BMW E36 Blog

What is BMW VANOS engine?

19th March 2007

What is BMW VANOS engine?

posted in Engine, Technical Info |


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Hello Guys,

 

I heard many times about E36 BMWs with VANOS engine and I heard that it’s a very special engine that can boost performance and enhance the overall car responsiveness. But to be honest, I have never read or see that engine in person :-p. Today I did a search for some information regarding this cutie and I found a great article that I thought everyone should read . So as usual, here we go, enjoy and remember to drop me some lines if you have more information about it  that you think is missing in this article.

 

 

 

Introduction:

 

VANOS is a combined hydraulic and mechanical camshaft control device managed by the car’s DME engine management system.

The VANOS system is based on an adjustment mechanism that can modify the position of the intake camshaft versus the crankshaft. Double-VANOS adds an adjustment of the intake and outlet camshafts.

 

VANOS operates on the intake camshaft in accordance with engine speed and accelerator pedal position. At the lower end of the engine-speed scale, the intake valves are opened later, which improves idling quality and smoothness. At moderate engine speeds, the intake valves open much earlier, which boosts torque and permits exhaust gas re-circulation inside the combustion chambers, reducing fuel consumption and exhaust emissions. Finally, at high engine speeds, intake valve opening is once again delayed, so that full power can be developed.

 

VANOS significantly enhances emission management, increases output and torque, and offers better idling quality and fuel economy. The latest version of VANOS is double-VANOS, used in the new M3.

VANOS was first introduced in 1992 on the BMW M50 engine used in the 5 Series.

 

 

Here’s how it works:

 

In overhead cam engines, the cams are connected to the crankshaft by either a belt or chain and gears. In BMW VANOS motors there is a chain and some sprockets.

The crankshaft drives a sprocket on the exhaust cam, and the exhaust cam sprocket is bolted to the exhaust cam. A second set of teeth moves a second chain that goes across to the intake cam. The big sprocket on the intake cam is not bolted to the cam, for it has a big hole in the middle. Inside the hole is a helical set of teeth. On the end of the cam is a gear that is also helical on the outside, but it’s too small to connect to the teeth on the inside of the big sprocket. There is a little cup of metal with helical teeth to match the cam on the inside and to match the sprocket on the outside. The V (Variable) in VANOS is due to the helical nature of the teeth. The cup gear is moved by a hydraulic mechanism that works on oil pressure controlled by the DME.

 

 

At idle, the cam timing is retarded. Just off idle, the DME energizes a solenoid which allows oil pressure to move that cup gear to advance the cam 12.5 degrees at midrange, and then at about 5000 rpm, it allows it to come back to the original position. The greater advance causes better cylinder fill at mid rpms for better torque. The noise some people hear is the result of tolerances that make the sprocket wiggle a bit as the cup gear is moved in or out.

 

Double VANOS

 

Double-VANOS (double-variable camshaft control) significantly improves torque since valve timing on both the intake and outlet camshafts are adjusted to the power required from the engine as a function of gas pedal position and engine speed.

 


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On most BMW engines that use a single VANOS, the timing of the intake cam is only changed at two distinct rpm points, while on the double-VANOS system, the timing of the intake and exhaust cams are continuously variable throughout the majority of the rpm range.

With double-VANOS, the opening period of the intake valves are extended by 12 degrees with an increase in valve lift by 0.9 mm.

Double-VANOS requires very high oil pressure in order to adjust the camshafts very quickly and accurately, ensuring better torque at low engine speeds and better power at high speeds. With the amount of un-burnt residual gases being reduced, engine idle is improved. Special engine management control maps for the warm-up phase help the catalytic converter reach operating temperature sooner.

 

Double-VANOS improves low rpm power, flattens the torque curve, and widens the powerband for a given set of camshafts. The double-VANOS engine has a 450 rpm lower torque peak and a 200 rpm higher horsepower peak than single-VANOS, and the torque curve is improved between 1500 – 3800 rpm. At the same time, the torque does not fall off as fast past the horsepower peak.

 

The advantage of double-VANOS is that the system controls the flow of hot exhaust gases into the intake manifold individually for all operating conditions. This is referred to as “internal” exhaust gas re-circulation, allowing very fine dosage of the amount of exhaust gas recycled.

 

While the engine is warming up, VANOS improves the fuel/air mixture and helps to quickly warm up the catalytic converter to its normal operating temperature. When the engine is idling, the system keeps idle speeds smooth and consistent thanks to the reduction of exhaust gas re-circulation to a minimum. Under part load, exhaust gas re-circulation is increased to a much higher level, allowing the engine to run on a wider opening angle of the throttle butterfly in the interest of greater fuel economy. Under full load, the system switches back to a low re-circulation volume providing the cylinders with as much oxygen as possible.

Wait for more from . . . BMW E36 Blog

 

Best regards,

Tony Sticks.

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There are currently 16 responses to “What is BMW VANOS engine?”

Why not let us know what you think by adding your own comment! Your opinion is as valid as anyone elses, so come on... let us know what you think.

  1. 1 On March 19th, 2007, Ryan said:

    That is a very interesting article and explanation of the VANOS system. I’ve always wondered what it was and how it worked, since I’m an admirer of BMWs. :)

  2. 2 On March 19th, 2007, Tony Sticks said:

    I’m really glad you liked it Ryan.

  3. 3 On April 25th, 2007, Mic said:

    If you look at a power curve graph (torque or HP) of a BMW E36 with Vanos, you’ll see the effect right around 4000 rpm. It is indeed a very clever technology.

  4. 4 On April 25th, 2007, Tony Sticks said:

    BMW is the ultimate driving machine… isn’t it?

  5. 5 On March 6th, 2008, mouyyad said:

    well i have to say that you are correct and i drive an E36 vanos and its great and if you dont care about the fuel you should get one its better when you drive it belive me

  6. 6 On October 24th, 2008, Andreas said:

    I have a 94 520 with the M50 engine 24 valve, single vanos. It`s a superb technology but mine needed a rather expensive service
    having done more than 290.000km.
    Now the engine is back at running silksmoothly. It`s amazing how well balanced the BMW straight 6 is, you can balance a coin
    on the top of the engine while it idles.

    Remember this is 14 years old car, and the car and engine is so quiet and without any rattles or annoying noises

  7. 7 On December 14th, 2008, monyete30 said:

    i juz need 2 noe, can it be fitted to a 1989 model.

  8. 8 On June 14th, 2009, pambmw said:

    I have a question lately I always wonder why do I hear a ratling noise in the morning when starting my car and it comes from the vanos then it will all go away after it is warm and never heard. I have a BMW 325i I did pull out this documentation:


    BMW E39/E52 VANOS Rattle Noise After Engine Start

    BMW E39/E52 VANOS Rattle Noise After Engine StartShort Description
    E39 M5 and E52 Z8 with S62 engine produced up to 11/30/00. A rattling noise coming from the front of the engine (VANOS area) may be heard for a few seconds after start up. The VANOS adjusting units may cause a momentary rattling noise after the engine is started due to varying torque of the camshafts before sufficient VANOS adjustment oil pressure is built up. When the engine is switched off, oil bleeds out of the high-pressure chamber in the VANOS adjustment cylinder. This can cause the VANOS adjustment piston to move freely against the housing during engine start up causing the momentary rattling noise. This noise has no effect on engine power output or durability.

    ANY SUGGESTIONS???

    Thanks

  9. 9 On October 28th, 2010, Bjorn said:

    How can you see it’s a VANOS motor,or are all’93 till ’96 motors single VANOS and all ’96+ dubble VANOS?Thanx

  10. 10 On May 10th, 2011, XXRT said:

    Very funny…. This is basically the VVT(variable valve timing) technology which has been use by Toyota VVTL-I/Mitsubishi/ Honda I-VTEC/Peugeot CVVT etc etc with many, many, years ago. Presently all petrol engine, have VVT control on at least intake valves. VVT can have “step control” or permanent control of angle of intake valves which can be adjusted from 0 to 50 degrease on some engine (Peugeot engine for example). Together with VVT-I some engines, use “Valve lifting” technologies which help engine to gain good torque at very high speed (more than 4000 rpm). The VVT help the engine to gain better torque at low rpm and “valve lifting” technologies helps at high rpm.
    This system has been use first time by Fiat somethime on ’60… BMW start to use VVT control (in steps NOT permanent) in 1992 after another companies, as FIAT, HONDA, PORCHE, Alpha Romeo, Nissan which develop this system for many years already . BMW is coming up now with this technology, changing the name in VANOS for market reasons. The most advance VVTL (Variable Valve Timing and liftuing) technologi can be found on Japanese cars as Honda, Mitsubishi & Toyota and FIAT. BMW still has a lot to learn on this business…

  11. 11 On May 12th, 2011, sam said:

    the best car in the world 4 ever from 1916 to infinity

  12. 12 On May 12th, 2011, sam said:

    the double vanos motor is on the m3 e36 24 valve

  13. 13 On May 14th, 2011, XXRT said:

    SAM said: “the best car in the world 4 ever from 1916 to infinity” He knows… He is all, he is Alpha and Omega… I am expected that you to say that “German cars are the best”, VW the best car and another nonsenses. Anyhow, you need to eat more and grow more… you are too “green”!

    Well, check the Mitsubishi FTO and you will see an engine 2.0 liter which can delivery 200Hp. The engine is VVT and VVL controlled with the Mitsubishi technology MIVEC. Note that this engine has been made in 1995 AND it is NOT turbo or compressor!!! Show me and BMW engine which can delivery 200HP from 2 liter (NON turbo)!!!!!!!!! And this is only an example.
    PS:
    Mr. Sam is better for humanity if you will chose to kill yourself!

  14. 14 On May 22nd, 2011, sam said:

    why u r angry we just make a comment not a war every human have an opinion my opinion is the german cars are the best :D

  15. 15 On November 9th, 2011, Chris said:

    I have just been told that the Vanos adjustment unit on my 2003 BMW M3 needs to be replaced due to it jamming up . The car was running poorly at times and was lurching while driving in 1st and 2nd gears. The dealer states the cost is $1,900.00 discounted price by the way. Does anyone have any ideas or opinions regarding this . The car has 68,000 miles.

  16. 16 On July 4th, 2013, antony thomas said:

    Hi ive got a 1999 e36 323i coupe. The tick over as gone really lumpy and my fuel econermy as gone and it judders in low revs i had it on a computer and it said vanos mecanical faliure.i was told it could be the vanos solinoid or the camshaft position sensor but theres no codes for the sensor.its still got full power when you put your foot down and there is no noise comeing from the vanos.i read that you you test the solenoid by puting power to it and if it clunked it was working i tried that and there was no noise.im at loss carnt afford to take it to a garage and if the seals have gone inthe vanos it wouldnt be worth doing so if anybody as got an ideas i would be grateful.sorry one last thing can the cam sensor go with out making a error code..

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