Author Topic: Converting to AlphaN (TPS vs RPM)  (Read 58779 times)

Offline dnb

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Re: Converting to AlphaN (TPS vs RPM)
« Reply #15 on: July 11, 2007, 02:02:49 pm »
I think it would have helped me if the IAC position could be made to affect the AlphaN TPS/MAP axis when the IAC is active.  This would make the map 3d for idle instead of 2d.

Offline cliffb75

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Re: Converting to AlphaN (TPS vs RPM)
« Reply #16 on: July 11, 2007, 07:23:01 pm »
Sounds like you're falling into the race car / road car gap here....

TPS based systems are generally used on cars that can't use a MAP system because the signal is too noisy. That generaly means lumpy cams etc. For these engines idle quality isn't an issue, so they don't use idle bypass valves.

You want a road car based setup, but are trying to get around a noisy/aggressive MAP signal using TPS, which limits your options.

Things to try

1) Use the ignition based idle controller. The IAC should only really be used for quite slow corrections, or to copensate for additional loads (like friction when cold or alternator loads). The ignition path should then do the fast work to stabilise the idle and react to changes in load (before the air path has a chance to). Hopefully the idle igntion will become 'proper' PID controlled at some point, with error compensated PID terms tables (are you listening Rob? ;))

2) Try fitting a damper in the signal line to the MAP sensor - something like a 0.5mm restrictor hole. This might calm the signal down enough to use it (or it mihth not)

Regarding you other point about shunt on fuel cut/reinstatement, check that you have blended out the VE table to the minimum pulsewidth (you'll need to investigate what that is) and also blend away the ignition at the low load sites (you may need to play with the load sites to get this right). This will smooth the torque away as you tip out and enter fuel cut, hence reducing the torque step between fuel on and fuel cut. You will still get some step since you don't have control of the throttle an ignition in the same way as you do on a modern torque based system, but you should be able to improve things.

Oh, and what's SD?

Offline miniminor63

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Re: Converting to AlphaN (TPS vs RPM)
« Reply #17 on: July 11, 2007, 07:53:48 pm »
i would guess sd is speed-density?

Offline dnb

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Re: Converting to AlphaN (TPS vs RPM)
« Reply #18 on: July 11, 2007, 11:44:41 pm »
Already doing 1 - it's the only way I've found to tame the idle.  (It works very well too, even without PID control)  I'm not using the idle stepper other than to set the base idle point.  (I have no AC etc and don't care at the moment if the idle speed creeps around slowly)

I am not finding the MAP signal all that noisy having spent another night tweaking things (I used the thinnest hose I could find) - I just wanted to try alphaN to see what it was like.

About the fuel cut:  It sounds like I need to drop the ignition away more than I currently have!  I hadn't blended out the VE table so I can do that too, and it now makes sense.  (Amazing how it's obvious now...)  I was a bit worried about it all going lean and wrong on me... 

SD = speed density.  Laziness on my part ;)

Offline dnb

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Re: Converting to AlphaN (TPS vs RPM)
« Reply #19 on: July 11, 2007, 11:53:14 pm »
Big improvement with deceleration now :)  Nic will be pleased at the return of engine breaking.
Still a little shunty at low speeds, but then that's wild cams and letting someone like me doing the cal for you...

I really must try using more than 50% throttle one day.  I haven't felt the need yet, even when a new BMW 6 series tried to   get away from me at some traffic lights ;) 

Offline sidewaysbill

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Re: Converting to AlphaN (TPS vs RPM)
« Reply #20 on: August 14, 2007, 07:47:44 pm »
Do you still have to use acceleration enrichment when using AlaphN...?

Offline rob@vems.co.uk

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Re: Converting to AlphaN (TPS vs RPM)
« Reply #21 on: August 14, 2007, 09:16:43 pm »
Yes, but you tend to use only very small amounts, the fuel map tends to provide the fueling adjustments.

Rob

Offline sidewaysbill

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Re: Converting to AlphaN (TPS vs RPM)
« Reply #22 on: August 14, 2007, 11:35:59 pm »
do you use barometric compensation when using AlaphN or am I imagening things ....?

Offline rob@vems.co.uk

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Re: Converting to AlphaN (TPS vs RPM)
« Reply #23 on: August 15, 2007, 08:30:46 am »
You have a choice to use barometric correction or not.

Offline irishtwincam

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Re: Converting to AlphaN (TPS vs RPM)
« Reply #24 on: November 03, 2008, 04:06:12 pm »
You have a choice to use barometric correction or not.


How does one check this?
If this setting si turned off, it could explain the issue we discussed on the telephone.
If it IS turned on, can you do a quick explanation of using the blending option.
Alpha N to 4000rpm/SD from 4-9000rpm

Setting a new RPM bin, and setting the new throttle/KPA bin combo.
When blending, does the KPA axis value mean KPA or throttle constantly?


Offline rob@vems.co.uk

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Re: Converting to AlphaN (TPS vs RPM)
« Reply #25 on: November 03, 2008, 06:33:58 pm »
Barometric correction is enabled/disabled using Settings->Constants then selecting On or Off in the Active drop down below the Barometric correction label.

AlphaN blending is found in Extras->AlphaN / Speed Density Blending
Set MAP Multiplication to: Enabled

Set max RPM for Alpha-N (rpm) to the RPM point just above where the MAP signal starts to read cleanly.

Set max RPM for Speed Density (rpm) to a value just below the Alpha-N value.

Offline irishtwincam

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Re: Converting to AlphaN (TPS vs RPM)
« Reply #26 on: November 03, 2008, 11:25:05 pm »
For alpha N, I would assume barometric correction should be left on to help compensate for
Hot/cold weather, the ramair effect when driving?

Is it safe to say it should only be done BEFORE mapping begins?

When going blended, is it correct to say that at the point you know what your stable vacuum will be,
you should change the nearest TPS axis point to match this?
I'll paint brush some illustrations.


Barometric correction is enabled/disabled using Settings->Constants then selecting On or Off in the Active drop down below the Barometric correction label.

AlphaN blending is found in Extras->AlphaN / Speed Density Blending
Set MAP Multiplication to: Enabled

Set max RPM for Alpha-N (rpm) to the RPM point just above where the MAP signal starts to read cleanly.

Set max RPM for Speed Density (rpm) to a value just below the Alpha-N value.


Offline tweek

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Re: Converting to AlphaN (TPS vs RPM)
« Reply #27 on: November 03, 2008, 11:37:59 pm »
Barometric correction is enabled/disabled using Settings->Constants then selecting On or Off in the Active drop down below the Barometric correction label.

AlphaN blending is found in Extras->AlphaN / Speed Density Blending
Set MAP Multiplication to: Enabled

Set max RPM for Alpha-N (rpm) to the RPM point just above where the MAP signal starts to read cleanly.

Set max RPM for Speed Density (rpm) to a value just below the Alpha-N value.



does the barometric correction be set to on or off when mapping?

Offline rob@vems.co.uk

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Re: Converting to AlphaN (TPS vs RPM)
« Reply #28 on: November 04, 2008, 12:21:12 pm »
For alpha N, I would assume barometric correction should be left on to help compensate for
Hot/cold weather, the ramair effect when driving?

The only way you'll see the compensation for ram air is with the MAP sensor connected to a suitable feed on the inlet manifolds.

It should be enabled before mapping, what state is it currently in?


Offline irishtwincam

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Re: Converting to AlphaN (TPS vs RPM)
« Reply #29 on: November 04, 2008, 12:21:56 pm »
Its on.

Need to get the speed density thing set up over christmas!