to not get flutter at partial thrtl or let off-takes some adjusting on specific cars, but in the end is well worth it)-I think the idea of tapping the IC and routing that boost to the intake is great-there should be enough vacuum to open a valve-is there anywhere post SC that would work other then the IC? GL on the mod-I also agree that the damage was NOT a result of boost in the SC-it looks like something got in there and got puree'd on the blades!
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I (personally) think it is needed-even at low(er) boost levels-you'll wear out internal parts much faster then if you did not-and you get a mega/uber kewl sound too.....whhhhooooossssshhhhhhh
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From: MD
2007 C230 and 1985 Monte SS
When the TB closes, the SC keeps pumping, and it will create a vacuum. Whatever it manages to pump can go into the motor, unrestricted (because there is no throttle b/w the SC and the cylinders) If you actuate a bypass valve under this vacuum condition, its only going to suck more (un metered) air in.
It's not like the turbo setup on OEM setups.
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From: PA
S600, GL450, GLC 43
Hey Hooley:
I had and raod raced a whipplecharger, aka positive displacement blower, for over 10 years without a bypass valve. Simply put, it will do NOTHING for you. As was stated above, even with the blower spining all the time, when the throttle body is closed, your engine is NOT going to see boost.
On a flip side of the coin KB made one, which I never used, that would divert the air with its ONLY purpose being was to lower your IAT's while NOT under boost. AKA small throttle positions. I ran a vacume/boost gauge on my toy and would routinly see vacume under normal driving conditions. Sure put your foot into it, and woala, BOOST.
If you are going after EVERY last once of mielage, sure get one. As far as WIDE open power, it will do NOTHING.
Keep in mind that I did NOT have an IC. Also keep in mind that everytime you put your foot into it, the IAT's will still spike wether you have a bypass valve or not. Simple physics here.
Good luck my friend.
See yeah
I had and raod raced a whipplecharger, aka positive displacement blower, for over 10 years without a bypass valve. Simply put, it will do NOTHING for you. As was stated above, even with the blower spining all the time, when the throttle body is closed, your engine is NOT going to see boost.
On a flip side of the coin KB made one, which I never used, that would divert the air with its ONLY purpose being was to lower your IAT's while NOT under boost. AKA small throttle positions. I ran a vacume/boost gauge on my toy and would routinly see vacume under normal driving conditions. Sure put your foot into it, and woala, BOOST.
If you are going after EVERY last once of mielage, sure get one. As far as WIDE open power, it will do NOTHING.
Keep in mind that I did NOT have an IC. Also keep in mind that everytime you put your foot into it, the IAT's will still spike wether you have a bypass valve or not. Simple physics here.
Good luck my friend.
See yeah
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From: Delran, NJ
05 C55
the problem with no bypass valve, is when the throttle closes quickly, the blower is still making boost. the boost backs up in the intake tract and damages the impellers. ive run procharger, vortech, whipple and have always had a valve that redirected boost back into the intake. not sure what boost level youre at, but i ran 14-21 on the centrifugals, and 11 i think on the whipple. would you happen to know the make up of the AMG rotors? are they cast pieces?
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From: South of the Border
06 C55
As I understand things, and I will freely admit I am no expert, but it is my understanding that without a path for the pressure wave after you let off the gas, you can get damage to the compressor side of the equation in either s/c or turbo applications. Hence the bypass valve for S/C and blowoff valve for turbo.
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From: seattle
1990 300ce supercharged and intercooled
The thing is that there is not a pressure wave with the throttle upstream of the supercharger. It is no different than closing the throttle on a n/a motor. The n/a motor goes into a vacuum just the same. If you restrict air flow to the supercharger it goes into a vacuum also. As stated before the aftermarket bypass valves simply improve light throttle fuel efficiency and intake heat soak. But at full throttle they have no benefit. If there was a pressure wave with a positive displacement blower it would blow up immediately and all the intake tracts. The pressure would basically go up unlimited and either stuff would break or the blower would have to stop turning.
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Former Vendor of MBWorld
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From: Glendale Arizona
C55,SL55,C63
Thanks guys for the much needed input.
We have decided to go with a twin diverter valve setup. They will be welded into the surge tanks and a "T" will be welded into the Pipe Line after the throttle body. Should all be done tomorrow.
Below is a rude drawing of what it should look like when its finished.
We have decided to go with a twin diverter valve setup. They will be welded into the surge tanks and a "T" will be welded into the Pipe Line after the throttle body. Should all be done tomorrow.
Below is a rude drawing of what it should look like when its finished.
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From: PA
S600, GL450, GLC 43
the problem with no bypass valve, is when the throttle closes quickly, the blower is still making boost. the boost backs up in the intake tract and damages the impellers. ive run procharger, vortech, whipple and have always had a valve that redirected boost back into the intake. not sure what boost level youre at, but i ran 14-21 on the centrifugals, and 11 i think on the whipple. would you happen to know the make up of the AMG rotors? are they cast pieces?
See yeah
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From: MD
2007 C230 and 1985 Monte SS
Blower pushing through the throttle body -> TB closes and blower keeps pumping... you get pressure spikes.
Blower pulling through the throttle body -> TB closes and blower keeps pumping... you get vacuum.
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From: North NJ
2002 C32 AMG, 2013 GLK 350/4, 2015 E63S AMG Wagon
Is that why on my C32 my boost gague reads negative most of the time until I step on it? Makes sense.
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Yep-engines are on a vac unless something like a turbo or supercharger starts to press more air into the intake then would be pulled in by said vac-even FI cars run a vac until you spool up-
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Joined: Dec 2008
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From: MD
2007 C230 and 1985 Monte SS
