Quote:
Originally Posted by Jack Dempsey
Need advices
Hi gents,
After reading some of your post I still can’t make a clear decision. Most of the N54 vs N55 comparisons I red only concern the tunability and powerband. Actually I’m on the market for buying a used 135i MT. I want the best fuel efficiency as possible, the lowest long term maintenance cost and the best reliability. Which engine comply the most with my needs? Should I go with N54 or new version N55 engine and why? Does it worth the price to pay more to get a more recent car with the twinscroll single turbo? Feel free to reply with any comments that could guide my choice or refer to existing post if information already there.
I’m not planning to modify the car and I will use it as my daily drive. I’m not interested anymore in a twin clutches transmission.
My previous car is a modified Ralliart 2009 (12.9s@104mph), stock turbo, 26psi
Thanks for your expertise.
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The only *major* issue seen with the N54 engine was the high-pressure fuel pump, but there is a new part in circulation that solves that problem. BMW extended the warranty on the HPFP for some ridiculous term (like 100,000 miles), so you really don't need to worry about it, outside of the fact that if you do buy an N54 with the old part, you'll probably have to have it replaced at some point. When the HPFP goes, you're dead in the water, so that means a wait for a tow truck and a few days in the shop. If you search the forums, you can find the new part number and have the car checked out before you buy it.
Outside of tuning potential, there isn't a lot of practical difference between the N54 and N55 for someone who is just going to drive it day-to-day and not mod it. The N55 has the newer VALVETRONIC system, which eliminates the need for a throttle body and increases efficiency. The N55 also has a single turbo with a design that uses two inlets at with different geometry relative to the turbine. This design is supposed to have all the advantages of a twin turbo setup, but without the extra weight and complexity. Over the really, really long term, that means only one turbo to replace.
Vangard performance has a nice page outlining the differences between the two engines here:
http://www.vanguard-performance.com/...mw-n54-vs-n55/
Since your primary focus is reliability and efficiency, I'd say go for an N55 car. If I recall correctly, the N55 came with the new HPFP part from the beginning, so your chances of avoiding that problem are much better.
I don't know if this will work, but this link should show you an 2010 (N54) 135i compared to a 2011 (N55) model:
http://www.fueleconomy.gov/feg/Find....29828&id=30011
In case that doesn't work:
2010 135i: 18/20/25 city/combined/hwy
2011 135i: 20/23/28 city/combined/hwy
I own a 2011 135i with a 6-speed manual, and I get around 24 MPG with an 80/20 city/hwy mix. I drive it conservatively most of the time.
If I were in your shoes, I would look for a CPO 135i, but finding a manual might be a challenge. According to my dealer, less than 1% of the 1-series imported have a manual transmission.
My lease goes back in July of this year. I don't know what your timeline is, but my car is incredibly clean. We don't have kids, and I don't eat in the car. The car is spotless, with the exception of one chip on the front edge of the hood. No door dings, because I park in the middle of nowhere, and the car has never been modded. All service has been performed at the dealer (thanks to BMW service being included).
I don't know how off-lease cars work, but if you wanted an inside line on my car, I'd be willing to connect with you at turn-in to see if I can funnel the car your direction.