Total crap sounds like the backbox is blowing against the ground,awful.-Tom- said:https://www.youtube.com/watch?v=SL-cfmtEj5w&feature=youtube_gdata_player
There's a link for what looks like a 3.0si. My ears are bleeding from the video coming through my phone
The guy treats his car like crap!!
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After making the exhaust more free-flowing by removing the silencers (down-stream flow) you may already have lost performance unless you have increased the upstream flow at the air-intake end. Unless you've done ECU data-logging of the situation before you've removed the OEM silencers then you can have no idea what has happened to performance. You may have lost performance, but you certainly won't have improved it.Dean26390 said:I've no idea how I could calm down the low end apart from maybe 2 small mufflers but then I don't want to lose any performance from stock...
Exhaust shops really should explain this to people before doing such work, but then again I guess they'd be doing themselves out of a lot of jobs!exdos said:After making the exhaust more free-flowing by removing the silencers (down-stream flow) you may already have lost performance unless you have increased the upstream flow at the air-intake end. Unless you've done ECU data-logging of the situation before you've removed the OEM silencers then you can have no idea what has happened to performance. You may have lost performance, but you certainly won't have improved it.
Of course you'd be told that you'd gain power, especially by the exhaust supplier. I've been messing around with air-intakes and exhausts for the Z3MC and Z4MC for about 8 years or so, mostly aided by an ECU datalogger and I've posted lots of information about this on this forum: do a search. I've often been surprised by the results of datalogging, which doesn't lie.Dean26390 said:I was actually told it would gain power, I always thought less restriction=more power but obviously not, what if I combined it with an improved intake and had it remapped? That surely can't still lose power? :?
Yes. Think about it: the maps need to be able to allow the car to operate in Scandanavia in deepest winter, in North Africa or Asia in the heat of summer, as well as at altitude or sea level, and in temperate or tropical climates. As such, the maps need to adjust fuelling to accommodate the airflow that occurs irrespective of air temperature, pressure and humidity. Therefore, if you make modifications to the intake/exhaust whilst the car is still operating in Normally Aspirating guise, whatever you do will still mean that airflow remains within the wide parameters that the ECU maps can cope with. Once the ECU has calculated the Mass Air Flow, the appropriate amount of fuel is added dependent upon engine load etc. If your modded intake/exhaust can replicate the same amount of air that you can get naturally at Sea Level, in deepest winter when High Pressure conditions prevail (i.e. densest charge), then your car's ECU will cope and it will have a little bit of leeway to spare!Dean26390 said:So the OEM maps automatically adjust to any mods done apart from forced induction?