3.2 ( and also 3.6 ) MAF Conversion

[PorscheRally]

Dear Friends,
What are your experiences with the MAF conversions for the stock 3.2 and 3.6 motors and also street mod motors ?
In one of the related threads people were highly recommending S-CAR’s MAF conversion and fuel system components however I could not locate Sal’s website.
Thank you

[Steve W]

Extensive A > B > A > B > A > B dyno testing I did years ago between the factory air flow meter vs a MAF sensor shows no HP/torque difference throughout the full rpm range, not even 2 hp at full throttle at 7000 rpm. The factory air flow meter was one that used an aftermarket cone air filter setup such as from MSDSInc, as it is the factory airbox filter cover, and not the meter, that has a slight flow restriction. The MAF was a one that used a Bosch HFM5 sensor through a carbon fiber velocity stack with a 90mm diameter entry with reverse lip, down to the 70mm diameter of the rubber throttle body boot. The Motronic ECU programming was equalized and optimized for each setup for the test comparisons, both using the same ignition timing, and the air fuel ratios were mapped and optimized to precisely 13.0:1 through the rpm range, so that chip tuning was not responsible for any deviation comparisons. From just chip tuning alone you can gain 18-20 hp on a 3.2 or 964, and opening the airbox cover or using a good cone air filter setup nets another 4 hp, you gain 22-24 hp just from that, so if MAF kit claims a 22-24 hp gain, (like Autothority back in the day), the gain comes from the chip retuning that comes with the kit. Because there are no power gains just from a MAF sensor, that is why you will never find any legit before and after dyno charts online from anyone either on a 3.2 or 964 showing a true before and after comparing the stock meter setup to a MAF kit. Any gains come from optimizing chip tuning.

I vaguely remember a valiant effort many years ago done by a UK 3.2 owner trying to put together a MAF replacement for his car. It was an extensive post in the UK Porsche forums that went on like 30 pages for for weeks with hundreds of posts, with a bunch of interested 3.2 owners interested in the setup, kit and results. The car was dyno'd before I believe with one of my standard chips. After the MAF was all set up and running and retested on the dyno, which show no hp gains, if anything probably lost like 2 hp, that thread died overnight.

The 964 3.6 uses the same air flow sensor as the 3.2, and almost every month I am contacted by someone, either owner or a shop regarding helping them to fix the headache of extensive running, stalling, and drivability problems with an FVD or Cargraphic MAF on a 964 - the sensor on those kits I believe is adapted from the 993. Due to the frequency of complaints over the years, I can only conclude the programming is poorly developed. And if it won't work well for a factory 3.6, it does not get any better when the motor is modified with cams, or into a 3.8, as FVD/Cargraphic tell the buyer they are unable to accommodate custom programming for anything other than standard. Well I can't fix their MAF programming as chips for the factory air flow meter setup are incompatible with any MAF sensor, and those require an extensive development effort that need to be done for each company's particular sensor, and that I cannot do. After they reinstall the original factory meter, and I provide them the proper corresponding chip programming for their engine build, do all the problems go away, and the car makes more power, punch, response, and has perfect drivability throughout the rpm range.

On my personal cars I can run any setup, including a variety of MAF sensor kits setups I have here, but can you guess what I use on my personal cars? So my suggestion is don't waste your money on that and direct it to somewhere else that actually makes a difference.

[PorscheRally]

Originally Posted by Steve W

Extensive A > B > A > B > A > B dyno testing I did years ago between the factory air flow meter vs a MAF sensor shows no HP/torque difference throughout the full rpm range, not even 2 hp at full throttle at 7000 rpm. The factory air flow meter was one that used an aftermarket cone air filter setup such as from MSDSInc, as it is the factory airbox filter cover, and not the meter, that has a slight flow restriction. The MAF was a one that used a Bosch HFM5 sensor through a carbon fiber velocity stack with a 90mm diameter entry with reverse lip, down to the 70mm diameter of the rubber throttle body boot. The Motronic ECU programming was equalized and optimized for each setup for the test comparisons, both using the same ignition timing, and the air fuel ratios were mapped and optimized to precisely 13.0:1 through the rpm range, so that chip tuning was not responsible for any deviation comparisons. From just chip tuning alone you can gain 18-20 hp on a 3.2 or 964, and opening the airbox cover or using a good cone air filter setup nets another 4 hp, you gain 22-24 hp just from that, so if MAF kit claims a 22-24 hp gain, (like Autothority back in the day), the gain comes from the chip retuning that comes with the kit. Because there are no power gains just from a MAF sensor, that is why you will never find any legit before and after dyno charts online from anyone either on a 3.2 or 964 showing a true before and after comparing the stock meter setup to a MAF kit. Any gains come from optimizing chip tuning.

I vaguely remember a valiant effort many years ago done by a UK 3.2 owner trying to put together a MAF replacement for his car. It was an extensive post in the UK Porsche forums that went on like 30 pages for for weeks with hundreds of posts, with a bunch of interested 3.2 owners interested in the setup, kit and results. The car was dyno'd before I believe with one of my standard chips. After the MAF was all set up and running and retested on the dyno, which show no hp gains, if anything probably lost like 2 hp, that thread died overnight.

The 964 3.6 uses the same air flow sensor as the 3.2, and almost every month I am contacted by someone, either owner or a shop regarding helping them to fix the headache of extensive running, stalling, and drivability problems with an FVD or Cargraphic MAF on a 964 - the sensor on those kits I believe is adapted from the 993. Due to the frequency of complaints over the years, I can only conclude the programming is poorly developed. And if it won't work well for a factory 3.6, it does not get any better when the motor is modified with cams, or into a 3.8, as FVD/Cargraphic tell the buyer they are unable to accommodate custom programming for anything other than standard. Well I can't fix their MAF programming as chips for the factory air flow meter setup are incompatible with any MAF sensor, and those require an extensive development effort that need to be done for each company's particular sensor, and that I cannot do. After they reinstall the original factory meter, and I provide them the proper corresponding chip programming for their engine build, do all the problems go away, and the car makes more power, punch, response, and has perfect drivability throughout the rpm range.

On my personal cars I can run any setup, including a variety of MAF sensor kits setups I have here, but can you guess what I use on my personal cars? So my suggestion is don't waste your money on that and direct it to somewhere else that actually makes a difference.

Hi Steve,
Many thanks for all the information. Fully understand.
I have 2 x 1986 3.2 Carrera ( Euro spec ). One of them is under a restoration and the other one is a kind of a pleasure driver with a SSI and 2 central exit system. Other than that it is a stock motor. Although it is not a fresh engine ( approx. 120k miles ) I would like to renew most of the fueling components on that engine such as the injectors, AFM etc. Therefore, while at it I would like to buy a performance chip from you. So, I will be contacting you thru your web page accordingly.

Kind regards,
Kerem

[nospiners]

You will be very well advised to contact scarceller here on this forum , tremendous wealth of information and an invaluable source for 3.2 engines,a great guy too..

[Michael.]

Maybe a silly question but doesn't the AFM have a door inside the housing? Isn't there a throttle response benefit with a MAF?

[mepstein]

Originally Posted by Michael.

Maybe a silly question but doesn't the AFM have a door inside the housing? Isn't there a throttle response benefit with a MAF?

Yes. We did one in a 964 engine. Made the car a lot more fun. Even if the hp was the same, it was worth it.