The Grand Vanos VS. Non-Vanos Thread

[MaxBell]

YEP! I think that is what allows a VANOS engine to take M3 cams, netting a larger hp increase.

[Leo_328i]

You must also take into consideration that the non-VANOS M50 motors run a hotter inlet cam than the VANOS motors.

The peak power of both motors is the same but the VANOS motor achieves this with a less aggressive cam.

I believe the M50 NV is a 240 cam and the VANOS motors are 228 degrees.

[MaxBell]

didnt know bmw has vtec

It's not as reliable as VTEC, but it's essentially the same idea.

I feel like swapping an M50 is only really a worth while endeavor if giving yourself Vanos. With Biesan Systems doing a $60 rebuild kit, there's not really any downsides. I just wish there were more performance upgrades that were not engine swaps or turbos. BMW does too good a job tuning their engines, we have nothing to do...

I was out with some friends who run swapped M50 E30s, and they all say the beefier non-vanos is a bunch of ancient mis-information. They've rebuilt them, not me, so I'm going of their word.

[e30trooper]

Pretty sure we're not comparing M50s to M20s in this thread.

I know im just saying ,I was comparing from what you said how you went eta to nvm50 thats a big upgrade. b25 to m50nv is kinda pointless unless you are mod happy. Id still love to have a 24v

[Jand3rson]

Pretty sure we're not comparing M50s to M20s in this thread.

[e30trooper]

m50nv isnt much faster than a good running stock m20b25...

[Jand3rson]

Darin peeped me onto this thread a few months back, lots of good info here:

http://forums.bimmerforums.com/forum/showthread.php?t=1116523

I could honestly give a rip if my M50 is Vanos or Non. It's a metric shit-ton faster than my chipped eta was. I've driven both, the difference I noticed while driving them was minor. When you start getting into things like the 2.8L M52 and then S50/S52, you start seeing large differences in power.

[DREWHALL]

I've heard the non-VANOS is actually faster in the upper RPM range. Not sure if that's true. That being said I've got a VANOS M50 in my car and it's quick, I'd venture a 14 second car of some caliber. I wouldn't be so generous as to call it fast by any means, but the way the car handles already and the extra power/driveability over the beat M20 that was in there I'm pretty pleased. I'd have to drive one without VANOS to tell you though. It would be nice not having to deal with the extra work timing without it. Good run down though!

[rares]

thank you for the write up sir... had no idea about this VANOS you shprechen about, but now i do... thank you kindly...

keep up the good work

[e30trooper]

didnt know bmw has vtec

[MaxBell]

So far R3VLimited has discussed this several times.

I searched through the forum and found all the threads and so here we are going to consolidate them all into one thread.

First off...
What is VANOS?

VANOS (Variable Onckenwellen Steuerung) is a cam phasing system for BMWs. It's similar to the Honda VTEC system for BMWs, which advances or retards the timing of your engine at different RPM speeds to optimize the engine. (VTEC goes farther then this and none in stock engines have ever broken)

What does THAT mean? Basically VANOS can mean a 40-50 ft/lbs of torque in the low end (2000-2500 RPM in a 540i). Above 4100 RPM, Dyno charts agree that VANOS ends up doing nothing; it actually just shuts off.

Now that we know what VANOS is, lets discuss...
The Pros and Cons of VANOS!

1.
As previously discussed, VANOS provides more low end power. Most people agree that this low end torque is noticeable most when daily driving. If you plan on driving this car predominately on the track or plan on driving your car above that 4100 RPM threshold, then you will not notice this as much.

2.
Currently the record for the fastest stock BMW 325 was a manual 1993 325is with VANOS (June, 1993 issue of Car and Driver). That car did 6.5 sec from 0-60mph.

As well, the fastest stock automatic BMW 325 was an automatic 1994 325i with VANOS (August, 1994 issue of Car and Driver). That car did 7.7 sec from 0-60mph.

That says a lot for the E36, as well as for M50B25TUs in general. Powerful engines, even more so with the addition of VANOS.

3.
There are more performance options for a VANOS engine, but keep in mind, like an our stock M20s, these engines come highly tuned from the factory. There is not a huge amount of things you can do to an M50 (VANOS or non) that will net any huge gains. The two things that are recommended are S50 cams (E36 M3) and a chip, which will bump you up to about 220 hp.

Don't waste your money on injectors or MAFs, even cold air intakes (CAI) net VERY small gains. The only real thing you can do is turbo, and we're not going into that here.

4.
The drawback to a M50TU is that the Vanos is no VTEC. They do break, and when they do, it can be $500-$1000 to fix. Even while they do work, after about 150,000 km they start to rattle, which is also tough to fix.

The issue is an o-ring within the Vanos unit, specifically a piston seal, which go after about 30,000 km, eventually leading to failure. Unfortunately BMW does not sell these individually, they only sell rebuild Vanos units for about $500. These rebuilt ones still have the same rings that degrade in the engine environment and fail.

EDIT: Apparently bimmerforums has someone there who runs Beisan Systems. They manufacture a teflon o-ring ($30) for failing Vanos units, addressing the reason for failure (bad material), as well as a repair kit (also $30) for that annoying "Vanos Rattle". They even sell the expensive Vanos tool for $5.

http://www.beisansystems.com/products.html

So let's discuss the...
Pros and Cons of hunting a Non-Vanos

1.
The M50 had thicker vale stems and dual valve springs. Some have said the block is SLIGHTLY thicker as well, allowing one to bore out to 86mm vs. only 85mm in a M50TU. (It's been brought up that the S50 block is a M50TU block bored to 86mm, so this may be a moot point)

However it has been argued that the second valve spring is only there since the valve stem is thicker, and the valve stem is thicker because it was on the M20.

Either way, this engine's stock internals lends themselves better to boosting. Again, not talking about that here, but E30Tech.com has more information on this.

2.
The M50 can be cammed by moving the exhaust cam to the intake side and adding a Schrick cam to the exhaust. However, Schrick cams have been discontinued. If you can find one used, power to you.

VAC Motorsports now offers some M50 cams on their website, made by CAT.

M50 Non-Vanos CAT Cams @ VAC Motorsports

Other then that, the same applies for this engine in terms of performance mods. Chip it and be done. Maybe a CAI, save your money for suspension and drivetrain stuff.

3.
The major drawback to an M50 non-vanos is that the cars they come from are older, therefore more kms. They also were made for only late-1991 until late-1992, so finding one is a little harder. Parts are mostly interchangeable, so fixing one is no more difficult.

4. Big bonus? Less things to go wrong. A Vanos unit failing is not common, but it does, like everything else, not have an infinite lifespan. However, if you're mechanically inclined, fixing it yourself MAY not be that difficult, considering the parts are cheap through Beisan Systems.

CONCLUSION:

This debate will be concluded when two brand new, completely stock 325i cars get dyno'd. Until then, we will argue.

One thing is certain, the M50 is a moderate upgrade from the M20. About 30 more hp/torque, a timing chain rather then a belt...

If you've got anything to add, do it NOW!

Some threads:

http://www.r3vlimited.com/board/showthread.php?t=221301&highlight=NV+hot+cam

http://www.r3vlimited.com/board/showthread.php?t=61192

http://www.r3vlimited.com/board/showthread.php?t=38527

http://www.r3vlimited.com/board/showthread.php?t=208528

http://www.r3vlimited.com/board/showthread.php?t=55290