Topic: BMW 2.0 liter four cylinder N20 turbo motor already having issues?

[roundupready]

Read this over at bimmerfest.  Guess I'll have to re-think my plans.   


http://www.germanboost.com/content.php?3651-BMW-2-0-liter-four-cylinder-N20-turbo-motor-already-having-issues-Head-cracks-under-stress-above-331-pound-feet-of-torque

Some interesting information was posted in the N20 section of the BimmerBoost BMW forums regarding the durability of the N20 motor. Now, the motor is becoming very popular and is winning multiple awards and rightfully so as it is currently the best factory 2.0 liter turbo four cylinder in production. The keyword there being factory as apparently it is not going to be a stout aftermarket tuning platform at least not yet. Take the information you are about to read as unconfirmed but from an interesting source.

There are companies that stress test engines for OEM's. One of these companies has been testing the N20 apparently. The advice given is not to go beyond Stage 2 on the N20 which means a slightly more aggressive tune on the factory turbocharger. Why? The N20 head apparently cracks at around 331 pound-feet of torque. That is not exactly a whole lot of torque in the turbo tuning game especially considering the motor puts out an underrated 258 pound-feet from the factory.

Apparently the engine is just running very hot and multiple heat cycles are creating problems. BMW behind the scenes is supposedly trying to correct the issue. For whatever reason BMW seems to have a reputation for problems with new motors. S54 bearings, S65 bearings, and the next BMW new motor issue looks to be the N20 head cracking.

The story is that one of the lead designers and engineers for the N20 was flown out to the USA to inspect the findings for himself. It is doubtful BMW would do that unless there was something of substance to this. This same company also apparently tested other BMW motors including turbo motors such as the N54 and N55 when they were new and they did not run into these head issues.

So what is going to happen? Well, right now it is not recommended for N20 owners to push their motors too far which they can't anyway as there are not aftermarket turbo options out just yet. BMW will likely resolve the problem with a new head which will mean for those with the N20 there will either be a recall or there will be a BMW part number option to get the new head. We will have to wait and see what happens but N20 owners should be aware of the potential issue especially if intending to tune as BMW is unlikely to say anything until they have to.

[quadzilla]

Read this over at bimmerfest.  Guess I'll have to re-think my plans.   

What where your plans?

[mmret]

So it doesn't have much headroom for tuning. As long as it doesn't puke out at stock settings, I doubt BMW will care too much.

That said they haven't had a wonderful time with turbo motor reliability in the last little while.

[Sir Osis of Liver]

I'd be ok with a normally aspirated 2, or 3 series with the 6, but I'd steer clear of a BMW turbo until they get consistently good reliability ratings.

[aquadorhj]

BMW engine running HOT, No Way!!!      my engine stays hot for 6 hours after a highway run during summer.  even in winter, 2~3 hours no problem..

[mmret]

129 lbft per liter. And it feels like more. Yep, a fair amount of boost going on there.

Really nice motor to drive though, imho.

[PJ]

I worry about problems like this happening in a lot of todays high powered turbo engines.  Even stock they are cranking out a lot of boost and spending a lot of time doing it as most are in heavy cars and trucks.

In the short term problems seem to be rare but once the cars are 5 to 10 years old it could be very different.

[mmret]

Probably best to avoid used turbo gassers unless maintenance and care can be 100% verified.

[Travel360]

Probably best to avoid used turbo gassers unless maintenance and care can be 100% verified.

especially FGC!

[mmret]

Probably best to avoid used turbo gassers unless maintenance and care can be 100% verified.

especially FGC!

Well they are the biggest users of turbos.

Acura, Lexus, Infiniti lines are entirely naturally aspirated (might be a few exceptions but I believe I'm on the mark here).

Ford and GM are getting into it too.

[PJ]

Probably best to avoid used turbo gassers unless maintenance and care can be 100% verified.

especially FGC!

Well they are the biggest users of turbos.

Acura, Lexus, Infiniti lines are entirely naturally aspirated (might be a few exceptions but I believe I'm on the mark here).

Ford and GM are getting into it too.

Doesn't Acura have a turbo version of the CRX?

[mmret]

I think you mean CR-V?

The 1st gen RDX was a 2.3 T4 but the current one uses the corporate 3.5 V6.

My recollection is that the turbo motor was pretty punchy but really drank a lot.

[PJ]

I think you mean CR-V?

The 1st gen RDX was a 2.3 T4 but the current one uses the corporate 3.5 V6.

My recollection is that the turbo motor was pretty punchy but really drank a lot.

Whoops, I meant the CRV.  You're right. 

[Vanstar]

Anybody who reads my posts knows I am not much of a fan of turbochargers. The design tolerances of a 2 litre making  this kind of power are extremely close and the hotter and engine runs, the more efficient it is. On such highly stressed designs, it doesn't take much of a flaw to make a disaster. I do maintain that turbo engines make excellent choices for anyone who wants one, a group that does not include me, however.

Not that it matters. BMW cars are overwhelmingly leased for the warranty period. I would be confident that the N20 would make it that far and nobody seems to car that five year old Bimmers are reliability nightmares. It's a win-win for BMW.

[sailor723]

I have to admit that this question has crossed my mind. I wonder about the longevity small turbo engines putting out 250 or more hp....especially in the hands of average drivers and receiving (sometimes) less than perfect maintenance. I don't doubt the recent German offerings will last the warranty period and probably beyond but I wonder what the failure rate will look like past 150K and  in years 7/8/9 etc?   I was involved in a Subaru store in the early 90's and can remember all the 80's era GL10's and XT coupes getting towed in after grenading.