I was just wondering why my 997tt uses an MAF (as do a lot of OEM manufacturers) and yet something as budget as a Honda Fit runs speed density.


I was under the impression that speed density setups were superior to MAF based systems. Given all the headaches and extra maintenance an MAF introduces into a system....I would imagine the Honda way would of been more commonplace.


Do Porsche race engines still use MAF based fuel injection?

Porsche moved away from using MAF sensors on the 997.2. Airflow is entirely modeled and not true coming off a sensor. They only use TMAP sensors. 997.1 and earlier are MAF based but you can tune with speed density instead.

Does it cost extra to switch over to speed density when going with a Cobb AP pro tune?

We wouldn't charge but its best to let your tuner know that you'd like to do a MAF-less tune ahead of time. Having said that on a 997 the stock airbox is a great design so getting rid of them isn't necessary and you're actually better off having them for true airflow readings. We still happily run them with our A3076s

996tt used both maf and map...I cant recall for 997.1tt but I suppose it did so as well...

You're right

the dual setup is usually using the map sensor for boost control....the ecu/dme is still using MAF for fuel injection purposes. That is why leaks in system cause so many issues. In MAF setup the air was already recorded as having come into the system...so when it leaks out before combustion its just bad.

Interesting to know...
So my car and other protomotive tuned cars which run with fenderwell intakes operate with a gimped boost control? So if I were to switch to cobb tuning for any reason, boost control would still be very limited?

Subscribed. I'm running a MAFless Proto tune.

Agreed. Great explanation Tony.

I think its really just the typical mods on the 996 intake and MAF limitations that should be blamed for people carrying it over to the 997. Many people end up blindly following the same path they do with a 996 and apply it to the 997s without considering what was already taken care of for them at the factory (i.e. far improved intake, twin fuel pumps, dual MAFs on the 997). Blame it on the "more mods = more power" mentality its unfortunate to say the least. Certain hardware vendors are also to blame for polluting the 997 market with either simply inferior or unnecessary modifications compared to OEM as well furthering muddying it up

Has anyone looked at larger Bosch MAF sensors? I know this is quite common for other cars.

Even if new pipe work has to be modified. It's pretty straightforward.

After speaking with Tony@EPL for a bit yesterday, I plugged my MAFs back in.


Thanks for the help!

Tony....thank you for enlightening the community!!!!