Post by oldschool on Apr 30, 2007 18:46:42 GMT
On quite a number of forums some funny comments and theories about induction kits and filters are made, which frequently raise the eyebrows of specialists.
One of the favorites seem to the one that pre-oiled cotton gauze filters would damage the AFM. Interestingly I have fitted these to many cars and in all those years I had only one car with oil contamination and this was due to engine oil being pushed back through the breather. What is even more funny is the fact that this is often mentioned (when people ask for induction kits) in connection with twin cone or cone filters. The very same people recommend to rather use a CDA or DIA. Nothing against them as filter mediums/units, but they aren't any different. They use the same oiled cotton gauze.
Alternatively it is often recommended to use sponges. They usually need to be oiled too to have the same filtration capacity and even then the flow rate is not as good as cotton gauze filters. Additionally most of them age and break up in due course.
Another filter medium that people love to have a go at is steel mesh ones. Accordingly to some quite peoples believes they don't flow well. According to my and my colleagues rolling road test they are flowing exceptionally well.
Some people would like to present some other speculation about induction kits as facts. Their claims usually boil down to the same point. Factory induction kits are so good that they can't be improved. This is utter urban myth.
To understand why induction kits can be improved over the standard induction fitted by the manufacturer when designed properly is what the manufacturer expects from it.
Today virtually all engines produced are much better than they ever were in terms of specific power delivery.
95bhp from a 1368cc FIRE (example) is quite some power output and the torque delivery is not bad either. It might not be much more than some 20 years ago, but the stakes are different.
Manufacturers have to put up with lower grade fuels than then. Exhaust system aren't build to quality rather than to a price and they have to comply with much tougher noise regulations. Emission regulations not only require a power killing cat set-up, but also the map is affected by it. Fuel consumption figures have to be reasonable with all the other measurements taken and the induction has to prevent intake noise to be heard through it. And last but not least insurance requests come into play as well.
The other problem induction kits have is that they are very expensive when made to a high standard. This requires to find a cheap alternative that does the job, but will never what a high quality after market induction kit is. Due to manufacturing reasons cost might only be kept down if it is built in several sections. Additionally parts of the system have to take up the slack because of engine movement. Steps and convoluted parts, poorly designed bends and mouth pieces as well as poorly designed air boxes all will contribute to losses. All this might be topped by mathematical inaccuracies that are unavoidable when working to cost.
The fact that induction systems can be improved does not mean that every design is working in the from the buyers point of view wanted effect. Some do make performance even worse. Not necessarily only because of poor design, but in some cases because of the wrong location of the mouth or filter. When designed properly some of the induction have shown a peak power increase of well in excess of 10%.
Sometimes the positive effects will only be seen to a higher degree when some of the other components are uprated. Without the improved induction the other uprated components would then never show the results either.
One of the favorites seem to the one that pre-oiled cotton gauze filters would damage the AFM. Interestingly I have fitted these to many cars and in all those years I had only one car with oil contamination and this was due to engine oil being pushed back through the breather. What is even more funny is the fact that this is often mentioned (when people ask for induction kits) in connection with twin cone or cone filters. The very same people recommend to rather use a CDA or DIA. Nothing against them as filter mediums/units, but they aren't any different. They use the same oiled cotton gauze.
Alternatively it is often recommended to use sponges. They usually need to be oiled too to have the same filtration capacity and even then the flow rate is not as good as cotton gauze filters. Additionally most of them age and break up in due course.
Another filter medium that people love to have a go at is steel mesh ones. Accordingly to some quite peoples believes they don't flow well. According to my and my colleagues rolling road test they are flowing exceptionally well.
Some people would like to present some other speculation about induction kits as facts. Their claims usually boil down to the same point. Factory induction kits are so good that they can't be improved. This is utter urban myth.
To understand why induction kits can be improved over the standard induction fitted by the manufacturer when designed properly is what the manufacturer expects from it.
Today virtually all engines produced are much better than they ever were in terms of specific power delivery.
95bhp from a 1368cc FIRE (example) is quite some power output and the torque delivery is not bad either. It might not be much more than some 20 years ago, but the stakes are different.
Manufacturers have to put up with lower grade fuels than then. Exhaust system aren't build to quality rather than to a price and they have to comply with much tougher noise regulations. Emission regulations not only require a power killing cat set-up, but also the map is affected by it. Fuel consumption figures have to be reasonable with all the other measurements taken and the induction has to prevent intake noise to be heard through it. And last but not least insurance requests come into play as well.
The other problem induction kits have is that they are very expensive when made to a high standard. This requires to find a cheap alternative that does the job, but will never what a high quality after market induction kit is. Due to manufacturing reasons cost might only be kept down if it is built in several sections. Additionally parts of the system have to take up the slack because of engine movement. Steps and convoluted parts, poorly designed bends and mouth pieces as well as poorly designed air boxes all will contribute to losses. All this might be topped by mathematical inaccuracies that are unavoidable when working to cost.
The fact that induction systems can be improved does not mean that every design is working in the from the buyers point of view wanted effect. Some do make performance even worse. Not necessarily only because of poor design, but in some cases because of the wrong location of the mouth or filter. When designed properly some of the induction have shown a peak power increase of well in excess of 10%.
Sometimes the positive effects will only be seen to a higher degree when some of the other components are uprated. Without the improved induction the other uprated components would then never show the results either.