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School me on MAF less

Old 03-28-2017, 11:05 PM
  #31  
wross996tt
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this thread is going no where...pissing contest. to the OP, MAFless tune is well without a MAF...doh. So instead of using the MAF to get an estimate of the air intake, something else is used...I don't know what. It has been used by a number (no idea how many) of folks who (from the small sampling) appear to be happy. Dock's point is you can get great power from the system with a MAF. Agreed. So what do you want? There are lots of ways to mod these cars....
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Old 03-28-2017, 11:25 PM
  #32  
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I wouldn't go back to a tune using a MAF. Too much power left behind pulling through that $hit MAF.

Talk to Sam, he'll hook you up
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Old 03-29-2017, 12:05 AM
  #33  
"02996ttx50
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wross...agree, but the whole question and point of the thread(?) was questioning the potential for or even perceived/real benefit of running MAF LESS. so even discussing maf's and tunes that employ them - whether oem or hitachi hammer time tunes - is superfluous.

oy.
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Old 04-02-2017, 10:26 PM
  #34  
JasonAndreas
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How does the MAFless tune deal with the loss in volumetric efficiency as the engine ages/mileage increases?
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Old 04-04-2017, 10:31 AM
  #35  
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Originally Posted by "02996ttx50 View Post
now i understand. i needed pictures. well, you should've been given a key chain with the tune. apologies to the op, the thread, and all.
"Der Hammer" not only means "the hammer" in German, it is used as an expression meaning ultimate or king-of-the-hill or similar. Different cultures come up with strange terms for this: Brits speak of dog's testes and people today like to say something is ill. I think the term entered American car culture here:
http://www.caranddriver.com/reviews/...ed-test-review

Originally Posted by BauerR View Post
I wouldn't go back to a tune using a MAF. Too much power left behind pulling through that $hit MAF.
Talk to Sam, he'll hook you up
Glad you're happy, but simply assuming MAFless is for everyone because of your experience is silly. There's a million roads that lead to Rome and each has advantages and disadvantages. And the MAF itself is not the issue, it's the tubing (as I'm sure you meant to say). There are ways of getting around that: Pete95zhn is running a 997tt airbox with 1 MAF and doubling the values. I will likely either go that route or, possibly MAFless at some point as well.


Sorry to the OP for the continued hijack. To continue your schooling:
https://en.wikipedia.org/wiki/MAFless_Tuning
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Old 04-04-2017, 11:24 AM
  #36  
"02996ttx50
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Originally Posted by SteveMFr View Post
Brits speak of dog's testes and people today like to say something is ill.
calling a tune, some spark plugs, and an air filter "the hammer"? epitomizes "the dog's bollocks".. but still, you've provided finally a nomenclature that i understand! thanks for that.

i was just takin the **** out of ****. still i suspect that a "stage 2" setup offering such modest gains as has been offered, would be called something a bit less *zealous* than the "hammer". but i guess it had to be called something? ( or did it lol ) again.. thx.
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Old 04-04-2017, 11:53 AM
  #37  
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Originally Posted by SteveMFr View Post


Glad you're happy, but simply assuming MAFless is for everyone because of your experience is silly. There's a million roads that lead to Rome and each has advantages and disadvantages. And the MAF itself is not the issue, it's the tubing (as I'm sure you meant to say). There are ways of getting around that: Pete95zhn is running a 997tt airbox with 1 MAF and doubling the values. I will likely either go that route or, possibly MAFless at some point as well.


Sorry to the OP for the continued hijack. To continue your schooling:
https://en.wikipedia.org/wiki/MAFless_Tuning
What part of my post did you read "MAFless is for everyone?" The TS created a thread soliciting feedback from MAFless owners. Which is what I did...gave feedback from MY experience.
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Old 04-04-2017, 05:25 PM
  #38  
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In that case: sorry!
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Old 04-04-2017, 06:02 PM
  #39  
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Originally Posted by EVOMS View Post
There are two schools of thought for this--

The stock Bosch MAF can only see something like 600hp worth of air flow, and the 996TT intake tract is quite long and convoluted. The stock MAF is also a common failure item. Many people feel the solution to this is to go MAF-less, relying on the factory ECU's fallback speed density/Alpha N system (boost pressure x throttle plate angle) to measure load. This system works by saying that at a given air pressure and temperature ahead of the throttle body, X% throttle plate angle SHOULD results in Y air mass should be drawn into an engine based on a calculation of air density (pressure x temperature), a mapped table of pressure differential across throttle body vs. throttle angle, and a mapped table of engine volumetric efficiency.

The reality is that this measuring system is not terribly accurate on this car, as unlike the 997.2 and 991 that come stock running speed density, there is no MAP sensor inside the intake manifold itself so there are a lot of assumptions/calculations made to come up with an air flow figure. This means that fueling and ignition timing is never totally on point, so especially at low load, partial throttle, and under transients the car tends to run richer/leaner than ideal, which reduces power and sharpness of engine response. Most of these cars run ok at full load where all the tuning is done, but the engine management can't really keep up outside of that.

There are other compromises you make when pursuing a MAFless system. There are a bunch of cars running around with 'MAFless' tunes with the stock airbox/inlet system in place. I assume the MAFless tune is done in these circumstances to deal with the limitations of the stock MAF, and you keep an intake tract that functions like stock otherwise--air drawn from the top of the car, no dirt/water ingestion issues, etc. With upgraded inlet ducts, these systems work well up to 800hp or so, but you have the driveability issues outlined above.

However, there are other cars that have the intakes off of the turbos, being drawn through the fender liners or intercooler ducts. This is tricky to do, as you end up sticking the filter some place where it is exposed to dirt or water off of the rear tires, or it takes valuable air flow away from the intercoolers. We've done cars like this before, mostly when we make more than 900hp or so and you don't have any other options to flow that much air. For a street car making 600-700hp, it isn't necessary and you compromise the usability of the car by doing it that way.

We went another direction. The MAF is fantastic because it gives you a direct measurement of airflow under any circumstance. If your MAF sensor and housing are properly calibrated, it is a very accurate and precise way of measuring air flow going into the engine, which makes it very straightforward to do calculate how much fuel needs to be delivered, and how much load the engine is under for calculating ignition timing, torque production, etc.

To get around the limitations of the stock Bosch MAF, we developed a conversion kit for our V-Flow intake to use a Hitachi MAF sensor and a software calibration to work with the new sensor. This sensor is much more robust than the Bosch sensor, and is capable of seeing very high air flow levels. With our V-Flow intake and high flow turbo inlet ducts (https://www.evoms.com/Porsche_Turbo_...kfaid996tt.htm) we build an intake tract that supports over 800hp, and does so with EXCELLENT driveability and consistency. It lets us do things like this, making 660wtq by 3500rpm and a peak of over 700wtq on a GT700 with a built motor. With a fuel pump upgrade, this car does just over 700whp now on the same induction system.



Another benefit is that keeping the MAF sensor in place allows us to maintain almost all of the factory diagnostics, so the car will self diagnose itself should it develop an air leak. Almost every single time we get a >Stage 2 996TT in here that is converted over to our software from other brand, the car starts throwing faults that can be traced back to minor air leaks/mechanical faults that were undiagnosed on the previous tune.

Sam
Thanks Sam. This post is the dog's bollocks of MAFless info
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Old 04-04-2017, 06:15 PM
  #40  
Dock
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Originally Posted by "02996ttx50 View Post
calling a tune, some spark plugs, and an air filter "the hammer"?
The Stage II Hammer tuning makes more power than the regular Stage II tuning. It did not require different plugs or a different MAF. Additionally, it did not consist of just a different air filter, it is a different air filter and air box.
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Old 04-04-2017, 10:21 PM
  #41  
"02996ttx50
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I'm sure it's terrific dock..
I was amused at the mention of its being called a "hammer tune" and I'm sure that much was painfully obvious.

I've sobered up considerably since then, and am less amused now. Thanks for your understanding. I still think it's the dog bollocks though, lol but what's in a "name"!?
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Old 05-31-2017, 11:44 AM
  #42  
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Originally Posted by RDS928S View Post
Its all about the tune & quicker spool time/flow to & from the turbos.
Mafless systems support 600+ HP & much more.

Mafless incorporates larger y-pipe, eliminates factory air box & turbo air supply plenum. Most use fender well intakes.
All this piping (ductwork to turbos) and filters, where did you source and did you also run the waterproof prescreen on the filters?
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Old 05-31-2017, 04:51 PM
  #43  
Jones R
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Originally Posted by SteveMFr View Post
There are ways of getting around that: Pete95zhn is running a 997tt airbox with 1 MAF and doubling the values. I will likely either go that route or, possibly MAFless at some point as well.

https://en.wikipedia.org/wiki/MAFless_Tuning
Can you elaborate on "doubling the values"? I get the concept and actually had the same idea a while back, but how was this executed? Op-Amp?
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Old 06-05-2017, 12:37 AM
  #44  
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Old 06-10-2017, 08:10 PM
  #45  
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I finished my mafless setup today and the car runs perfectly fine on a MAF tune, but it throws ABS/PSM errors as expected. The difference in sound is quite different, however. I only went to 0.6 BAR, but the billet K16s are singing by then. Unfortunately I didn't have enough gas in the tank, nor did I have the rear bumper on, but I can't wait to make a full pull to see if the mafless setup made a noticible difference in power.
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