Good stuff Jon.

Now, how about an E85 tune

 

Yes!!

It's so abundant on Long Island. I'd love to take advantage of the extra octane rating, if there's any benefit to be had with a tune. Assuming the fuel system can support the volume of fuel needed and the materials are up to snuff to endure exposure to large quantities of ethanol.

 

Thanks for the clarification Jon. This question indeed had come up in my mind when reading recent posts.
Ernst

 

If I am correct, doesn't FVD allude to doing this in another post by opening up sensor ranges? Maybe I misunderstood. Maybe they can chime in...

 

I am more concerned about statements I have heard from a couple pro tuners like Cobb intentionally leaves some HP on the table with their OTS tunes so pro tuners can extract more power and justify an up charge.

I am fine with the approx $1200 cost of the tune. The $500 up charge for an optimized canned tune from several suppliers out there is putting a bad taste in my mouth.

 

I think using the word intentionally is probably a mischaracterization; as if they do it just to lure one into the pro-tune market and spend more money. I would think COBB is just trying to be safer with their tune given they don't have the vehicle in-hand to tune it to its limits. They probably don't want to push the boundaries as far because if they do and, for example, engines in rougher climates/elevations start detonating, then they don't want that "blood" on their hands.

 

Seems a bit odd from an engineering perspective, for Porsche to leave out active Knock mitigation. Considering that in my state, there places where only 91 octane is available, or even to the worst case, where drivers intentionally put 89 fuel into their cars for various reasons, wouldn't it be negligent, to not include an active safety net?.

 

They are overly cautious with the timing they pull out based on each knock event as well as adding in a long decay time for the timing corrections to mitigate. However, knock still must first occur for timing corrections to take place. There isn't a proactive logic system implemented by Porsche to pull timing based of recorded prior knock events.

 

I get it now, they have a reactive system rather than a proactive. As far as I understand, your concerns in regard to octane, is more in line with those who may use lower octane fuel than the recommended 93, and thus have the possibility having issues develop due to the way Porsche ECU regulates knock.

 

That is an aspect of it yes, but I was also trying to highlight that a tune that can auto-adjust for octane using Porsche logic doesn't exist in stock form or other and the claims that there are "octane adjusting tunes" are made by the uninformed for reasons unknown but can likely be deduced. Not for the well being of the Porsche driving public who seeks to extract power safely and reliably.

 

After reading all this cool stuff about how the ECU works with timing and knock, I think everyone can see now how adding 2-3 three gallons of race gas would help our cars run better and safer at the track. It is not so much about getting more horsepower, but about keeping what you got and running at the optimum levels allowed by a regular or tuned ECU. Running in sport plus and banging off one pdk shift after another with high revs puts the most extreme load on our cars, and I have to say though, it seems like my car is happiest doing just that. Porsche builds amazing engines!

At any rate, let say you add 3 gallons of 101 or 105 octane race gas to your 17 gallon tank. That will add a total of 24 or 36 octane points divided up into your 17 gallon tank as compared to just straight 93 octane pump gas. This intern will raise the octane value of the entire tank by 1.4 or 2.1 points per gallon. I like the thought of having 94.4 or 95.1 gas in my tank, and if it is crap gas, you are still likely to be at 93 octane. Again I am not after the power, but want the added margin of safety offered by the higher octane fuel. In the summer when it is hot and you are at the end of a 30 minute session, I would rather my knock sensors be asleep than sensing trouble constantly. Adding this extra gas costs about $60-70 more per weekend and I believe is money well spent especially when considering the cost of tires, extra oil changes, modifications, event fees, track insurance, hotels, etc. I think is cheap insurance to protect your car. Fortunately there are pumps with race gas right at the track where we go for PCA weekends.

 

Idk in my view 'reliability' goes a longer way than 5 more HP. I'd pick a tune backed by a reputation rather than a posted dyno chart. I personally have no idea what the tune will do to that car and must trust the tuner that it isn't going to explode the engine. The only way to establish this trust is through reputation (no amount of technical reading would convince me because I'm not a combustion engine engineer)...it would be too sketchy to have my car ECU tampered with by a tiny 'lets see what this does' shady small shop (of course, I'm not insinuating that someone is doing this).

 

Jon,
So coming from many years of Subaru with a Cobb AP and ATR tuning I have never seen the Porsche tables in ATR. So what your saying is there is no Fine Knock learn with the default Porsche tables but with the Cobb OTS maps that feature is available where it learns knock events, holds them in the table if they meet criteria and then adds the timing back in over time when no noise is heard? (as opposed to just feedback knock and timing being pulled). Is that what you are saying, the default map can not store timing corrections based on requested torque/ load and rpm? Whereas the Cobb map can?

 

Very good question Snoopy!

Short answer: no, we utilize the factory knock control strategy but fine tune it for the proper octane.

Long answer: What you are describing with the Subaru is what we refer to as a pro-active knock control system. Subaru will store knock events that it has seen over time that happen in certain load/RPM areas into what it calls fine-knock learning. If it sees consistent or heavy knock in an area it will remember that next time the car is in that area and will pull timing before a knock event happens. It couples that with what Subaru calls dynamic advance which is a multiplier value which is paired with one or a set of ignition timing adder table(s). This value is either 1 or 16 depending on the ecu. When the car knocks consistently this value drops as well. It is a two fold proactive system in the Subaru. They also have a reactive system called feedback knock that will pull timing when a knock event is seen.

Porsche doesn't have any proactive system, it relies heavily on an overly cautious reactive system with large timing corrections and long decay periods before that timing is added back in. By cautious timing corrections I am mean it pulls out more timing then may be justified for the knock event. 1* being pulled may suffice to subside knock but the ecu will pull 2.25* at minimum for each perceived event per cylinder.

The custom code that would need to be injected to alter the Porsche ignition strategy would be a large undertaking and honestly it is not needed as long as the proper tune is run for the octane. When these claimed "octane-adjusting" tunes are saying you can run whatever octane you want and the car will adapt they are just relying on the factory knock control system to do the work, however knock events still must be occurring for timing to be pulled. And what happens if the knock sensor fails? Since the public can not datalog these "octane-adjusting" calibrations and possible knock corrections it can make for a somewhat deluding and dangerous situation.

Hopefully that answers your question but if you'd like more clarification please don't hesitate to ask.

 

Do you guys have a 91 ACN map that reduces timing for the craptastic gas in Arizona, CA and NV? I know with the subaru line up there were ones for every stage.
I had emailed Bill Gregg a while back right before I got rid of the Subaru ( still have another one) but had to leave the AP installed on it so its now a dust collecting paper weight! I asked him basically this ; In any case being that the 981 is a NA car and there is now Boost to manipulate, bigger injectors, turbo swap, etc. What does the AP allow you to change on a PDK 981 ? For a stock car what parameters would it really change with no bolt on parts?

 

We have control over ignition timing, Cam timing, torque tables, airflow tables, fuel targets, and variable intake manifold control to name a few. All essential systems to properly calibrate the engine are contained within our software as well as the ability to live monitor and datalog their associated parameters.

 

What I find morally objectionable practice is the fact that you're basically calling out one of your direct competitors without saying their company name. Everyone knows who you are alluding to and the fact that you're making a PSA clearly demonstrates the threat they seem to pose to you.

Essentially what you've done is open a can of worms with your competitors and this won't end well if they decide to chime in and start a war of words about which product is superior/inferior.

I find it ironic in this self motivated PSA about transparency when your company in the past did not warn prospective customers that not all ROMs were supported at the time of the release of your product. Several customers were left with essentially a nice paper weight on their desk while you worked to resolve support for all ROMs on the market, which would have been a nice piece of transparent information for early adopters of your product. It would have been the choice of your customer to take that risk or not, but that option was never presented.

While I did find the information you posted to be educational, the motives behind the post seems far less informative and more self serving.

 

I can understand the frustration when it comes to ROM support at the time of release. When attempting to find and consolidate all ROMs for a world market release, no matter how many ROMs we had cataloged prior, there was inevitably a few that we are unable to obtain through our typical channels. It is true our roll out of the product had room for improvement but when you are first to market with a product there are bound to be some minor hiccups. We have taken notice and will revise our strategy as best we can for future releases. When an unsupported ROM was submitted we worked quickly to get it added. We offer a no questions asked 30 day return policy. If our extensive customer service was unable to accommodate all of our customer's concerns we would gladly refunded their money. If there remains any outstanding issues please feel free to contact us at porsche.experts@cobbtuning.com and we will do everything in our power to make sure you are happy.

True, this was a PSA. We felt it best in the position we are in and the knowledge we have to inform fellow members about "octane-adjusting" tunes and their inherent possible threat. We invite anyone to join the thread who can refute what was stated in this PSA with any evidence they may have in forms of datalogs or similar empirical evidence.

We are not threatened by competition in the market. In fact quite the opposite. We are very welcome to it. Competition drives innovation. In the end you, the end user, ends up winning in the form of new maps and updated features. We have encountered competition in all of our other Porsche platforms and we continue to thrive because we supply the community with an unparalleled product, complete with unmatched features, coupled with wonderful customer service. The Accessport is also able to be uninstalled and resold to recoup much of the investment in the original price of the unit in the event you sell your car.

If you have further questions or need clarification please don't hesitate to ask. I'll be happy to help!

 

Hello Everyone!
However Porsche doesn't have a proactive knock system in place to pull timing before knock occurs based off of prior knock events. Any timing correction seen is the direct result of what the knock sensor observes to be knock.

So what exactly does a "pro-active" system do? Can it predict a knock without observing one? (How?)

As far as I know, "basic" knock control observes a knock using the knock sensor - and changes the timing globally... After some time, this is relaxed, as a sanity check to make sure it is still needed. Otherwise timing couldn't improve if a knock causing factor improves. (Got better gas, altitude, whatever..)

I have read some cars have "fine knock control" that just does the same as the above, just has different entries for different RPM ranges.

 

I think what he's getting at is the ECU's ability to make changes on the fly. For instance in my other cars I run E85 with a flex fuel sensor so depending on the gas the computer will make the appropriate changes based on ethanol content to pull or advance timing, etc based on several tables that work off one another in the tune. This is using HP Tuners or EFI Live. I'm new to the Porsche world so I'm guessing this flexibility isn't there due to the ECU functioning differently or the tables not cracked and made available to provide a more dynamic tuning solution.

 

I know on the Subaru platform you have Feedback Knock (timing is pulled instantly when a single or multiple knock is heard), then you have a Fine Knock Learned (where timing is pulled at a specific calculated load / RPM and it is stored in a table and re-applied each time that range is gone through again, then after it stops hearing noise it gradually adds the timing back in), lastly there is DAM (dynamic advance multiplier which if its a 1.0 is giving you 100% of timing and advance, if it were 0.9 it would be removing 10% across the board). Each strategy is used under different situations or simultaneously. I just don't know how all this translates to a Porsche.

 

I too found this is a good post to read through. Looking forward to having more Pro-Tuners competing for our business on our 981 cars. Hope the current offerings on tune prices will go down with more competition as well. Having a COBB Pro-Tuner approved does protect the consumer by these tuners as well with a least some level of regulation by the original equipment manufacturer. The business model will only allow Pro-Tuners using COBB the Accessport to exists if the tunes are safe for the end-users, else their license agreement will get pulled.

 

I have been a long time Cobb AP user on the Subaru side. While I have had no issues with loosing an engine from their OTS maps or even one tuner i have used over the years, I will say this, they will not bump a tuner out of their program because someone lost an engine. They can't tell a tuner how to tune. They are just selling them the software that keeps their maps locked and listing them on their website.