rockitman

Does the motronic DME automatically adjust the amount of fuel feed into the engine when more air is introduced into the intake??? Or is this something that requires a reprogram/mapping in order to make sure the motor does not run too lean because of the increase in air/oxygen???

bob_dallas

As I understand it will adjust some over time. To accelerate this you can disconnect your battery for a while to reset the computer. I can't recall how long but around 30 mins should suffice. Make sure you have the code to reprogram your radio after you reconnect.

Aggressive modifications will probably require reprogramming to achieve full benefits (if there are any).

rockitman

Radio code??? What code is that??? I had disconnected my battery during the roll bar install for over 24 hrs...The radio worked fine when it was reconnected...Confused???

Jack

Don't be confused -- there is no code for the newer digital, fibre-optic Porsche radios starting in '03 on.

bob_dallas

aha - I learn something new everyday...

Steve Weiner-Rennsport Systems

Rockitman:

The MAFS sensor's job is to measure air density and tell the ECU to adjust fuel mixture according to feedback from the oxy sensors.

Within the engine's airflow demands, the MAFS can handle and adjust for changes in the airflow and throttle opening,...

rockitman

Thanks Steve...one more question...If I increase the airflow say with a high flow panel filter or a cold air ram air system..ie GruppeM with the cone filter isolated inside the box, still getting air the same way as the stock from vents in the deck lid, coupled with a free-er flowing exhaust, what kind of performance advantages could I get, if any??? Will I lose low end torque with decreased exhaust back pressure even though I am adding more air through the intake. Just trying to decide is this would be a waste of money and worse yet, decrease performance. The other option is just a panel filter replacement with a BMC. Thanks for your advice....

Steve Weiner-Rennsport Systems

The MAFS is capable of handling an airflow change from different filters and things like that.

If you connect the intake to a forced-airbox of some kind, that will likely make the MAFS throw a code and make the car shut off. If the change in air pressure and density is great enough, this is the usual result,..(we see this in TT's all the time).

The GT-3 airbox and filter is well designed and is no restriction to the airflow demands of these engines. Even the GT-3 Cup cars already have a good intake,......

Only the GT-3RS and GT-3RSR's have a better intake system for the 420+ HP and 9000+ RPM that they turn.

You may add a BMC panel filter that is servicable, but its of no advantage over a clean paper one.

Cupcar#12

I agree with Steve on this one - the Air Box on the GT3 is quite good - Different story on some other models. The DME contains only a set number of fuel maps (i have not looked at the GT3 system programming however) and will dynamically adjust to the air flow (within limits) and your drving style (again with in limits) but once it runs out of options it will throw a code and put the engine in limp home mode - you have to reset it (disconnect the battery for 5-10 minutes, 30-45 minutes to discarge the airbag capacitors if your doing work like that btw). Me i would leave the stock filter in place and just buy new ones at every oil change - cheap and good.
the Grouppe M one looks flash but Ram Air? in the rear? Me not buying it - and there is no way to really verify it on a dyno. the airflow at the rear of the car is pretty turbulant as well and with out access to clean high pressure air i'm not really convinced.
but hey - that's just me. I would reduce the weight in the rear first (well after suspension anyway)
my 2 cents anyway (not a GT-3 owner)

rockitman

Thanks Steve and Rob...that's given me some good insight. Think I may try the BMC in the existing air box coupled with fabspeed maxflo mufflers's for more aggressive sound, lighter weight and free-er flowing exhaust to work with the slight increase in air intake the BMC would provide to the motor. I feel that other than the sound, the throttle response would quicken a bit with that combination....

Cupcar#12

I would give it a try. I used a BMC in my 01 Boxster and liked it - but if your not careful about cleaning it and letting the excess oil drain off - it will throw a check engine code on the car. My solution was to by 2 of them and rotate, but then again i change the air filter with the oil (still do 3000 miles even though they recomend 15K). The fab speed muffler hopefully is better quallity than the B&B, and GHL stuff (i've had both for the boxster and B&B for the complete headers on the cup car, and frankly they were not up to snuff).
is the throttle sluggish? or is it more of a sound thing, the BMC increased my intake noise and that was the main reason i kept using it - sounded better.

MKW

On any car with electronic throttle, ( Porsche's from 2000 on ) , be sure to readapt the throttle position sensor after disconnecting battery or ECU . Turn ignition to ON , but don't start engine, for 60 seconds, then OFF for at least 10 seconds. Then start engine and allow extra idle time before driving off. Vary throttle position and a tip-in force a lot for next hundred miles or so to reset fuel trims.

rockitman

Thanks for that info MKW, I will do that...

Cupcar, it's not real sluggish but I feel there is room for improvement...I put a BMC on my Cayenne and it was a quite noticeable improvement.