2018-2019 Buying an used car
bought Mazda 6 2.0i 2010

Searching a naturally aspirated engine
gasoline direct injection (GDI), also known as petrol direct injection, direct petrol injection, spark-ignited direct injection (SIDI) and fuel-stratified injection (FSI). 
 variable valve timing (VVT) is the process of altering the timing of a valve lift event, and is often used to improve performance, fuel economy or emissions.
 can be used with both direct and indirect injection 
 
 best would be to find a indirect injection engine, like on Mazda 6 GH 2.0 pre-facelift (2008-2010) and all Mazda 6 GH 1.8 (2008-2012). 
 VTi (Valve Timing injection) engines created by PSA Peugeot Citroën and BMW Group uses indirect injection
 there are 2 variants, 1.4 with 95 bhp and 1.6 with 115bhp 
 
 MIVEC is the brand name of a variable valve timing (VVT) engine technology developed by Mitsubishi Motors 
 Honda VTEC .. 
 Ford TI-VCT, non GDI 
 PM (particulate matter) is produced only by engines with direct injection 
 EURO 6
 it is achived basically only with direct injection with very few exceptions 
 Toyota has some small 1.33 MPI EURO 6 engines 
 
 EURO 5
 most engines are designed with direct injection, 
 few exceptions for >1.6, like Mazda MZR 1.8i 
 easier to find for small engines, <1.4 
 
 EURO 4
 many engines can be found with indirect injection 
 but many use with direct injection, think about VW/Audi FSI

Mazda
Mazda 6 GH 
 Initial release 2008 
 sequenzielle elektronisch geregelte Saugrohreinspritzung 
 abgasnorm EURO 4 
 1.8i 88 kW 
 2.0i 108 kW 
 2.5i 125 kW 
 2010 Facelift 
 1.8i 88 kW - unchanged
 KFZ Steuer 524E (44E/mo) 
 
 2.0i 114 kW - DISI = Direct Injection Spark Ignition
 Benzindirekteinspritzung gibt sein Debüt im neuen Mazda 6 und ersetzt den bisherigen Zwei-Liter-Motor mit Saugrohreinspritzung 
 http://ww2.autoscout24.at/erster-test/mazda-6-facelift/fruehes-facelift/44465/171603/ 
 https://www.heise.de/autos/artikel/Mazda-6-mit-Facelift-Fahrbericht-mit-neuem-Benziner-994220.html?artikelseite=2 
 https://de.wikipedia.org/wiki/Mazda6#6_(Typ_GH,_2008%E2%80%932012) 
 
 2.5i 125 kW - unchanged
 KFZ Steuer 863E (72E/mo)

Citroen
C4 
 First Generation Facelift 2008 - 2010
 1.6 seem to be very rare in AT 
 
 Second Generation 2010 - 2014 
 2015 Facelift does not have VTi engines anymore 
 1.6 VTi 120 PS (88 kW) 
 C4 Picasso 
 First Generation 2008-2012 
 1.6 VTi 88 kW

Ford
Focus Mk2 and C-MAX 
 2008 Facelift - 2010 
 1.6 Duratec Ti-VCT 115 PS, 74 kW 
 1.8 and 2.0 Duratec HE - developed by Mazda (LF model of MZR series) 
 Focus Mk3 
 no engine with indirect injection, all engines are Ti-VCT GDI - Duratec HE GDI 
 C-MAX Mk3 
 1.6 Ti-VCT 77 kW 
 1.6 Ti-VCT 88 kW 
 1.6 Ti-VCT 92 kW

Mercedes-Benz
B Class T245 
 all petrol engines are with indirect injection
 Motor codes M 166 E xx (E = Saugrohreinspritzung, xx = engine size in deciliter) 
 
 C Class W204 
 MPI engines use a Kompressor, while GDI engines a turbocharger 
 C 180 Kompressor BlueEFFICIENCY 2008 - 2010 - 115 kW
 from 2009 this engine was produced with gasoline direct injection 
 
 C 180 Kompressor 2007 - 2008 - 115 kW 
 C 200 Kompressor 2007 - 2010 - 135 kW
 from 2009 this engine was produced with gasoline direct injection and turbocharger 
 
 C 250 was produced after 2009, only with gasoline direct injection 
 C 230 is a V6 engine with indirct injection - 150 kW

BMW
BMW 3 Series E9x 
 E9x series with petrol engines, especially L4 N43, are known to have problems with oil leaks, water pump, cooling.. 
 inline 6 cylinder engines (325i) seems to be the best for car enthusiasts, but quite expesive to own 
 N43 and N53 use direct injection 
 N45, N46 and N52 engines use indirect injection 
 N46 found on pre-2018-facelift 318i 95 kW and 320i 110 kW 
 N52 found on pre-2018-facelift 330i 190 kW

Audi
A3 Second Generation (2003-2012) 
 FSI engines 
 facelift 2008 
 1.6 -> 2010 - 102 PS (75 kW)

Skoda
Octavia Second Generation (2005-2013) 
 facelift 2009 
 same platform with Golf Mk5 and Audi A3 Mk2 
 no interesting engine. Only option is 1.4, but it has only 80 PS

Hyundai / KIA
i30 Second Generationa (GD) 2012-2017 
 GDI models and T-GDI are engines with direct injection, T stand for turbo 
 CVVT and MPI are engines with indirect injection 
 1.4 CVVT 73 kW (99 PS) EURO 5 
 1.4 CVVT 74 kW (101 PS) EURO 6