Quote:
Originally Posted by sabbanick
Whether this thought is rational or not, I have a hard time with the fact that these tune files you create are not car specific. My fear is that for instance just to make a point..... my car will be the THAT one car that although "feels right" running evolve's tune is silently being stressed in a way that is detrimental to its overall health especially when being stressed in a racing/on track environment.
General speaking....
How much variance to you expect to see car to car running an off the shelf tune?
Does aftermarket modifications add to the unpredictability of creating consistency in performance gains/ideal operating conditions from the tune you create from WOOT's car assuming it is in proper running condition to begin with?
Is there a benefit to remote tuning and if so is this a possibility you would offer to us North Americans?
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Hi,
The tune files on all of the Z4M's in stock format are exactly the same. They all run the same and the only reason they all dyno differently is because of :
Temperature and therefore temperature compensation maps
Tyres on the dyno (yes they do make a difference)
Gear used
Fuel grade
Efficiency of spark plugs
Efficiency of other sensors
We have dyno tested hundreds of S54's on our own machine and the shape of the curves are almost identical on 99%.
The peak HP and torque figures can vary and this is down to how much ignition timing is being run on that particular test.
On cars with tunes the same variance applies.
Compensation is very aggressive on the MSS70 DME, far more aggressive than MSS54. As mentioned before in this thread and many others, there are multiple ignition target maps and they vary vastly. All depends on what ignition map the DME decides to run based upon it's logic. Easy way (but not so clever way) around this is to set all of the ignition maps to they are equal to each other :-)
As for the additional stress of the tune. Well, we don't run them lean. We don't use too much timing. We most certainly don't make them knock or even come close to that. We know this from thousands of miles of running them and logging the knock values. We have multiple race cars out there running our tunes and never once a problem.
Our tuning strategy is not aggressive and never has been.
After market parts can change things very much. Cheap headers with poor flowing merge collectors and incorrectly made deCAT pipes do cause issues and physical factors like these cannot be tuned out in some cases.
Incorrect setup of the cars also cannot be dialled out in a tune.
Blocked OEM CAT's cannot be dealt with.
There are multiple threads on m3forum.net where people have had problems and we spend as much time as necessary to fault find and make the cars run as they should. We have had cases of popular exhausts (not Italian) causing very high back pressure due to incorrect pipe diameters being used. We have seen headers with very much blocked CAT's. Poor headers.
You name it, we have experienced it and gone through hell and back with customers!
Then there is the discussion about the DME itself. This is mostly a target based DME. The ignition timing is not fixed and has huge variability. The AFR is fixed to a degree but that doesn't often tend to be a problem. VANOS is target based but has little compensation. So on and so on.
Custom tuning each individual car has never yielded much gain unless we change the strategy of the tuning.
We've had a few die hard guys come here and argue with us on custom tuning. We have put the tuning in their hands, explained how the DME works and then they immediately understand it is rather pointless in most cases.
What we say to everyone is this - make sure your sensors are all working. Make sure if you can your cam timing and valve clearances are where they should be. If you are going to invest thousands in tuning then at the very least make sure everything else is working as it should and DO NOT BUY cheaply made parts (irrespective of price) for these wonderful engines.
As a minimum I would say everyone should have new spark plugs, valve clearances and new pre CAT 02 sensors fitted before any type of tuning is done.
Adam's car is a 59,000 mile car and by no means a garage queen. This is a car that is used and enjoyed like it should be. Everything is in working order, no errors of any type, every sensor is doing what it should.