Hi everyone , any views or doubts about fitting a direct replacement K andN air filter. A friend of mine has fitted one and says that throttle response is better. The car is standard apart from a Sportex rear silencer.
Thanks in advance
For the NB if you go with the K&N Typhoon (not direct panel filter replacement) you get a really nice induction howl… whether you also get better response or not, or a placebo effect is debatable.
For me it was worth it for the noise alone
Do you pay for the induction roar in fuel though?
Only if you lean on the loud pedal more because of it.
A panel filter will do very little, an induction kit will add noise.
Combined with your exhaust, maybe you’ll have about 2hp more than stock, but don’t count on it.
I fitted a direct replacement K&N filter along with new Bosch plugs and noticed an increase in response. Whether it was the filter, the plugs or both I don’t know. But the main reason for fitting the K&N was because it is washable and will save pennies in the long run.
K&N panel filter in the stock air box is good.
No insurance upgrade hassle
keeps performance consistently through service range
re usable many times ie life of the car
Has a very good reputation over decades of use road and track
well worth the money and pays for itself over time.
It may offer only a small increase in performance on its own but it dos`nt deteriorate with use as standard filters do as the miles rack up.
We wanted to add a K&N Typhoon to ours but our insurers (LV=) said they wouldn’t insure us if we did so we will have to wait until the next renewal and find another insurer.
Has anyone else had this problem and, more to the point, which insurers don’t see this as problem?
I don’t think Adrian Flux would have a problem with it.
Interesting read here: http://www.nicoclub.com/archives/kn-vs-oem-filter.html
Roughly: K&N and similar filters flow more air because they restrict the flow less, they trap fewer particles and allow more muck to pass through into your engine.
Paper filters might need renewing more often, but there’s a reason why almost every manufacturer uses them - they are extremely good at what they do.
If your filter allows a better airflow into the engine, this will make zero difference unless a) your exhaust system allows the increased airflow to escape, and b) your fuelling is adjusted to suit, otherwise all the extra air gives you is a leaner mixture.
I’m no expert, but I haven’t seen anything (apart from superb advertising) to convince me that K&Ns are a worthwhile addition.
Your talking around £40.00 for a K&N filter and about £4.00 standard air filter, easy to work out how many filters at a yearly change you could get for the price of 1 K&N.
I change my Mazda brand air filter every six months. The part cost is minimal compared to overall ownership/running cost, also even I can manage to do it.
Yeah but no but yeah, you get a nice K&N sticker to go on your air box though
I’d get no extra power, less filtration, drip oil into the induction, and possibly void or need to inform/pay more for insurance. Even just putting stickers under the bonnet would be an invitation for a thorough inspection of a boy racer car if I were involved in an accident. So I sold it on again
This isn’t meant to sound negative to enthusiasts who enjoy modding but if you’re going to do anything which will involve declaring to the insurers then go the whole hog or don’t bother imho. Anything less than 20% extra power on a naturally aspirated car really is not worth doing, as the power usually means less torque low down and any extra right at the top end, and the cost even to get that much is horrendous usually involving cams and head work. Forced induction of course is a different matter .
My only experience with the K & N filters was with a Triumph Spitfire. I guess it did improve the airflow 'cos with the K & N’s the engine wouldn’t rev above 4000 rpm - the previous owner (who’d fitted them) hadn’t changed the needle/springs in the carbs. Had a similar effect many years ago when I replaced the air filters with induction trumpets on a similar car. In both cases the inside of the carb got gunked-up pretty quickly, so the K & N’s on the later car were quickly replaced with a standard filter box and filters. I did get the impression that although there was plenty of muck trapped in the K&N’s they were letting far too much through, almost as much as having no filter at all.
IMHO it’s great to have the extra bit of noise and the extra performance if there is any, but especially nowadays I want the motors to last as long as possible, so keeping the incoming air clean is more important. (Properly jetted they do work on the Spitfire tho!) So my MK3 has the Mazda air filters, just replaced twice as often as the service schedule or if they look dirty (this approach has served me well on a variety of cars over the last xx years)
And don’t forget these days that you have emissions checks, so a worn bore might mean an MOT failure well before the wear stops the engine working. Although of course bore wear will affect performance …
PS I am making a bit of an assumption here that the paper K&N’s are as effective at filtering the car as the oiled-wire-mesh versions!
http://www.knfilters.com/news/news.aspx?id=422
Take a read.
No smoke without fire? Why take a chance? The original paper filter does a superb job.
I’m sure you are right. I wasn’t saying that K&Ns don’t flow more air (they obviously do) but as you found there is no point in having more air going into the engine unless there is more fuel to mix it with (bigger jets in carbs, tweaking the fuel map with EFI) and a bigger 'ole at the other end to let the gases out. In other words, you need to consider the whole system from the air filter to the exhaust outlet if you want to improve power. Incidentally, if the whole system is modified in this way, you will likely get more power and torque throughout the range, and also better economy if you don’t use all the extra, as you are making the whole thing more efficient. But altering one thing (such as a foam filter) without tackling the other things is only likely to lead to running issues. Same with a big-bore exhaust if you don’t change the air intake and jetting to suit.
I guess on an older car (where the fuelling is less precisely metered) a K&N might make an improvement if the intake was a bit restricted to start with. But on a modern car, I would stick with what the manufacturer provides, unless you are making changes in a methodical way to the whole intake/exhaust tract.
As to filtering efficiency, there is this: (http://www.autoblog.com/2005/09/07/how-well-do-k-n-air-filters-work/)
Unless you put on 60k a year, waste of money, and probably shortening the life of your engine.
All that a clogged filter is going to do is make your engine run less well; it an extreme case it might be so clogged, that it crushes, and disintegrates. But none of us will ever reach that stage. But a brand new filter does not filter that efficiently, so constantly changing, without need, filters can cause premature damage to the engine.
Worth a read:
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.122.3342&rep=rep1&type=pdf
Excerpts:
Filter life is less determined by mileage, but by environmental conditions, and filter changing should be determined by the extent of clogging. Hence air filter indicators are becoming preferred;
More useful papers on premature air filter changes:
From the last paper, prepared by ORNL (the same place that came up with the A-bomb):
Impressive to read how massive air draw on a high powered V8 would basically rip apart a clogged filter in a modern airbox.
In practice most of our driving is at medium revs and lowish throttle opening. The standard induction system is designed for this and has resonators to improve cylinder filling. A KN filter might be slightly less restrictive than the factory one at over 5000 rpm and WOT but in all honesty will you notice any difference. As NicD says the best improvement to make is to learn to drive the car properly and be in the right gear at the right time.