Thoughts of deleting vanos on a bmw s54 (or any variable valve timing engine) for a dedicated track car, curious of pros and cons.

I plan to build my e46 m3 for track usage only. Would like to use the link system as there are more resources for it and user friendly compared to the mss54.

I plan to rebuild the motor and possibly use cams that are mild over stock in performance and with slight pump in compression. So I would degree the motor to optimize and find the safe clearances.

I would think tuning would be less complex with vanos deleted (less parts breaking down) and adjusting the cam according to measurements found during the build and find the optimize cam angles for the rpm range usage during the tuning process.

So with this in mind I would find that rpm usage during road racing conditions would be in the 3500-8000 rpm range.

Anyone using a bmw motor that deleted vanos or any variable valve timing engine for a dedicated track car? Would like to hear from you opinions guys.

Thanks

I'm building a M52 engine at the moment (single intake VANOS only) and went through the same though process including whether I should use an M54 as the base engine to get exhaust cam control as well. After many discussions with people in the know (a US based BMW racing parts supplier, my local BMW guru and my tuner) the conclusion and understanding I came to is:

- Intake cam control helps increase the rev range where it makes good power. Given I don't have a close ratio gearbox having better torque when you are outside the optimal rev range seems handy.

- Exhaust cam control assists mainly with emissions control.

Not being a tuner myself who knows if this is accurate or not. I'm sure the cam control questions is true across most engines not just the BMW ones.

I'd love to tell you the results but have been waiting 4 months for pistons and the same for an ECU so haven't got much to show in the way of progress :(

Interesting yes I was thinking of getting a close ratio gearbox like a samsonas 5 speed geared tight with the transfer to minic top speed of a 4.10 ring gear.

I was under the assumption as well if you optimize cam timing for the higher area of the rpm range you can delete vanos and have short gearing pull you out in the mid range area.

it’s all about the recipe, it’s just trial and error and someone has got to try.

I assume all the professional race cars don’t use variable valve timing. I would think because of high rpm usage and variable valve time is great from 1k-4k rpm for a street driven car because that’s the rpm it would likely see more often

I spent my morning remote-tuning a E30 M3 race car with an S54 engine and dual vanos. It's such an advantage to be able to tune for best power everywhere, I really don't get why you would want to remove it.

Hi David what system are your running and what are max degrees you can run on either intake and exhaust?

If you are asking what ECU we were using, it's a MoTeC M600. I don't have the config in front of me, but I think we were about 40 deg advance on the intake, and perhaps 25 retard on the exhaust. The cams would be mechanically stopped to limit the advance / retard, I would expect it may be as much as 50 deg on both intake and exhaust, but I haven't explored to find where the stops are.

If you're building a play car for track days, maybe some casual racing for fun, and want to reduce complications because you're doing your own tuning, then there may be some merit on removing/disabling any camshaft control.

However, if you're looking at taking it more seriously then it would seem to be foolish to avoid something that will give a useful extension of the power/torque curves and so give more over-all power. It may also make the vehicle easier to drive as it should give more flexibility in gear selection for some corners and in the wet or on slippery tracks a more progressive power delivery can give better control of wheelspin and balance.

Perhaps a good compromise would be to build the engine, and car, with the cam' controls in place but disabled, with the V2P clearances checked* for different camshaft timings that may be applied, then when you're more confident you can start to use the variable cam' timing option?

On the other hand, if you're determined not to use it, why not optimise the piston design - compression and maybe reduced valve pockets - with a 'better' camshaft profile, if you're changing those anyway?

AFAIK, any team will use this if it's legal, because it gives an advantage - not all classes and race series' allow variable timing of the camshafts.

*You asked what range they were being used over - this is going to be something you need to double-check for yourself, as different engines can be expected to be a bit different from each other, especially when modified. The problem areas are when advancing the intake, and retarding the exhaust.

I would keep at least the intake vanos operational if you are sticking with the OEM cam profile, the S54 high pressure vanos system is quite reliable and will give you a decent increase in midrange torque over locked cams. Dedicated race engines with big cams, sequential gearbox etc you would generally lock the vanos as you are not going to be using the midrange very often so might as well remove the complication and potential failure point.