Turbo whine

[boostin]

Originally Posted by Canexican

Holy crap, I didn't realize that stock boost was only 8.8 psi. Increasing boost by 10psi is pretty ridiculous on stock turbos - especially with how small they are. I personally wouldn't want to increase it more than 6psi over stock.

yeah, usually for the N54, people stay around 14-15 psi (5-6psi over stock) if they're not going for crazy horsepower records.

[M3_Dust]

Originally Posted by rcracer_tx

Care to enlighten us how the engine will "never make big power" with your infinite knowledge?

[rcracer_tx]

Originally Posted by M3_Dust

You still didn't answer the question. You know something about the block that nobody else on the forum does? Have you taken apart the block and done stress test, or found test where people have? Or are you just pulling this shit out of your ass?

[rcracer_tx]

Originally Posted by boostin

yeah, usually for the N54, people stay around 14-15 psi (5-6psi over stock) if they're not going for crazy horsepower records.

Terry had the boost at 18lbs to set a new record on the dyno and see if the turbos could hold that much boost... regular people will almost never see that type of boost...

[rcracer_tx]

Originally Posted by mvaccaro

so...do you really think he will ever tell if he replaced the turbos?
I would really like to know how many miles that car will hold up together....but i guess will never know...

I think he has tested the turbos to their limits on purpose, and I do know that he recently bought a set from a member on his forum...
(his wouldn't be a good example to use for longterm reliability as he regularly uses a non public turbo melter map at the drag strip that is tuned at 16.5psi)

[rcracer_tx]

Originally Posted by mvaccaro

i know...i'm just saying that only time will tell how much those turbos running jb3 14 or 15psi of boost will last....

the difference between the the turbo melter and the regular maps is like what? 2 or 3 more psi... about 15% 20% more so even if the reliability is not strictly proportional to the boost...the reliability of the regular jb3 maps shoudn't be too far away from the melter map....

so if you blow up the turbos in 2 years with the turbo melter tune...you will probably blow them up too in about 3 with the regular maps...

Don't get me wrong...if you enjoy the boost in performance and you have the money to replace them....then go for it

Low mileage used ones are cheap, I spent a lot at $400 shipped to get an extremely low mileage pair with wastegates and manifolds... Not really concerned about price, only catastrophic failure. Upgraded twins FTW.

[Nixon]

Originally Posted by martinsmu

Turbo Whine

Has anyone here experience this? There is a huge thread about it on E90 and its got me thinking. Go to the link and you will see what I am talking about. Quite scary....

http://www.e90post.com/forums/showthread.php?t=137302

They call it "Turbo Lady".

[dcafs]

Originally Posted by mvaccaro

i know...i'm just saying that only time will tell how much those turbos running jb3 14 or 15psi of boost will last....

the difference between the the turbo melter and the regular maps is like what? 2 or 3 more psi... about 15% 20% more so even if the reliability is not strictly proportional to the boost...the reliability of the regular jb3 maps shoudn't be too far away from the melter map....

so if you blow up the turbos in 2 years with the turbo melter tune...you will probably blow them up too in about 3 with the regular maps...

Here is something to consider from BMW's own technical papers on the stock N54 engine:



"At full load the engine operates at an overload of 0.8 bar"

0.8 bar is equivalent to 11.6 psi of boost.

I know the current stock boost peak is 9 psi, but the point is that it would appear that the N54 was designed to handle 11.6.

So one can reasonable conclude that companies like Dinan, Vishnu or BMS are not really pushing things too far with boost levels of 13-15 psi on their regular customer maps.

The experimental race maps are a different story....but those are not intended for public use.

[bmore135]

bcuz then the M3 wouldnt look as attractive on a showroom floor...

[Terrance28]

Originally Posted by vgame64

OT: Your GNX ain't gonna be faster than

I think the lesson is: Don't expect to push your car hard with the V3 or JB3 and expect it to last forever...8.8 psi to 16-18psi is going to cause wear a lot faster.

Holy shit!!!

This is one of my favorites.

[boostin]

Originally Posted by mvaccaro

So, if it was designed to handle 11.6psi why isn't BMW pushing 11.6psi then?

the turbos will last longer if the psi is lower. plus, if it made 3 more psi stock, the M3 would look WAY overpriced...

[drivrswntd]

Originally Posted by dcafs

Here is something to consider from BMW's own technical papers on the stock N54 engine:



"At full load the engine operates at an overload of 0.8 bar"

0.8 bar is equivalent to 11.6 psi of boost.

I know the current stock boost peak is 9 psi, but the point is that it would appear that the N54 was designed to handle 11.6.

So one can reasonable conclude that companies like Dinan, Vishnu or BMS are not really pushing things too far with boost levels of 13-15 psi on their regular customer maps.

The experimental race maps are a different story....but those are not intended for public use.

Am I reading this differently or are you numbers off? If it says it operates at up to .8bar over boost, and factory boost is 7-8 psi, .8 is equal to 11.6 psi, so wouldnt that mean at times it is running at 18.6-19.6psi?

[jeremyc74]

Originally Posted by drivrswntd

Am I reading this differently or are you numbers off? If it says it operates at up to .8bar over boost, and factory boost is 7-8 psi, .8 is equal to 11.6 psi, so wouldnt that mean at times it is running at 18.6-19.6psi?

They're talking about boost above normal atmospheric pressure. It's a translation issue with the terminology I think.

[Evolved]

Originally Posted by drivrswntd

Am I reading this differently or are you numbers off? If it says it operates at up to .8bar over boost, and factory boost is 7-8 psi, .8 is equal to 11.6 psi, so wouldnt that mean at times it is running at 18.6-19.6psi?

I doesn't matter as what was posted is fairly irrelevant. We're talking about turbo failure, not pressure in the intake manifold.

[rcracer_tx]

Originally Posted by Evolved

I doesn't matter as what was posted is fairly irrelevant. We're talking about turbo failure, not pressure in the intake manifold.

This is very relevant. When BMW states that the turbos are allowed to boost up to 11.6 lbs. stock, It makes us realize that 13-14 lbs. of boost is not that far off from what BMW had them manufactured to handle.

[dcafs]

Originally Posted by rcracer_tx

This is very relevant. When BMW states that the turbos are allowed to boost up to 11.6 lbs. stock, It makes us realize that 13-14 lbs. of boost is not that far off from what BMW had them manufactured to handle.

+1

I don't think it's a stretch to think that the turbo lag issues which surfaced after the launch of the N54 have a lot to do with BMW de-tuning the engine from it's original specifications.

Keeping the wastegates open at idle resulted in a less responsive engine off the line and is well documented in these forums.

So it does not surprise me that they keep peak boost a little lower as well. Maybe as others have speculated this was in part not to piss off the M3 market.

But at some point before all this took effect, someone at BMW designed the engine for 0.8 bars of ATMOSPHERIC overpressure (not over stock boost) and they published this statistic in their technical papers.

Sorry but I didn't publish this....BMW did.

I do have to agree though that at some point you are starting to introduce the potential for serious problems if turbos are extended way beyond their efficiency range, but it's going to be compressor rpm that does them in.

As some have pointed out already, in the VW/Audi and Subby world, boost pressures north of 20 psi are the norm.

That's NOT a lot of air pressure!

The standard household water pressure in your faucets is around 30 to 40 psi. Do you lose sleep over your toilets blowing up?

I think the two main enemies of running a tune are execessive compressor rpm and engine detonation/pre-ignition due to too much timing for the boost levels.

It's probably more accurate to debate those parameters than to blindly say that 16 psi of boost is unsafe because it's double that of stock.

The peak boost chosen by BMW is undoubtedly a compromise between creating a smooth power curve and achieving fleet fuel efficiency and emissions compliance targets.

Tuners don't have to worry about these factors and can exploit the headroom available within design specifications to maximize power delivery for more performance.

[randomquickness]

Originally Posted by Terrance28

Holy shit!!!

This is one of my favorites.

seriously folks...I am not stopping until you can hear that kind of turbo spool coming from under my hood.

[boostin]

Originally Posted by drivrswntd

Am I reading this differently or are you numbers off? If it says it operates at up to .8bar over boost, and factory boost is 7-8 psi, .8 is equal to 11.6 psi, so wouldnt that mean at times it is running at 18.6-19.6psi?

you are understanding it wrong. it is saying that the turbos can run .8bar (11.6psi) at full load so people that are running that psi or 1-2 more think they feel safe. you don't add the factory boost plus what its running under full load.

[N54POWR]

Originally Posted by M3_Dust

just get a supra, the N54 will NEVER make big power, the block is just not engineered for it

Came across this post randomly and just happen to see this comment.
Have you eaten your words yet? Lol.
What a difference 9 years makes....