[dlwhite]

My head asplode!

[stressdoc]

Originally Posted by Orb

We can’t dismiss the change in the fluid properties at altitude and thus difference in pressure drop for the whole system. I don’t think the turbo will see the same pressure or shaft speed as you said.

Orb

I was hoping Orb would explain my hedging... I will stand aside and let the brainiacs give it to us.

What do you guys (scalbert, orb, et al) think the boost limits are that BMW is comfortable with?

[adc]

Originally Posted by fedinand

In my experience (the only other twin turbo car I am familiar with is the B5 S4...and there were a lot of turbo failures), I can't ever recall an incident where both went at the same time - it was either the driver's side or passenger side turbo.

B5 S4 had a twin turbo V6, where each bank of cylinders had its own turbo, intercooler and intake.

The N54 is an inline 6, and there is a common intake path through the intercooler. There is no "driver side" or "passenger side" turbos, they're both on the passenger side, and the intake on the driver side.

So if there is some ingestion of small parts in the intake path, it is conceivable it can end up in both turbos. Not saying that is what happened in this case, just responding to your specific concern.

[scalbert]

Originally Posted by Orb

We can’t dismiss the change in the fluid properties at altitude and thus difference in pressure drop for the whole system. I don’t think the turbo will see the same pressure or shaft speed as you said.

True, the lower air density will also decrease air resistance with the compressor wheel but at the same time, less air is "grabbed" per revolution. As we know, as the compressor speeds change, so does the efficiency. However, the hot side is unchanged for the most part. If anything, the lower ambient pressure may help to speed up exhaust flow a little (probably not easily measureable).

Let's say car A is at sea level and running 7.5 PSI. Yet, if car A went to Denver or higher, it may well hit 10 - 11 PSI per BMW's design. That is about a 40% increase in boost. With changes in efficiency, I suspect the shaft speed would need to be higher, possibly 50% more (most likely more). Run that same vehicle at the same shaft speeds as the high altitude pulls and you will see more than 10 - 11 PSI. Without splitting hairs, say it is just 12 - 13 PSI which is still within the potential designed operating conditions set by BMW. Now add 2 more PSI and there is a 16% increase beyond the factory determined operating range. I am sure more buffer room was applied than that.

Again, this is just hypothetical. But we do have some facts. The stock turbos can supply 18 - 19 PSI at redline. I am not saying they are not choked at that point nor am I saying they are doing any other than blowing hot air. But that does lend credence that they are not choked at 14 - 15 PSI.

[scalbert]

And let me add, we are all just guessing. So... lets have a race to see who can truly explode their turbos the first.

[fedinand]

I wasn't saying the turbo set up is the same...just saying how odd it was that both turbos went out at the same time - if it was failure from high boost, I'd think you would see one turbo fail before the other. If there was foreign matter in the intake plumbing, then both turbos going out at the same time seems more likely. I guess we won't know until the turbos are examined.

[Orb]

Originally Posted by scalbert

True, the lower air density will also decrease air resistance with the compressor wheel but at the same time, less air is "grabbed" per revolution. As we know, as the compressor speeds change, so does the efficiency. However, the hot side is unchanged for the most part. If anything, the lower ambient pressure may help to speed up exhaust flow a little (probably not easily measureable).

Let's say car A is at sea level and running 7.5 PSI. Yet, if car A went to Denver or higher, it may well hit 10 - 11 PSI per BMW's design. That is about a 40% increase in boost. With changes in efficiency, I suspect the shaft speed would need to be higher, possibly 50% more (most likely more). Run that same vehicle at the same shaft speeds as the high altitude pulls and you will see more than 10 - 11 PSI. Without splitting hairs, say it is just 12 - 13 PSI which is still within the potential designed operating conditions set by BMW. Now add 2 more PSI and there is a 16% increase beyond the factory determined operating range. I am sure more buffer room was applied than that.

Again, this is just hypothetical. But we do have some facts. The stock turbos can supply 18 - 19 PSI at redline. I am not saying they are not choked at that point nor am I saying they are doing any other than blowing hot air. But that does lend credence that they are not choked at 14 - 15 PSI.

Hum...can't replay to this in full right now but I do believe you need to look at the fluid viscosity and this as a whole system and what the turbo sees for pressure only. Pressure drop is not going to be the same for most parts of the system.

Orb

[aaronb]

Originally Posted by E82tt6

Increased boost=less reliability. You'll never see a tuner do the kind of testing you want, it just isn't possible. No one knows what it will take to pop engines, and the only way to find out is to see several go. No tuner for any manufacturer ever has, or ever will do this testing. BMW does not conduct this level of testing!

I don't mean to sound like a smartass, but what you're suggesting isn't possible. I'd suggest sticking with a completely stock car if you're adamnt about it being 100% backed up. Even BMW doesn't know when something will go wrong, but they're betting big bucks that it will be after the warranty runs out

I'm taking the bait.

It is possible, and it's not called "testing", it's called "engineering". Folks like Dinan have engineered a solution that operates within the operational parameters of the components involved. And even if they didn't or if they're wrong, they're at least putting their ass on the line by offering a warranty. If Shiv or Terry are so sure their products aren't going to blow anything up, why not offer a warranty?

With that said, there are tuners and users alike who want the maximum performance possible, even at the cost of longevity. This is the bleeding edge, and as I posted before, when you ride that edge, prepare to bleed. These are the people who could give a shit about a warranty, because they are WILLING to pay to play. The guy with the blown snail even understands this. He got the thing fixed at the dealer, and even after dumping $15k is going to put the shit back on.

Bottom line is everyone needs to understand how much they're willing to put on the line. There's a reason Dinan is selling these even when they don't offer the best bang for the buck.

[M4TW]

Originally Posted by scalbert

True, the lower air density will also decrease air resistance with the compressor wheel but at the same time, less air is "grabbed" per revolution. As we know, as the compressor speeds change, so does the efficiency. However, the hot side is unchanged for the most part. If anything, the lower ambient pressure may help to speed up exhaust flow a little (probably not easily measureable).

Let's say car A is at sea level and running 7.5 PSI. Yet, if car A went to Denver or higher, it may well hit 10 - 11 PSI per BMW's design. That is about a 40% increase in boost. With changes in efficiency, I suspect the shaft speed would need to be higher, possibly 50% more (most likely more). Run that same vehicle at the same shaft speeds as the high altitude pulls and you will see more than 10 - 11 PSI. Without splitting hairs, say it is just 12 - 13 PSI which is still within the potential designed operating conditions set by BMW. Now add 2 more PSI and there is a 16% increase beyond the factory determined operating range. I am sure more buffer room was applied than that.

Again, this is just hypothetical. But we do have some facts. The stock turbos can supply 18 - 19 PSI at redline. I am not saying they are not choked at that point nor am I saying they are doing any other than blowing hot air. But that does lend credence that they are not choked at 14 - 15 PSI.

If this is the case, shouldn't all boost enhanced cars be blowing up like crazy in high altitude regions?

[scalbert]

Originally Posted by Sparkplug

If this is the case, shouldn't all boost enhanced cars be blowing up like crazy in high altitude regions?

They are, haven't you heard??










Again, all this talk is just speculation. In three to five years we will know for sure what affects there are and what the limits are.

[adc]

Originally Posted by trueblue

Please enlighten me on what cars the information does NOT apply to and why. I love to hear this.

+1.

I would also like to read Shiv's response to your original post. I thought your post provided some extremely interesting information, but Shiv seemed to allude that some of it was incorrect, and he mentioned he would respond that very evening.

Haven't heard anything from him yet. I hope he posts soon as to where your reasoning might be flawed. Otherwise I'll just assume he agrees with you, and was simply blowing smoke.


Again, this thread has been absolutely enlightening to guys like me, who are more or less waiting on the sidelines for the game to clear up a little.

[Potty_Pants]

Originally Posted by aaronb

If Shiv or Terry are so sure their products aren't going to blow anything up, why not offer a warranty?

I'm a Dinan guy but how can Shiv or Terry enforce a proposed warranty... Dinan already has the dealer network in place. While I would like to see a warranty from those guys i dont feel its even remotely possible. And even if they could offer a warranty they would need to charge $2k plus for it.

ppp

[adc]

Originally Posted by E82tt6

Increased boost=less reliability. You'll never see a tuner do the kind of testing you want, it just isn't possible. No one knows what it will take to pop engines, and the only way to find out is to see several go. No tuner for any manufacturer ever has, or ever will do this testing. BMW does not conduct this level of testing!

IMO, BMW most definitely does this sort of destructive testing. And I would not be surprised if big names like Alpina did it as well.

Just looking at the output of the B3 - and the mods deemed necessary to support it - sort of gives me a very good idea as to what a reliable output might be on this engine.


Just as all the manner of Alpina BiTurbos still running around 20 years later, or Dinan twin-turbo big sixes with six-digit mileage on them, reassure me to some degree about their latest offerings...

[hotrod182]

Originally Posted by Panoz

Well...it took me almost 30-40 minutes to read all these pages. Going back to the above "video" i believe that this means nothing. My turbos sounds like that since the very first moment I've installed the catless DPs.
Cats are working as silencers and when removed its expected the car to be more noisy. I dont find this sound to be neccesary the "prophet of future turbo failure"...but this is my opinion.

In regards to this thread in general...iI believe that a modded 335-driven agressively- is likely to face tech-issues more easily than a stock car. You need to drive wisely when you mess up boost pressure in stock turbos...

This is the same turbo noise from inside that car. Do yours really sound as loud as the ones in this video? Remember, this car has totally stock exhaust/intake:

[Panoz]

Originally Posted by hotrod182

This is the same turbo noise from inside that car. Do yours really sound as loud as the ones in this video? Remember, this car has totally stock exhaust/intake:

Is this comming from stock exhaust intake? Hmmm...then i guess this guy has a problem. It is pretty louder than mine indeed.

[E82tt6]

Saying "engineering" is easy, doing it is hard.

As I said in a later post, one could completely disassemble the engine, find what stresses in terms of heat, bending force, compressing force, etc a given component could be subjected to before breaking, including those in the turbo. With all of this information in hand, as well as compressor maps, turbine maps, flow benching, VE testing, IC efficiency testing, along with some testing of the flow rates and capacities of the various fueling components one could have a good idea about what is "safe". This isn't easy. The equipment needed to take these measurements is expensive at the degree of precision require. The testing procedures aren't easy either. It all requires a lot of skilled labor, and fancy math. It's certainly doable, but I've never head of ANY tuner completely taking apart the powertrain of a car to find the weak links, and find exactly what they can and can't survive, even Dinan.

Dinan makes some semi-educated guesses, but they really don't know much more about the N54 an anyone else, outside of the people at BMW who engineered it, and know exactly how much stress each part can take. They have a very conservative program. They basically run the car within stock tolerances, or SLIGHTLY beyond them. They took a guess at what the safety envelope that BMW allowed was, and made DARN sure not to breach it. They're betting money that the car can withstand 10-20% more boost than it will see stock. That's probably a safe bet.

I think people overblow how thoroughly "engineered" Dinan's tune is. Procede v3 and Helix's Attache control more engine parameters than Dinan, and procede in particular has more safe guards in place in terms of dynamic overboost and IAT based protection beyond the already excellent knock control of the stock DME. The biggest difference is that Dinan is a HUGE company, that sells more tunes than anyone else because of their support within some BMW dealers, and they put their money where their mouth is, so to speak. They're betting big bucks that they don't blow up your car. Shiv could probably do the same, if he eliminated end user tunability completely, ran a slightly more conservative map, and charged $800 more a tune to cover his ass in the rare event of a failure.

Not ragging on Dinan, just saying, there isn't all that much more extra "engineering" that goes into their tune, if ANY more. They just run less boost in the upper RPMs than other tuners, and charge a bit more for the built-in "insurance"

Originally Posted by aaronb

I'm taking the bait.

It is possible, and it's not called "testing", it's called "engineering". Folks like Dinan have engineered a solution that operates within the operational parameters of the components involved. And even if they didn't or if they're wrong, they're at least putting their ass on the line by offering a warranty. If Shiv or Terry are so sure their products aren't going to blow anything up, why not offer a warranty?

With that said, there are tuners and users alike who want the maximum performance possible, even at the cost of longevity. This is the bleeding edge, and as I posted before, when you ride that edge, prepare to bleed. These are the people who could give a shit about a warranty, because they are WILLING to pay to play. The guy with the blown snail even understands this. He got the thing fixed at the dealer, and even after dumping $15k is going to put the shit back on.

Bottom line is everyone needs to understand how much they're willing to put on the line. There's a reason Dinan is selling these even when they don't offer the best bang for the buck.

[scalbert]

Originally Posted by Railgun

Why would it take that long?

Big enough sample group of failures.

[KWA VaTech]

Originally Posted by adc

IMO, BMW most definitely does this sort of destructive testing. And I would not be surprised if big names like Alpina did it as well.

Just looking at the output of the B3 - and the mods deemed necessary to support it - sort of gives me a very good idea as to what a reliable output might be on this engine.


Just as all the manner of Alpina BiTurbos still running around 20 years later, or Dinan twin-turbo big sixes with six-digit mileage on them, reassure me to some degree about their latest offerings...

+1

It’s a joke to say BMW didn’t do proper research and development on this engine. I am sure 90% was done with computers and later backed up with experiments on working models (much cheaper that way). I am sure they took these guys to destruction; a company name is a big thing to protect.

With the profit margins that some of these tuners are seeing they should be putting money back into R&D. There is no question about it. But, they will continue on, guessing and testing, cranking up the boost a little more and a little more. Guess who the testers are? Guess how there’re going to get their long term data? Easy part is this game; you can just change your name!

To some it’s a risk worth taking but, don’t rule out a little R&D just because there’re tuners. Not hard to do a little modeling, some instrumentation, some hand calculations for crying out loud.

[stressdoc]

Originally Posted by O-cha

NOT Originally Posted by e.n335
When somebody earns 500k net profit with a tuning product it's nothing more than normal to buy a lambo.

OK, now there is the insult to Shiv that has to be dealt with. How about you (O-cha) agree to be Shiv's 4th V3 installer babe at Bimmerfest? And no fraternizing with #3...

Or maybe stand and let the guys dying to do R & D see if they can break your nose by throwing packing peanuts as hard as they can at you...

[Numb3rs]

Originally Posted by scalbert

The shaft speeds required to generate 11 PSI at, say, 8000 feet would be much more than just a 25% increase. That same shaft speed at sea level might equate to 13 - 14 PSI at sea level. So, the shaft speed is within normal operating ranges when generating 13 - 14 PSI at sea level.

So there is everyones defense with the dealer and regional when all of these turbos grenade in the next few days.

??

BMW uses different wastegate mappings for higher altitude. Less wastegates, more PSI...

Correct?

They don't spool the turbos any faster!

[Garissimo]

Originally Posted by E82tt6

I think people overblow how thoroughly "engineered" Dinan's tune is. Procede v3 and Helix's Attache control more engine parameters than Dinan, and procede in particular has more safe guards in place in terms of dynamic overboost and IAT based protection beyond the already excellent knock control of the stock DME. [..]

Without having printouts of Dinan's firmware, how do you know the piggybacks have more built in safeguards? Do the piggybacks have access to hardware the DME doesn't?

[5soko]

the SSTT uses the high altitude mode, does this mean its within bmw safety, accpetable boost range?