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Old 12-23-2014, 08:38 AM   #61
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Good data presented by Sav.

Agreed, 235 is stretching stock injectors. The AO has been shipped with a recommended 200 rwhp max unless the injectors are drilled out. (figure of speech)

My objective in asking the questions was to let this thread figure out the answers. The example was made for convenient arithmetic.

It appears to be established that there is useable fuel available past 100% dc because/when the VE falls off.

Agreed, it is risky unless you have your hands on the particular machine.

I seem to be able to see this stuff better when I think of one putt at a time. I know its a transient system, but IT IS a transient system composed of a series of individual putts hooked together.

Thanks Dann.

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Old 12-23-2014, 10:02 AM   #62
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And yet, I posted actual logs, and neither you, nor Dann, nor Sav have commented on the data that shows PW not dropping or dropping very insignificantly past peak torque.

I guess it was a waste to post actual data.

...I obviously agree with you about the fuel available past 100% part
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Old 12-23-2014, 10:25 AM   #63
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Old 12-23-2014, 10:29 AM   #64
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Wait, more actual evidence/data?
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Old 12-23-2014, 10:31 AM   #65
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oh i forget the dyno...




I'd post a bunch of mine but I don't have them online anymore.
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Old 12-23-2014, 11:00 AM   #66
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OK, Scott, you pulled me back in (not that anyone should care).

Those graphs and Dyno make total sense. VE drop is nullified because you let boost rise from 9 to 11 psi. Rising HP requires rising fuel.

Duty cycle climbs more than PW due to RPM. All this makes sense.

For flat or falling torque, PW still climbs, likely due to AFR falling, and, perhaps, as Savington suggests, efficiency is less.

There is no more fuel past 100%DC. There may be less required fuel, so that the 100% duty cycle can supply it, as in falling HP. In fact, at 100%, you are even using up the "dead time", as there is no open and close.

Now it is being said that the A-O should be limited to about 200WHP. That is something that MSM guys have been saying is possible on stock MSM injectors for some time now. I don't know what the curves look like (as in where the peak HP occurs RPM wise).

What size injectors were you using at only 64% DC?
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Old 12-23-2014, 11:03 AM   #67
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What about my plots where boost falls and commanded afr actually tapers leaner and PW still climbs?

Since corky mentioned that this is "just a discussion" I won't keep referring to the AO, but the fact remains: PW still doesn't drop much, if at all.
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Old 12-23-2014, 11:51 AM   #68
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Vlad, not sure I'm following the question. The first dyno / log you posted had the boost falling, but it does not show AFR or PW (but does show DC).

If the efficiency plots that Savington showed holds for boosted engines (why not), then the fall off of efficiency would require more fuel and more air for same HP output. Yes, it would seem that as RPM goes up, more, not less fuel would be needed, for same HP.
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Old 12-23-2014, 12:05 PM   #69
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Sorry I'll be more specific: I'm referring of the MLV screenshots I posted of my '00 miata in posts 55, 57, and 58.
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Old 12-23-2014, 12:18 PM   #70
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Oh I actually found one of mine:






460cc injectors, 1.6L fuel rail, so about ~50psi. PW was pretty flat from ~6-7K.
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Old 12-23-2014, 12:20 PM   #71
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More perfect examples of PW not dropping past peak torque

Quote:
Originally Posted by nitrodann View Post
I agree that torque=pulse width.

You still don't understand thats pulsewidth at a given duty cycle changes with rpm.
That baffles me.
You wanna go ahead and explain this to me again based on the plots posted or you want to shut your big fat yap now?
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Old 12-23-2014, 12:23 PM   #72
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I'll have to dig up my last one where I put on the smaller turbo and have 240tq at 4K but drops to about 175tq at 7K.
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Old 12-23-2014, 12:48 PM   #73
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Vlad, yours show: 55, PW falls at end; 57, rises; 58, pretty flat, though you note it falls from 15.1 to 14.4. But no dyno with that.

I think you are right that Scott's posted pics have the best info and show what is typical.

WHAT? the FPR was set higher on the 1.6's than the 1.8's? I thought both were 43, but only the shape of the vacuum port was different.
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Old 12-23-2014, 02:31 PM   #74
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that was supposed to be 50psi; at atmosphereic it's closer to 50psi.
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Old 12-23-2014, 05:09 PM   #75
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Quote:
Originally Posted by 18psi View Post
More perfect examples of PW not dropping past peak torque



You wanna go ahead and explain this to me again based on the plots posted or you want to shut your big fat yap now?
Pick a fixed duty cycle and calculate the pulse width for it at 2 different rpm.

Holy **** dude.
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Old 12-23-2014, 05:16 PM   #76
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I don't need to do that because I have multiple logs from myself and scott showing me everything I need to see. You know, real world results not bench racing...
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Old 12-23-2014, 05:38 PM   #77
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I think you have a comprehension issue with this point
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Old 12-23-2014, 09:13 PM   #78
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Quote:
Originally Posted by DNMakinson View Post
If the efficiency plots that Savington showed holds for boosted engines (why not), then the fall off of efficiency would require more fuel and more air for same HP output. Yes, it would seem that as RPM goes up, more, not less fuel would be needed, for same HP.
Ding ding. Scott's post #70 shows it perfectly - flat MAP, flat AFRs, falling torque, flat power from 6k to 7k, but both PW and IDC rise the entire time.

To be honest, I'm actually a little surprised that PW rises the entire time there - I would expect PW to sit flat or slightly decline on engines that are more heavily boosted (i.e. more torque drop from peak to redline), but I would never expect IDC to decrease unless you rev the engine way, way past peak power (and even then, it would surprise me).
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Old 12-24-2014, 03:55 AM   #79
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Quote:
Originally Posted by Savington View Post
Ding ding. Scott's post #70 shows it perfectly - flat MAP, flat AFRs, falling torque, flat power from 6k to 7k, but both PW and IDC rise the entire time.
An old dyno plot, FM2, 2560, 2.5 inch exhaust, stock NB motor with a Hydra 2.5 on a Dynapack. I merged the Dynapack and Hydra CSV files with R, then plotted. The PW value doesn't vary enough on the chart to be really visible (the red line at the bottom), but DC (orange) is obvious.

Power (light blue) drops after 6000, but DC only tails off very slightly.

Frictional losses go up a lot as the RPMs climb. This is really obvious if you get a dataloggable MAF-based car and compare the MAF/RPM and power/RPM curves. I did this on my Audi once, but I don't have the data logs any more.



--Ian
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Old 12-27-2014, 04:07 AM   #80
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Quote:
Originally Posted by exexx View Post
Computer control of internal combustion engines is easy compared to world class petrochemical plants.
Off topic:

Ever run into the Dow chemical MOD5 control system running "dowtran" language? I think our plant would be better off running on an MS3!

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