turbo target pressure map

Give input on tuning as well as any tips and tricks you may have. Also feel free to share base mapping files for various engine types.
TRN
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Joined: Mon Jul 29, 2013 2:39 pm
ECU Model: S100 Pro
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turbo target pressure map

Post by TRN »

Hello,

I'm creating a base map for our turbo engine. We've set it up to use MAP vs RPM as Load.
Now when looking at the "turbo target pressure" map I'm a bit lost.

Say you have some arbitrary boost target in mind of 200kPa @ 3000rpm that drops off to 150kPa @ 8000rpm. Wouldn't that just mean that the 3D boost target map will become 2dimensional with every column the same value per rpm-value?

So say every cell on the 3000rpm row will be 200 kPa? Under what circumstance will this 3D table be used? Only when using TPS as Load?

thanks!

-Tom
Alex DTA
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Re: turbo target pressure map

Post by Alex DTA »

No.
Surely you don't want to target 200 kPa at 5% throttle? If you do enter that, the ECU would just keep the waste gate shut then, as you will never see that amount of manifold pressure.

Think of throttle position as an indicator of desired boost. Then you can build your target map based on RPM and throttle position
TRN
Posts: 28
Joined: Mon Jul 29, 2013 2:39 pm
ECU Model: S100 Pro
Firmware Version: 89

Re: turbo target pressure map

Post by TRN »

Hi Alex, I'd understand that when using TPS as load. But right now my tables use MAP as load? So on the Turbo Target Pressure map the horizontal label is MAP kPa with my pressure columns as per the "Map Columns" table.

So I still don't quite understand...
katana
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ECU Model: S60 Pro
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Re: turbo target pressure map

Post by katana »

I may be wrong but how can you look-up table something ie 'target boost' with one of the axis representing boost? Surely you need something like rpm x TP = target boost for a 3D map to work?
Alex DTA
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Re: turbo target pressure map

Post by Alex DTA »

TRN wrote:Hi Alex, I'd understand that when using TPS as load. But right now my tables use MAP as load? So on the Turbo Target Pressure map the horizontal label is MAP kPa with my pressure columns as per the "Map Columns" table.

So I still don't quite understand...
You can't target turbo pressure against turbo pressure. That makes no sense.
You have to have something else to target against.

The only input in to the ECU that indicates what the driver wants to do is throttle position.
So if the RPM is 3000, and the drivers foot is flat to the floor, you are asking for maximum power. In your case you will be targeting 200 kPa at 3000 RPM.

The fuel delivered will be independent of throttle position, as you are mapping against MAP and RPM.
If the MAP is actually 200 kPa, you will get x fuel. If the MAP is only 150 kPA, then you will get .75x (ish).

So the target pressure is defined by the RPM and throttle position.
The fuel (and ignition) value is determined by the RPM and MAP actually achieved.
stevieturbo
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Re: turbo target pressure map

Post by stevieturbo »

I think it might be better to ask what he's trying to achieve and then guide to doing that....because I couldnt understand what he is asking in the first question.
Rob Stevens
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Re: turbo target pressure map

Post by Rob Stevens »

TRN 'Map as load' is where the ecu is told how much fuel to inject from a 3d table made up from rpm and manifold pressure, are you clear about that bit?

If this is the first time you have used this ecu can I suggest that you start on wastage pressure only and turn all the turbo settings off !!! :)
TRN
Posts: 28
Joined: Mon Jul 29, 2013 2:39 pm
ECU Model: S100 Pro
Firmware Version: 89

Re: turbo target pressure map

Post by TRN »

Hi guys, thanks everyone for replying.

I'll try to clarify: my first post isn't something I WANT to do, it's something that seems impossible to me but I stumbled upon in dtaswin, which kinda follows all your replies.

We've done a couple of N/A engines on DTA in the past (using ITB's), all running TPS as load.

Now we're ready to start mapping our new turbo engine (which indeed will first be mapped witn 0% PWM/control off to have it running smooth on the wastegaste spring).

We want the fuel, ignition and cam advance maps all to be MAP vs RPM, since we feel that's more logical to map than having TPS vs RPM maps with a MAP correction. The engine will be mapped on eddy-brake hub dyno's alowing steady state so we have a way of mapping a broader range of cells than one would have mapping on a rolling road accelerating.

So far so good I think. Now, when enabling the boost control, the ECU needs to know what boost target to try and achieve, and I agree with all your replies that the only way the driver input is read is through the TPS.
But when opening the Turbo Target Pressure table, the X-asis reads MAP in stead of TPS. And this is where I got confused, since up until that point I was following the same train of logic as you guys.


So how do I go about filling this target pressure table if I want to use MAP vs RPM on all my other tables?

Hope this clears it up. Thanks for all your replies!
stevieturbo
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Re: turbo target pressure map

Post by stevieturbo »

you do realise that the base lookup map vs rpm table is just that. A base duty lookup table YOU need to fill in much the same as any fuel or ignition table, where the ecu needs to know approximately what output value to send in order to tie in with that particular load cell. After that other corrections may also apply.

The same way you fill in a value in the fuel table, because the ecu needs that base starting point for any given load cell. Same with ignition.

The values in the table are not a boost target.
TRN
Posts: 28
Joined: Mon Jul 29, 2013 2:39 pm
ECU Model: S100 Pro
Firmware Version: 89

Re: turbo target pressure map

Post by TRN »

Hi Stevie, isn't that the PWM table you mean? I understand the ECU still needs to be mapped so it knows what to output in order to achieve xxx boost at xxx rpm.

But I'm talking about the other table, turbo target pressure.
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