[supracg]

^Okay thats what I thought and it makes sense. With v3 you probably had to stack lines of code on top of other code to try to compensate for outlying situations when estimating DME target load, all of this could be deleted simply through reading this variable through the CAN-bus.

[jale france]

Thanks for all these log / explanations. I am impressed by the IAT, shiv you used the degrees Celsius (not fahrenheit) in your logs ?
With my original fmic when i start at 30 degres celsius i finish at 47 degres, with your fmic when you starded at 30 degres you finish at 33

[phazedkid]

Originally Posted by Kelvin1000

Shiv,

Why does the JB3 place so much emphasis on IAT versus the Procede? Terry always said that IAT had a big influence in everything the JB3 was doing...

Possibly because JB3 depends on DME's IAT controls? I'm thinking the amount of boost the engine sees with a JB3 depends a lot on IAT as shiv explained earlier

Originally Posted by shiv@vishnu

To be fair, the jb3 is probably running on the low side of the its boost target range due to the IAT being so low. It's only 50F out today and my car has a FMIC that keeps temps within a few degrees of ambient.

The Procede doesn't care about IATs (withing a certain broad range) and will target the same boost curve regardless.

Originally Posted by shiv@vishnu

With v4, we don't piggyback on top of the factory boost control system. Which means that we aren't subject to the factory DME's IAT-based boost adjustments. Instead, we apply our IAT (and coolant and oil temp) based boost compensations. In these particular testing conditions (moderate temps), there is no boost correction applied. Things need to get a bit older and a bunch hotter before boost is reduced.

hence, IAT has more of an "influence" on JB3 than it does on Procede. That's my understanding, at least.

[Mike@N54Tuning.com]

On the length of code with the JB3 I'm not really privy to it nor is that my area of expertise. But I will say in general it is a very efficient tuning environment. The chip itself has space for 16kb and the firmware, boot loader, mapping for up to 100 maps, etc, and all fit in there with around 40% left to spare.

Another area we should really discuss in more detail is this notion of "error rate". In the V4 chart it corresponds to the difference between the boost target (how much boost the tune would like to make) and how much boost the tune is actually making. The same delta is also visible in the JB3 chart comparing ECU target and PID target. This delta has absolutely nothing to do with processing and everything to do with the authority range given to the tune to increase wastegate duty cycle.

I personally, and I think I speak for my customers on this as well, would much rather hit 15psi instead of 16psi (having a 1psi "error rate") if that means the turbos are working below a limit that has been predetermined by my tuner. The last thing I want to see for long term life is my wastegates snapping back and forth from 0%-100%-0% and then holding whatever duty cycle is required to hit some arbitrary target. There should always be a limit and both tuners agree. With the V4 this has been implemented in software and is user adjustable. With the JB3 this has been implemented in software AND hardware and is less user adjustable. On the JB3 side for those crazy guys that want to run Stage 4+ maps pushing 17+psi they can be easily accommodated provided they understand the risks but it is not as easy as downloading a 17psi map and going off and running. You need to physically remove the safety from the box before you can hit those targets.

On area I personally really want to look at, and I say this having no idea what the result will be, is the actual duty cycles of the stock, V4 and JB3 tunes as they get on and off boost. Which ones are snapping the fragile wastegates to 100% and back and which ones are moving the wastegates more progressively to hit their boost target. Or maybe they are all doing the same thing. Will be interesting to see the differences.

Mike

[ianthegreat]

In a round-a-bout way, the same thing I was asking earlier.

[OpenFlash]

Isn't a wastegate a flap? . Sorry Mike but your last post was a bit over the top.

[2point3]

Can a flap be overworked?

[huyner328]

Originally Posted by Mike@N54Tuning.com

On area I personally really want to look at, and I say this having no idea what the result will be, is the actual duty cycles of the stock, V4 and JB3 tunes as they get on and off boost. Which ones are snapping the fragile wastegates to 100% and back and which ones are moving the wastegates more progressively to hit their boost target. Or maybe they are all doing the same thing. Will be interesting to see the differences.

Mike

+1, I'd like a more in depth discussion of this as I don't quite fully understand the duty cycle talk.

[FotiosF90M5]

Originally Posted by huyner328

+1, I'd like a more in depth discussion of this as I don't quite fully understand the duty cycle talk.

+1 I agree. I want to understand it all better.

[OpenFlash]

Originally Posted by fotios335i

+1 I agree. I want to understand it all better.

+1 I agree as well. In the 15 years I've been tuning turbo engines, this is the first time I've ever head anyone voice a concern about a wastegate actuator (not a turbo) being overworked. I'd love to hear Mike's explanation of this. This is also the first time I've heard anyone suggest that sloppy boost control is actually a good thing.

Shiv

[OpenFlash]

Originally Posted by huyner328

+1, I'd like a more in depth discussion of this as I don't quite fully understand the duty cycle talk.

Wastegate DC is a representation of how much the boost control solenoid is in the open position. 0% means it is fully closed. 100% means fully open. 50% means alternating open and closed evenly. The greater the DC, the more vacuum signal is applied to the wastegate actuator. The more vacuum signal applied, the more the wastegate arm actuates and the more the wastegate flapper door closes, The more the door closes, the less exhausts gas is bypassed around the turbine wheel. The more exhaust directed to the turbine wheel, the faster it spins. The faster spin, the more airflow pushed out of the compressor side of the turbo. The more airflow, the more boost (holding rpm constant). Phew.

A boost control system's job is to adjust the position of the wastegate flapper door so that the systems boost pressure stays at the desired boost target (boost set point) during all conditions. As mentioned above, it does this by regulating the boost control solenoid's duty cycle.

Mike suggests that the Procede, because of its unique ability to assume 100% control of the signal going to the solenoids, creates excessively high and excessively low swings in duty cycle. And these high and low swings cause stress on the wastegate, causing the flapper to close and open too abruptly and with too much gusto. And this is how the Procede achieves it's superior boost control accuracy/response. Is that right, Mike?

Shiv

[OpenFlash]

Originally Posted by jale france

Thanks for all these log / explanations. I am impressed by the IAT, shiv you used the degrees Celsius (not fahrenheit) in your logs ?
With my original fmic when i start at 30 degres celsius i finish at 47 degres, with your fmic when you starded at 30 degres you finish at 33

The Helix FMIC really does work great. I've always been satisfied with its ability to keep temps, even during high boost conditions, within a few degrees of ambient. It's like always driving on a cold day

Shiv

[Mike@N54Tuning.com]

We all know increased duty cycle means increased turbo wear. The real differences there will be quantified with better logs once they are available.

The wastegate problems with this platform (rattling, failure, etc) are well documented. BMW has been releasing update after update trying to solve them with different software approaches and recently also made the wastegate hardware beefier for newer model cars. It's important because if there is a failure you basically need to R&R the turbos to fix it. I think we can all agree faster and more aggressive movement will negatively impact wastegate life and long term performance. It's pieces of metal moving around of course there is going to be wear. We can also agree that more aggressive wastegate movement will help the motor build boost faster. So what we need to see is data on the stock tune and how quickly and to what degree it moves the wastegates, and then compare that with data from the JB3 and V4 to see how they
differ.

Shiv in your 15 years of tuning how many platforms have you tuned where the default wastegate position is fully open and they must be pulled closed to build boost?

Mike

[Mike@N54Tuning.com]

Originally Posted by shiv@vishnu

The Helix FMIC really does work great. I've always been satisfied with its ability to keep temps, even during high boost conditions, within a few degrees of ambient. It's like always driving on a cold day

Shiv

+1 The Helix intercooler is a great unit. Its really a must mod (upgraded FMIC) as the stocker is a sucker!

Mike

[OpenFlash]

Originally Posted by Mike@N54Tuning.com

We all know increased duty cycle means increased turbo wear. The real differences there will be quantified with better logs once they are available.

The wastegate problems with this platform (rattling, failure, etc) are well documented. BMW has been releasing update after update trying to solve them with different software approaches and recently also made the wastegate hardware beefier for newer model cars. It's important because if there is a failure you basically need to R&R the turbos to fix it. I think we can all agree faster and more aggressive movement will negatively impact wastegate life and long term performance. It's pieces of metal moving around of course there is going to be wear. We can also agree that more aggressive wastegate movement will help the motor build boost faster. So what we need to see is data on the stock tune and how quickly and to what degree it moves the wastegates, and then compare that with data from the JB3 and V4 to see how they
differ.

Shiv in your 15 years of tuning how many platforms have you tuned where the default wastegate position is fully open and they must be pulled closed to build boost?

Mike

Do you really believe what you are saying? Or is this a preemptive strike against the next batch of test results which comparative demonstrate targeting speed/accuracy.

Originally Posted by Clap135

Wow Mike, Really? This is pushing things now lol.

I had a big response ready to go but I deleted it. I've learned that engaging in a technical discussion with someone who has no loyalty to facts is a waste of time. Especially when there is a large percentage of the readers who can't distinguish from factual info and disingenuous pseudo-science. Back to testing...

Shiv

[supracg]

Originally Posted by Mike@N54Tuning.com

We all know increased duty cycle means increased turbo wear. The real differences there will be quantified with better logs once they are available.

The wastegate problems with this platform (rattling, failure, etc) are well documented. BMW has been releasing update after update trying to solve them with different software approaches and recently also made the wastegate hardware beefier for newer model cars. It's important because if there is a failure you basically need to R&R the turbos to fix it. I think we can all agree faster and more aggressive movement will negatively impact wastegate life and long term performance. It's pieces of metal moving around of course there is going to be wear. We can also agree that more aggressive wastegate movement will help the motor build boost faster. So what we need to see is data on the stock tune and how quickly and to what degree it moves the wastegates, and then compare that with data from the JB3 and V4 to see how they
differ.

Shiv in your 15 years of tuning how many platforms have you tuned where the default wastegate position is fully open and they must be pulled closed to build boost?

Mike

I don't fully understand, just because the PROcede has full control over the wastegates doesn't mean that the duty cycle has increased. The reason turbo's die are because of high wastegate duty cycle (being closed), not because of the back and forth movement of the wastegate. And I don't see how reaching your target can be seen as a negative? If you want 1 psi less then set your target to 1 psi less.

[supracg]

Originally Posted by shiv@vishnu

I had a big response ready to go but I deleted it. I've learned that engaging in a technical discussion with someone who has no loyalty to facts is a waste of time. Especially when there is a large percentage of the readers who can't distinguish from factual info and disingenuous pseudo-science. Back to testing...

Shiv

Shiv, don't hold yourself back from explaining, many people learn from your (and Mike's) posts and usually truth comes out in the end of these discussions.

[OpenFlash]

Originally Posted by supracg

I don't fully understand, just because the PROcede has full control over the wastegates doesn't mean that the duty cycle has increased. The reason turbo's die are because of high wastegate duty cycle (being closed), not because of the back and forth movement of the wastegate. And I don't see how reaching your target can be seen as a negative? If you want 1 psi less then set your target to 1 psi less.

+1
You understand it just fine.

Originally Posted by supracg

Shiv, don't hold yourself back from explaining, many people learn from your (and Mike's) posts and usually truth comes out in the end of these discussions.

Ok.. here goes...

Where Mike is wrong is that he bases his whole argument on the notion that a larger boost control correction spike mean that the wastegate arm is physically opening and closeing with the same duration and amplitude of the spike. This is untrue because there isn't a solid/fixed connection between wastegate DC and wastegate arm movement. Instead, it's a pneumatic system that is controlled by air pressure (vacuum).

A good and realistic analogy for wastegate control system would be like suspending a big D cell battery from a 2' long stretchy rubber band and trying to precisely regulate the its height off the ground. Having the ability to yank or drop on the end of the rubber band sharply (solenoids DC%) gives you better control over the location of the hanging battery (wastegate actuator rod location) than only being able to apply small and slow up and down movements to the band. It does NOT mean that the first system makes the battery move up or down more. It just moves up or down more accurately. In fact, it's the second system which will more likely find itself in situations where the battery is hanging either too low or too high momentarily.

In Mike's flawed argument, he believes that there is a inflexible chain between connecting to the battery. In that case, yes, big yanks on the other end of the chain will make the battery bounce around as well. And yes, a small lifts/drops of the chain would be desirable. If this were the case, boost control systems would always be easy to tune, free of spikes, undershoots, oscillation, etc,.

I hope that makes sense.

Shiv

[NRG]

^ Not that I'm on either side but man... Shiv you really know how to put it out and explain things, gotta give you the props here. Great info!

[Mike@N54Tuning.com]

Originally Posted by supracg

I don't fully understand, just because the PROcede has full control over the wastegates doesn't mean that the duty cycle has increased. The reason turbo's die are because of high wastegate duty cycle (being closed), not because of the back and forth movement of the wastegate. And I don't see how reaching your target can be seen as a negative? If you want 1 psi less then set your target to 1 psi less.

I think you confused two of my posts.

We all agree higher duty cycle means the turbos are working harder and thus will have a shorter life all else being equal. So if duty cycle is fixed and boost is not getting up to target you can either lower that target or have an under targeting error. The net effect is the same, only with the under targeting error the user is alerted to the potential issue and makes spotting boost leaks and other problems easier.

The wastegate movement is a completely different issue. The suggestion that yanking on the end of a 2' rubber band isn't going to make an attached battery fly up a proportionally higher is silly. The battery will rise too high and then you'll need to yank on the other side hard to slow it down. If the battery were a delicate egg you'd pull on the rubber band very gently to raise it. Much as I suspect the factory tune does with the wastegates.

Also there is no accusation here simply a request for logs for everyone to study. For all I know the factory ECU and V4 pull the rubber band gently and the JB3 yanks it around.

Mike

[JoeyFiasco]

don't all tunes increase the waste gaste DC? if they didn't they would produce the same boost and responsiveness as stock.

[scalbert]

Originally Posted by Mike@N54Tuning.com

I personally, and I think I speak for my customers on this as well, would much rather hit 15psi instead of 16psi (having a 1psi "error rate") if that means the turbos are working below a limit that has been predetermined by my tuner.

Which ones are snapping the fragile wastegates to 100% and back and which ones are moving the wastegates more progressively to hit their boost target. Or maybe they are all doing the same thing. Will be interesting to see the differences.

More to come but tied up right now.

However, I find it funny now what BMS allows for. Prior to JB3, BMS's stated exhaustive testing of turbo speed suggested a maximum of 14 PSI is what the turbos can tolerate. Once they were able to extend the pulse width, that idea has quietly disappeared. I certainly understand the need to market something and give ones angle. But this isn't the first u-turn.

And am I reading this right. Are you suggesting the solenoid duty cycle causes the wastegates to cycle similarly? If so, the discussions should stop until an understanding occurs. You should know the duty cycle is to get an appropriate amount of vacuum to get the wastgates at the needed angle to generate the desired boost. I apoligize if I read this incorrectly but that is my take on the statement.