turbo charged engines.reliabilty?

[Alan Smithee]

Originally Posted by JCL

BMW introduced a production turbocharged vehicle in 1973, almost 40 years ago. This isn't exactly a new concept.

...and up until the twin-turbo 3.0 N54, they only built one other turbocharged gasoline model (the 745i, in very limited numbers, in the early 1980s). A new concept? No. Has BMW proven long-term reliability with gasoline-powered turbos? Hardly.

[JCL]

Originally Posted by Alan Smithee

...and up until the twin-turbo 3.0 N54, they only built one other turbocharged gasoline model (the 745i, in very limited numbers, in the early 1980s). A new concept? No. Has BMW proven long-term reliability with gasoline-powered turbos? Hardly.

Fair enough. How about the early '80s BMW turbo diesel? Turbos are a pretty simple concept, and they aren't different between gasoline and diesel engines. Do you see the turbo as the failure point, or the resulting specific power output of the engine?

I just don't think the turbos are a reliability or durability issue. Sure they have only been around for four years. So has the E70 platform, so it isn't any more proven. How about the new 8 speed ZF transmissions? One year now. The modified x-drive? Since 2010. All more prone to failure than a turbocharger.

[JCL]

Originally Posted by BGM

Hey Jeff---I agree it's not always going to be less reliable. But the '08 535 you had with it you had only maybe 3 years tops (if people lease then it's not a big deal it's under warranty). The e70 is also a lot heavier of a vehicle than the 535 as far as weight to move--which can stress the turbo more. Also, when the warranty runs out I don't trust an Indy who has never seen nor barely worked on e70 twin turbo--they might only see 1 if that. To me, better safe than an engine re-build. My $.02.

I had the 535 for 45 months. Sold it before the warranty expired. That had nothing to do with the turbochargers, but rather the rest of the vehicle. We have no BMW extended warranty available here. I don't really want to own a newish BMW without a factory warranty, whether NA or forced induction..

A good independent mechanic is not phased by a turbocharger IMO. By the vehicle programming, possibly.

I think these vehicles are so complex that we aren't going to be driving them 300,000 miles very often as the price of repairs will rise so much. Given that, and since the engine will likely last longer than the reset of the vehicle, we may as well enjoy the ride (hp) and the efficiency along the way. Just my thoughts.

[Alan Smithee]

Originally Posted by JCL

Fair enough. How about the early '80s BMW turbo diesel? Turbos are a pretty simple concept, and they aren't different between gasoline and diesel engines. Do you see the turbo as the failure point, or the resulting specific power output of the engine?

I just don't think the turbos are a reliability or durability issue. Sure they have only been around for four years. So has the E70 platform, so it isn't any more proven. How about the new 8 speed ZF transmissions? One year now. The modified x-drive? Since 2010. All more prone to failure than a turbocharger.

Unlike gasoline turbos, BMW has been making turbo diesels continuously for years. I am no expert on the subject, but diesels typically use lower revs, lower boost, and therefore generate less heat. Heat is what will shorten the life of everything in the engine compartment.

[nd200]

there's no need to worry about the fact that it is a turbo engine unless you are going to own the vehicle long term (8+ years and/or 120,000+ miles).

[aimtimes100]

miles on JCL's 5 series and BGM's X vehicles please?

[BGM]

Originally Posted by aimtimes100

miles on JCL's 5 series and BGM's X vehicles please?

My first X5: '01, 3.0, 105K miles bought new (only retired because it got totaled--hit by someone), no issues. Current: '08, 25K miles.

[ard]

Originally Posted by aimtimes100

miles on JCL's 5 series and BGM's X vehicles please?

I actually laughed... what possible relevance could these numbers be to your question?

opinions on bmws turbo charged engines? i dont know much about the E70 ones but from what i heard about the 3 series coupe there typically bmw(not realiable) but however in 2013 bmw is releasing a new turbo charged 4 cyl engine.looks like they're trying to compete with audis 4cyl considering audis outputs 211hp and bmws new engine outputs 240hp.how are the engines on the general the smaller the engine, the more reliable it is but in a bmw, anything can happen.opinions?

not sure where you are going with this- (BMW competing with Audi, but smaller engines are more reliable..but maybe not BMWs...pass me a period, comma and space, please.)

Your questions is unanswerable. Well, actually you ask for 'opinions' so you can collect up opinions. But if you are looking for data from which to draw a supported conclusion, you will not get that on a forum.

So carry on, many more posts for sure...nonsense like 'the e70 is heavier and that will stress turbos more', or 'more parts on the turbo means less reliable' (uh, duh- but that assumes EVERYTHING else is the same, which it is not...like mixing apples and crankshafts)

I predict you will conclude precisely what you want to conclude.

[JCL]

Originally Posted by aimtimes100

miles on JCL's 5 series and BGM's X vehicles please?

For my 535i, 50,000 km when I sold it. But that has very little to do with reliability, which is what the thread title was about. It could relate to durability, ie will the engine last 300,000 or whatever the target is. The important thing from a reliability standpoint is that it went four years with zero turbo issues. If the rest of the vehicle was as reliable as the turbochargers then half the posts on this forum wouldn't be required, we'd just be driving them.

I have only owned three turbocharged vehicles (535i, Landrover diesel, VW diesel), but I have worked with turbocharged engines (diesel and natural gas) for 24 years.

[JCL]

Originally Posted by Alan Smithee

Unlike gasoline turbos, BMW has been making turbo diesels continuously for years. I am no expert on the subject, but diesels typically use lower revs, lower boost, and therefore generate less heat. Heat is what will shorten the life of everything in the engine compartment.

Since you bring up revs, let's consider two high output BMW engines.

The V10 S85 in the M5 had 5 litres, and 500 hp. Specific output of 100 hp/litre.

My N54 in the 535 had 3 litres, and 300 hp. Specific output of 100 hp/litre.

Those two engines were offered in the same 5 series chassis (with some mods for the M5, obviously, but it was the same physical space). Which do you consider would be more reliable, the V10 turning at 8250 rpm redline, with 10 sets of piston/conrod/etc, or the turbocharged 3 litre engine with peak torque reached at 1200 rpm, and only six sets of pistons/conrods/etc?

Obviously BMW could have built a 5 litre turbocharged engine to get 500 hp (and they did a few years later) but comparing these two in terms of specific power output, since they were available during the same time period, I would take the N54 over the S85 every time for reliability. And for fuel consumption. And for lower cost. Turbochargers and all.

If I wanted incredible engineering-as-art in my engine, I would buy an S85. I have huge respect for it. I just wouldn't expect above average reliability.


Sidenote: diesels typically have higher compression ratios in order to ignite the air-fuel mixture, achieved with higher boost. Gasoline turbos are stressed less, as peak cylinder pressures are lower.