991.2 Cobb Accessport, post your results
06-09-2020, 10:35 AM
#421
Three Wheelin'
The new engines produce more HP and have different components. The engine isnt "done" and the 992 is based on the same platform, but its not the same engine.
Google it, too many little changes to copy and paste
Google it, too many little changes to copy and paste
06-09-2020, 10:48 AM
#422
Rennlist Member
Nabil: I think I was one of the first to experience this and it seems to happen on cars producing the most Torque and HP, mostly GTS cars with PDK. It is widely believed that the ECU has a table/limit and when the torque hits that limit the ECU "retards" the shift to protect the engine from too much torque. I have had 3 different tuners produce 3 different Protunes and none of them could solve it. The solution COBB came up with was to just reduce the overall Torque and HP from the tune and voila, no more stutter from 3-4th. That wasnt a suitable solution for me, but it certainly stopped the shift issue.
If your tuner can figure it out and at the same time keep the numbers as high as they currently are, I will be impressed and will give him a call to tune mine..
PDK tune will not fix this issue as it has nothing to do with clutch pressure or clutch plates slipping, it has to do with the actual engine limiter being hit at redline from 3-4th.
If he can raise that limit/table somehow at that one spot (or slightly limit the tune at that one spot) then he will be able to do what no other tuner has been able to do.
If your tuner can figure it out and at the same time keep the numbers as high as they currently are, I will be impressed and will give him a call to tune mine..
PDK tune will not fix this issue as it has nothing to do with clutch pressure or clutch plates slipping, it has to do with the actual engine limiter being hit at redline from 3-4th.
If he can raise that limit/table somehow at that one spot (or slightly limit the tune at that one spot) then he will be able to do what no other tuner has been able to do.
Here are my latest 91 baseline numbers, to compare with my scheduled 91 APR tune next week.
This was a 1500 rpm "launch".... that I botched. Would have been a 10.9xx if I'd gotten a 3.3 0-60.
06-09-2020, 10:56 AM
#424
Three Wheelin'
The 91 tune is less aggressive than the 93 tune which produces more HP and torque. The PDK tune "fixing" your 91 tune was an anomaly. At any point, on any tune, if the HP and Torque exceeds what the ECU is programmed to feel is excessive, then the ECU will retard the power at that point. It just so happens that the most torque and HP on our cars occurs from 3-4th shift so thats where the problem lies for us all.
06-09-2020, 12:11 PM
#426
Yesterday I loaded another tune-file from my COBB pro tuners. Did a WOT run to 7.5K from 2nd, 3rd, 4th gear recording on the AP. This time it was perfect. No flutter or throttle pull back at all.
Looking at the logs after the runs, to my surprise I noticed that there was a pull back on the "Throttle Angle" as before but this time it was much smoother and slower reacting. So what has been happening is my "Engine Torque Actual" was getting too close to the "Engine Torque Limitation" real fast, within 20 ft. lbs. or less and that caused the "Throttle Angle" to pull back fast, too fast. Now when this same WOT runs the "Throttle Angle" is pulling back slower and so the "Engine Torque Actual" is adjusting sooner and keeping the distance from "Engine Torque Limitation" a little more than 20 ft. lbs. The logs show around 620 ft. lbs as the torque limitation and I was hitting 605 ft. lbs. on some runs. I will keep testing and maybe some fine adjustments from time to time.
Looking at the logs after the runs, to my surprise I noticed that there was a pull back on the "Throttle Angle" as before but this time it was much smoother and slower reacting. So what has been happening is my "Engine Torque Actual" was getting too close to the "Engine Torque Limitation" real fast, within 20 ft. lbs. or less and that caused the "Throttle Angle" to pull back fast, too fast. Now when this same WOT runs the "Throttle Angle" is pulling back slower and so the "Engine Torque Actual" is adjusting sooner and keeping the distance from "Engine Torque Limitation" a little more than 20 ft. lbs. The logs show around 620 ft. lbs as the torque limitation and I was hitting 605 ft. lbs. on some runs. I will keep testing and maybe some fine adjustments from time to time.
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GT3FZS (06-10-2020)
06-09-2020, 12:19 PM
#429
06-09-2020, 01:15 PM
#430
If you're not breaking stuff, you're not making enough power. Modified Nissan GTRs are rolling around with 2500+hp now. There was a LOT of breaking parts. Buddy of mine has a 1500whp Viper. The stock block actually held that power through dyno tuning and dozen or so 1/2 mile runs before he snapped the crank.
06-09-2020, 01:23 PM
#431
06-09-2020, 02:40 PM
#432
@PTS-BRG man that sucks, Im very interested on the APR tune i'm actually ready to pull the trigger on the E85 file however everywhere i've looked all they post is Dyno Numbers. I love their results but let's be honest Dyno numbers don't tell the full story.
I'm almost tempted to just buy it and test it post my results call it a day Ill loose 1600 bucks if the 60-130 inst 6.999 but it is what it is.
I'm almost tempted to just buy it and test it post my results call it a day Ill loose 1600 bucks if the 60-130 inst 6.999 but it is what it is.
06-09-2020, 03:11 PM
#433
Three Wheelin'
Until someone can dyno test a GTS and compare the numbers from APR to Cobb, we wont know who's tune provides better performance.
We also need some real world testing and Dragy numbers to know if the shift flutter persists with the APR tune.
We already know that by dialing back the power the 3-4th shift issue disappears, so to say APR has no shift issues isnt really the point because if they did what Cobb did and neutered the tune to eliminate the stutter, then we are no better off with APR than we are with Cobb.
I think we have seen the limitations of what the GTS can do with bolt on modifications. Its possible to get 0-60 in 3 seconds and a 1/4 Mile trap speed of 130mph.
The tune is limited by what we have, not by the tuners who all seem to do a good job. We need to find the table or "trick" to eliminate the shift issue and we will all be pretty much maxed out performance wise until we decide to go with bigger turbos, injectors, etc..
We also need some real world testing and Dragy numbers to know if the shift flutter persists with the APR tune.
We already know that by dialing back the power the 3-4th shift issue disappears, so to say APR has no shift issues isnt really the point because if they did what Cobb did and neutered the tune to eliminate the stutter, then we are no better off with APR than we are with Cobb.
I think we have seen the limitations of what the GTS can do with bolt on modifications. Its possible to get 0-60 in 3 seconds and a 1/4 Mile trap speed of 130mph.
The tune is limited by what we have, not by the tuners who all seem to do a good job. We need to find the table or "trick" to eliminate the shift issue and we will all be pretty much maxed out performance wise until we decide to go with bigger turbos, injectors, etc..
06-09-2020, 03:39 PM
#434
Until someone can dyno test a GTS and compare the numbers from APR to Cobb, we wont know who's tune provides better performance.
We also need some real world testing and Dragy numbers to know if the shift flutter persists with the APR tune.
We already know that by dialing back the power the 3-4th shift issue disappears, so to say APR has no shift issues isnt really the point because if they did what Cobb did and neutered the tune to eliminate the stutter, then we are no better off with APR than we are with Cobb.
I think we have seen the limitations of what the GTS can do with bolt on modifications. Its possible to get 0-60 in 3 seconds and a 1/4 Mile trap speed of 130mph.
The tune is limited by what we have, not by the tuners who all seem to do a good job. We need to find the table or "trick" to eliminate the shift issue and we will all be pretty much maxed out performance wise until we decide to go with bigger turbos, injectors, etc..
We also need some real world testing and Dragy numbers to know if the shift flutter persists with the APR tune.
We already know that by dialing back the power the 3-4th shift issue disappears, so to say APR has no shift issues isnt really the point because if they did what Cobb did and neutered the tune to eliminate the stutter, then we are no better off with APR than we are with Cobb.
I think we have seen the limitations of what the GTS can do with bolt on modifications. Its possible to get 0-60 in 3 seconds and a 1/4 Mile trap speed of 130mph.
The tune is limited by what we have, not by the tuners who all seem to do a good job. We need to find the table or "trick" to eliminate the shift issue and we will all be pretty much maxed out performance wise until we decide to go with bigger turbos, injectors, etc..
I get what you are saying, based on the base tunes that are out there, their tune is more in line with the old cobb stage 2 tunes that made crazy power and the draggy results are showing incredible times. With that said, I think they advertise ~615 rwhp and around 578 rwtq. which is around the 600 at the crank, very similar values you are getting on some of your pulls so its hard to say for sure if they are limiting torque for that same reason. Thus why I said, give them a shout and tell them what you are looking to do and be ready to get it loaded, go drive to give it some miles to settle and then book some time to slap on a dyno, and do your own draggy results. If the issue is still there, return it and load the cobb file back on, get a refund.
06-09-2020, 03:43 PM
#435
Three Wheelin'
You make it sound so easy...
Got to find an APR dealer and drive the car to them to load MAP.
Then drive it and Dragy test it to see real world performance.
Then, if its no better than Cobb or worse, go back to APR Dealer to remove it.
No idea how the Cobb tune and unlock would work with the APR tune and unlock and if overwriting the Cobb Tune with APR would trigger some security issue or require something from Cobb to get it flashed back.
I've been the guinea pig for a lot of stuff on Rennlist, I wont be the guinea pig for this one..
Got to find an APR dealer and drive the car to them to load MAP.
Then drive it and Dragy test it to see real world performance.
Then, if its no better than Cobb or worse, go back to APR Dealer to remove it.
No idea how the Cobb tune and unlock would work with the APR tune and unlock and if overwriting the Cobb Tune with APR would trigger some security issue or require something from Cobb to get it flashed back.
I've been the guinea pig for a lot of stuff on Rennlist, I wont be the guinea pig for this one..