Discussion
I've never had a positive result from a K&N without some tuning to increase the power and need for more air. I imagine most cars have filters that flow the right amount of air required for the standard tune.
I have only used K&Ns because I have American cars so they last a bit longer and I don't have the nuisance of importing paper ones. Other than that, I stick to paper, not least because K&N oil can pollute your throttle body and isn't it just easier to sling one away and replace it rather than having to clean and re-oil?
I suppose much depends on the cost of replacement but I would only do it for economy reasons rather than performance reasons.
I have only used K&Ns because I have American cars so they last a bit longer and I don't have the nuisance of importing paper ones. Other than that, I stick to paper, not least because K&N oil can pollute your throttle body and isn't it just easier to sling one away and replace it rather than having to clean and re-oil?
I suppose much depends on the cost of replacement but I would only do it for economy reasons rather than performance reasons.
Ozzie Osmond said:
98elise said:
I ran a GTV for 2 years without an air filter, so you would be very unlucky to ingest anything that would harm the engine.
Judging by the look of my air filters when they get changed I'd be cautious about that.
Ozzie Osmond said:
98elise said:
I ran a GTV for 2 years without an air filter, so you would be very unlucky to ingest anything that would harm the engine.
Judging by the look of my air filters when they get changed I'd be cautious about that.The air filter is probably the most restrictive part of the intake system on your car therefore it will be the best way of reducing the pressure drop. And the pressure drop of an intake is more important than exhaust system for performance and CO2 production.
Less is obviously better but to the point you'd notice? Doubt it.
Less is obviously better but to the point you'd notice? Doubt it.
LuS1fer said:
I've never had a positive result from a K&N without some tuning to increase the power and need for more air. I imagine most cars have filters that flow the right amount of air required for the standard tune.
Quite. We're not talking about 70s frying pan airboxes sucking air from over the exhaust manifold anymore! It's easy for manufacturers to get around the restrictiveness of paper filters by simply making them rather large.
If they were such that they actually represented a significant efficiency loss to the engine then the MPG and emissions figures, as well as the power figures would be naff compared to the competition which would simply upsize the air filter until it no longer represented a signficant loss.
Paper doesn't flow very well but it catches a lot of crap. When you have a 65mm throttle body sucking through the best part of a square foot of air filter, the low flow rates of paper just don't matter.
If they were such that they actually represented a significant efficiency loss to the engine then the MPG and emissions figures, as well as the power figures would be naff compared to the competition which would simply upsize the air filter until it no longer represented a signficant loss.
Paper doesn't flow very well but it catches a lot of crap. When you have a 65mm throttle body sucking through the best part of a square foot of air filter, the low flow rates of paper just don't matter.
TNH said:
Only car I've known to gain any performance from a K&N induction kit is the Fiesta ST (last generation 2.0)
The standard filter flows all the air this engine needs in terms of capacity so it would need tuning or the filter would have to be very dirty.As for running without filters, i had an A-series that i ran through an alloy trumpet and the dirt pretty much eroded the plugs copmpletely so that is a no-no. At the very least, it's like tipping sand into your sump.
LuS1fer said:
I've never had a positive result from a K&N without some tuning to increase the power and need for more air. I imagine most cars have filters that flow the right amount of air required for the standard tune.
I have only used K&Ns because I have American cars so they last a bit longer and I don't have the nuisance of importing paper ones. Other than that, I stick to paper, not least because K&N oil can pollute your throttle body and isn't it just easier to sling one away and replace it rather than having to clean and re-oil?
I suppose much depends on the cost of replacement but I would only do it for economy reasons rather than performance reasons.
Modern ECUs will account for a change in airflow up to about 8%, so no retuning required. I have only used K&Ns because I have American cars so they last a bit longer and I don't have the nuisance of importing paper ones. Other than that, I stick to paper, not least because K&N oil can pollute your throttle body and isn't it just easier to sling one away and replace it rather than having to clean and re-oil?
I suppose much depends on the cost of replacement but I would only do it for economy reasons rather than performance reasons.
OP, the stock paper filter will be sufficient, just change it more often so dirt does not reduce flow over time.
Julian Edgar at Autospeed (www.autospeed.com) did various experiments measuring pressure drops across different air filter / air intake / filter box arrangements years ago and generally found the differences in pressure drop across aftermarket and OEM filter elements to be negligible.
The real gains were achieved changing the filter box, offtake and/or air scoop arrangements, and of course ensuring cold air feed from outside the engine compartment.
The real gains were achieved changing the filter box, offtake and/or air scoop arrangements, and of course ensuring cold air feed from outside the engine compartment.
I used a K&N Kit on my car, it was a bit expensive as it was a proper metal kit rather than a simple plastic induction kit. You can see the power graph they provided. My car produces more power than shown on the graph as I have other modifications
This graph is assuming everything else is stock with just the intake
So it goes to prove that though the increase is slight, there is some additional power made. Some people will tell you they do nothing but change the sound or possibly even reduce performance with heat soak. That may be true for cheap cone filters but not a decent kit
This graph is assuming everything else is stock with just the intake
So it goes to prove that though the increase is slight, there is some additional power made. Some people will tell you they do nothing but change the sound or possibly even reduce performance with heat soak. That may be true for cheap cone filters but not a decent kit
hedges88 said:
I used a K&N Kit on my car, it was a bit expensive as it was a proper metal kit rather than a simple plastic induction kit. You can see the power graph they provided. My car produces more power than shown on the graph as I have other modifications
This graph is assuming everything else is stock with just the intake
So it goes to prove that though the increase is slight, there is some additional power made. Some people will tell you they do nothing but change the sound or possibly even reduce performance with heat soak. That may be true for cheap cone filters but not a decent kit
Within the tolerances I'd expect for the same car on back-to-back runs with no changes on a rolling road to be honest.This graph is assuming everything else is stock with just the intake
So it goes to prove that though the increase is slight, there is some additional power made. Some people will tell you they do nothing but change the sound or possibly even reduce performance with heat soak. That may be true for cheap cone filters but not a decent kit
Those graphs admit that the "after" run was done on a cooler day and at higher ambient pressure, albeit it more humid.
Still within the realms of "hasn't done anything" in my book I'm afraid.
I cant be bothered these days, generally most bolt on tuning on N/A cars is pissing into the wind, the exceptions are things like where manufactureres have hamstrung one model via some crude method to offer two models ont he same basic engine,
BMW 328 gets a good gain from a different manifold
Rover 80 bhp K seriescan be turned into a 105 bhp one by changing a throttle body, half hour job.
Mini One (Mk1 new Mini) can becom3 a Cooper, in engine terms via a remap
Other than that, air filter, exhaust, fuel pressure regulators (FSE Boost valve anyone ?) are mostly either a power drop, no gain or sometimes a barely discernible improvement, the other side of the coin is sound and that is usually worth it but best not to try and dress it up as performance gains, I spent quite a bit on a Golf GTI on all the bolt ons and if the claims were to be believed the car would have 130 bhp, it had 116.5 on the rollers, an increase over the 112 it was meant to have but the operator said bog stock ones sometimes made as much if not more, down to the individual unit, how it was run in, fuel, ambient temp, air density yaddad yadda yadda, so I spent probably £800 over a year that I couldn't really afford to not make any difference.
I think we focus too much on engine performance, decent brake pads, fluid and disks, slightly uprated or new standard suspension, good tyres and whatever make the most difference, as does knowing how to drive.
There are some worthwhile mods, a good remap on a turbo car can work wonders and there are other mods that can make a huge difference but by and large its a waste of money relative to buying something that has more power and capability to start with.
I say this as I am installing a new exhaust to my 350Z but I only bought that as it was cheaper than the Nissan original, and better quality, oh and a little less muted so I can hear that V6 howl better but not bothered if it makes any more power, dont think the ECU lets it, thats the rub with most tuning nowadays, spend a fortune on your car, then you need to tell the ECU all about it, another rolling road session, another £300, the manufacturers do know actually what they are doing, I am not anti tuning, absolutely not but its so easy to waste money that could be better spent by upgrading the whole car to another one.
Still, it keeps commerce turning and if people get something out of it, then its all good.
BMW 328 gets a good gain from a different manifold
Rover 80 bhp K seriescan be turned into a 105 bhp one by changing a throttle body, half hour job.
Mini One (Mk1 new Mini) can becom3 a Cooper, in engine terms via a remap
Other than that, air filter, exhaust, fuel pressure regulators (FSE Boost valve anyone ?) are mostly either a power drop, no gain or sometimes a barely discernible improvement, the other side of the coin is sound and that is usually worth it but best not to try and dress it up as performance gains, I spent quite a bit on a Golf GTI on all the bolt ons and if the claims were to be believed the car would have 130 bhp, it had 116.5 on the rollers, an increase over the 112 it was meant to have but the operator said bog stock ones sometimes made as much if not more, down to the individual unit, how it was run in, fuel, ambient temp, air density yaddad yadda yadda, so I spent probably £800 over a year that I couldn't really afford to not make any difference.
I think we focus too much on engine performance, decent brake pads, fluid and disks, slightly uprated or new standard suspension, good tyres and whatever make the most difference, as does knowing how to drive.
There are some worthwhile mods, a good remap on a turbo car can work wonders and there are other mods that can make a huge difference but by and large its a waste of money relative to buying something that has more power and capability to start with.
I say this as I am installing a new exhaust to my 350Z but I only bought that as it was cheaper than the Nissan original, and better quality, oh and a little less muted so I can hear that V6 howl better but not bothered if it makes any more power, dont think the ECU lets it, thats the rub with most tuning nowadays, spend a fortune on your car, then you need to tell the ECU all about it, another rolling road session, another £300, the manufacturers do know actually what they are doing, I am not anti tuning, absolutely not but its so easy to waste money that could be better spent by upgrading the whole car to another one.
Still, it keeps commerce turning and if people get something out of it, then its all good.
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