C63 w205 turbosmart recirc valve
The proper term for these devices is "Priority Valve". They were first used on the 1986 M44/51 engined Porsche 944 turbo for improved throttle response. By t990 most two liter WRC qualifier proaction cars had them, Subaru WRX, Ford Escort RS, Mitsubishi Galant, 2nd gen Toyota Celica GT4 (the MR2 use the 3S-GTE motor as well) to name a few.
Are we sure we are not being sold a "performance" part that is redundant? I did read the 2018 M178 AMG TT V8 has a pair of electronic diverter or priority valves. The parts books show a pair of "solenoid valves" on the pervious TT V8 that are most probably Priority Valves. Solenoid valves would be more reliable and not depended on the linearity of pneumatic control logic such as traditional vacuum operated ones.
Purpose is to equalize the pressure on the high and low sides of the compressor wheel so it does not stall the the throttle is shut. Additionally, there a spring that slows the return to closed position, a very trick little idea that "'free wheels" the compressor momentarily so the turbine speed is greatly increased, providing boost as the throttle is re-opened. This effect is noticed a just about any throttle setting.
The "Blow-off" valve everyone seems to know about, but misunderstands was, in modern times first used on the Porsche 930 1100np flat-12. The inertia of the large, turbochargers, was such that shutting the slide throttles would so over-pressure the intake tract and the seams of the manifold could burst. That was the huge CHIRP! of every gear change. This is NOT a problem in road cars, yet for a long time every kid with a turbo wanted one. What the kids did not know was that the 917 (and 936) had two throttles, one on the low side and one on the high side of the compressor. The throttles were connected via a carefully adjusted mechanical link so the first set opened just slightly faster than the throttle valve behind the compressor. Then, someone at Porsche thought of the $45 dollar plastic Priority Valve.
Indeed the AMG TT V8 have them already, but for anyone wanting mechanical ones (with larger intercoolers) I suggest just using a pair 944T: Kayser 993 110 337 51 They were designed for the 2.5 liter motor and using a pair would work on any 4 to 5 liter V8. There is an aluminum replacement for some $100 dollars, but function is identical.
Last edited by Mike__S; Jul 8, 2020 at 02:19 AM.
The proper term for these devices is "Priority Valve". They were first used on the 1986 M44/51 engined Porsche 944 turbo for improved throttle response. By t990 most two liter WRC qualifier proaction cars had them, Subaru WRX, Ford Escort RS, Mitsubishi Galant, 2nd gen Toyota Celica GT4 (the MR2 use the 3S-GTE motor as well) to name a few.
Purpose is to equalize the pressure on the high and low sides of the compressor wheel so it does not stall the the throttle is shut. Additionally, there a spring that slows the return to closed position, a very trick little idea that "'free wheels" the compressor momentarily so the turbine speed is greatly increased, providing boost as the throttle is re-opened. This effect is noticed a just about any throttle setting. I am somewhat surprised the AMG TT V8 does not use them(??), but I have never worked with the AMG V8 Mercs, so I do not have a clue if they do or do not.
The "Blow-off" valve everyone seems to know about, but misunderstands was, in modern times first used on the Porsche 930 1100np flat-12. The inertia of the large, turbochargers, was such that shutting the slide throttles would so over-pressure the intake tract and the seams of the manifold could burst. That was the huge CHIRP! of every gear change. This is NOT a problem in road cars, yet for a long time every kid with a turbo wanted one. What the kids did not know was that the 917 (and 936) had two throttles, one on the low side and one on the high side of the compressor. The throttles were connected via a carefully adjusted mechanical link so the first set opened just slightly faster than the throttle valve behind the compressor. Then, someone at Porsche thought of the $45 dollar plastic Priority Valve.
If indeed the AMG TT V8 does not have them already, I suggest just using a pair of them: Kayser 993 110 337 51 They were designed for the 2.5 liter motor and using a pair would work on any 4 to 5 liter V8. There is an aluminum replacement for some $100 dollars, but function is identical.
PS I just got curious and there is a quite complete discussion, maybe a good laugh at: https://mbworld.org/forums/coupe-roa...bov-not-2.html
Ok.... now the install. Order from your dealer A2780106001 Drill and tap it 1/8npt thread in a 1/8 npt to 1/4" hose barb into the top of it. Standard 1/8" npt drill size is 21/64" I went a couple sizes bigger to reduce the chance of the tap cracking the plug. I also added some epoxy to the threads just to make sure it seals well. If you screw up, buy another, or if you are confident you could buy none and just modify the one on your car. It will look just like the Weistec map adapter somebody posted a picture of in another thread, when you are done.
Next find said plug on the passenger side about midway back on the intake manifold pointing up. You can see it about 7"behind the coolant bottle.
Turn it clockwise around 45deg while depressing the locking tab so it can turn. The locking tab is slightly blocked from view by the upper cylinder head overhang, and sits around 12o clock when viewed from the passenger side. I used a pick to squeeze the locking tooth down so it could turn past the locking tab on the manifold. Once unlocked I had a difficult time pulling the plug out, so i gently pried it out with a small flatblade. The o ring gets a little stuck with the heat i guess.
Put in your drilled and tapped piece. Hook up a hose to it. Run the hose to the BOV's install a tee and connect to both valves. You can also choose to put a tee into the evap line as some have mentioned. That can work too. Or you could drill and tap the plug on both manifolds and run a single hose to each valve. The driver's side plug is a little harder to access
The valves themselves are straight forward. Take off your intakes and remove the 3 T30 fasteners holding the plastic wire harness down. That will allow enough wiggle room to re/re the valves
It's easiest if the engine is cold but it can be done under pressure after a 30 min drive with your daughter asking "Dad... how much lomger? Why do you keep burning yourself?"😉
Last edited by RyanL; Jul 8, 2020 at 10:52 PM.
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And here's the dual port version: https://www.turbosmart.com/product/k...dual-port-vr2/
The Best of Mercedes & AMG
Passenger side of engine
Bung tucked down side with yellow mark on
Turn clockwise 90 degrees then pull out, bit tight on o ring.
Bung with barb tapped in and epoxy on thread for double security
And here's the dual port version: https://www.turbosmart.com/product/k...dual-port-vr2/
•Catless downpipes
• BMC filter inserts
•Turbosmart mechanical recirc valve with electrical blanking plugs as supplied.
• CSF charge cooling heat exchanger (radiator)
• Hybrid turbos custom done rated 800
• Going for mapping next week with figures and pics to follow 👌
•Catless downpipes
• BMC filter inserts
•Turbosmart mechanical recirc valve with electrical blanking plugs as supplied.
• CSF charge cooling heat exchanger (radiator)
• Hybrid turbos custom done rated 800
• Going for mapping next week with figures and pics to follow 👌
Just out of curiosity, do you know where the evap line is located as another option?
BUT the engine temps have risen major due to charged air (HOT) being vented to atmosphere were these are located. Engine temps up +10 degrees.
There are semi hard to install. Need to cut the casing to the loom for the fixtures to screw back in. Tight fit.
So if not running big boost get the other.
They sound super quiet and yes the factory items leak. These will bring on boost faster and hold it better.
Last edited by blowoff; Jul 9, 2020 at 12:31 PM.
BUT the engine temps have risen major due to charged air (HOT) being vented to atmosphere were these are located. Engine temps up +10 degrees.
There are semi hard to install. Need to cut the casing to the loom for the fixtures to screw back in. Tight fit.
So if not running big boost get the other.
They sound super quiet and yes the factory items leak. These will bing on boost faster and hold it better.
BUT the engine temps have risen major due to charged air (HOT) being vented to atmosphere were these are located. Engine temps up +10 degrees.
There are semi hard to install. Need to cut the casing to the loom for the fixtures to screw back in. Tight fit.
So if not running big boost get the other.
They sound super quiet and yes the factory items leak. These will bing on boost faster and hold it better.
1. Port being Vented To Atmosphere
2. Port being vented To Recirculation
The black hoses you ask about are the recirculation hoses.
The hot charged air before was being doused back into the system now some of it is vented out of these.
Everything under bonnet is now a lot hotter.
Last edited by blowoff; Jul 9, 2020 at 01:25 PM.
1. Port being Vented To Atmosphere
2. Port being vented To Recirculation
The black hoses you ask about are the recirculation hoses.
The hot charged air before was being doused back into the system now some of it is vented out of these.
Everything under bonnet is now a lot hotter.










