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Cobb Pro Tune for 991.2.. Its ready

Old 01-07-2019, 03:13 AM
  #31  
Mojo.K
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Originally Posted by reacher View Post
​​​​​​
​​​​​​No, it would be pretty impressive if it did. But no.
What are the options with those with PSE?
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Old 01-07-2019, 03:37 AM
  #32  
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Originally Posted by reacher View Post
​​​​​​
​​​​​​No, it would be pretty impressive if it did. But no.
Doesn’t the GTS have PSE by default? There is a tune for it, unless I am missing something?
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Old 01-07-2019, 03:41 AM
  #33  
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Originally Posted by TXGold View Post
Just curious when whoever was reviewing your logs says that 90% of knock is gone. What metric was used to show this? Also wouldn’t any knock at all be bad?

Regarding the the comment that they are curious how they got more power and torque AND it was lean, it’s my understanding from my piston flying days that peak power is made lean of peak cylinder temp. I’m sure there are many other factors but from what we could control, full rich for landing and take off and in cruise lean it out for max range, and power at a particular RPM and MP.

I was cranking thru the datalogs. Road pull -12 is before protune, -17 is after protune. Before the protune by Mitch, there was timing pulled from every cylinder except #5 in the mid-range of up to 4.5 degrees. Another observation is the middle cylinders (2 and 5) tended to knock less than the other four at the ends. My guess is due to the intake manifolds starving the 4 cylinders at the ends a bit whereas the middle cylinders get the straight shot of air from the plenum. Anyway, after the protune, there was a little timing pulled from one cylinder higher up in the revs. On another protune run, it was completely knock free with no timing pulled at all. Typically, peak power is around a lambda of 0.95, so just a little tiny bit rich. With car engines and old school port fuel injection, lambda had to be around 0.75, or an A/F ratio of about 11.0:1 to prevent knock by excess fuel for fuel cooling. Well, and to keep the cat from melting too. With modern direct injection engines, they can actually keep the air fuel ratio right at stoich 14.7 (lambda = 1) for quite a bit longer before having to enrich. I started noticing this with BMWs after they went direct injection and turbocharged a while ago. I'm not up to speed on modern fuel injection technology, but they might be doing things like multiple fuel injection sprays per power stroke. Anyway... lots of questions, but tuners aren't the type to give up their secrets.
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Old 01-07-2019, 05:05 AM
  #34  
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Originally Posted by PTS-BRG View Post
I am also not 100% sold on the header gains.. I am still on the fence about their overall benefits as well.
Wow, if this is the case, then you definitely bought the wrong headers. With mine, there is no if's buts or maybe, it was HELL YES, thanks for coming these kick ***.

I don't really care about the IPD, but BGB saw a gain on his dyno, and your mate sticky also sang their praises. I think I only noticed, because that was the very first mod I did. I think people who do the BMC as the first mod may feel something. Because it was deep down my list, I felt nothing with the BMC.

But the Headers made a very noticeable difference. No debating necessary at all. It was sit you back in the chair harder than ever before noticeable. I am wondering are you suffering because you don't have inter coolers?

The inter coolers were basically the second mod I did, so every mod after them gained their benefit as well.

Butt dyno can be subjective, but not in the case of COBB stage 1 and Vektor headers. They both added very noticeable power. The Akra cats at first were quiet and didn't seem to do that much, but after a couple of hundred km's they become louder more noticeable and felt stronger. But sound can make it feel stronger also. I think that order matters. Because you previously had sports cats, you had gotten used to that power. Then when you did headers, whilst you changed cats, you already had sport cats power. Whereas I did the Headers first and they made the big difference, and then the Cats were no where near as noticeable. That may explain your lack of love for headers.

Whilst inter coolers are really a Stage 3 mod, I think your car would benefit from them. More tune means more heat. I will do the PWR front 3 radiators for Stage 3 as well. Whilst they won't add power, they will keep the car cool and stop it form pulling timing when the boost is even higher.
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Old 01-07-2019, 09:33 AM
  #35  
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Here on the east coast we dont often get into temperatures like Texas and Florida. In addition, I will never ever track my car or even race it, so I have no need for intercoolers. If I found it to be a real concern, I would add a single radiator in the center where there is space and it is missing, but a full intercooler swap is not on my list.

I don't arrive at my opinions of plenums and headers out of thin air, I do so from opinions of others who are far more knowledgable than I am. I also have done more dyno testing on 991.2 GTS models than anyone else I can think of. Based on my dyno data, my experience with AM Parts and the opinions of those who do this for a living, the IPD plenum is a worthless mod and the headers may or may not add something somewhere. Let me also add something that many of us do not consider... This is a business. The parts guys make a living selling parts. The tuners and dealers make a living selling them. While it would be noble for a dealer to publicly tell us that part X doesnt do anything it is something that will never happen. No one is going to alienate a manufacturer or be the black sheep in the business to trash talk a part. However, I have had many of these same people PRIVATELY tell me that the IPD does absolutely nothing and the BGB dyno showed a reduction in power across the entire curve from the IPD, so you and I will have to continue to disagree on the IPD. Sticky's opinion and data collection is a joke as everyone who has ever been to his site or met him in person will tell you. Still waiting on his Header showdown, its now 2019. Keep waiting for that The IPD is an $800 part. If it did something it would be the single cheapest mod I can think of next to an air filter or spark plug. Who WOULDNT buy it if it worked?

Since you 4 point 0 haven't done before and after dyno runs with and without each part (like I did) then your butt dyno doesn't have much by way of hard data. I wish you would do it so we could have some real data.

Psorcery: If you didn't want to comment on the logs then you shouldn't have agreed to review them and post. I provided them to you as requested. It has nothing to do with my identity, the data logs are in CSV Excel and there are hundreds of lines, cells and worthless info, so I wouldn't even know what to cut and paste and it would be so small it wouldnt be legible. Sorry it gave you a headache, next time don't ask..

SPDRACERUT: Thank you for taking the time to get this information interpreted and publicly disseminated. I appreciate this more than you can imagine and you are a great asset to the Porsche community. Thank You!!

MOJO K: Yes, the Cobb Tune can and does work with a bone stock car with factory PSE. You will gain about 80hp or so with no other mods. Stage 1
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Old 01-07-2019, 10:48 AM
  #36  
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600HP at the wheels - should trap at well over 140 mph - impressive stuff. Could you post a timeslip please?
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Old 01-07-2019, 10:51 AM
  #37  
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I dont race or drag race so no time slip will be available from me. But, this is bolt on stuff with Cobb Tune, so I am sure there will be plenty of guys who will soon be able to post slips..

Thinking about getting something in the car to give me accurate 0-60 and 60-130 and quarter mile numbers. Any one know which is best and most accurate?
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Old 01-07-2019, 10:53 AM
  #38  
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VBOX

http://www.vboxaustralia.com.au/performance-box.html

Its available from Racelogic - simple to use and is 10Hz (10 readings per second) so perfectly fine for what you're doing

Racelogic USA 27260 Haggerty Rd, Suite A2, Farmington Hills, MI 48331. Contact: Paul Ferreira. Tel: 248 994 9050 / Fax: 248 994 9054
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Old 01-07-2019, 11:14 AM
  #39  
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Just did some youtube reviews and going to go with the Dragy. Cheaper, smaller, lighter, can video overlay and can view it all on my iPhone.
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Old 01-07-2019, 11:47 AM
  #40  
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Originally Posted by PTS-BRG View Post
Just did some youtube reviews and going to go with the Dragy. Cheaper, smaller, lighter, can video overlay and can view it all on my iPhone.
while the vbox is more accurate and only approved device for 6SO QT’s it requires review on a computer and using software. It is outdated and over priced. Luckily being so close to Mexico many have them and lend them out. I use the draggy and find it to be a lot of fun and easy to use. The leaderboard leaves a lot to be desired but still is fun. You’ll like the Draggy especially if they get it out of beta in the future.
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Old 01-07-2019, 01:05 PM
  #41  
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Originally Posted by groundhog View Post
600HP at the wheels - should trap at well over 140 mph - impressive stuff. Could you post a timeslip please?
That was my original estimate based on the road pull data from -12 data. I thought it was a bit odd the torque curve started going back up at the high rpms, but I thought maybe it was due to the colder ambient temps of only 50F. The ICs were also not heat soaked with IATs only being 75F. But with the additional -17 data from after the Protune which represents more of an expected curve, I'm guessing on the -12 run, it might have gotten hit by a tailwind or a downhill section. I also estimated that the GTS turbos are good for 560whp on 93 octane, so the 600whp was above that. Again, I thought maybe the colder air, but likely not as the -17 data was in nearly identical temperatures with an ambient of 48F, though the ICs were heat soaked resulting in IATs of about 95F.

Lots of assumptions in my calculations and there's a lot of scatter in the data where I draw in a line. Basically like smoothing function on a dyno chart. Not to mention, the data in the datalog is not exactly clean and requires some processing due to lack of sample rate and accuracy. I calculated torque and power just using physics, F = ma. Force of drag comes from coefficient of drag, frontal area, air density, and speed. cD is only 2 significant digits, I found the number for frontal area which was only two decimal places, assumption on air density, assumption on vehicle mass (car options, fuel level, driver weight being variables). Speed has to be calculated from tire size and gear ratios. So there's error in actual tire diameter (air pressure being a variable affecting it along with manufacturing accuracy vs tire size specification) So yeah, lots of sources of error, but it gives approximate values (maybe +/- 7% give or take) and shape of the curves. I figure 550whp estimate based on the -17 data is closer to actual. Absolute numbers are like whatever, but there is no debate on the massive mid-range gains from the Protune. I figure the car will trap in the low 130mph range. Maybe 132-133mph?
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Old 01-07-2019, 01:16 PM
  #42  
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I actually like the fact that changing hardware such as headers, intake, y pipe, does not do much. Exhaust makes sense due to emission considerations that Porsche must adhere to. But this tells me within reason that Porsche did a good job engineering the car. Obviously as you get up into the high RWHP numbers you need to re engineer the entire system for increased air flow in and out including turbo.
I tune my own cars with HP Tuners(Z06 vette)...and although a different animal than the Porsche, I can tell you the power improvement are in the tune. The compromises the manufacturer must make for emission, longevity, driving style, fuel grades, and environment leave power on the table. There are compromises with timing and tables that reduce power due to high IAT, bias the AFR and timing between air and coolant temp, etc.
Seems the bang for the buck with our cars is the tune.

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Old 01-07-2019, 01:20 PM
  #43  
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"Seems the bang for the buck with our cars is the tune."

No one will disagree with you there. No single better and bigger gains to be had above the tune. Everything else is incremental in comparison.
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Old 01-07-2019, 05:42 PM
  #44  
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Originally Posted by PTS-BRG View Post
"Seems the bang for the buck with our cars is the tune."

No one will disagree with you there. No single better and bigger gains to be had above the tune. Everything else is incremental in comparison.
+1 I'm happy with all my mods but after a tune the results are marginal. I think we will see the benefits of all the bolt on mods when going bigger turbos
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Old 01-07-2019, 06:36 PM
  #45  
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Originally Posted by PTS-BRG View Post

Psorcery: If you didn't want to comment on the logs then you shouldn't have agreed to review them and post. I provided them to you as requested. It has nothing to do with my identity, the data logs are in CSV Excel and there are hundreds of lines, cells and worthless info, so I wouldn't even know what to cut and paste and it would be so small it wouldnt be legible. Sorry it gave you a headache, next time don't ask..
You're emailing me amateur data logs from a burner account Mr. "Medium Well". You take the time to PM back and forth, then email. Then comment. Just post them.

How about you push the log button the moment before you want to test and the push it again immediately when it's over. That way you have a clean, non polluted log. Next time, don't mention your logs.

My comment: Your logs suck.
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