Discussion in 'Forced Induction' started by E92Dreier, Jun 18, 2008.
Day-um...that's really unfortunate...
That is horrible luck and I most certainly have sympathy for the person as many of us know how addictive more boost can be, oh yes we do...
HOWEVER... This is why when you do start playing with boost, power, chips, software suspension, whatever...anything that mods the way your car performs that you should do your research and talk to actual people that really do know something about your car. Then when you choose mods and upgrades you choose wisely, not just for the power they make per dollar but for the reliable performance they provide. If for instance this owner would have gone the Dinan boost enhancement route his engine mods would not have been self--destructive, and if he/she would have had a problem it would have been covered under Dinan's warranty. Too often all we concentrate on is price, and not quality. BMW's are expensive, modifying them properly is also expensive. But when it all comes together its worth every penny.
Yes, I am a Dinan dealer, and all of the above is a big reason why.
whoa..... that would leave me with a permanent nervous twitch.....
It was only a matter of time that this was going to happen. BMW is not going to (nor should they have to) pay for repairs that aren't their fault. Not to say that every mod out there is destructive to the car, but it is easier for them to say no mods then it is to test every one and find out which ones are destructive. Obviously if they ship the car with the turbos making 8lbs of boost and you turn that up to 14lbs, some stuff might break sooner than if left stock.
I almost bought my buddy's '04 STi for a track car/weekend car last year, but decided against it because it was so heavily modified that something big was eventually going to break.
It always boggles the mind how people make these kinds of changes to their cars and then whine and moan when BMW doesn't cover it when you engine explodes. No sympathies.
I'm a member over at E90Post, and trust me when I say that this is the number one discussion item. I'll shoot straight and tell you I bought the 335i for one particular reason, I'll let you guess, but I can definitely agree that it is not BMW's responsibility to warranty a product that has been altered beyond intended operating parameters. There is a line that gets drawn though. For example, you can't just void a powertrain warranty because one replaced their speakers.
I have been putting turbo's on BMW's for 27yrs. And this memeber got screwed
by the A. Mfg, B. or the dealer, C. or both. Here's WHY.!
To over boost today's modern Turbo. One has to get to boost in the high 20psi
to start. Say 27psi. Larger trim turbos' can live @ 30psi+. before one has concerns.
Now let's say that he adjusted his T boost to 27psi on his 335I. Granted they are
very small T's. That's were they get their great 0 to 60 times@ FACTORY PSI.
But after that they fall off quickly. i.e. lack of CFM output..
Enter our member. Say he's staying with most cars he's dicing with until say 70MPH.
Cant have that.!! Turn-up the boost. Here's the where the BMW T is the murder
in this case. Everybody think about it. If the BMW turbo"small."
is good for. Say 27psi before it self dis-strucks. Hmmm. Then the crank & rods in the
pistons not to mention the head gasket, etc, etc, in the 335I are better than
I would ever expect SAY to 28psi+. Conclusion: cheese ball impeller wheels.
It wouldn't cost BMW @ the OEM level maybe + $15 per turbo to put in beef wheels.
I rest my case. p.s. bet he wasn't running no more than 15/17psi max
I disagree. He was super dumb for modding a leased car. He did not own it. Dumb. His mods did not account for the turbo design. He did not avoid compressor surge. "good for 27psi" does not mean designed for 25% higher RPMs. A small turbo must spin faster to make more boost. Once out of the efficient range, the temps go up and the stresses on the turbo go up. Once past a certain range, there are damaging pressure waves caused by transonic flow. If it is designed for a certain RPM (say, 100k) then spinning it to 125k is bad bad news. The stresses in the compressor wheel rise with the square of shaft speed! BMW did not design those compressors, they specced them from a turbo manufacturer. If, as you say, they "beefed up" the compressor wheels, they would likely not have the performance that BMW wanted. The rotational inertia would be higher causing more lag. The max RPM would be LOWER due to the increased mass which increases stresses in the compressor wheel. These turbos were specced for good low end torque, low lag operation. If he wanted lots of power he should have spent the money on bigger turbos. Go cheap and pay in the end. I bet you would never spec a turbo that small for a car if you wanted to run 15PSI. This is not BMWs fault, not the turbo manufacturers fault, not the dealer's fault. The blame rests solely on the modder, and he accepted that responsibility and paid the price for a new motor.
Now, I don't like many of the moves BMW has been making engineering-wise, but this is not their fault. Defense rests.
What Moose said X 10.
Design parameters for automobiles are not just about heavy duty parts they are about a balance between the cars performance and also making the installation and everyday drivability seamless for all types of drivers. I'm quite sure this engine could be capable of 500-600, even more horsepower with big turbos and huge intercoolers but it would be horrible to drive and unsuitable as a street car. I'm remembering fondly but with a grain of salt some of my own turbo projects from back in the day. However, it was his car to do what he wanted to with, yes even though it was leased. He just went about it the wrong way and like many of us at one time or another he was bitten by the greed for cheap power. There is no such thing, plain and simple.
I believe you possibly missed the point I was making to those in this thread.
Remember. "everbody think.". If it takes approx: 27psi to exceed the RPM safe
range of BMW 335I small turbo's. My point was "Think". Hell!! the engine would have already self destructed @ around 18 to 20psi with 11: to CR even with fuel re-mapping & inter-cooler upgrades. It was never fitted with components to handle
18 t0 20psi of boost. i.e. bent rods, broken crank, melt down pistons,etc.
Thus the small turbo impellers were inside their safe range of operation. If they were
any good. As far as your "surge" comment. I have never seen, or heard of compressor side
impellers discingating into very small piece's of metal he claimed the BMW dealer found
in the engine. Extreme over surge would only bend the vanes over. An only once.
Beef: was not to infer they should be heavier. But NOT made from a brittle metal.
Which would be the only possible solution to why his impellers where fragmenting.
Better alloy they would have only bent over. Thus no BOOST after they did. BMW went cheapo.320FAST
p.s. Leased or not it's his@ the end. unless he opps out.
I get what you are saying there, but onle likely cause of this sort of damage is backflow from inadequate pressure handling on closed throttle operation. Active uses a very fast and efficient BOV to prevent this happening. The other thing- 27psi is a different shaft speed depending upon the engine speed and load (airflow.) You can extract 27psi from those turbos at 3000 RPM all day long. Now rev the engine up to 7000RPM. The flow through the turbos goes up, the shaft speed goes way up, and the stresses go up EXPONENTIALLY, not linearly. Like it or not, lightwieght high strenght alloys tend to be very brittle. Making them less so involves making alloys that might handle the abuse of out of design running conditions, but they might not be light enough or the may have problems with creep or they may simply not work. The turbo manufacturer designed it, not BMW. If he wanted to spend money to soup it up, he should have gone with larger turbos vs. overboosting these little guys. The only way to get them to move more air is to spin them faster. They were not designed to spin that fast, he did anyway without thinking of the consequences. Truth is, BMWs used to be overBUILT now they are overENGINEERED. Speaking as an engineer, this means lots and lots of effort went into making sure it was the fastest, lightest, best handling machine it could be. This means stuff was lightened by using less metal, FEA analyses, cycles to failure calculations, etc. Back in the day, they made it strong enough, and then some. That is why you can boost the nuts off a big 6 or 4 banger without worry. I am running a 325e engine to over 6500RPM - which the cast crank was not designed for - but have never had a problem because they overbuilt the engine. I would not dare overrev my M50 by 1500 or more RPM, and absolutely not an S54! Those engines kept getting engineered to be street-worthy race car engines and were designed with much more critical tolerances and limits. People expect things out of cars today that would have been unthinkable in a supercar 20 years ago. Case in point. 256hp 3.5L E28 M5. Phenominal in the day, now family sedans have outputs this high as a matter of course.
+2. He didn't even own the car which is good enough reason NOT to mod the turbo.
I will have to agree with EuroWekz. Spending that extra dollor or two would have covered his azz. The saying is true ''you get what you payed for''.
Interesting discussion. I note that some are faulting BMW for not building (or sourcing) parts that will hold up to modifications for which the car was not originally designed. Well, duhhh!
Let us consider another of their twin-turbo efforts, the 400-horsepower V8 that you find lying around in, say, an X6 or a new Seven. I am sure Unca Stevie D will be able to find an easy hundred ponies without trying hard. But the M GmbH boys not only had to find more ponies, they had to build an engine---starting with what they had---that would hold up to the sustained demands of a different breed of animal: the X6 M. The first thing they did was specify new twin-scroll turbochargers. Then they built a nest of snakey tubes in the vee: tubes from two consecutive cylinders---that is, consecutive in firing order---go to each scroll, so four tubes go to each turbocharger from ports on either bank. (The non-M motor uses one manifold for the right bank's turbo and one for the left's.) Since the exhaust port for one tube is closed when its twin is blowing, there is no back-pressure to the cylinder, and the sequential pulses do not have erratic flow rates. Of course, since they want to up the boost pressures, they also have to forge new pistons with a lower compression ratio. . . and remap the entire engine curve. . . and on and on and on.
The result is an additional hundred-fifty ponies. . . but as you can imagine, this RV&D ain't cheap.
But hey! Bill Bob's Aluminum Storm-Door Company And BMW Repair says they can up my boost for pennies with this here piggy-back chip and a twist of this regulator screw!
By the way, twin-turbo fans: Remember that anything that goes through the engine goes through the turbos. Sand and grit? Piston chips from overrevved downshifts? Oh, mama: new engine. New VERY EXPENSIVE engine---including new huffers. Let's be careful out there.
100% agreement --
I have a friend who just popped his overboosted N54 motor -- one turbo actually had disintegrated. He was using one of those piggy-back ECU controllers -- his engine is destroyed.
Cost of factory N54 - $19,000
Estimated cost of motor replacment with labor - $27,000 -
I saw tears, and lots of them.
We are trying to find a used motor for his vehicle, but this is the likely consequence of irresponsible modification...
Sorry to revive a long quiet thread, but I am currently debating myself on whether or not to Dinan-ize my 335i...this thread caught my eye.
Dinan mods do not void the warranty, so you can be assured that any Dinan mods that are applied will be safe for your engine.
I didn't see any mention of what kind of "racing" this guy was doing, but note that Dinan's warranty is voided if the car is used in "competition".
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