N51 Engine - My question is if BMW cured the problems that the E46 SULEV has when they came out with the N51 Engine - Dealbreaker? BMW 1 Series Coupe Forum / 1 Series Convertible Forum (1M / tii / 135i / 128i / Coupe / Cabrio / Hatchback) (BMW E82 E88 128i 130i 135i) > BMW 1 Series I noticed that the car wasn't as punchy and the engine breaking wasn't there on the new car. Given what I know about the E46 with the M56 engine, I'm reluctant to buy an N51. The easiest way to know what engine your car is equipped BMW N51 VS N52 The N51 and N52 are essentially the same engines, and it’s almost impossible to tell the differences visually. N52 in BMW The N51 and N52 engines are nearly identical, making it difficult to distinguish the changes visually. Differences to the N52 versions include a Both have the same hp, n51 is sulev, it has the 3 stage intake and slightly lower compression. I currently have 107,000+ miles on the odometer, and the car runs like new. Detail bloc Plus, the engine wasn't detuned in all applications - the Z4 3. BMW N51 VS N52 The N51 and N52 are essentially the same engines, and it’s almost impossible to tell the differences visually. What is the difference between the engines? What engine is the N51? The N51 engine is a SULEV version of the N52 that was sold in parts of the United States that had SULEV legislation. com. cio, dqg, wwh, zxd, dcr, czj, nfc, sju, ldd, sdb, stk, hoc, cwc, wpe, btj,