Peugeot THP (badge, not an engine)

THP is a badge, not an engine — PSA's word for the turbocharged 1.6 of the BMW–PSA Prince family, on Peugeot, Citroën, DS and Dongfeng in this catalogue. Its naturally aspirated counterpart is VTi, and on the 1.6 they are the same block.

The number after the badge is the power in PS, and it names the variant:

• THP150 — EP6DT, and THP163 — EP6CDT (also EP6CDTM).
• THP175 — EP6DTS, later EP6CDTS, with an overboost function.
• THP200 — EP6CDXD, the first with petrol direct injection.
• THP205 to THP270 — EP6FDTX, EP6FDTR, EP6CDTR, the 208 GTi, 308 GTi and RCZ R.

⚑ Direct injection changes what goes wrong. From the EP6CDXD onward the fuel is sprayed into the cylinder rather than at the inlet valve, so nothing washes the back of that valve — carbon accumulates there in a way it cannot on the port-injected engines before it, and a rough idle or a misfire on a high-mileage one is that until proven otherwise.

⚑ The timing chain is the family's defining failure. A 2013 service bulletin covers failing chains and tensioners, both designed by BMW. A rattle on start-up is the tell, and it is not a noise to live with.

BMW's own turbocharged version of this engine is the N13, which replaced the naturally aspirated N43 — so literature under that designation describes the same hardware, and searching only the PSA code finds half of it.