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SKU: CHP-M20B27 Categories: , Tags: , , , ,


IMPORTANT! We NEED to know if you are running a 24 or 28-pin ECU before we can ship an appropriate chip! Please see the FAQ below for more information.

Bring your M20 to life with this fully tuned, daily driven, and track tested  performance chip. The SSSquid Tuning performance chip is the most complete tune on the market, with every aspect of the mapping being optimized from idle to wide-open-throttle.

This chip is compatible with:

  • 1984-1987 BMW E30 325e
  • 1984-1988 BMW E28 525e/528e


  • How do I know if my ECU is 24 or 28 pin?
    • Unfortunately there is no way to tell without opening the ECU. Fortunately, if you are unsure and do not wish to check, the 24-pin chip works in either the 24 or 28-pin socket! Simply leave the top 4 pin sockets (toward the notched end) of the 28-pin chip socket unpopulated (empty).
  • Only stock injectors are available under “Injector Size”, but I want to use upgraded injectors. What do I do?
    • The 325e ECU uses an out-dated injection control system that is not compatible with most every injector manufactured after 1985. Unfortunately, this means that there are very few plug-and-play injector upgrades for the 325e.
    • The 325e utilized low-impedance injectors, whereas most every injector that fits into the rail will utilize a HIGH-impedance system. A low-impedance injector gets a current of 5-6 amps, whereas a high-impedance injector will receive a current of only around 1 amp.
      • Putting 6 amps of current through an injector that is only designed for 1 amp means the injector WILL fail soon, and it WILL NOT flow correctly.
    • You MUST run low-impedance injectors as an upgrade. Unfortunately, most are not a compatible form factor, are for diesel applications, and flow huge amounts (80lb/hr+) that are not easily compatible with the 325e system (which flows only 13lb/hr stock).
  • I have mustang injectors (19lb/[email protected], aprx. 17.6lb/hr on the M20 3bar system), will they work?
    • Please see above question about impedance. They will not work.
  • I have M50 injectors (17.5lb/[email protected], or aprx. 15.3lb/hr on the M20 3bar), will they work?
    • Once again, please see the above question about impedance. They will not work.
  • TURBOCHARGER: I want to turbo my 325e!
    • While it is possible to turbo the 325e with a few changes, the stock ECU is very limited and the electronics limit your injector choice to pretty much just the stock injectors (the 325e system uses a LOW impedance injection system, whereas almost every other vehicle and injector produced after 1984 uses a HIGH impedance system). The M20B25 or M30B35 ECUs are much more capable and are able to handle lower levels of boost quite well (sub 14psi)
    • If you choose to stick with the stock 325e ECU, you will be limited to using an RRFPR with the stock injectors as they cannot scale large enough for boost. A ratio of 10 or 12:1 would be ideal for 8psi, but the stock injectors with an RRFPR cannot handle more than that.
    • Ideally the VAM (AFM) will be placed as a draw-thru, but if you must place it as a blow-thru we can tune for that as well. However, as a blow-thru it does harm some scalability and smoothness.
    • We ALWAYS recommend upgrading to the Motronic 1.1/1.3 electronics if possible, but it’s not a strict necessity.


0.5 12 13 800
1.0 15 18 1000
1.5 22 25 1200
2.0 45 53 1600
2.5 60 75 1600
3.0 75 88 1800
*over a stock vehicle on a stock tune. HP/TQ numbers are general estimates and will vary.

Don’t know what stage you need? Looking for a little advice? Please see the GETTING STARTED page or CONTACT US for more information!

Additional information


027 24 pin, 027 28 pin


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