c1pher

Looking forward to some firsthand reviews. Mine is supposed to arrive November 1, but might not be able to install for a couple of weeks due to travel.

Avera

Me too!

I love the prospect of a PDK tune, but I am under impression COBB only ramped ‘start-up’ mode a bit and did nothing to PDK/Sport mode for GT4. . . if my impression is correct, stock PDK/Sport mode does not cut it for ME, and I am not after a little more out of ‘start-up’ mode. I am after a more aggressive PDK/Sport mode.

Avera

COBB Tuning

No worries! These are definitely complex systems that require a lot of care and testing to get right. Subarus are often times much more straightforward due to more direct control strategies. We do have some ideas for custom features we and customers would like to see implemented. We know that exhaust flap control is something a lot of people want. We just need to figure out the best way to do so

- Andrew

c1pher

Are there any changes to throttle mapping on the stage 1 tune?

ufgtrs2007

I have a full akrapovic exhaust (OAP + muffler) that improves hp even with the stock tune. do you have a map that works with OAP? thanks

Avera

I believe this question has been answered in prior posts pertaining to stage 1 tune, which I am under the impression you are inquiring . . . rather than PDK tune?

All stage 1 testing was done with fully stock exhaust/intake system. Once you start altering air flow dynamics with aftermarket exhaust parts, then it is possible/likely you will need custom mapping. This scenario is typical of stage 1 tunes that are produced based on stock vehicle setups.

Stage 2 tunes typically take into consideration aftermarket exhaust/intake modifications that increase air flow. Andrew indicates COBB has no immediate plans to produce a stage 2 tune, rather, relying on custom mapping.

I think this is a wise decision on the part of COBB, as it would be nearly impossible to produce a stage 2 tune that takes into consideration all the aftermarket exhaust/intake options and combinations therein.

Replacing ONLY the rear box seems to be a safe bet in obtaining a stage 1 tune, as all cats/resonators (headers/OAPs) remain intact - air flow will not be altered significantly.

Avera

MrFunk

I see on your blog a 91 octane dyno and a 93 octane dyno.

Is this a single tune that can be run with 91 or 93 octane? Are these two seperate tunes (you either buy the 91 or the 93 tune)? Are these two seperate files (you buy the software and own both files but chose to load one or the other)? The software you flash has both files you can easily toggled between with the loader?

I'm asking because all the vehicles i hace with tunes were 93 specific and ive gotten tired of trying to plan road trips around where I can get 93 octane or using octane booster...

If it's two different files you'd have to buy separately. What is the dyno of a 91 file running 93 octane? Any improvement over the 91 file running 91?

COBB Tuning

From my rudimentary Saturday morning review of our tuning software it doesn't appear that we do in either our GTS or GT4/Spyder Stg 1 OTS maps. I'm just working off table names though and I am most certainly not a calibrator so I'll leave this one officially for Andrew, who was co-calibrator on this project, to correct me if I'm wrong on Monday.

Avera pretty much nails it down here below, thanks!

Long story short we're unable to confirm various exhaust component combinations compatibility with the Stage 1 OTS maps at this time because there are just too many to test and we quickly get into potential emissions compliance issues. As Avera stated any rear muffler change should be fully compatible, OAPs you start getting a little bit touch and go. I definitely recommend pulling logs and having them reviewed with the potential for a Protune being needed. Headers? Even catted those will almost certainly need custom tuning.

The Accessport will come with both Stage 1 91 and Stage 1 93 maps preloaded on it (along with Stage 0 which is the factory tune converted to a flashable map the AP can understand). All the maps are included with the purchase cost of the unit and you can flash between maps, or uninstall/uninstall as often as you like. Install/Uninstall take considerably longer (~15 minutes) than a map change and a full size battery charger is strongly encouraged during those procedures as it's crucial the ECU sees an even voltage throughout the process. There are several high current draw events that can occur during the install/uninstall process (such as the Aux side fans engaging) and even a brand new battery in optimum condition can dip below the programming voltage threshold and could result in the ECU losing communication...which means you'll probably be on the phone with our customer service team shortly afterwards being walked through the recovery screen menu on the Accessport. However, map changes are significantly faster (~2 minutes) and can be accomplished without a battery charger in most circumstances with a well maintained battery. For your scenario, you'd be looking at changing the map from the Stg1 93 to the Stg1 91 during your trip which would take roughly 2 minutes at a gas station.

However, with all of that said, and wayyyy too many back and forth drives across West TX to Socal under my belt, I generally just flash the car to the Stg 1 91 map before I even leave just so I don't have to deal with the hassle of wondering where and when I'm going to be pumping gas and reflashing the car. You can always run a lower rated map with a higher octane fuel in the car without any issues so flash the car to the 91 map before you leave with 93 still in the tank, run it dry during your road trip and refuel with 91, carry along with the road trip on 91 until you get back and run the 91 out of the tank, refuel with 93, flash back to the 93 map. That rolls us into the last bit of your question which is actually fairly common but usually phrased something along the lines of if it's worth throwing like...5 gallons of 100 octane in the car with 93, keeping the car on the 93 map, and then running the car on track/etc. In either of those scenarios (100oct in tank on a 93 map, 93 in tank on a 91 map) the ECU does have the ability to adjust timing for fuel quality within a certain range but it's not going to make an appreciable difference in power gain to even the most calibrated butt dynos. The benefit is really the other direction, and usually only seen during long track sessions. Running a higher octane fuel on a lower rated map will generally prevent the car from pulling back timing as much, or as quickly, which when it does occur means the engine is dialing back overall power. As everything gets hotter the chances of detonation increase so the ECU will take steps bringing timing down to protect the engine. Again though, for normal street driving even a few hard highway pulls or a blast down a canyon road isn't going to be enough for the ECU to dramatically reduce timing (unless the fuel quality is subpar), the ECU needs to see sustained long stretches of high load which is generally only occurring during a longer track session. Long story short; 5 gallons of 100 on a 93 map isn't going to get you more power, but it will get you more insurance against losing the power you do have, same deal with 93 on a 91 map but to a lesser degree.

Thanks!

~Jared

COBB Tuning

Jared is correct in that we didn't alter the throttle mapping directly. We do have different torque requests per accelerator pedal position but we kept the overall shape of the curve the same so that the "feel" of the pedal is the same, albeit, with more power associated with these positions. We use this strategy to keep the overall feel of how the car drives the same. One thing Porsche nailed on many of their cars is creating a good sensation of speed and we try to retain that rather than creating a jerky feel by loading low throttle input up with high torque demands. This also helps keep the car very drivable on the street. With that said, throttle remapping is definitely possible with a custom tune but that would be more intended for special uses. I think most customers will be happy with it as it is.

- Andrew

c1pher

Thank you. I really like the throttle response in sport mode so am happy to hear that.

ufgtrs2007

thank you for the information. Good to know we can do custom mapping utilizing Cobb's software.

Reedy

Can you remove the god damn soft limiter from this car? I want to redline my car when stationary.

COBB Tuning

We unfortunately haven't found a table for this specific function. We believe it may be imposed at least partially by the transmission type but all of the limit tables we've found thus far are either already set to 8000 or have been calibrated to do so.

I also wanted to share some information about our research into exhaust flap control tables that we performed this week. We have been working on adding these tables to our ATP software for Protuners to use when making custom maps! For anyone also following BGB's thread, I posted this there earlier today as well.

We had a GT4 in this week and I had some time to test our new tables that Protuners can calibrate. There are 39 tables that are used and I'll outline the structure/functions below.


The first four tables are used to control "map slots" for the exhaust flaps in Normal and Sport modes and in each gear. The secondary tables are copies of the primary tables but we may be able to use those in the future to control individual banks. There are no differences between Sport and Normal in this car since the GT4 doesn't have different engine modes.


Next are the map slots. They all correspond via the number with a map slot assigned by the previous table. These tables are used depending on the map slot, drive mode, and whether or not the button is active for exhaust flap "high noise". There's a lot of redundancy here but with some tweaking, we may be able to use it for some really customized functionality. The data in the tables is output as the exhaust flap closure % based on RPM and airflow into the engine.



The output data is either 0 or 100 with 0 being flaps open and 100 being flaps closed. The 0-100 range suggests that there are values in between but any output greater than 0 results in the flaps closing completely. So really, it's very binary.



Finally, we have three tables that determine flap position on engine startup. On this GT4, flaps are always open on a cold start but close on hot "repeat" starts which is likely to happen if the Auto On/Off engages.

I hope this shows some of the intricacies of the exhaust flap control. We plan on doing some more testing and hope to be able to see some cool projects with it from our Protuners!

- Andrew

Pokerhobo

Wouldn't redlining the engine stationary be a problem with lack of cooling?

Reedy

That makes sense for it to be attached to the transmission. Also explains why putting a PDK car in gear and pulling both paddles lets you rev a little higher, but still not all the way to 8k for some reason.