[cn555ic]

Forget it SHiv...read your post...I have nothing to worry about...thanks...will be looking forward to V3, well for me V2.1 upgrade without the PNP....Can't wait!

[RiXst3r]

Originally Posted by cn555ic

Yeah I know Rick, but the engine seeing 16.6 can't be good either, even though its for a split second right??

I get spikes of 12psi during shifts, especially one with a kickdown, on a STOCK car using the peak recall... Its such a short spike, you don't even barely see it when it happens, but it logs it for the recall... 16.6 for a blink of an eye isnt enough to cause any damage IMHO... but I am not a tuner...

[OpenFlash]

Originally Posted by cn555ic

Yeah SHiv I have the sec cat deleted, but do I have anything to worry about with the 16.6 peak measuring from the lines of the diverter valves...Should I lower my torque settings of 92% for the meantime until I get the V2.1 upgrade??? Thanks shiv

You are fine. And there is no such thing as a v2.1 upgrade. It's just what we called early version of v3 during the beta testing process. BTW, one of the reasons I don't like digital boost gauges is that they give no idea of how sustained or short a spike is. Nor do they have a quick enough update rate to show oscillation. Nor can ones brain function quick enough to really read it when your driving hard. Get a good analog gauge before fear forces you to do anything

Shiv

[RiXst3r]

Originally Posted by shiv@vishnu

You are fine. And there is no such thing as a v2.1 upgrade. It's just what we called early version of v3 during the beta testing process. BTW, one of the reasons I don't like digital boost gauges is that they give no idea of how sustained or short a spike is. Nor do they have a quick enough update rate to show oscillation. Nor can ones brain function quick enough to really read it when your driving hard. Get a good analog gauge before fear forces you to do anything

Shiv

not true with the highrez VEI... it has an ultra sensitive peizo-electric sensor built into the gauge, it reacts MORE that fast enough to show oscillation... it also has a bar graph for the quick glancing. I went through 6 digital gauges before finding this one... and because of its features, its EASIER to watch your boost than on an anolog gauge

yes, 90% of digital gauges SUCK... but this one rocks

[OpenFlash]

Originally Posted by RiXst3r

not true with the highrez VEI... it has a sensor built into the gauge, it reacts MORE that fast enough to show oscillation... it also has a bar graph for the quick glancing

If it's reacting fast enough to show a proper representation of oscillation, the LED screen would be a blur The bar graph can help a bit nothing really beats a needle gauge for ease of observation. Maybe its just my eyes/brain that works that way. Just my opinion. If it works for you, that's all that matters.

Shiv

[RiXst3r]

For someone who's brain is trained to watch an analog boost gauge, I am sure its easier to stick with that... but for someone who just wants to see their boost, as accurate as possible, and have extra features like ambient calibration, and peak recall, without spending hundreds of dollars, the new VEI is the clear winner

I've ran 8 different gauges... 5 of those being digital, 3 analog, and the one that keeps making its way back into my car as my favorite is the vei digital... because its just so dang accurrate...

I ran the VEI digital gauge on a procede v3 beta car, and what we saw on the VEI gauge EXACTLY matched up with his datalogging.

Originally Posted by shiv@vishnu

If it's reacting fast enough to show a proper representation of oscillation, the LED screen would be a blur The bar graph can help a bit nothing really beats a needle gauge for ease of observation. Maybe its just my eyes/brain that works that way. Just my opinion.

Shiv

[scalbert]

There are multiple things to consider. First, is there a mechanical reason for the tapering?

Some turbo vehicles cannot physically maintain boost after a certain point no matter how hard you push the snails. The K03's on the B5 S4 as well as the T-25 on the 2nd gen DSM's. Both of those had a natural taper as the turbo's had no way at all to maintain boost no matter how fast they were spun.

With this engine, there may be another mechanical reason, the solenoid bypass and the dependency on the DME. These types of tunes require the taper to keep the DME happy.

But then there is a philosophical difference. The fact that the turbos can naturally maintain 15 PSI or so at redline suggests they have not completely run out of steam. It does not mean they are not just blowing hot air at that point and not making more power. Historically, most turbo vehicles would be tuned in the aftermarket to push the stock turbos to their max. Meaning, they would be pushed until they physically ran out of steam. Granted, there were more mild tunes available which made less power while siding on longevity which is the philosophical difference. However, if the stock snails can maintain 18 – 20 PSI to redline (which I doubt they can), running 15 PSI is not an issue.

Granted, we currently do not know the limits or threshold of the stock snails nor will be ever fully understand. Take the B5 S4 for instance, many stock turbos failed and were replace more than once. Concurrently there were many chipped cars, with varying degrees of intensity, which the stock turbos were still running strong after 100k miles. There was just no definitive answer as to what would happen. About the only consensus there was is that all stock turbos would fail at some point, regardless of tune. Chipping the car would cause turbo, which were going to fail sooner anyway, to fail that much sooner.

I am aware AA had a failed set of turbos when pushing their shop car. However, a single unit sample group is irrelevant when attempting to show statistic on the topic. There could be other reasons for their failure. If running more boost with little taper spells doom for the turbos, I would suspect that there would be many V2 owners as well as JBR customers replacing failed turbo assemblies. We just haven’t seen it and only time will tell.

Dinan, IMO is something else as they have to insure greater reliability or it comes out of their pocket. Historically they have always been tamer as that warranty matching demands it.

Another consideration is the percent of driving in the extreme range. It appears most of the tunes make similar boost in the mid range; some more, some slightly less. Now let’s consider the amount of time actual driving at the higher boost level and then also calculate the amount of time at or near redline. The later would account for probably less than 0.01%, if even that. Yes, eventually you will get to a stress limit which causes immediate failure but so far that has not been seen. Long term wear is the unknown variable so far.

I guess the only answer is that no one knows the limits (well, I am sure Mitsubishi has an idea of the Mean Time to Failure, but not on a single unit). Guess are made in the aftermarket on observations as well as perceived limits. But perception can be swayed based on needs; sales, warranty coverage or even technical/mechanical limitations.

[OpenFlash]

Originally Posted by scalbert

There are multiple things to consider. First, is there a mechanical reason for the tapering?

Some turbo vehicles cannot physically maintain boost after a certain point no matter how hard you push the snails. The K03's on the B5 S4 as well as the T-25 on the 2nd gen DSM's. Both of those had a natural taper as the turbo's had no way at all to maintain boost no matter how fast they were spun.

With this engine, there may be another mechanical reason, the solenoid bypass and the dependency on the DME. These types of tunes require the taper to keep the DME happy.

But then there is a philosophical difference. The fact that the turbos can naturally maintain 15 PSI or so at redline suggests they have not completely run out of steam. It does not mean they are not just blowing hot air at that point and not making more power. Historically, most turbo vehicles would be tuned in the aftermarket to push the stock turbos to their max. Meaning, they would be pushed until they physically ran out of steam. Granted, there were more mild tunes available which made less power while siding on longevity which is the philosophical difference. However, if the stock snails can maintain 18 – 20 PSI to redline (which I doubt they can), running 15 PSI is not an issue.

Granted, we currently do not know the limits or threshold of the stock snails nor will be ever fully understand. Take the B5 S4 for instance, many stock turbos failed and were replace more than once. Concurrently there were many chipped cars, with varying degrees of intensity, which the stock turbos were still running strong after 100k miles. There was just no definitive answer as to what would happen. About the only consensus there was is that all stock turbos would fail at some point, regardless of tune. Chipping the car would cause turbo, which were going to fail sooner anyway, to fail that much sooner.

I am aware AA had a failed set of turbos when pushing their shop car. However, a single unit sample group is irrelevant when attempting to show statistic on the topic. There could be other reasons for their failure. If running more boost with little taper spells doom for the turbos, I would suspect that there would be many V2 owners as well as JBR customers replacing failed turbo assemblies. We just haven’t seen it and only time will tell.

Dinan, IMO is something else as they have to insure greater reliability or it comes out of their pocket. Historically they have always been tamer as that warranty matching demands it.

Another consideration is the percent of driving in the extreme range. It appears most of the tunes make similar boost in the mid range; some more, some slightly less. Now let’s consider the amount of time actual driving at the higher boost level and then also calculate the amount of time at or near redline. The later would account for probably less than 0.01%, if even that. Yes, eventually you will get to a stress limit which causes immediate failure but so far that has not been seen. Long term wear is the unknown variable so far.

I guess the only answer is that no one knows the limits (well, I am sure Mitsubishi has an idea of the Mean Time to Failure, but not on a single unit). Guess are made in the aftermarket on observations as well as perceived limits. But perception can be swayed based on needs; sales, warranty coverage or even technical/mechanical limitations.

Great post!

BTW, on a low back-pressure/inlet restriction-less application (ie, catless and intakes) the factory turbos can support 18-19psi at redline. The limiting factor in making power beyond 15psi at redline turned out to be fuel system limitations, not ultimate turbo capacity which I suspect can support, at absolute max, 440-450whp. This, needless to say, was surprising give all our expectations when we started tuning this car. Then again, it has mitsubishi turbos so maybe we shouldn't be surprised. We routinely pull 100whp out of those too. And they have tiny 2l motors

shiv <- evo fan

[scalbert]

Originally Posted by cn555ic

Yeah I know Rick, but the engine seeing 16.6 can't be good either, even though its for a split second right??

A momentary spike in that range is harmless.

[scalbert]

Originally Posted by shiv@vishnu

BTW, on a low back-pressure/inlet restriction-less application (ie, catless and intakes) the factory turbos can support 18-19psi at redline.

That is encouraging.

[ontopofm]

i love to read scalbert's post, very educational, ty

[Sniz]

good thread

[NM_BMW]

Originally Posted by Sniz

good thread

+1 Very informative.

[turbotko]

THANK YOU GUYS!!!! Finally a good informative post that's not clogged with this tuner and that tuner BS!! Damn, why can't it always be this way.

Great information Shiv, Scalbert, and Rixter.......I just learned someting from each of you and I've been a BMW Master for 6 years!

Looks like I'm going to have to get myself a VEI Rixst3r as the Cyberdyne guage I have now just isn't fast enough. I love your setup, but would rather just have the guage by itself.

Shiv, I've been wondering about all the V2.1 beta maps holding full boost to redline, but I had no idea the old maps tapered because of boost control issues. I can back Shiv up though, the turbos will hold 18+ psi to redline........ask me how I know

[jpsimon]

how do you know?

Originally Posted by turbotko

........ask me how I know

[O-cha]

Originally Posted by turbotko

ask me how I know

How do you know.

[e.n335]

Thanks to all of you for the very informative replies !

@ turbotko: how do you know ?

[RiXst3r]

Originally Posted by turbotko

THANK YOU GUYS!!!! Finally a good informative post that's not clogged with this tuner and that tuner BS!! Damn, why can't it always be this way.

Great information Shiv, Scalbert, and Rixter.......I just learned someting from each of you and I've been a BMW Master for 6 years!

Looks like I'm going to have to get myself a VEI Rixst3r as the Cyberdyne guage I have now just isn't fast enough. I love your setup, but would rather just have the guage by itself.

Shiv, I've been wondering about all the V2.1 beta maps holding full boost to redline, but I had no idea the old maps tapered because of boost control issues. I can back Shiv up though, the turbos will hold 18+ psi to redline........ask me how I know

The cyberdyne is crap... that was one of the ones I tried...
If you get the VEI, make sure its the NEW high resultion model, thats the one with the new sensor in it... even o-Cha swears by it, and if you know O-Cha, thats saying a lot... lol

[e.n335]

Originally Posted by RiXst3r

The cyberdyne is crap... that was one of the ones I tried...
If you get the VEI, make sure its the NEW high resultion model, thats the one with the new sensor in it... even o-Cha swears by it, and if you know O-Cha, thats saying a lot... lol

+1

I have the latest high resolution 52mm gauge and got 2 days ago the 41mm version with the external boost sensor as well. I am curious whether it is as fast as the 52mm version - still to test.

[kitw]

Let me just say that running V3 with 15psi is pretty eye opening compared to my previous tune. Wow! It's amazing steady, and produces boost with throttle position. It's really cool, I can dial in 5psi or 10psi or 15psi by pushing the throttle less. My last tune sure as heck couldn't do that! Makes corner exit much more controllable, especially when I'm one-legging it...

[Orb]

Originally Posted by scalbert

There are multiple things to consider. First, is there a mechanical reason for the tapering?

Some turbo vehicles cannot physically maintain boost after a certain point no matter how hard you push the snails. The K03's on the B5 S4 as well as the T-25 on the 2nd gen DSM's. Both of those had a natural taper as the turbo's had no way at all to maintain boost no matter how fast they were spun.

With this engine, there may be another mechanical reason, the solenoid bypass and the dependency on the DME. These types of tunes require the taper to keep the DME happy.

But then there is a philosophical difference. The fact that the turbos can naturally maintain 15 PSI or so at redline suggests they have not completely run out of steam. It does not mean they are not just blowing hot air at that point and not making more power. Historically, most turbo vehicles would be tuned in the aftermarket to push the stock turbos to their max. Meaning, they would be pushed until they physically ran out of steam. Granted, there were more mild tunes available which made less power while siding on longevity which is the philosophical difference. However, if the stock snails can maintain 18 – 20 PSI to redline (which I doubt they can), running 15 PSI is not an issue.

Granted, we currently do not know the limits or threshold of the stock snails nor will be ever fully understand. Take the B5 S4 for instance, many stock turbos failed and were replace more than once. Concurrently there were many chipped cars, with varying degrees of intensity, which the stock turbos were still running strong after 100k miles. There was just no definitive answer as to what would happen. About the only consensus there was is that all stock turbos would fail at some point, regardless of tune. Chipping the car would cause turbo, which were going to fail sooner anyway, to fail that much sooner.

I am aware AA had a failed set of turbos when pushing their shop car. However, a single unit sample group is irrelevant when attempting to show statistic on the topic. There could be other reasons for their failure. If running more boost with little taper spells doom for the turbos, I would suspect that there would be many V2 owners as well as JBR customers replacing failed turbo assemblies. We just haven’t seen it and only time will tell.

Dinan, IMO is something else as they have to insure greater reliability or it comes out of their pocket. Historically they have always been tamer as that warranty matching demands it.

Another consideration is the percent of driving in the extreme range. It appears most of the tunes make similar boost in the mid range; some more, some slightly less. Now let’s consider the amount of time actual driving at the higher boost level and then also calculate the amount of time at or near redline. The later would account for probably less than 0.01%, if even that. Yes, eventually you will get to a stress limit which causes immediate failure but so far that has not been seen. Long term wear is the unknown variable so far.

I guess the only answer is that no one knows the limits (well, I am sure Mitsubishi has an idea of the Mean Time to Failure, but not on a single unit). Guess are made in the aftermarket on observations as well as perceived limits. But perception can be swayed based on needs; sales, warranty coverage or even technical/mechanical limitations.

You are stating that running a turbo past its choke point is okay when it is not. Once we get past that choke point RPM increases dramatically while compressor efficiency nose dives and this is a given. The actually operational limit of this turbo will be at the choke point as going beyond will result in premature bearing wear and structural fatigue of the components even under low duty cycle. I guess you could say we don’t know that choke point but we do have idea that it is around 14 PSI. Given that small changes in pressure drop result in good gains for either a CAI or IC we can see some correlation that this is result of compressor efficiency not the discreet component by itself. I do agree the AA turbo failure is somewhat a useless piece of data at this point.

With a few more sensor and logging of the car you could at least characterize this with not a lot of effort to some degree that is useful but not entirely accurate. Just knowing the RPM alone with other OEM sensor data will give you a lot information. I don’t think this out reach of any tuner given some effort. At some point you may find a point to exceed the choke point in a safe and controlled (reasonable life reduction) manner but this yet another unknown.

The goal of any tuning is to design a robust and strong tune. Pushing the compressor past it choke point doesn’t meet this criteria. There is more than one way to get more power out of this car and a continue attack on boost pressure is just the cheapest way of doing it.

I not sure why you are implying that on should keep pushing the turbo until they yield no more? I guess this okay to do this as long as the end user knows this is with risk.

Orb

[stillclaimndp]

First: Shiv, you're a savage answering tech questions at 5-6am (CA = PST gents). Second, Shiv states he tested the stock turbos as being able to support 18-19 psi whereas the rest of you are speculating. If they can do it, they can do it... How? Not sure, they have a pretty small housing but must have an ample turbine wheel size. The fact is the can and have, key word fact

DP