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Old 10-16-2017, 08:35 AM   #1
Brock31
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Default 2008 STi -- General Tuning Questions (Now with Boost Q's)

***See Post 10 for my current quandary.***

Just a little background:

I got into tuning in 2006 with Enginuity (became Romraider) with my 2004 WRX. Tuned it from Stage 1 up to stage 3.

I know and understand the basics, but now have a 2008 STi and the 32 bit ECU and CAN Bus setup are quite a bit different from the 16 bit ECU in the 04.

I bought the car back in June. Has an Opensource "Stage 2" Pro-tune done on a dyno by a local Speed shop to support the Cobb Short Intake and Cobb Catted Exhaust. It produced 332whp and 376 lb/ft.

I have the Openport 2.0 on the way. My "Antique" Tactrix version 1 will now have to be submitted to the Smithsonian.

Anyway, now for the questions:

1) No green connectors and No Flash block connector?

2) The STi has 3 driving modes. [i]Intelligent, Sport and Sport #.
Is there a different map for each driving mode? For example, when I go to
read the ROM and I have the selector in "Sport" and pull that map and
then do the same thing when its in "Sport #" and compare the maps side
by side....will they be different? Sport for me hits 18 psi and Sport # hits
24...what is this wizardry!?!

3) Wideband access. My old WRX had to use a completely separate USB
cable from the Innovate wideband I had. The 2008 STi has an AEM
wideband. Does the Openport 2.0 access the wideband and show up as a
parameter in Romraider?

These are my main questions....If there is any reference material that could point me to a better understanding of the differences between the 2004 and 2008, that would be great. Or if anybody has any first hand experience with the 08 STi, that would be great too.

Thanks in advance!
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Last edited by Brock31; 11-06-2017 at 03:41 PM.
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Old 10-16-2017, 09:43 PM   #2
RockThePylon
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Quote:
Originally Posted by Brock31 View Post
Just a little background:
1) No green connectors and No Flash block connector?

2) The STi has 3 driving modes. [i]Intelligent, Sport and Sport #.
Is there a different map for each driving mode? For example, when I go to
read the ROM and I have the selector in "Sport" and pull that map and
then do the same thing when its in "Sport #" and compare the maps side
by side....will they be different? Sport for me hits 18 psi and Sport # hits
24...what is this wizardry!?!

3) Wideband access. My old WRX had to use a completely separate USB
cable from the Innovate wideband I had. The 2008 STi has an AEM
wideband. Does the Openport 2.0 access the wideband and show up as a
parameter in Romraider?
1) Correct. Nothing under the dash to dick with. Just plug in the OpenPort and go to town.

2)
There is only 1 map per driving mode that defines the difference. They are all in a single ROM. You'll see once you pull a map and start looking at it. The drive-by-wire cars have something called "Requested Torque", which is a value used by other maps. It's just throttle mapping.

You have "accelerator" position, which is your pedal. And "throttle" position, which is the actual butterfly valve on your engine. Drive-by-wire.

So, as a very broad example using made up numbers...

In Sport mode, with your accelerator to the floor, you have "300" requested torque. This number is used by your boost table to say, "Target 18psi".

In Sport# mode, with your accelerator to the floor, you have "400" requested torque. Which results in a target of 24psi.

The neat thing, is that at say, "200" requested torque, the throttle plate may actually be open all the way. The rest, up to a value of 400, is all just boost control. It's a big advantage over drive-by-cable for nice, linear, controllable power. And not having your turbo working it's nuts off against a half-closed throttle plate.



3) You'll still need a separate cable. The AEM wideband is a standalone, doesn't interface with the ECU at all. Unless you do some trick stuff for the sake of logging.
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Old 10-17-2017, 08:28 AM   #3
Brock31
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Thanks for chiming in RTP! Thank you also for taking the time to make some really good explanations.

Looks like I've got some learning to do. The 32 bit ECU seems far more complex than the 16 bit ECU.

My game plan right now is to:

1) Sort out the wonky AFR learning values I'm seeing
2) Figure out why my HWY mpg is absolute garbage (16-17 mpg at best while city is 21-
22)
3) Deal with a little WOT FBKC between 4300-4800 rpm and 2.9-3.10 load
4) Figure out how to connect the AEM wideband to get accurate Wot AFR's (also to see if
the sensor is any good)
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Old 10-25-2017, 08:37 PM   #4
Pro60modman
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Your boost control maps are scaled by requested torque on the x axis and rpm's on the y. You can map out the I, S and S# modes to request a certain torque at 100% pedal. This allows 3 different boost settings as it will target different sections of the boost target map based on requested torque.

As for what you said above you need to log AF Learning, AF Correction, Comm Fuel Final(final AFR target in closed loop) and MAF voltage at the very least to see what your AF Correction and Learning are at each voltage point in the MAF curve.

If you have a AF Correction of 12.74% and an AF Learning of -2.34% at MAF breakpoint .96v then you would multiply the value under .96v by 10.4% which would be 1.104. MAF Scale v2.2.9 is useful tool in scaling the MAF quickly without having to try and target each point of the MAF curve manually.

You could wire the 0-5v output of the AEM into the rear o2 or TGV signal and log the voltage. The AEM instruction will have the transfer function to convert the voltage properly.
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Old 10-26-2017, 03:53 AM   #5
NSFW
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For MAF scaling I find it helpful to disable closed-loop fueling and just compare actual AFR with the Final Fueling Base AFR. AF Learning and AF Correction are both very noisy indicators.

I also tend to make MAF scaling adjustments by about 3/4 of the error indicated by the logs during the initial adjustments, and then make corrections by half of the error when the scaling is getting pretty close. Even with AFC and AFL disabled, the data is still fairly noisy, so trusting it too much will lead to overshooting some of the adjustments.
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Old 10-27-2017, 08:40 AM   #6
Brock31
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Thank you guys for your input.

I feel like I'm having to completely learn a new tuning strategy with the 32 bit ECU versus the old 16 bit on the 04 WRX...

I've rescaled the MAF using the Cobb SF scale since the numbers looked to be about 10% higher and my corrections were +15-16. So far, 20 miles in my corrections are +/-5...Still a bit early to tell what long term corrections will be.

Would it be bad to revert the OL/CL transition back to stock? At least until I get my wideband wired up for logging?

**edit.
I've posted over at RR with my ROM revision
http://www.romraider.com/forum/viewt...p?f=15&t=14185

Last edited by Brock31; 10-27-2017 at 08:46 AM.
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Old 10-27-2017, 08:45 AM   #7
Brock31
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Quote:
Originally Posted by Pro60modman View Post
Your boost control maps are scaled by requested torque on the x axis and rpm's on the y. You can map out the I, S and S# modes to request a certain torque at 100% pedal. This allows 3 different boost settings as it will target different sections of the boost target map based on requested torque.
This is what I'm really having to study. For some reason my brain hasn't wrapped itself around this concept yet.

Thank you for your explanation though. If you have any useful links that would be great.
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Old 10-28-2017, 05:24 PM   #8
Brock31
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Ecuflash saves read ROMs in a .srf format that is not read by Rom raider.

Can I "Save as" and have ECuflash save it as a .bin so Romraider can open it?

Will saving as a .bin cause any issues when I rewrite it to my ECU?
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Old 10-31-2017, 05:41 PM   #9
BURNING4ORCE
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Save it as .hex. No issues with .bin when you flash it to the ecu.
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Old 11-06-2017, 03:36 PM   #10
Brock31
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Question regarding Target Boost at the Requested Torque Values.

In Sport # my current Target Boost is 20.42 psi at 3600-4000 rpm's at 380 Requested Torque.

During a WOT pull, I logged 18.43 psi at 3800 rpm's at 426.5 Requested Torque. Boost reached 18 psi at 3400 rpm's and just leveled off staying below target boost.

Because the Boost Map Requested Torque Value maxes out at 380, does the target boost above 380 requested torque stay the same? Or does the target boost extrapolate outwards from the 380?

In other words...would Target boost at 426 Requested Torque be 20.42 psi or would it be some value greater than that?

I'm trying to figure out if I'm way undershooting target boost in Sport# due to a boost leak.
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Old 11-06-2017, 11:05 PM   #11
NSFW
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It does not extrapolate beyond the edges of the table, it just uses whatever value is at the edge of the table.
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Old 11-07-2017, 08:36 AM   #12
Brock31
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Thanks for your input NSFW. I attached some images for reference regarding my Boost and WG tables.

If I understand correctly, I'm essentially undershooting my target boost by about 2psi.

If I determine its not a leak, I wonder if upping the Max WG Duty Cycle a few %.

I need to collect some more data logs and focus on boost, WG and TD error.



Last edited by Brock31; 11-07-2017 at 08:57 AM.
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Old 11-12-2017, 07:50 PM   #13
NSFW
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If it overshoots and then oscillates, turn down the gains.

If it overshoots but doesn't oscillate, you need less WGDC in the range before the overshoot happens. Whether that means turning down the max or initial WGDC depends on what you find in the logs. If it's not hitting the max, then obviously you need to turn down the initial instead.

Also, consider setting the gains to zero, and tuning boost as best you can with just the initial WGDC table. Then set the max to about 10% more than initial, and put the gains back, and see how that goes.

Also, consider a hybrid (solenoid + MBC) setup. It makes boost tuning really simple, and it's nice to be able to dial in whatever boost level you want just by turning a knob. To tune different ranges of the fueling or timing tables, or to make the car more docile for a valet, or to go back to minimum boost in between changing something and finishing retuning, etc. There's a sticky thread on hybrid boost control here, I think it's a great way to go.
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