Why BMW's N63 twin-turbo V8 eats batteries

Non-technical forum for other car makes. Good example: VW fan sites.

Moderator: Moderators

Post Reply
User avatar
Sabre
DCAWD Founding Member
Posts: 21432
Joined: Wed Aug 11, 2004 8:00 pm
Location: Springfield, VA
Contact:

Why BMW's N63 twin-turbo V8 eats batteries

Post by Sabre »

Road and Track
I have lots of friends who work on cars for a living. You could call them mechanics, but I think of them as supersleuths. I could write a book about some of the mysteries they've solved, like whacked-out windshield wipers caused by faulty fuel pumps or stability control that refuses to work because of dirty engine oil. Today's cars are so electronically interconnected that problems manifest themselves with the most bizarre symptoms. Here's one for you: BMW turbochargers are killing batteries in search of fuel savings.

BMW is no stranger to strange problems. The company has an admirable track record of introducing new technologies. Unfortunately, the new tech tends to be unreliable at first. The latest example giving BMW's warranty department gas is the N63 twin-turbocharged V8, introduced in 2008.

BMW of North America has recognized a number of N63 components with high failure rates, including timing chains that stretch and snap, leaking crankcase ventilation and fuel lines, and malfunctioning fuel injectors, mass airflow sensors, and vacuum pumps. Rather than waiting for them to break, BMW NA is proactively replacing the parts with improved components through its shrewdly named Customer Care Package, or CCP. This is not a recall, because recalls address vehicle safety. Instead, BMW says, the CCP represents its "commitment to the long-term reliability of our most technologically advanced products." It is undeniably a good customer service move.

BMW is also quietly dropping the V8's oil-service interval from 15,000 to 10,000 miles­. Not because of oil-life concerns, but to smokescreen the N63's appetite for motor oil. By shortening the time between oil changes (and sneaking an additional quart into the sump), there's less chance customers will get a low-oil-level warning. Insiders at BMW in Germany say the oil consumption happens to customers who don't ever flog their powerful, turbocharged V8s hard enough to fully break them in. Ironic.

Finally, the CCP offers a way to cover up the N63's habit of chewing through batteries: It contains a technical service bulletin to replace them at every oil change. This is where things get confusing. Why not just fix the underlying electrical problem? As it turns out, BMW can't.

As part of its EfficientDynamics push, BMW's cars are loaded with expensive systems to save fuel wherever possible. One of them, the smart-charging system, operates on the premise that you can increase fuel economy slightly by charging the battery only when coasting. Unfortunately, American drivers aren't coasters, we're cruisers, so the system was murdering batteries. BMW's solution was to throw money at the problem, replacing the batteries with Absorbent Glass Mat (AGM) units that can cope with deeper and more frequent discharge cycles.

That worked until the V8 gained turbos. With two very hot turbochargers in the very hot valley of its vee, the N63's cooling system must continue to run long after the engine's been turned off. The system's draw is more than the batteries can deal with, so BMW is now swapping out the old 90-Ah AGMs for 105-Ah units—and hoping they'll survive for at least 10,000 miles.

The simple solution would be to reprogram the engine computers to keep the battery's state of charge at a higher level. But in modern cars, everything affects something else, often in the most unlikely of ways. Charging the battery more often would affect fuel economy, which would require BMW to recertify the cars with the EPA. The revised mpg numbers would inevitably be lower than the ones advertised. Hello, class-action lawsuit.


So BMW can't actually fix the battery problem, it can only mask it. While it may be counterintuitive that turbocharging resulted in engines so understressed that they never break in, it's understandable. But who'd have thought adding turbos in search of better fuel economy would accidentally increase battery consumption? I feel for the guy who had to figure that one out.
I find it hilarious that in order not to change their EPA numbers, they will burden the environment with extra batteries so save face.

Honestly, good on them for replacing and finding the reason, but damn... shouldn't have this stuff come out during the beta testing?!?!
Sabre (Julian)
Image
92.5% Stock 04 STI
Good choice putting $4,000 rims on your 1990 Honda Civic. That's like Betty White going out and getting her tits done.
User avatar
Mr Kleen
DCAWD Founding Member
Posts: 15034
Joined: Mon Apr 18, 2005 6:46 pm
Location: Wiesbaden.DE

Re: Why BMW's N63 twin-turbo V8 eats batteries

Post by Mr Kleen »

Taxes and CAFE numbers are based on fuel consumption, not battery consumption.

ASS (Automatic Start Stop) burns the starter a LOT more often to save CO2 emissions and to improve fuel economy.
User avatar
Mr Kleen
DCAWD Founding Member
Posts: 15034
Joined: Mon Apr 18, 2005 6:46 pm
Location: Wiesbaden.DE

Re: Why BMW's N63 twin-turbo V8 eats batteries

Post by Mr Kleen »

The BMW guys are convinced that German cars (well, BMW's and Porsches) are the best engineered cars in the WORLD and all American cars are mechanically identical to the ones sold in 1979.

Meanwhile one guy with a mild tune on a 2011 135i car woke up to gas poring out of his exhaust when he tried to start the car. Just randomly, no reason. Now he'll be "happy" if he only has to spend $1000 on 3 new injectors.

wat
User avatar
Sabre
DCAWD Founding Member
Posts: 21432
Joined: Wed Aug 11, 2004 8:00 pm
Location: Springfield, VA
Contact:

Re: Why BMW's N63 twin-turbo V8 eats batteries

Post by Sabre »

Holy hell, that's crazy!
Sabre (Julian)
Image
92.5% Stock 04 STI
Good choice putting $4,000 rims on your 1990 Honda Civic. That's like Betty White going out and getting her tits done.
User avatar
Mr Kleen
DCAWD Founding Member
Posts: 15034
Joined: Mon Apr 18, 2005 6:46 pm
Location: Wiesbaden.DE

Re: Why BMW's N63 twin-turbo V8 eats batteries

Post by Mr Kleen »

I posted a link to the battery story on the BMW club's FB page.
30+ people saw it.
Not one comment.
Not. One.


The latest update on that guy's car is failed coil packs. He's replacing all 6 and installing new spark plugs. Not sure what it's going to cost but it should be cheaper than $1000 (I hope). But yeah, he was still without his car for several days (and counting) and he had to have it towed to the dealer.
User avatar
Sabre
DCAWD Founding Member
Posts: 21432
Joined: Wed Aug 11, 2004 8:00 pm
Location: Springfield, VA
Contact:

Re: Why BMW's N63 twin-turbo V8 eats batteries

Post by Sabre »

lol, why am I not surprised that there are no comments... I'm sure the first will be "See, BMW is taking car of us!" :lol:

I hope that fixes the guys problem... that sucks!
Sabre (Julian)
Image
92.5% Stock 04 STI
Good choice putting $4,000 rims on your 1990 Honda Civic. That's like Betty White going out and getting her tits done.
User avatar
Mr Kleen
DCAWD Founding Member
Posts: 15034
Joined: Mon Apr 18, 2005 6:46 pm
Location: Wiesbaden.DE

Re: Why BMW's N63 twin-turbo V8 eats batteries

Post by Mr Kleen »

The coils did NOT fix the issue. Next up: 3 injectors. Did I mention that on the N54 and N55 you have to replace the injectors in banks of 3, not just the one that's malfunctioning?
User avatar
Mr Kleen
DCAWD Founding Member
Posts: 15034
Joined: Mon Apr 18, 2005 6:46 pm
Location: Wiesbaden.DE

Re: Why BMW's N63 twin-turbo V8 eats batteries

Post by Mr Kleen »

"Take care of her?" [making gun hand gesture]
"No NO NO! Take her out, show her a good time."
User avatar
Sabre
DCAWD Founding Member
Posts: 21432
Joined: Wed Aug 11, 2004 8:00 pm
Location: Springfield, VA
Contact:

Re: Why BMW's N63 twin-turbo V8 eats batteries

Post by Sabre »

:lol:

That's absurd about the injectors... but I shouldn't be surprised. The coil packs on Cadillac's are in banks of 4 (as I found out on my dads car recently)
Image
Sabre (Julian)
Image
92.5% Stock 04 STI
Good choice putting $4,000 rims on your 1990 Honda Civic. That's like Betty White going out and getting her tits done.
User avatar
ElZorro
DCAWD Founding Member
Posts: 5958
Joined: Thu Aug 12, 2004 8:00 pm
Location: USA! USA!

Re: Why BMW's N63 twin-turbo V8 eats batteries

Post by ElZorro »

Very inefficient and wasteful. Bad German, bad.
Jason "El Zorro" Fox
'17 Subaru Forester 2.0XT
DCAWD - old coots in fast scoots.
User avatar
Mr Kleen
DCAWD Founding Member
Posts: 15034
Joined: Mon Apr 18, 2005 6:46 pm
Location: Wiesbaden.DE

Re: Why BMW's N63 twin-turbo V8 eats batteries

Post by Mr Kleen »

The coil packs can be replaced individually; injectors have to be done 3 at a time.
Coil packs are cheap; injectors are not.
User avatar
Sabre
DCAWD Founding Member
Posts: 21432
Joined: Wed Aug 11, 2004 8:00 pm
Location: Springfield, VA
Contact:

Re: Why BMW's N63 twin-turbo V8 eats batteries

Post by Sabre »

Just depends on the car as always! Ijectors for the caddy are $35/ea, coil pack is $144. On the RS injectors are $62/ea, and $80 per coil pack. Since they have three of them together, it's definitely going to cost more :(
Sabre (Julian)
Image
92.5% Stock 04 STI
Good choice putting $4,000 rims on your 1990 Honda Civic. That's like Betty White going out and getting her tits done.
User avatar
Mr Kleen
DCAWD Founding Member
Posts: 15034
Joined: Mon Apr 18, 2005 6:46 pm
Location: Wiesbaden.DE

Re: Why BMW's N63 twin-turbo V8 eats batteries

Post by Mr Kleen »

I meant for the N54/55.
Post Reply