Sync Accel Temp Factor?

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Torque
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Sync Accel Temp Factor?

Postby Torque » Wed Jan 31, 2018 8:59 am

On Z32ECU ->

The Sync Accel Temp Factor Table looks odd (off the scale).

What does it actually do? And what are the other two tables for please?

Also shouldn't the AlphaN Increase Table not rather be grouped under Throttle Enrichment

NTSYNC.JPG
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Re: Sync Accel Temp Factor?

Postby Matt » Thu Feb 01, 2018 12:18 am

Tables available in 'expert user mode' are not all necessarily documented or functions completely decoded

However, the temperature factor is the main table used to adjust for synchronous acceleration (when throttle is opening). It is the base table, which the others are multiplied by. More info here:
https://www.nistune.com/docs/Workshop%20Training%20Notes%20Web.pdf

With the Z32 ECU, I've determiend that 64 is 100% at normal operating temperature, but when solder than 80degC then reaches upto 223%, hence the display in the graphics. I guess I could adjust the scaling from say 0%-200% to normalise the display, but its not that important

Torque
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Joined: Wed Jun 16, 2010 10:08 am

Re: Sync Accel Temp Factor?

Postby Torque » Fri Feb 09, 2018 7:53 am

Thanks Matt,

On page 13 the document says I should disable the Alpha/N table on turbo charged vehicles.
However on Z32 this table is valid (judging from the OEM Roms)

NT_A_N_Z32.JPG
NT_A_N_Z32.JPG (26.58 KiB) Viewed 711 times


I'm not sure I understand the difference between Alpha N Increase Fuel (ANIF) function and
the Sync Tables.

My car runs quite rich when I press down the throttle quicker than under normal conditions, so for example while accelerating a bit more pronounced.
That doesn't happen when I press the throttle slowly.
I have no AFR measurements atm but I can see in the rear view mirror that it's running rich.

So I was thinking that maybe one of the accel tables operates in % not considering the larger injectors.
(similar to the cranking tables)

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Re: Sync Accel Temp Factor?

Postby Matt » Fri Feb 09, 2018 3:30 pm

Original R33 Alpha/N ECU values copied from the R33 RB25DET ECU had a table looking like this

NA Z32 also had a lower value table, but turbo ones maxed them out (from memory)

Set your table to 255. When TPS goes over the line in this table it will access the last column of the fuel map (in the background) which may make it run rich

Torque
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Joined: Wed Jun 16, 2010 10:08 am

Re: Sync Accel Temp Factor?

Postby Torque » Sun Feb 11, 2018 4:58 am

The RB25 table looks like this, though I don't know if that's transferable to the Z32 table with the same name:
NT_RB25_AN.JPG
NT_RB25_AN.JPG (27.92 KiB) Viewed 699 times


All Z32TT OEM files have the same table values.

NT_Z32_AC.JPG
NT_Z32_AC.JPG (107.67 KiB) Viewed 699 times

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Re: Sync Accel Temp Factor?

Postby Matt » Mon Feb 12, 2018 1:52 pm

Those are all VG30DETT (turbo ones) not VG30DE which are non turbo

Torque
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Re: Sync Accel Temp Factor?

Postby Torque » Tue Feb 13, 2018 4:15 am

I think we are out of cadence ... or maybe I understood something wrong.

But what I got from your response was that I should disable that table by setting all values to 255, right??

I replied I don't see why, because the Z32TT has that table enabled.
and my car is RB25DET.

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Re: Sync Accel Temp Factor?

Postby Matt » Tue Feb 13, 2018 4:45 pm

Yes set to 255 (whole table) on RB25DET

Z32 normally only used this enrichment abover 1500rpm and above 1000-1300mV TPS values (so stabbing throttle under 1500rpm will make it use last column in fuel map)

Torque
Posts: 615
Joined: Wed Jun 16, 2010 10:08 am

Re: Sync Accel Temp Factor?

Postby Torque » Tue Feb 13, 2018 10:36 pm

But wouldn't this disable enrichment functionality completely?
I think I tried that once and the throttle response got sluggish.

You wrote the Z32 (I assume TT) uses enrichment only over 1500rpm.

My understanding of this table is as follows:

255/FF in tables disables any enrichment.
The mV denotes the threshold voltage were enrichment is enabled @ rpm on the X-Axis.

So on Z32TT enrichment only takes place till around 1500rpm.
Right?
NTZ32ENRICH.JPG
NTZ32ENRICH.JPG (63.63 KiB) Viewed 690 times

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Re: Sync Accel Temp Factor?

Postby Matt » Wed Feb 14, 2018 6:22 am

But wouldn't this disable enrichment functionality completely?

Yes. We normally disable it during tuning so it is not jumping to last column (invisibly) whilst trying to adjust the maps

I think I tried that once and the throttle response got sluggish

If you find after tuning that you need to lower the bottom end for better response then that is fine. It will just use the last colunn of the fuel map when your throttle goes over the mv values in this table at said RPM

You wrote the Z32 (I assume TT) uses enrichment only over 1500rpm.

Sorry that should have been _under_ 1500. Details of this table are in the mapping guide also

255/FF in tables disables any enrichment.

TPS doesn't normally reach 5.12 volts (5120mV = 255 raw value) so if the table values are set this high, then the ECU never moves to last column to do this enrichment

The mV denotes the threshold voltage were enrichment is enabled @ rpm on the X-Axis

Correct

So on Z32TT enrichment only takes place till around 1500rpm.

Correct

Torque
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Re: Sync Accel Temp Factor?

Postby Torque » Sun Feb 18, 2018 2:09 am

OK, yes .. all good then.
Thanks for the explanation .. good point disabling it during tuning!


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