Re-jetting and Re-mapping

[rac3r]

Bikes need to be re-jetted/mapped when you fit a full exhaust or air filter right? so how does this work with cars because most people don't have the ecu re-mapped when they fit an exhaust/performance air filter. Just curious really

On a side note if you fit ONLY a new air filter to a bike without any other mods does it still need to be re-jetted/mapped?
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Bikes : 2006 CBR125R - 2004 Monster 620ie - 2004 ZX-6R B1H - 2005 Monster S2R 800 - 2011 Street Triple - 2009 Streetfighter 1098 - 2014 ZX-6R 636

[chrisw]

[NSR Mick]

Cars are easier to get away with as theres usually 3 sensors that control the fueling. Airflow Meter (MAF), knock sensors and Lambda sensors which will allow the ecu to alter the fueling / timing according to the results it is fed from them.

Bikes I think run a predetermined map according to revs and throttle opening.

Although I may be wrong.
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If you dont like the way that I ride.......Stop trying to keep up!!!

[stevo as b4]

Yeah car maps are more adaptive than bike injection/ignition ECU maps generally. They also use more sensors and have to run over a wider range of variables normally. Few injected bikes have knock sensing AFAIK, but quite alot of cars do, and some allow the ignition timing to be advanced a fair bit if you use a high RON fuel, which can give more power and better throttle response.

Their are limits to how much extra airflow a car's ECU can cope and allow extra fuelling for, but normally any bolt on exhaust and induction changes are no problem. Higher lift and longer duration Cams can cause a poor idle and low down throttle response on engines with Plennum based fuel injection, where as you tend to get far better idling and low speed response with Individual throttle bodies, which is the norm on most multi cylinder bike engines.