Anyone pick up the Cobb Accessport for their 996TT?
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Joined: Jan 2012
Posts: 710
From: South FLA
Rep Power: 208
Not sure on the boost level for the 91 map but you should definitely do a leak lest as soon as you can. 
Recently purchased an Accessport for my 2001 996 and installed the stage 1 91 octane OTS map and immediately had some stumbling or stuttering under any heavy throttle. Swapped in some fresh spark plugs which I think were still the originals and that seems to have cleared up the problem. I did find when I had things apart for the plug change the driver side inlet hose wasn't completely locked into the retaining clip and based the greasy buildup at that connection it had been that way since prior to me buying the car.
Prior to the reflash I was typically seeing .6 bar in the dash with occasionally hitting .7 bar. Now I typically see .7 bar with occasionally hitting .8 bar. I'm assuming both the stage1 91 octane and 93 octane maps are 1.0 bar and the 91 is just a safer tune.
Can anyone confirm this is the case and not that the 91 octane is lower boost?
So if the map is indeed 1.0 bar, I'm wondering if maybe either the display in the dash might be inaccurate and I need to actually log with the Accessport to see the accurate boost numbers, or I have a boost leak, or if by chance there might be an issue with one of the turbo's or wastegates. The intercooler hose that was loose on the drivers did seem a bit oily inside.
I believe the diverter valves were replaced with the uprated version of the stock valves a couple years back. My plan was to do some logging next to see if that reads different from what I'm seeing displayed on the dash reading. If that wasn't different find some 93 octane and try the stage1 93 octane map. I also haven't done any sort of boost leak test yet so that's also on the list.
Prior to the reflash I was typically seeing .6 bar in the dash with occasionally hitting .7 bar. Now I typically see .7 bar with occasionally hitting .8 bar. I'm assuming both the stage1 91 octane and 93 octane maps are 1.0 bar and the 91 is just a safer tune.
Can anyone confirm this is the case and not that the 91 octane is lower boost?
So if the map is indeed 1.0 bar, I'm wondering if maybe either the display in the dash might be inaccurate and I need to actually log with the Accessport to see the accurate boost numbers, or I have a boost leak, or if by chance there might be an issue with one of the turbo's or wastegates. The intercooler hose that was loose on the drivers did seem a bit oily inside.
I believe the diverter valves were replaced with the uprated version of the stock valves a couple years back. My plan was to do some logging next to see if that reads different from what I'm seeing displayed on the dash reading. If that wasn't different find some 93 octane and try the stage1 93 octane map. I also haven't done any sort of boost leak test yet so that's also on the list.
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Joined: Mar 2014
Posts: 55
From: Minneapolis
Rep Power: 25
Is this a suggested method? I saw mention of pulling the airfilter housing and maf, but this looks simpler to pull the inlet hose at the turbo compressor. Seems the most logical as the boost starts on the other side.
https://www.6speedonline.com/forums/...ig-w-pics.html
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Joined: Feb 2011
Posts: 1,120
From: Austin
Rep Power: 183
Alright, boost test asap it is!
Is this a suggested method? I saw mention of pulling the airfilter housing and maf, but this looks simpler to pull the inlet hose at the turbo compressor. Seems the most logical as the boost starts on the other side.
https://www.6speedonline.com/forums/...ig-w-pics.html
Is this a suggested method? I saw mention of pulling the airfilter housing and maf, but this looks simpler to pull the inlet hose at the turbo compressor. Seems the most logical as the boost starts on the other side.
https://www.6speedonline.com/forums/...ig-w-pics.html
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Joined: Mar 2014
Posts: 55
From: Minneapolis
Rep Power: 25
Ok, I'll look at testing using the outlet hose then. Is the idea being to avoid potentially pressurizing the oiling system?
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Joined: Apr 2014
Posts: 408
From: cincinnati
Rep Power: 54
I'll wait for markski to jump in here, but boost leak test is huge on these cars. There's a ton of lines that can rip or come off (especially by the plenum behind the throttle body) which can throw off a lot of things.
I also wouldn't trust the gauge in the dash, what is the accessport saying it's hitting as far as manifold pressure?
In terms of stuttering, coils and plugs should really be the first mod for these cars, mine failed almost immediately once I started modding.
Mitch can probably tell you what the OTS tunes are supposed to hit but I bet they are over 1 bar and you have a boost leak somewhere. Make or buy a kit and test first before moving to the next step.
I also wouldn't trust the gauge in the dash, what is the accessport saying it's hitting as far as manifold pressure?
In terms of stuttering, coils and plugs should really be the first mod for these cars, mine failed almost immediately once I started modding.
Mitch can probably tell you what the OTS tunes are supposed to hit but I bet they are over 1 bar and you have a boost leak somewhere. Make or buy a kit and test first before moving to the next step.
Recently purchased an Accessport for my 2001 996 and installed the stage 1 91 octane OTS map and immediately had some stumbling or stuttering under any heavy throttle. Swapped in some fresh spark plugs which I think were still the originals and that seems to have cleared up the problem. I did find when I had things apart for the plug change the driver side inlet hose wasn't completely locked into the retaining clip and based the greasy buildup at that connection it had been that way since prior to me buying the car.
Prior to the reflash I was typically seeing .6 bar in the dash with occasionally hitting .7 bar. Now I typically see .7 bar with occasionally hitting .8 bar. I'm assuming both the stage1 91 octane and 93 octane maps are 1.0 bar and the 91 is just a safer tune.
Can anyone confirm this is the case and not that the 91 octane is lower boost?
So if the map is indeed 1.0 bar, I'm wondering if maybe either the display in the dash might be inaccurate and I need to actually log with the Accessport to see the accurate boost numbers, or I have a boost leak, or if by chance there might be an issue with one of the turbo's or wastegates. The intercooler hose that was loose on the drivers did seem a bit oily inside.
I believe the diverter valves were replaced with the uprated version of the stock valves a couple years back. My plan was to do some logging next to see if that reads different from what I'm seeing displayed on the dash reading. If that wasn't different find some 93 octane and try the stage1 93 octane map. I also haven't done any sort of boost leak test yet so that's also on the list.
Prior to the reflash I was typically seeing .6 bar in the dash with occasionally hitting .7 bar. Now I typically see .7 bar with occasionally hitting .8 bar. I'm assuming both the stage1 91 octane and 93 octane maps are 1.0 bar and the 91 is just a safer tune.
Can anyone confirm this is the case and not that the 91 octane is lower boost?
So if the map is indeed 1.0 bar, I'm wondering if maybe either the display in the dash might be inaccurate and I need to actually log with the Accessport to see the accurate boost numbers, or I have a boost leak, or if by chance there might be an issue with one of the turbo's or wastegates. The intercooler hose that was loose on the drivers did seem a bit oily inside.
I believe the diverter valves were replaced with the uprated version of the stock valves a couple years back. My plan was to do some logging next to see if that reads different from what I'm seeing displayed on the dash reading. If that wasn't different find some 93 octane and try the stage1 93 octane map. I also haven't done any sort of boost leak test yet so that's also on the list.
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Joined: Feb 2011
Posts: 1,120
From: Austin
Rep Power: 183
Logging is very easy then you will know exactly what the tune is targeting.
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Joined: Mar 2014
Posts: 55
From: Minneapolis
Rep Power: 25
With the immediate stuttering I stopped getting on the throttle right away and didn't get it logged. Fresh plugs did indeed fix the stutter but was a short drive and didn't have the accessport hooked up to log. I'll start with the boost test and if I don't find anything then next step will be to get a couple logs with the manifold pressure and see if that is actually showing different then the dash.
I'll report back on the boost test results. Thanks for all the responses!
I'll report back on the boost test results. Thanks for all the responses!
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Joined: Sep 2011
Posts: 1,266
From: Colorado
Rep Power: 94
Has anyone picked up the Access Tuner Race for the COBB in order to DIY tune? It says in their site, that it's the same software that Pro users use, except for no locking of maps and can be shared.
Registered User
Joined: Mar 2014
Posts: 55
From: Minneapolis
Rep Power: 25
I hooked the accessport back up and did two logs in 2nd gear which confirm the manifold pressure is showing lower than the dash at around 5-6psi max vs .7-.8bar.
The same logs are also showing lean afr's and knocksums during boost, so the car isn't coming back off the lift until I find something. I'm hoping the afr's are related to check valves and the fpr. I've pulled one of the turbo to IC hose's off the car to make it easier to put together a boost leak tester, and currently looking at MARKSKI's thread on "Boost Leaks- how to find them...."
The same logs are also showing lean afr's and knocksums during boost, so the car isn't coming back off the lift until I find something. I'm hoping the afr's are related to check valves and the fpr. I've pulled one of the turbo to IC hose's off the car to make it easier to put together a boost leak tester, and currently looking at MARKSKI's thread on "Boost Leaks- how to find them...."
I'll wait for markski to jump in here, but boost leak test is huge on these cars. There's a ton of lines that can rip or come off (especially by the plenum behind the throttle body) which can throw off a lot of things.
I also wouldn't trust the gauge in the dash, what is the accessport saying it's hitting as far as manifold pressure?
In terms of stuttering, coils and plugs should really be the first mod for these cars, mine failed almost immediately once I started modding.
Mitch can probably tell you what the OTS tunes are supposed to hit but I bet they are over 1 bar and you have a boost leak somewhere. Make or buy a kit and test first before moving to the next step.
I also wouldn't trust the gauge in the dash, what is the accessport saying it's hitting as far as manifold pressure?
In terms of stuttering, coils and plugs should really be the first mod for these cars, mine failed almost immediately once I started modding.
Mitch can probably tell you what the OTS tunes are supposed to hit but I bet they are over 1 bar and you have a boost leak somewhere. Make or buy a kit and test first before moving to the next step.
Registered User
Joined: Sep 2014
Posts: 295
From: SD
Rep Power: 70
Just got my car back up in running after a major engine out for preventive maintenance and upgrades.
1000cc Cobb injectors, to go with my A28 turbos. 5 minute flash with new MAFless tune.
Effortless startup and running!
Just shaking her down today, but drive-ability is spot on. Haven't given her to boot yet, but part throttle drive ability is where the magic is, and she feels stock.
Can't give enough kudo's to Sam from ByDesign for his guidance and tuning.
1000cc Cobb injectors, to go with my A28 turbos. 5 minute flash with new MAFless tune.
Effortless startup and running!
Just shaking her down today, but drive-ability is spot on. Haven't given her to boot yet, but part throttle drive ability is where the magic is, and she feels stock.
Can't give enough kudo's to Sam from ByDesign for his guidance and tuning.
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Joined: Jun 2015
Posts: 829
From: Fargo, ND
Rep Power: 76
It is the same software just can only be used with that accessport unlike pro tuner which can be used on any accessport.
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Joined: Jul 2006
Posts: 8,930
From: ga
Rep Power: 552
I just got a Mafless Cobb Tune from the guys themselves. Motor has never been this strong before. Accessport has changed the game for sure. Made 596 wheel torque and so had to dial it back a bit.
