The actual correct term for backbox is actually a latin term, "tergum exitus foramen pro debilito stomachata" which means "rear exit hole for exhaust fumes", however it is a mouthful to say to your local motor factors and so the term "backbox" was used instead.

The subaru "exhaust manifolds" are called headers simply because it sounds better and it is easier for the japanese to say.

 

I'm not an expert but my 2p

Headers, aftermarket ones....
- spool up the turbo later (bad). In changing the spool point, makes the factory ECU map less than optimal.
- can give more torque/bhp but need to be purchased intelligently...

IMO porting the standard headers is more worthwhile unless aiming for 'large' power increases supported by a hefty bank balance.

Also IMO, usefulness of knock sensors does vary, more in relation to where they are placed on what manufacturer's engine and the skill with which the ECU can be programmed.

J.

 

The apexi ecu is a very capable ecu, the fact it doesnt have a reactive ignition map is irrelevant as it has been mapped to suit your specific car by someone who knows what they are doing and therefore in normal use wont detonate.

Getting to the question you have regarding the varying signal from knock sensors,
You can program the apexi ecu to flash the engine management light in the event that a pre-set knock level is met or exceeded or any other engine parameter for that matter. This is set at the time the car is mapped and gives you a visual indication that all is not right, be it a bad batch of fuel or a faulty component bla bla.......
When i had my apexi mapped, the un-questionably very clever man that was mapping it commented that the signal from the knock sensor was quite high, it is only a microphone at the end of the day so it picks up just about everything. The difference being identifying the spike associated with det from the background noise.
Since you can hear what the engine is doing through the det cans you rule out the fore mentioned noises and listen for det, then set the noise as a base line. So far as i remember the apexi has a scale of 1 to a 100 for which it measures det, my warning light is set at 40 where as my mates car done on the same day was set at 20 something.
Corrosion under the sensor or how tightly it is done up can also effect the signal it gives.
Since all the standard ecu's on a given model are programmed the the same the ecu might over react to something and go into safety mode or not notice potentially dangerous det.

The method the standard ecu uses to protect the engine suits the masses Pete, but there are people who are prepared to spend money on good quality aftermarket equipment and reep the benifits. Just think Pete if you got one you would probably get even more mpg since the ecu isn't simply running rich as safety precaution!

Who said anything about me being paranoid? I'm not paranoid about anything, my car is serviced and looked after properly and driven "briskly" shall we say, almost evertime i take it out, if i break it so what? ill fix it's no big deal.

I feel another futile discussion coming on here think we'll have to agree to differ again pete!!

Kenny