Alpha N vs. MAF

[mamarand@xxxxxxxxxxxxxxxxxxxxxxxxxx (mamarand)]

  Regarding the recent thread regarding the Alpha N vs. MAF conversion:
  
  <i have heard some mixed reviews on the alpha N. Heard that someone ran
  lean and blew up his motor. but this offers more power however, the MAF from 
  split second does not produce as much power, but it comes with the air fuel 
  meter and the calibrator they cost the same $900.>
  
  The Split Second MAF kit is a complete solution for MAF conversion.  The ARC2 
  calibrator provides all the adjustment necessary to fit a MAF sensor to a car 
  designed for an air flow sensor.  The elimination of the air flow meter 
  provides a significant increase in horsepower and torque while also improving 
  throttle response.  The ARC2 also provides the necessary adjustments needed to 
  compensate for different air filter assemblies, throttle bodies, cams, 
  headers, turbochargers, superchargers, injectors etc.
  
  The ARC2 is calibrated by the use of the ARM1 air fuel ratio meter as a 
  feedback device.  It provides all the resolution necessary to accurately 
  adjust the ARC2.  It is also uniquely suited for use while driving.  With 
  signal filtering and a bright 5 color display, it gives meaningful information 
  that can even be interpreted with peripheral vision.
  
  The Split Second kit has been used on M5, M3, 535i, 944 turbo, supercharged 
  NSX, supercharged miata and other models.  It made 18 horsepower and 18 ft-lbs 
  on my normally aspirated M5.  The conversion absolutely transforms forced 
  induction cars.
  
  <>i have heard some mixed reviews on the alpha N. Heard that someone ran >lean 
  and blew up his motor.
  
  No one "ran lean" and blew up their motor.. what someone DID do was run the 
  system on a motor it wasn't calibrated for..>
  
  One of the beauties of the Split Second system is that with the air fuel ratio 
  meter, you can tell if you have a dangerous lean condition.  That condition is 
  shown by a bright red light.  If that condition is seen at wide open throttle, 
  there is a definite problem.  Anyone with a modified engine should be running 
  an ARM1 to insure that everything is running properly. 
  
  <If you change ANYTHING on an alpha-N motor, you must recalibrate..
  Cam gear?? recalibrate..
  Exhaust??  Recalibrate!!>
  
  Recalibration is readily accomplished by adjusting one of the detented 
  controls on the ARC2.  In this way an application using the Split Second 
  conversion can always be recalibrated by the user from the driver's seat 
  whenever an engine change is made.  Even something as simple as a swap from 
  the stock air box to a cone air fliter can alter the state of tune of the 
  engine and be cause for recalibration.
  
  <>however, the MAF from split second does not produce as much power, but it 
  >comes with the air fuel meter and the calibrator >they cost the same $900.
  
  Ohh.. here we go AGAIN.. Would you ALL please make this the LAST time I have 
  to say this *grin*
  
  You CANNOT tune with a stock Oxygen Sensor.. the cheapest REAL meter is well 
  over $1000 dollars by itself.. this "systems" are being sold
  with BS air fuel meters that are dependent on stock-type Oxygen Sensors which 
  CANNOT and DO NOT yield reproducable results from run to run.. 
  
  Don't believe me.. then call Robert BOSCH.. they developed the sensor, I think 
  they might know ;)>
  
  The Split Second ARM1 does exactly as is advertised. Its primary virtues are 
  its usefulness while driving due to its filtering and 5 color display and low 
  cost making it affordable for the driving enthusiast. It displays air/fuel 
  ratio to a resolution of one part in ten due to its ten segments.  While it 
  does not possess 3.5 digit resolution, it does not have to for its intended 
  purpose.  
  
  The philosophy behind the Split Second system is to keep the DME in closed 
  loop mode at idle, and low and mid loads.  This is characterized by an 
  alternating rich/lean reading on the ARM1 which is also called dithering.  If 
  the dithering is balanced, that indicates that the DME is well in control of 
  air/fuel ratio and adjusting it according to how it is mapped.  The intent of 
  the ARC2 and ARM1 combination is not to remap the engine.  Rather it is to 
  hold the DME in the center of its closed loop control range throughout the 
  engine load range.
  
  The fuel mapping in the DME is still being used with the Split Second system.  
  That is why it is compatible with the stock chip or the after-market chip of 
  your choosing.  
  
  <ALPHA-N is NOT for street cars.. it doesn't belong on a daily driver, it's 
  for race cars.. my system is an improvement over that on the Gruppe A touring 
  cars.. NOT FOR STREET USE!
  
  And yes, I know some people ARE running it on the street, but it's not my 
  suggestion, nor is it my wish!>
  
  While the Split Second solution is sold for off road use only, it has 
  excellent drivability, low emissions and good fuel economy.  It is ideally 
  suited for competition applications yet equally applicable to street cars 
  where local laws allow its use.
  
  <As far as any external box with knobs and a MAF...  well.. if'n it were THAT 
  easy to drop a MAF on any car, you'd see a lot more BOSCH cars with MAFs! It 
  isn't.. it requires a COMPLETE code rewrite!>
  
  The Split Second approach is to leave the DME code alone. Testing has shown 
  that due to the completely different nature of the MAF sensor signal compared 
  to the air flow meter, an acceptable solution cannot be attained through a 
  code rewrite.  The ARC2 gets away from the traditional chip change paradigm.  
  It puts fuel control in the hands of the user.  Of course the ARC2 is much 
  more than a box with knobs.  It is a precision calibration instrument designed 
  specifically for this purpose.  
  
  <PS: The whole thing comes down to this.. (for you math heads)
  
  Try to match a LogE curve to a 5th order polynomial using 3 points and then 
  tell me how much error you get.. (hint: lots)>
  
  The calibration function of the ARC2 was developed after extensive analysis of 
  MAF sensors and air flow meters.  The adjustments on the ARC2 provide a best 
  fit curved line approximation to the desired fuel curve.  What this means is 
  that all points along the transfer function are adjusted, not just three 
  points.  Testing in many vehicles over many miles proves that the adjustment 
  resolution is sufficient to achieve reliable closed loop operation.
  
  This conversion works!
  
  Mark Amarandos
  '88 M5
  

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