Originally Posted by 8isgreat
I have read on other forums that the standard ecu can only cope with small changes and that more changes can lead to an actual loss of power as the changes you made is outside the range of what the ECU can compensate for. Is this true for my Jeep?
The WJ HO's have a ECU already modified for high output. Not many people have been able to tune them. However there is a very good tuner called Hemifever, which you can look up, that has had success with them.
That being said, the 4.7l HO is pretty good right from the factory.Even though the exhaust is larger than stock, a lot of people replace it with a 3 inch single exhaust after the y pipe with a flow through cat and low restriction muffler with good results.
This exhaust ,or any past the O2 sensors, does not affect the ECU.