Filed under: Maintenance, BMW
BMW owners claim software update degrades performance
BMW's N54 engine has won the International Engine of the Year award for the past two straight years. It has also been listed as one of Ward's 10 Best Engines during the same period. The engine produces 306 hp and 295 ft-lbs of torque in a 3.0L inline six package thanks to the use of twin Mitsubishi turbochargers and direct injection. The N54's quick response and smooth torque curve has been an attraction for many enthusiasts, including myself - I call my Montego Blue coupe the turbo Cookie Monster. That is why a few BMW 335i owners are miffed by a feeling of reduced performance after a recent service update. Posters on the BMW forum e90post.com claim that a software update to adjust rattling wastegate valves has induced lag into the turbochargers that wasn't there before.
As illustrated in the gallery below, the N54 turbochargers differ from most setups in that the wastegates default to the open position. This allows for better emissions due to the ability of the exhaust gas to bypass the turbochargers on start up so the catalytic converters can heat up faster. It certainly follows suit that BMW has the ability to adjust the ECU settings in order to hold those wastegates open, thus altering the turbochargers' peak boost point and adding to the perception of lag. Currently all performance degradation discussion has been based on seat of the pants feel, along with increased exhaust noise and fuel consumption. Despite the claims, BMW North America and service centers have, thus far, found no critical issue with the new settings. If owners want to present true evidence, they should use a simple OBD scanner device to data log the manifold pressure or simply run a dyno comparison test. Thanks for the tip everyone!
Gallery: BMW N54 Engine and Turbos
[Source: e90Post.com]
_opt_thumbnail.jpg)
Reader Comments (Page 1 of 2)
_Jon 1:40PM (8/22/2008)
So, basically, it isn't *your* car, it is BMW's and they let you drive it.
Kinda the same attitude Microsoft has with their operating system and their customer's PC's....
Reply
jtower 2:37PM (8/22/2008)
and that's why i drive an old bmw and run linux
DKB_SATX 2:57PM (8/22/2008)
For the most part in the US, this is true in a literal sense. They're mostly leased, so in fact the driver DOESN'T own them.
Chuck 1:43PM (8/22/2008)
My 135i has this problem, thank you for finally bringing it to the masses.
Reply
Sucko Pseudo-Fix 7:40PM (10/15/2008)
http://www.bmwtis.com/tsb/attachments/B060408Slides.pdf
Page 14 - Read it!
C.W. 1:48PM (8/22/2008)
You could replace BMW with Mazda in the post's title also. MazdaSpeed6's go in for service and come out with the automotive equivalent of ankle weights.
Reply
Benfolio 2:39PM (8/22/2008)
They just feel slower. Pretty sure it's been proven that they make the same power, but in a more linear (less laggy and peaky) fashion.
Sucko Pseudo-Fix 7:33PM (10/15/2008)
http://www.bmwtis.com/tsb/bulletins/bulletin_graphic_temp/B111307g.htm
Read it!
Bubbles 2:12PM (8/22/2008)
Finally, the truth is out. Many of us have been suffering with this issue for quite sometime. BMW are you listening?
Reply
3seriesisking 2:17PM (8/22/2008)
I got the update about a week and a half ago and have not had any problems. It sucks so many people are though, hope BMW gets this worked out ASAP.
jjpg2000 2:18PM (8/22/2008)
Wouldn't it be better if the ECU opened the waste gates until the cat's are heated, then close them?
Reply
Geeky1 2:39PM (8/22/2008)
Depending on how the system is set up, not necessarily. A system that defaults to the wastegate being open may be much more fault tolerant than a system that defaults to it being closed, in the sense that the chances of the wastegate and its control system failing in such a way as to cause the wastegate to stick shut and create an overboost condition are probably somewhat (if not significantly) lower.
why not the LS2LS7? 2:24PM (8/22/2008)
These reports of "new lag" will grow and grow. People aren't used to turbo torque curves when they get a new turbo car and think that they've found the lag free turbo car.
But then they notice that when leaving from stoplights the car doesn't really perform super well off the line, and various other situations where turbos are just showing their limitations. And while the initial astonishment over the performance on boost wears off, the mild disappointment in situations where turbos show their limitations remains and can nag at you a bit. Add in the tendency for people to whine on the internet and you've got trouble.
I'm sorry to hear that BMW engines have their own (seemingly unnecessary) turbo noise. Audi 2.7Ts frequently have tweeting from the bypass valves at part throttle. I was glad to hear this isn't the case on my friend's 535i, but it sounds like they have their own issue.
Looking at the engine pics here, that's nice packaging on the FMIC. Good job BMW.
Reply
Prof3ssor 2:42PM (8/22/2008)
Your kidding, right? I have had turbo cars all of my life and I am a current 335i owner who picked up the car 3 weeks ago for delivery. I brought it in for a faulty headlight 1 week later and they updated the software and I now the car is a different animal. I guess you are going to tell the engineers at BMW that they did not invent a car where the turbo spools at 1500 rpm and call them liars. Well the turbo now spools at > 3000 rpm. I know though, I am a liar and just posting this because I wanted to whine
ik 9:48PM (8/22/2008)
ls7,
you're completely wrong on this one
the software update does in fact reduce the responsiveness of the engine in low rpms
read up on e90post
why not the LS2LS7? 4:03PM (8/22/2008)
No, I'm not kidding. This whole thing is like a rerun of when Audi came out with the S4, just 8 years later.
Also, saying turbos "spool" at a given RPM is misleading (pretty much inaccurate). Unless you are in an overboost situation, the turbos are spinning and the waste gates are closed. The amount of boost out is then only determined by the efficiency of the turbos at a given flow rate.
I have no idea what your crack about BMW and 1500rpm and engineers means. Are you trying to imply BMW created something new here? Making peak torque at low RPMs is not unusual for a low-pressure turbo setup. My Audi 2.7T makes peak torque below 1850rpms. The only thing to remember (for both cars) is that in normal driving where you don't go WOT from idle, you won't see those torque figures at those revs.
Look up people with Audi S4s talking about taking the power cable off their batteries to "restore full power". You'll find the stories in 2000 and 2001. Same kind of thing. Someone gets it in his head that the performance is change now. You can't measure it (usually), but their "butt dyno doesn't lie". Here's your chance to be a hero, start the power cable workaround meme in the BMW community.
Turbo engines can be great, but they just don't act like NA engines under all conditions. The combination of low revs and low throttle openings is particularly penalizing.
Kevin White 8:08PM (8/22/2008)
I definitely felt the limitations of the turbo when I owned a 1991 Dodge Stealth R/T Twin Turbo. Couldn't fault that car's brakes or road grip at all, but the engine note was pure sewing machine. But the main thing is that it was heavy (heavier than the GTR) and had gearing that was WAY too tall. The result of all this is that it had no excitement or liveliness, and when the turbos weren't ready to go it felt SLUGGISH.
Barry 2:30PM (8/22/2008)
Word in the forums is this is a cheapy attempt to fix hardware problems with software. A few lines of code is much cheaper than replacing flimsy HP fuel pumps and exhaust wastegates with more robust versions. BMW is being too clever by half here and it may very well backfire, considering NHTSA's investigation into BMW's inability to get a handle on the fuel pump failure issues.
Can you say "class-action"?
Reply
Sucko Pseudo-Fix 7:26PM (10/15/2008)
http://www.bmwtis.com/tsb/bulletins/bulletin_graphic_temp/B111307g.htm
Read it!
DKB_SATX 3:02PM (8/22/2008)
An interesting possibility here... if in fact this update affects fuel mileage as some owners seem to have reported, is it acceptable for BMW to put this change in place and continue to claim the EPA numbers they generated using the previous software? Since it's a closed-loop system, I'm guessing that this doesn't have a negative effect on emissions, but if it does that could get BMW into trouble as well. Now that engines are so heavily software-controlled, this kind of change could be construed as invalidating the powertrain certification that was issued under the previous software.
Reply