"From the numbers presented here, I conclude the MAF is a 30hp bolt on.
That is not easy for me to believe. But the data, thus far, does not allow me
to dismiss it."

Really? And the data have been corrected for the probable "timing push" which
most likely contributes to the majority of the delta?

Most "tuners" have the option of selling a "pushed timing" chip/mod for
about $500 or packaging it with other mods, e.g. MAF, and basically
tripling the sales return.

Bottom line: Where are the data for these mods exclusive of "the package",
so one can truly evaluate each mod's singular effect and thus make a valid
economic decision?

 

I won't dispute the data other than to agree it looks too good to be true. In a couple of recent cases, there is a later admission that the car ran poorly before the conversion. A stock 964 in factory-standard tune runs brilliantly. My theory for the fabulous results is that engine faults are corrected during the MAF conversion. My car runs noticeably better after I adjust the valves, replace the plugs, and change all the filters and fluids. No MAF is required to get those benefits.

The claims are thermodynamically impossible. Raising power by 20% while keeping displacement and compression ratio constant requires 20% more air flow through the engine. Does anyone seriously believe that an MAF can flow 20% more air than an AFM on the same engine? Timing push could not do this, unless the DME was in "limp home" mode proir to the conversion (a strong possibility based on some reports).

I know of two Porsche owners who suffered poor running on an MAF kit, and switched back to factory stock AFM. Both report the car drives much better on the factory equipment.

 

"I know of two Porsche owners who suffered poor running on an MAF kit, and switched back to factory stock AFM. Both report the car drives much better on the factory equipment."

I think those guys had the wrong, MAF setup. The setup from vitesse incl. Piggyback is with fuel control so you max out the best Air / Fuel ratio. The Dyno for me was done at Beekracing in Holland. They took the data from the dyno and adjusted it al during the dyno, feeding the piggyback.

But he if you don't believe me its oke, you have always the don quichotes in the world.

 

Loren,

That would be interesting.
Speaking only from my experience with a modified engine, and though the tuning is incomplete, what has been achieved came from many modifications. Comparing my numbers to those here and elsewhere has been an on-going education.

 

I believe you are happy with the modification and I believe your car runs great. I also believe it is not physically possible to get 20% power increase from MAF alone. This board has been a friendly place. I hope in the future we can keep from calling each other unflattering names when we do not agree with an opinion.

 

Sorry it's not mine intention to name call, i just wanted to say that there are all way's will be skeptics, and non believers.

mine apology if i heard you're feelings.

 

No apology is necessary. Enjoy!

 

Here's an interesting comparison of the performance differences between a stock 964 AFM with airbox & paper filter, same without filter & lid and finally with AFM bypass tube (simulating a MAF) and airbox base only. I did on a low mileage 964RS some while back, the car running Motec which obviously made it possible to run without an AFM for the purposes of the tests. As Noah intimated with his experiences, each change makes a small difference in performance, but add a lot of small differences together and you get a large one.

I did the same test proceedure on the exhaust system (cat/bypass, rear/cup pipe, side/G pipe) and obviously found similar results. The answers are all there if you can be bothered to look for them....

 

Colin:

Very nice, and credible. Air temperature and barometric pressure are documented, and equal for each run.

This tells me I can increase peak power by as much as 10 HP (a 4% increase) simply by running with no air filter. All other factors equal, the MAF and AFM curves actually cross each other several times. Peak power is equal. Of course our track speed depends on the average power across the RPM range. The MAF power averages about 4 HP greater (2%). The same acceleration increase can be achieved by removing 64 lb of weight - about what you get by replacing the stock seats, or by removing the stock passenger seat for a track session. Weight reduction improves acceleration, but also makes you faster in turns, lowers fuel consumption, and improves braking. Power increase improves only acceleration.

Did I miss anything?

 

Paul,

I think have not missed anything.

Colin,

Thanks for the input. I always bother.

 

Some things never change!

A MAF without the software to go with it is useless as it will not work on the 964. Now combine a MAF with the required MAF software, add to it the tuning (the last I checked AFRs did make a difference in engine performance not just ignition timing) now you can compare a before and after.
When "customers" in various countries dyno their own car (before and after) and see a gain; when customers drive their converted car on the track and notice a positive difference, then this is the best proof that a product works. When multiple people get similar results from a product, when the results are repeatable , it tells me that the product is working.

Of course, some individuals that have never tried and never tested the product are the one that shoot it down. Oh well!

 

Loren, don't you think Air Fuel Ratio is important to make power?

I agree with you, "some tuners" do push the timing. A racer was using a "tuner" chip, he was recording a significant knock count. He switched to the MAF kit, gained performance without the knock (even on 91oct fuel).

When BOTH fuel and ignition are addressed properly, and when external variables like temperature etc.. are handled correctly you will make power.

 

John, STOP...it is a losing battle...The Internet wins over logic and experience every time.

 

I would not mind trying it on my car either way. Just can't come up with the cost of admission. Part of my joy of owning a 964 is part driving and part bonding with the car through diy modifications.

 

Thanks for all the answers; I am still trying to get my mind around how well my car runs after I reinstalled the upgraded Steve Wong chip (no affiliation) the word that best describes the engine is "eager" it does not seem to matter what RPM, it just pulls.