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MasterYous MasterYous is offline
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Default 07-25-2018, 10:13 AM

Quote:
Originally Posted by Turboh
I have summarized roughly a hundred WOT runs on various maps at various IATs. I have looked for the smoothest and quickest map and user settings. For each run I graphed timing, rpm, boost vs time. All on 93 octane. Same road, same elevation, different weather conditions, spring, summer, fall.

I imported the csv files with excel and ran the graphs with it. Rate changes are easily calculated using the excel trend lines. Slopes in the trend line equations are the rate of change, or equivalent to quickness. The higher the rate the quicker.

To me the rpm vs time graphs shows the effect of boost and timing best, without going to a dyno.


Looking at Maps 6, 5, 4,3,2, and 1, I think map 6 at 15.5 psi flat is the best overall. Map 5 and 3 appear a bit quicker at times but not very smooth and less adjustable. I assume that is due to internal timing adjustment spoofing by the JB4.

Comparing map results must be done at the same IAT.

Such fun....
Thank you for posting this, and for sharing your thoughts with all of us.
That's pretty cool.

Couple of questions/comments, if you don't mind.
First and foremost, can you post those summarized charts, with the datapoints?
Quote:
To me the rpm vs time graphs shows the effect of boost and timing best, without going to a dyno.
Do the slopes you produce on rpm mathematically (not just visually) correlate with boost at all? Do they correlate with mph? Have you tried to graph mph to time and see if it correlates more or less strongly to both boost or rpm? I have more on this below...
Quote:
Slopes in the trend line equations are the rate of change, or equivalent to quickness.
I agree on rate of change, assuming linear, but what you really want to do is slope of the slopes (second derivatives) because it's not exactly linear. What is your ultimate goal, e.g. how do you define "quickness?" Is it how quickly the car gets to 60mph, or maybe how quickly it covers a given distance, or some other metric? To me, boost and rpms and all that are just a means to an end, the end being how well the car accelerates, and what is its maximum speed for as long a time as possible. You could measure relative speed. If the distance is short enough, measure out the set distance, launch the car, record your times with each setting. You could measure acceleration - I think the JB4 records MPH and you could set the log rate to raw sampling or 2 seconds, then you would be able to see the second derivative (the rate of change of velocity over time a = dv/dt) approximating an acceleration curve.

I'm really curious why velocity over time is not a key metric in your measurements.

Obviously none of this substitutes for a dyno, which measures torque and power, increasing both of which would be my real end-game...
Quote:
Comparing map results must be done at the same IAT.
How do you control for IAT, since it correlates so strongly to results? Even with me injecting meth to lower IAT (which should yield better timing, etc), I can't see how you can control for a set IAT to experiment with?


2017 F23/M240i Convertible (B58) / 6MT / FF Wires / EWG Wires / BMS Air Intake / Stock Exhaust / 93 Octane + 2.5 gallons E85
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Turboh Turboh is offline
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Default 07-25-2018, 04:49 PM

Hi MasterYous,

Great questions. I wonder myself at times about them.

I am not targeting speed per se. i just want to get a sense of how timing, boost and IAT affect the selection of the map. More boost sounds great but if timing is depressed by it, where is the optimal boost vs timing point? Lots of boost could simply blow a lot of partially used fuel right out the exhaust, yet the pressure could help acceleration. So the question is, IMO, what is the minimum boost to get maximum power for the engine, fuel, temperature in question.

RPM is a rate of revolution, which is easily converted to speed by known gear ratios and tire size. Measuring change in rpm is equivalent to measuring acceleration. To me speed it not the issue.. engine performance is. So there must be a boost pressure which creates the maximum rpm change without over pressurizing and driving timing advance to zero.

I will send you a summary of results tomorrow, once I clean them up. All I did is log data during a standard WOT run (2000-6000 rpm). That range is very linear. Boost is not.

As far as comparison of rpm/time rates to different IACs, as you said, I have no control but for when the outside temperature is hot or cold. Do enough runs and a good portion will fall into the same IAT for different boost maps.

It is good fun too. My bride knows I am out doing doing WOTs and looks for handcuffs when I walk in.


2017 340iX with M track handling package, 6 speed manual, BMS intake, and JB4 piggyback; EWG and FP wires; 93 octane; and fun with Honda S2000; Ninja Z1000.
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MasterYous MasterYous is offline
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Default 07-26-2018, 09:21 AM

Your goals are interesting, albeit different from mine. I really didn't think much about that sweet spot of boost efficiency till you mentioned it. I'm just looking for the fastest possible acceleration in the smoothest manner, and increased top speed (and for how long). In other words, the racing scenarios, I suppose.

Yes, I guess you could derive velocity from RPM + gear + tire size + carried weight + a few other variables I can't think of. I may be oversimplifying but I suspect MPH or KPH (true velocity as measured by the car) controls for all those variables.

I agree that there is probably a boost pressure which creates the "maximum X change" without timing going to 0, I guess for me, X is speed.

Thanks for the tip on observing IATs... I am going to try to observe IAT behavior as well, that is interesting...


2017 F23/M240i Convertible (B58) / 6MT / FF Wires / EWG Wires / BMS Air Intake / Stock Exhaust / 93 Octane + 2.5 gallons E85
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Turboh Turboh is offline
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Default 07-26-2018, 10:59 AM

Thank you for the reply. We all have different views and can learn from each other that way.

FYI, I did complete my "optimal" evaluation. I compared map6 at 15.5, 15.0,14.5 and 13.5 at the same IAT. All flat boosts. FF does have some effect but seems to average out.


The optimal map for me is 15.5 psi. It gives the highest R/T and the best ignition advance average. Funny, you might think lower boost would do better, but that is not the case as far as R/T ratio. To me that makes a lot of sense and what I expected.

IAT is very important. I learned that too. In time I will look at minimal ethanol injection to bring the IAT down. IAT at 90F seems good. But that will be another story.


Take care.


2017 340iX with M track handling package, 6 speed manual, BMS intake, and JB4 piggyback; EWG and FP wires; 93 octane; and fun with Honda S2000; Ninja Z1000.
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MasterYous MasterYous is offline
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Default 07-26-2018, 11:11 AM

Quote:
Originally Posted by Turboh
IAT is very important. I learned that too. In time I will look at minimal ethanol injection to bring the IAT down. IAT at 90F seems good. But that will be another story.


Take care.
Your IAT findings will be very interesting to me as I try to figure out how much meth to inject to try and bring IAT down. This may also be the one time you'll hear me say that I might look forward to colder weather, also.

All of this might get blown to hell when flashes are widely available... because more octane allows you to deal much better with higher IAT and its effect on timing. What if you could fuel with 100% E85 without worrying about running too lean, because the DME (and upgraded fuel hardware) allowed you to throw as much fuel as you needed?


2017 F23/M240i Convertible (B58) / 6MT / FF Wires / EWG Wires / BMS Air Intake / Stock Exhaust / 93 Octane + 2.5 gallons E85
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Turboh Turboh is offline
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Default 07-27-2018, 06:23 AM

Hi Masteryous,

I have attached a summary of my M615.5 runs and the effect of IAT change on boost, acceleration, etc.

In short acceleration will drop 7.8%.


Hope this helps...

Alex
Attached Files
File Type: xls WOT 15.5 Summary.xls (83.5 KB, 7 views)


2017 340iX with M track handling package, 6 speed manual, BMS intake, and JB4 piggyback; EWG and FP wires; 93 octane; and fun with Honda S2000; Ninja Z1000.
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Turboh Turboh is offline
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Default 07-27-2018, 11:09 AM

More data for Masteryous.

Attached two wot runs at low and high iats at 15.5 flat

hope this helps.
Attached Files
File Type: xls 15.5 at high iat.xls (80.0 KB, 8 views)
File Type: xls 15.5 at low IAT.xls (78.5 KB, 10 views)


2017 340iX with M track handling package, 6 speed manual, BMS intake, and JB4 piggyback; EWG and FP wires; 93 octane; and fun with Honda S2000; Ninja Z1000.
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MasterYous MasterYous is offline
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Default 07-29-2018, 01:48 PM

thanks! Checking out all of this.


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