New Hot-film Airmass Meter (HFM)gives 535d extra power
05-18-2007, 05:36 AM
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Hi Guys,
I've got a 535d, bought new in june 2005, tuned at http://hs-elektronik.com/. About 320hp en 660nm.
Before the HFM change, GPS-clocked acceleration 0-200 km/h (0-160mph) in 20,5 secs.
After the change (after 75000km or 47000 miles) now it rockets in just 18,2 secs !!!
My advise to all of you is : DON'T wait untill you got check-control messages or other faults before replacing.
Just do it every 75000km!! Mine was for free now due to warrantee, however next one will cost about 300 euros ( $ 400).
Believe me it's worth it. Also improved mileage!
Some other (tecnical) facts:
* it's a Bosch hot-film air mass meter. They just changed the BMW part number from 13.62.7.793.633 to the one I have now : 13.62.7.805.415. It's still Bosch, the plastic holes where you put the bolts in are reinforced now.
* no ECU re-programming or anything else needed. Just plug and play...
* first few hunderd meters it's learning (a bit unsteady rpm). Literally a minute a so later it's good to go...
* be aware also that the automatic gearbox is shifting quicker at high rpm since it's related to HFM signal!!
* last but not least : change the airfilter as well and DO NOT put a sportfilter (K&N) in it, since it's an open airfilter and would damage the HFM almost instantly. And it gives you hardly any more power anyway.
A bit off-topic, but just nice to know: ZF in Germany, the automatic gearbox factory, gives as maximum allowed torque 600 NM for our 26Z gearbox. My tuner convinced me that +10% is fair, so don't go beyond 660NM. And DON'T use a powerbox as a tuning device, because you don't know how much NM it would be then...
Greetz,
Rawpower.
I've got a 535d, bought new in june 2005, tuned at http://hs-elektronik.com/. About 320hp en 660nm.
Before the HFM change, GPS-clocked acceleration 0-200 km/h (0-160mph) in 20,5 secs.
After the change (after 75000km or 47000 miles) now it rockets in just 18,2 secs !!!
My advise to all of you is : DON'T wait untill you got check-control messages or other faults before replacing.
Just do it every 75000km!! Mine was for free now due to warrantee, however next one will cost about 300 euros ( $ 400).
Believe me it's worth it. Also improved mileage!
Some other (tecnical) facts:
* it's a Bosch hot-film air mass meter. They just changed the BMW part number from 13.62.7.793.633 to the one I have now : 13.62.7.805.415. It's still Bosch, the plastic holes where you put the bolts in are reinforced now.
* no ECU re-programming or anything else needed. Just plug and play...
* first few hunderd meters it's learning (a bit unsteady rpm). Literally a minute a so later it's good to go...
* be aware also that the automatic gearbox is shifting quicker at high rpm since it's related to HFM signal!!
* last but not least : change the airfilter as well and DO NOT put a sportfilter (K&N) in it, since it's an open airfilter and would damage the HFM almost instantly. And it gives you hardly any more power anyway.
A bit off-topic, but just nice to know: ZF in Germany, the automatic gearbox factory, gives as maximum allowed torque 600 NM for our 26Z gearbox. My tuner convinced me that +10% is fair, so don't go beyond 660NM. And DON'T use a powerbox as a tuning device, because you don't know how much NM it would be then...
Greetz,
Rawpower.
05-18-2007, 09:15 AM
#2
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Originally Posted by 535d Rawpower' post='425839' date='May 18 2007, 03:36 PM
18,2 secs !!!
ROTFL!
05-18-2007, 10:08 AM
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Originally Posted by Veight' post='425922' date='May 18 2007, 07:24 PM
Zero to 160 MPH?
I need a place to do that!!!
I need a place to do that!!!
0-200 kmh is 0-125 MPH
05-18-2007, 03:09 PM
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My Ride: 520D 2006 - Media Package, M-tec Kit, Lighting package, extended lights, Leather seats, Auto High beam. Carbon Black, with black leather.
Originally Posted by AlexFW' post='425944' date='May 18 2007, 07:08 PM
0-200 kmh is 0-125 MPH
It sounds like you just ask them to replace it?
05-18-2007, 05:54 PM
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Originally Posted by AlexFW' post='425944' date='May 18 2007, 01:08 PM
0-200 kmh is 0-125 MPH
You can laugh about it, but I think for just a 3.0 liter diesel it's not that slow.Ok, my previous Audi RS4 tuned to 510 BHP did it in 14 secs driving from gas station to gas station.
05-18-2007, 06:00 PM
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Originally Posted by biggun' post='426077' date='May 18 2007, 06:09 PM
How did you manage to get an airmass meter, under warranty? Mine is 250mgs out at high rpm's
It sounds like you just ask them to replace it?
It sounds like you just ask them to replace it?
05-19-2007, 10:05 PM
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Sorry to rain on your parade, but I seriously doubt that the Mass Airflow sensor did anything for you. At the -most- the differing part number is allowing a bit more CFM of air to pass through it. Back in the day, we used to rip the screens off of the front and back of the Bosch MAF sensors on our Chevy 5.7L V8s...
Most likely though, it's not even an improvement - more like the computer has been forced to recalculate due to the change, or... the weather is colder, or less humid. Again, denser air charge when cooler. Or, your tires are worn a bit more and you're getting a better launch or you're getting more traction on shifts.
Here's a neat trick - unplug the MAF sensor and start the car. The car still runs. There's a limp mode, the engine computer just uses a fudge factor instead of real data.
Most likely though, it's not even an improvement - more like the computer has been forced to recalculate due to the change, or... the weather is colder, or less humid. Again, denser air charge when cooler. Or, your tires are worn a bit more and you're getting a better launch or you're getting more traction on shifts.
Here's a neat trick - unplug the MAF sensor and start the car. The car still runs. There's a limp mode, the engine computer just uses a fudge factor instead of real data.
05-21-2007, 12:05 AM
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Originally Posted by UUronL' post='426383' date='May 20 2007, 01:05 AM
Sorry to rain on your parade, but I seriously doubt that the Mass Airflow sensor did anything for you. At the -most- the differing part number is allowing a bit more CFM of air to pass through it. Back in the day, we used to rip the screens off of the front and back of the Bosch MAF sensors on our Chevy 5.7L V8s...
Most likely though, it's not even an improvement - more like the computer has been forced to recalculate due to the change, or... the weather is colder, or less humid. Again, denser air charge when cooler. Or, your tires are worn a bit more and you're getting a better launch or you're getting more traction on shifts.
Here's a neat trick - unplug the MAF sensor and start the car. The car still runs. There's a limp mode, the engine computer just uses a fudge factor instead of real data.
Most likely though, it's not even an improvement - more like the computer has been forced to recalculate due to the change, or... the weather is colder, or less humid. Again, denser air charge when cooler. Or, your tires are worn a bit more and you're getting a better launch or you're getting more traction on shifts.
Here's a neat trick - unplug the MAF sensor and start the car. The car still runs. There's a limp mode, the engine computer just uses a fudge factor instead of real data.
After the tuning with the original HFM, acceleration time was the same as it is now, being 18,2 secs to 125mph.
The fact is, power is fading slowly but steady with increasing mileage (wear of HFM due to air not being 100% filtered is not avoidable).
Ciao
