Change your map sensor and rescale

 

Change my map sensor to what? Didn't think there was anything available. Have you done this already? Details if so

 

I haven't done it personally, but Cobb has a 3.5bar maf they use on the 997.1 and in the 996 Cobb tuning software there is the settings to scale to a different map sensor. So it can definately be done.

Note that this would adjust what you can see/log from a boost perspective. It won't update the dash

 

I'm curious about the MAF also. My tune/setup is beyond the metering capabilities of the stock MAF. So my tuner has encouraged me to run MAFless. What do I lose without running a MAF. Or put it another way, what would I gain by running a MAF that has more headroom?

 

OEM "MAF" sensor maxes out early and tuning without is preferable unless you swap in an aftermarket larger unit which requires corresponding scaling changes in a number of tables in the tune.

OEM 'MAP' sensor is a 2.5bar (absolute) and a scaling table exists for that as well to use larger MAP sensors such as a 3bar that we use very often on the 997.1 and 997.2 Turbos.

Dzenno@PTF

 

I'm running MAF-less... which makes life a little easier in terms of piping. Most of the big HP guys are mafless. I'm not sure how it makes the tuners feel, but my car drives smooth, yet makes great power so not sure what i'm really missing with a MAF. I had a previous tuner tell me Mafless would make my drivability awful...yet the only awful drivability I had was with his tune and a maf lol.

 

I'm running a Cobb maf-less tune now. I agree, driveability is just fine, BUT you can't have any leaks. My car was fairly well sealed up, but initially driveability was crappy. Then I spent some real time making sure it was perfect and finding and fixing even the tiniest of boost leaks. Now - no problems.

 

^ That's a great point point about MAFless tunes. Though I'm unsure how the tune would be off in that case, other than general loss of power? Since the mapping only cares about absolute boost pressure in manifold.

Correct me if I'm wrong, but where the MAF benefit is lost is in fine fueling control for barometric changes in my mind. But these will auto correct eventually with closed loop fueling?

Just wonder what other failsafes might be lost with the MAF not in place?

 

RE Holder: There are COBB specific glass mount holders on Amazon and they arent expensive at all. I think around $15 so we get to avoid the P-Car tax there.

What is everyone running as far as the gauges on their unit? Now that mine will be glass mounted, I can actually see it while driving.

 

Awesome guys! It's been a pleasure working with all of you! Most I should say

 

manifold pressure, engine temp, intake air temp, lambda, short term fuel correction... occasionally switch it up to a few others but that's typical for me.

 

Umm barometric pressure is handled just fine with a MAP sensor - it's designed to measure pressure. IAT handles temp, together you can infer airflow if you have VE which is really what the injector table becomes.

 

Im interested in buying a Cobb unit, My tuner is also very comfortable with it as he says. In regards to maff-less tunes. Im very interested in this, I here a lot of conflicting info. I will be running the k24/71mm srm turbos with supporting mods, Just no rods this year. What interests me most is the simplified pipe work, Not sure if that is enough of a reason to go maff-less though.

 

It's enough reason to go with it, if you measured the pressure drop from the stock piping you'd be shocked, especially with higher flowing turbo!

 

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.