Hello,

I tried to remember my youtube membership password to contact people from Greece

you are also from Greece that you might contact with them easily and if you really after true performance forget about supercharger upgrade.

turbo conversion is the best solution.

if they can offer turbo conversion please let me and other performance addict benzworld members.


cheers

Ali

P.s I am from Cyprus (northern side)

 

Thanks for the reply but i'm not interested in turbocharging my car. I like the oldfashioned kompressor whine and i would like some more. I just want tto have an idea of what the difference will be with an adjustable bypass valve...

 

Anyone? Any idea at all?

 

Hi Kwstantinos
My name is George, I agree with you that the key is the bypass valve wich is controled by the ecu witch ecu is cotroled by the different engine sensors and it built in software
I try my self to trick ecu to keep bypass valve closed for highr boost ..if i fail to do so I will try to trick directly the bypass valve .By the way my car is an slk 230 of 1999

 

i'm not talking about tricking the bypass valve but swap it with an adjustable one. If you check on ebay for " Bosch adjustable bypass valve " you will notice that bosch ofers that BPV for replacing the OEM BPV of VW, Porsche, Audi etc. so why not ours too?
Also i have to mention that i'm not talking of disconnecting the Bypass valve, just tap it and let it open as much as it wants. We shall conect the air hose to the new adjustable valve and drill another hole on the air box.What do you think of that?

 

My friend, i am giannis from thessaloniki. I currently drive a w203 c200k with the 2.0l M111 and a 23cm pulley kit producing about 220BHP. this idea is great, i will discuss it with my mechanic and a friend of mine currnetly facing problems with his bypass valve staying open. Do you have a link with the adhustable by pass valve?

 

Bosch Turbo Bypass Valve for Audi Porsche VW ADJUSTABLE : eBay Motors (item 360076810223 end time Jan-26-10 17:39:39 PST) <---This is the link for the adjustable bypass valve. I will use it in the beggining as a test valve and if it works fine then i will put on something better.

P.S. i'm from veria and if you want pm me to explain some things in Greek.

 

... And now the BIG question: Has anyone ever consider putting an adjustable Bypass valve in the car to decrease the leak of compressed air? I'm asking this because i measured the the pressure with the leaking hole tapped and the gauge was about to climb over 1 bar (14psi) and then stopped cause i feared that something bad would happen. So, why should we change pulley and overheat the supercharger and not just swap bypass valves?
The supercharger itself creates more pressure than we need and use...

Very interesting... If this is true then MBZ is using the bypass valve for boost control instead of just surge control. That said, you would be correct that increasing spring tension on BV or replacing with an adjustable BV should get you more power without having to replace pulleys.

 

If i remmeber correctly the bypass valve on our vehicle is either open or closed. Not variable.

It closes only if you mash the gas pedal.

I dont see why having an adjustable one would in fact help

 

That is typically how BV works as it is generally only used for surge control. If what kwstantinos is saying is correct and that the SC makes more boost but is linited by the BV, then the BV is being used for boost control (similar to a wastegate on turbos sytems). This would be good news... this means that by simply increasing spring pressure on the BV, you would get more boost to the motor. An adjustable BV just makes adjusting boost easier.

 

It doesn't work the same.

Our bypass valve is a butterfly valve. Its either open or closed.. it does not work the same as a typical BPV or BOV.

I am not attempting to shoot people down here, as most of you should know if you read my threads im about performance on this..

 

well my friend the truth is in the middle:
1. the bypass valve regulates the circulation of uncompressed air. It is situated on the front of the compressor.Open it drives the UNCOMPRESSED air to the intake manifold, closed it drives the air in the supercharger.
2. So there is no compressed air to release as we have in turbos and BOV
3. it is not open or closed.It is full open at idle and it closes gradually as load and throttle increase.

 

From a purist standpoint, a bypass valve doesn't regulate anything. It is a tool for venting excess pressure from the compressor wheel when the throttle body is closed. Without this, the compressor will continue to compress air and since the air has no where to go, it goes back to the compressor causing it to surge.

Not sure about the bypass valves on our cars specifically but on most cars they open and close based on vacuum from the intake manifold. When the throttle body valve closes, vacuum is created in the manifold which is connected to a nipple on the bypass valve. This vacuum is what opens and closes the bypass valve.

There's also what's known as a dump valve... It's a spring loaded valve that opens when the pressure (boost) exceeds the spring tension rating. These are what can be used for boost control.

 

Our Bypass valve (butterfly valve) works exactly as a waste gate. It bleeds the amount of air that Mercedes thought we do not need.In my case is 0,5 bar (7-8 psi). It's a typical butterfly valve which works with power signal from 1-4 volts.1=open, 2=1/3closed, 3=2/3closed, 4=full closed (kick down). If you want to make a simple test tap the hose which goes to the butterfly ,connect a boost gauge and see for yourself.My M62 climbs easily over 1 bar at 5.000rpm but i stopped there. I don't want something more, just 0,8-0,9 in addition with a 4bar Fuel Pressure Regulator and colder spurk plugs. It was so easy from the beggining and i cant believe that no one else thought about that....

P.S. another good thing is that we can have steady boost without pressing te pedal to the floor and the adjustable BPV will bleed only after 0,8 (for example)....

 

I've been thinking about this and in order to do what you want to do, an adjustable bypass valve won't work because a typical bypass valve works off manifold vacuum. What you will need to use is a synchronic BOV like the ones sold by Synapse. Their BOV's can work off vacuum and/or boost.

The only issue i foresee is the possibility of getting a CEL if the wire connection to the factory BPV is disconnected. Not sure if the factory BPV is monitored by the ECU.

 

@Giannisanag,

You are wrong. If you see your air box ,it has 2 pipes/hoses,the big one goes fresh air to the supercharger and the little one recirculates the excess (for Mercedes) amount of air through the Butterfly valve back o the air box.

@sikdog,

That recirculation happens because we have a MAF sensor and if we bleed air to the atmosphere (except from the rednecking Pshhhhhhh...) we wil get a fault code. So the excess amount of air has to create a continuing flow of air in addition with the fresh one.

P.S. Excuse my english, i hope everything i say is weel understood.

 

That recirculation happens because we have a MAF sensor and if we bleed air to the atmosphere (except from the rednecking Pshhhhhhh...) we wil get a fault code. So the excess amount of air has to create a continuing flow of air in addition with the fresh one.

Gakz is correct... you would be correct IF the MAF was BEFORE the SC. Since the MAF is after the SC, you can vent to atmosphere as long as your vent is before the MAF. Venting after the MAF will cause the motor to run rich and possibly cause a CEL.

 

I will say, if you bleed excess to atmosphere you do not get a fault code.. as it stands now my current set up bleeds it to the atmosphere.. Friday and Saturday I should be working on a final product and have it bleed back into the intake... although we have been getting snowed in lately so I may not be able to get to it.

 

Interesting... what did you do with the factory BPV?? Did you remove it or left it alone?? If you removed it and replaced it with a BOV and didn't get a CEL, that would be great news as it would mean that it isn't monitored by the DME.

 

I have allready thought about a synchronic Bov (or double action Bov as we call that in Greece) but my mechanic told me it's not necessary. The upper hose of the Adjustable bypass valve will read vacuum and boost (from intake manifold). When i release the gas it will lift to recirculate, same in idle to 2.000 rpm when kompressor isn't working. Now when i have boost i can adjust the spring to be hard so the piston of bpv won't raise with small amount of boost. Even if you think it's odd, you can adjust a ballance between the vacuum/boost line (little hose) and the big hose that will hold the pressure from the suppercharger (the one under). But even if we need a synchronic Bov and not the one i mentioned think how much gain we'll have instead of changing pulleys etc...

P.S. i never told that i will disconnect the OEM BPV,just tap it so it won't affect the system boost. Then let it open/close as much as it wants....

P.S. 2 I will accept that if i bleed extra boost in the atmosphere won't give me a fault code because you run like this and you don't have a fault code. But anyway i didn't plan to do so but recirculate as Mercedes did.

 

P.S. i never told that i will disconnect the OEM BPV,just tap it so it won't affect the system boost. Then let it open/close as much as it wants....

If what you stated in your original post holds that the BPV is controlling boost, this won't work. You are going to have to eliminate or disable the factory BPV to get more boost.

P.S. 2 I will accept that if i bleed extra boost in the atmosphere won't give me a fault code because you run like this and you don't have a fault code. But anyway i didn't plan to do so but recirculate as Mercedes did.

I believe that the only reason MBZ recirculates excess boost instead of venting to atmosphere is for noise reduction.

 

If the Adjustable Bypass Valve works like most other bypass/blow-off valves, it opens from vacuum not pressure. In fact, pressure will keep it closed. If this holds true then it won't work as you have stated but if it will open with either pressure or vacuum then you are good to go... from what i read in the Ebay ad for the adjustable bypass valve, it says nothing about working with pressure.

If you plan on leaving the factory bypass valve in for surge control then what you need is a wastegate for boost control. In order to control boost, the device must be controlled by pressure and not vacuum.

 

kwnstantinos, what kind of engine mods do you have?

 

Guys you lost it somwhere. I WILL NOT USE THE OEM BPV...I will tap it, close it but NOT disconnecting it so i won't have a fault code. As the manufactures claims "The valve at idle will remain open (vacuum) and when boost comes in the BPV's piston, it will close so we won't leak. So far so good. But if we leave it like this we will go to 1,4 bar of boost and we don't want that for sure.
Now, my mechanic said that if we turn the BPV "softer" through the adjust mechanism we can find a "balance point" where the pressure from the hose will be able to raise the BPV's piston and leak. With some experimentism we can find that point. Imagine that as the pressure from the upper point will push the piston to close and the same pressure from the underside hose will push it to raise, only one of two can win and by softing the BPV we can make the underside one win and raise the piston to bleed pressure (just like an external wastegate acts...)But even if we can't we will take a Synchronic Bypass Valve and do the job for sure....

@giannisanag
I have a green filter (in the airbox, not cone filter), alluminium hoses for Kompressor inlet and outlet and at intercooler outlet too. I've done the Maf rellocation mod and i cut off the M62 supercharger's inlet restrictor (it has a metal restrictor in his inlet hose's base). Also i have changed the M62's bearing with a bearing able to hold up to 18.000rpm. That's all , and now i'm ready for some boost.

P.S. Oh i forgot the Supersprint exhaust for which i paid 900 Euros but it's amazing...

 

Another thing i would like to tell you is the big mistake with the whole pulley matter FOR M62 supercharger. As i said The M62 can produce over 1 bar of boost. I saw 1 bar at -5.000 rpm so i assume that he can boost another 0,2-0,4 more till the barrier of 6.300. So we have an amount of 1,4 bar. We only use 0,5 , less than 50%. That's because of the BPV. But it doesn't read the amount of pressure and acts afterwards to hold boost at 0,5 bar. It has some fixed positions. For example it knows that at 3.500 rpm must be closed only to 2/4, and at 5.000 3/4 till kickdown when it closes completely (but not for long). Now when we add a larger crank pulley we force the supercharger to spin fater and produce 0,3 bar more boost. But again we have the same leak (fixed positions remember?) so from 0,5 boost we go to 0,7-0,8...
And i think, why make all these stuff and not just use a litle more of what the supercharger allready produces? ... Easy thinking?

P.S. If you go here http://cgi.ebay.com/ebaymotors/Bosc...810223QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item53d64017ef and read , you'll see that this BPV is adjustable from 8 to 16 psi, and of course they mean boost , not vacuum... How to adjust that? Exactly as i said in the previous post with the two forces pushing and ultimately the underside one "wins" and raises the piston to bleed the extra boost just like the external wastegate does ... But with this BPV we can leak boost even when we let the gas pedal cause of the vacuum created, something that we can't have with a normal external wastegate.

 

What mods do you have?

The ECU in the SLK230 uses a MAF sensor. It has no idea about "boost", only the amount of air flowing in. Only way to set how much boost a charger makes is with crank pulley and or supercharger pulley - thats it.

the bypass valve does completely shut under full throttle (can show WIS documents later), and i believe Andre here had his car on the dyno and confirmed it does completely shut. I've measured boost at the outlet pipe at the s/c and recorded ~13psi. I measured boost at the FPR (fuel press reg.) and hit ~11psi. that's a 2psi drop across the system which is OK.

modifying the bypass valve WONT affect full power, only HOW (how early) the boost comes on.

modifying a vacuum controlled bypass valve is a common mod.

The boost bypass valve is a valve that controls when air is allowed to be pressurized in the intake manifold by the supercharger. During normal operation, the bypass valve remains open to allow pressure to bleed through the open valve and back into the intake system before the supercharger rotors. This increases gas mileage at low to mid throttle application but hampers performance by not allowing boost pressure to develop until heavy throttle application.

i played with putting a restriction in mine to build boost earlier but car was boggy and it made power "holes" thru the RPM range - i guess you would have to re-prog the ecu to suit. in the end it did not change full throttle power at all.

Boost Bypass Mod

 

And how do you explain that when i floored the pedal with everything in stock state i saw 0,5 bar in the FPR line and when i taped/sealed the hose of the bypass valve i saw it climbing to 1 bar? So the butterfly closes but not for long. You feel better boost but only a constant 0,5 bar and not 1+ bar thatthe S/C produces. Why?

 

kwnsantinos, I see that you have looked into it greatly.However I have two objections:
1. Do first the pulley conversion. I have the M111 with the 163ps (normally 0,37bar) and it is now 220ps (0,63 bar). Quite cheap (for the power increase) and with no experimenting. You will not spin your compresssor up to 18000 without that
2. the by pass valve stays closed at full throttle. this is for sure. DOing constantl everyday obd data logging I get ful pressure just by taping the gas pedal. Full load=full PRESSURE By puttin a bov you will not increase the max boost you take. You will get it faster thats for sure.
3.you ve got pm

 

oh i ahvent read your last post!!
What do you mean?
that I get the 0,6bar and the valve slowly opens to keep the pressure steady??