8000RPM Redline for Z4M?

[seank]

Originally Posted by O-cha

This is wrong on many levels, adequate oil pressure doesn't mean rod bearings won't be destroyed by higher RPMS. The OEM bearings are not designed to, and will not live for very long at 10k, even with perfect oil pressure.

As for the shift points, that is a very poor explanation, though it does sort of correlate with the correct. Shift points are wholly determined by thrust at the wheels. Thrust at the wheels is determined by torque and gearing. Essentially what you are looking for is where your wheel thrust in the current gear drops below where it will be in the next, that is the point you shift at. You cannot find this point simply by following your explanation and "adding up" HP numbers.

I missed the many levels.

10,000 was a slight exaggeration, but there are quite a few s54's making power to 8800 on stock internals. If the rod bearings had damage prior: revved when cold, wrong oils used, etc, the bearings old go at anytime. Even at 7500 rpm's.

As I stated,I did not invent the best shift points. I explained carrol shelby's ideas, which I have successfully used. Your explanation said nearly the same thing explained differently. They done "sorta correlate", they do

[mfanatic325]

Originally Posted by johanness

It's the same DashDyno unit that is telling him his stock Z4M is now making 370RWHP with the help of his home made intake (or roughly 450hp at the flywheel).

[StickMon]

Originally Posted by exdos

For some reason, the Absolute Throttle Position on the Z4MC at WOT records as being 76.1% rather than 100%...

I noticed this too when using DashCommand. Thought I went limp or something.
Then I found this thread. Turns out it's normal.

[exdos]

Originally Posted by O-cha

Anything could have happened between those two data points. Just because I demonstrated to you why your results are invalid doesn't mean I'm going to correct them for you.

You haven't demonstrated that my results are invalid at all. You have previously said: "You are however correct that it closes some in anticipation, but nothing like your graph shows." But you won't actually tell us how the throttle position will change. We're all here to learn from each other; teach us.

Whilst it would be nice to have access to a constant stream of data taken at much greater frequency, an OBDII datalogger doesn't make up the time-stamped data that it receives from the ECU. As an analogy: a film shot at 30 frames per seconds (i.e. a series of still images) will produce a movie which appears to give seamless transitions but if you only look at only the 1st and 16th frame each second is the information appearing in those still images less valid? I think not.

If the Z4MC's ECU says that at 298.767secs the ATP is at 75.7% and at 299.323secs the ATP is at 31.8% I believe it, and in all probability, at the time in between those two time stamps, it is most likely that the ATP is reducing from 75.7% to 31.8%. Whether the closure is linear or not is unknown to me but you imply that you have this answer. What is it?

[exdos]

Originally Posted by johanness

It's the same DashDyno unit that is telling him his stock Z4M is now making 370RWHP with the help of his home made intake (or roughly 450hp at the flywheel).

You've deleted your earlier posting and replaced it with the above. I've previously invited you to make your constructive comments in the thread which you consider to be so funny- I've yet to see them. It's quite clear that you do not understand the way that the torque curve effects the calculation of horsepower, which is a derived figure.

[exdos]

Originally Posted by StickMon

I noticed this too when using DashCommand. Thought I went limp or something.
Then I found this thread. Turns out it's normal.

Thanks for that link. Very interesting.

In that thread, they report that at 4k revs the throttle opens from 75% to 100% in the E46M3, but that's not what happens in the Z4MC. I wonder if there's an scope for this in the Z4M?

As an interesting point I've also discovered that in 1st gear, even in Sport Mode, the ECU doesn't let the AFR below 14.7:1, which is presumably another torque limiting strategy?

[O-cha]

Originally Posted by seank

As I stated,I did not invent the best shift points. I explained carrol shelby's ideas, which I have successfully used. Your explanation said nearly the same thing explained differently. They done "sorta correlate", they do

Carol Shelby knew a lot less about cars then you think he did. And no, it's not the same thing explained different, it's simply different. "Sorta correlates" means under certain circumstances it appears to be the same, but in others it wont be.

Originally Posted by exdos

You haven't demonstrated that my results are invalid at all. You have previously said: "You are however correct that it closes some in anticipation, but nothing like your graph shows." But you won't actually tell us how the throttle position will change. We're all here to learn from each other; teach us.

I'm sorry you can't see how they are invalid from my previous explanation, I'm not going to simply repeat it. You probably shouldn't science.

[exdos]

Originally Posted by O-cha

I'm sorry you can't see how they are invalid from my previous explanation, I'm not going to simply repeat it. You probably shouldn't science.

So why won't you draw a sketch plot to demonstrate your point for us all to see? I'm not asking for it to be absolutely exact, just the general shape of the typical plot you'd expect to see for ATP versus engine RPM. I am sure there are others besides me who would like to see this information.

[intoflatlines]

What O-cha is saying is that, if your data is being sampled once per second, for any 2 second period you will have 2 data points per measure. So assume that at 5 seconds (x=5), you measure y=100. Then at 6 seconds you measure y=0. You could "connect the dots" and believe that at x=5.5, y=50. However, this is not necessarily true, since you are assuming that the data between these 2 points is linear... but the truth is that you don't know this. It could stay at y=100, it could dip down to y=0 at 5.5 seconds, but since it's not measured it's not correct to say that after 5 seconds, the y value decreases. It could drop at 5.5 seconds, 5.99 seconds, etc.

[exdos]

Originally Posted by intoflatlines

What O-cha is saying is that, if your data is being sampled once per second, for any 2 second period you will have 2 data points per measure. So assume that at 5 seconds (x=5), you measure y=100. Then at 6 seconds you measure y=0. You could "connect the dots" and believe that at x=5.5, y=50. However, this is not necessarily true, since you are assuming that the data between these 2 points is linear... but the truth is that you don't know this. It could stay at y=100, it could dip down to y=0 at 5.5 seconds, but since it's not measured it's not correct to say that after 5 seconds, the y value decreases. It could drop at 5.5 seconds, 5.99 seconds, etc.

I see precisely what O-cha's saying and you have explained it very well. The actual interval between samples on 4 PIDs in the example is (299.323secs - 298.767secs =) 0.556 secs, and yes, a lot can happen in that time, but as two time-lapsed intervals in the plot of ATP, the throttle has closed from 75.7% to 31.8% between those points in time. However, the point that my graph demonstrates is: the throttles have begun to close sometime between 7631rpm and 8001rpm and that the throttles do not remain at WOT until the redline. I have lots of datalogs of these PIDs and the time stamps obviously vary with respect to the actual time the engine reaches 8,000rpm and this phenomenon occurs every time as the engine reaches the redline, which to me, seems to confirms the observation.

It appears to me that O-cha is saying that this is wrong and I'm simply asking him to do us all a favour and draw us a better graphical demonstration of what he says really happens. I'm just a bit surprised by his reluctance to be more helpful. Personally, I can't see the point of posting to say something is wrong without being prepared to properly demonstrate what you claim is correct.

[beta]

Originally Posted by exdos

It appears to me that O-cha is saying that this is wrong and I'm simply asking him to do us all a favour

You're not asking for a favor, you are demanding it.

An image of a different engine should illustrate:



The orange line represents the throttle. Do you get it now? To get a clean simple measurement like you are showing us, you'd have to average out the measurements with a much higher sampling rate.

The MSS70 ECU does 64 million operations a second. Your numbers are meaningless.

[Beedub]

damn.... tough crowd in here......

[johanness]

Originally Posted by exdos

You've deleted your earlier posting and replaced it with the above. I've previously invited you to make your constructive comments in the thread which you consider to be so funny- I've yet to see them. It's quite clear that you do not understand the way that the torque curve effects the calculation of horsepower, which is a derived figure.

Actually I contacted the mods wondering where it went. Certainly didn't delete it. Could have been the link I posted to the comedy on that 'other' forum.

Regardless, I have ZERO interest in listening to you defend 370rwhp from a simple air intake. I think you're deluded, and you DashDyno has been proven to misrepresent the #'s. If O-cha wants to take up the fight, I'll get the popcorn.

450ish crank HP from a home-made intake isn't reasonable in the least, so there's no reasonable discussion to be had.

[exdos]

Originally Posted by beta

You're not asking for a favor, you are demanding it.

??????????????

Originally Posted by beta

An image of a different engine should illustrate:

If you are referring to the top plot also with the green plot (Engine RPM?) there's not a lot of difference to what I've posted except it's on a different scale x/y scale.

Originally Posted by beta

The MSS70 ECU does 64 million operations a second. Your numbers are meaningless.

We know that the MSS70 ECU operates at incredible speed, but to say that a series of time-stamped data points recorded form this ECU are meaningless is just plain ridiculous!! Engineers in the old days would have given their right arms to have had the data that can be obtained by an OBDII datalogger.

[beta]

Originally Posted by exdos

but to say that a series of time-stamped data points recorded form this ECU are meaningless is just plain ridiculous!!

Did you even take a second to understand what I explained before responding? I guess I'll repeat myself one more time before giving up:

To get a clean simple measurement like you are showing us, you'd have to average out the measurements with a much higher sampling rate.

As an example let's take the values you posted:

298.767 - 75.7%

299.323 - 31.8%

How could these be meaningless? well if they looked like this:

298.750 - 99%
298.755 - 92%
298.760 - 100%
298.767 - 75.7%
298.770 - 93%
298.775 - 82%
298.780 - 98.9%
298.785 - 72.3%
298.780 - 94%
298.775 - 92%
...

If we average all those samples, we get 89.88%. That would be a better value for what the average throttle position is during these samples in this example.

Yet because you are sampling randomly, you could get a high value: 100%, a low value 72.3% or anything in between, so you have no idea how big your error is or in what direction.

[exdos]

Originally Posted by beta

As an example let's take the values you posted:

298.767 - 75.7%

299.323 - 31.8%

How could these be meaningless? well if they looked like this:

298.750 - 99%
298.755 - 92%
298.760 - 100%
298.767 - 75.7%
298.770 - 93%
298.775 - 82%
298.780 - 98.9%
298.785 - 72.3%
298.780 - 94%
298.775 - 92%
...

If the throttle position was changing position every 5 milliseconds in the way that you suggest, then they would be flapping at the same rate as a bee's wing. Are you seriously suggesting that this is happening? A cable throttle with EFI doesn't flap like that so why should the drive-by-wire system?

[beta]

Originally Posted by exdos

If the throttle position was changing position every 5 milliseconds in the way that you suggest, then they would be flapping at the same rate as a bee's wing. Are you seriously suggesting that this is happening? A cable throttle with EFI doesn't flap like that so why should the drive-by-wire system?

I give up. You're obviously more interested in talking about the particulars of my completely made up example, rather than understanding the underlying point I was trying to make.

O-cha, if your'e still around, how do the ITBs fit into all of this?

[mfanatic325]

Exdos...what everyone is/has been trying to tell you is that the software you're using simply does not provide a sufficient sampling rate, and therefore your resulting numbers are skewed. Plus, if you use any common sense, it would dawn on you that it is IMPOSSIBLE to gain that much power just from an intake swap. Having more (unpressurized) air going into the combustion chamber will not yield much if anything. Hence why forced induction is typically used if people want to squeeze more power out of the engine without upping the displacement, etc.

What you're claiming though Exdos is that your intake alone yields more power than the same car with ALL bolt-ons + ECU tuning to take advantage of said modifications. That should in itself throw a red flag

[exdos]

Originally Posted by beta

I give up. You're obviously more interested in talking about the particulars of my completely made up example, rather than understanding the underlying point I was trying to make.

You've previously said to me: "Your numbers are meaningless" because OBD datalogging produces time-stamped data at just over 0.5 secs intervals for 4 PIDs. Then you gave a "completely made up example" to explain why you are correct. I do understand your point, absolutely, and I've simply shown you that your explanation is highly unlikely to happen because the throttle bodies are more likely to remain still at WOT and will not flap. It amazes me that many on here are so quick to dismiss OBD datalogging but nobody can produce the definitive proof of what the naysayers are claiming.

[exdos]

Originally Posted by mfanatic325

Exdos...what everyone is/has been trying to tell you is that the software you're using simply does not provide a sufficient sampling rate, and therefore your resulting numbers are skewed.

Many different series of time-stamped data gives a very good indication of what is really happening. Personally, I find this to be far more informative than conventional wisdom based on internet hearsay.

Originally Posted by mfanatic325

Plus, if you use any common sense, it would dawn on you that it is IMPOSSIBLE to gain that much power just from an intake swap. Having more (unpressurized) air going into the combustion chamber will not yield much if anything. Hence why forced induction is typically used if people want to squeeze more power out of the engine without upping the displacement, etc.

This is not a matter for "common sense" but physics/mathematics. The formula to calculate horsepower is: HP = Torque x RPM ÷ 5252
Therefore if the torque can be increased and that peak torque occurs as far above 5252rpm as possible, then this has a very significant effect on the calculated HP. I have simply found ways of achieving this using well known science.

[johanness]

Originally Posted by O-cha

You probably shouldn't science.

This

[mfanatic325]

Use a universally-accepted/well-known datalogging software suite and recheck your numbers. Then we can all believe your claims.