I have just had my z4 2003 2.5 with sports mode and only 33000 miles remapped yesterday with great results was looking to upgrade the air filter with a k and n or a induction kit and put a sports exhaust any advice on what's the best and were to buy them from new to this forum so not sure how all this works
Upgrading z4 air filter and exhaust on 2003 2.5
- Thread starter Piggy
- Start date
NeilP said:
what Neil says ^
Due to the engine management it cant use more than a few % point improvement in inlet or outlet flow without mapping changes, so mapping should come after any mods. You could well see a decrease in output as the emu pulls things back if it detects out-of-spec flow and mixture readings. Have you got any stats or charts on the re-mapping? I'm always suspicious about what can be achieved on a naturally aspirated unit so would be interested to see the results
http://www.z4-forum.com/forum/viewtopic.php?f=2&t=76872&hilit=filter
The mapping was done by quantum tuning taking it from 192 to 110 it's all done via laptop so unless you get it rolling road tested .The throttle responce was deffenitly sharper and it seems to pull like a train being a 5 speed it always felt like you needed a extra gear not any more .Drove the same road to the centre there and back and set my fuel computer there and back the reading for the trip there was 34.9 driving quit steady there and on the way back even after putting my foot down on every occasions could it read 39.9 keeping it in fifth gear .Will speak to the guys who remapped it as they said changing the filter for a more free flowing one would only improve things without the need for a second remap .
I've recently fitted a AFE induction kit, can't really comment on any claimed increase in power but it definitely pulls well through the gears and the noise :lol:. Ive also had a small bypass carried out on my exhaust so its a bit more free flowing which I think had helped 
Unfortunately because a lot of tuning theory is counter-intuitive there is a thriving market for solutions that will 'obviously' add power but in fact do nothing more than produce more noise and almost certainly reduce actual engine output/efficiency - removing supposed obstructions in the air intake system and exhaust being prime examples. Modern engines NEED carefully tuned restrictions in the intake and exhaust system to increase the all-important velocity of gasses and harmonise the pulses of the gases as they move through - think funnelled down shape on a jet engine exhaust, if it was wide open gas velocity would be lost and it wouldn't work. Simply opening pipes or intakes will reduce power and efficiency.
A neat explanation http://www.forzacomponenti.com/documents/Exhaust%20Valve%20Bypass%20Controller%20Paper.pdf
Getting denser air in via a cold intake or through forced induction is actually the only worthwhile way to be able to get real gains, in either case more fuel will obviously be required so fuelling and mapping mods will be needed. Chip/mapping alone will produce next to nothing in terms of max bhp on a normally aspirated engine and certainly not the 10-15%+ being claimed for this 2.5 mapping. I'll happily eat my pants and post the clip if anybody can produce an independently dyno-tested re-map of a modern N/A engine that gives this sort of gain (particularly BMW that already have high specific outputs) :cheers: - small gains can only be made by restricting the safety margin built in to the knock sensing systems and weaken mixture/advance ignition fractionally - hence a slightly sharper pick-up and slight improvement in mpg. All good providing you stick to premium fuel and the engine cooling system is spot-on as weak running causes micro-detonations and hotter running. Ultimately you are sacrificing engine longevity and reliability for really negligible gains. Chippping/mapping turbo engines works because it up's the work the turbo does and the amount of fuel used so can give big gains.
Honestly guys a cold intake with mapping or super/turbo charging (and all the beans that go with it) is the only real gain to be had on the E85/86, removing imaginary obstructions to the intake/exhaust will be detrimental and a re-map is of questionable benefit.
A neat explanation http://www.forzacomponenti.com/documents/Exhaust%20Valve%20Bypass%20Controller%20Paper.pdf
Getting denser air in via a cold intake or through forced induction is actually the only worthwhile way to be able to get real gains, in either case more fuel will obviously be required so fuelling and mapping mods will be needed. Chip/mapping alone will produce next to nothing in terms of max bhp on a normally aspirated engine and certainly not the 10-15%+ being claimed for this 2.5 mapping. I'll happily eat my pants and post the clip if anybody can produce an independently dyno-tested re-map of a modern N/A engine that gives this sort of gain (particularly BMW that already have high specific outputs) :cheers: - small gains can only be made by restricting the safety margin built in to the knock sensing systems and weaken mixture/advance ignition fractionally - hence a slightly sharper pick-up and slight improvement in mpg. All good providing you stick to premium fuel and the engine cooling system is spot-on as weak running causes micro-detonations and hotter running. Ultimately you are sacrificing engine longevity and reliability for really negligible gains. Chippping/mapping turbo engines works because it up's the work the turbo does and the amount of fuel used so can give big gains.
Honestly guys a cold intake with mapping or super/turbo charging (and all the beans that go with it) is the only real gain to be had on the E85/86, removing imaginary obstructions to the intake/exhaust will be detrimental and a re-map is of questionable benefit.
well said Ewazix and your comments on exhaust and inlet mods are spot on . I don't usually read or comment on threads about remaps giving loads more bhp and 40 more miles to the gallon because my comments are usually falling on deaf ears having had impreza turbo and a few tdi cars remapped I know that good benefits to power exist by upping boost pressures ect but I have never saw an improvement in fuel consumption but that's to be expected only the gullible believe otherwise.
and your comments on exhaust and inlet mods are spot on . I don't usually read or comment on threads about remaps giving loads more bhp and 40 more miles to the gallon because my comments are usually falling on deaf ears having had impreza turbo and a few tdi cars remapped I know that good benefits to power exist by upping boost pressures ect but I have never saw an improvement in fuel consumption but that's to be expected only the gullible believe otherwise.