Thinking about picking up a new air filter for my car but don't really know what to look for. Are they all pretty much universal? Is there something in specific to look for? Brand wise?

Can you guys help me out? Thanks

I trust K&N

does it make any noticeable power/economy difference?

Uh I think the sports airfilter on my car was supposed to add about 5hp, but I also installed a free-flow exhaust system with a single silencer (which was basically not a silencer at all...) at the same time, which probably had more of an effect. Considering that my engine was probably only producing about 45hp before I rebuilt it, and an (estimated) 80hp after I rebuilt it, I certainly noticed the difference. A stock 1275cc A-Series in a Mk3 Midget puts out 65hp and my car is noticeably quicker off the mark than any stock one I have driven, even ones with rebuilt engines.

And yes I know 65hp isn't much. It's a 60s british sports car, it's light so it doesn't need a big engine.

How do you find it performance wise? Is it actually a quick car, or just not slow?

Stock it's fairly slow. You have to remember that this car was designed in the mid 1950s using an engine designed in the 40s, so until the mid 60s it was actually considered a fairly quick British sportscar. A stock mark 3 Midget will crack 0-60 in about 12 seconds, which is faster than most modern hatchbacks and economy cars.

However the performance in the Midget lies more with handling and its low weight helps this enormously. Also the A-Series engine can be really easily upgraded to around 140hp which will obviously give massive performance gains to such a light car. My tuning book gives records of race-prepped and heavily tuned Midgets that can crack 0-60 in less than 6 seconds, which is modern sportscar territory. I estimate that a well tuned Midget could do the 1/4 mile in 12-13 seconds, which is good for a car designed in the 50s using a 1.3 litre engine.

No offense dude, but your going to need something like 270 horsepower per tonne to do that. That works out to about 200 horsepower for a 70 kg driver.

I know thats probably possible from the engine, but... I wouldnt reccomend it on a daily driver.

Also, check your 0-60 times. I dont know if my source is any better than yours, but it says your out by a couple seconds.

I will give props to the engines revving ability though - judging that it power peak is 6000, id assume it should be designed to safely go to 6500 or so? Its quite undersquare and it doesnt have modern technology, so while its not amazing by modern standards... it is quite remarkable for the time and dimensions.

Well I'm kinda guessing about the 1/4 mile time. You gotta remember that a race prepped Midget will only weigh about 500kg at absolute most and also the book says that there was once an original Mini that ran 12s. I'm not sure whether or not I believe that (we don't normally do 1/4 mile tests in the UK so I don't really know what 0-60 time that compares to) but considering that a Midget is rear wheel drive and therefore has better traction than a Mini, and also better aerodynamics, I'd bet a Midget could do better than a Mini. Given that you say it takes 270hp/tonne to run 13s, given that the car, with fuel and driver, weighs in at roughly 570kgs, and the engine could produce up to 140hp, which gives about 245bhp/tonne which isn't far off. A mad tuned A-Series with nitrous and a turbo could possibly crack 150hp which, although I don't know if such an engine has been attempted, gives 263hp/tonne which might be enough to run 13s.

Although I'll admit that 13 seconds is probably a bit of an overestimate.

As for the 0-60 times, 14 seconds is the normal time for the Mark 3 with either the American emissions control equipment, which the UK version doesn't have, or the twinbox silencer system, which was fitted to all 1275cc units apart from those made in late 1969 MG/Leyland crossover which for some parts sourcing reason had a Leyland competition manifold and single box silencer which bumped up the 0-60 time by a couple of seconds. Mine is that late '69 crossover model. After that they went back to the old incredibly restrictive twinbox and cast iron manifold.

As for revving capabilities, being a pushrod engine it's actually not that great at high revs. A standard Midget tachometer has a warning orange section starting at 5,500 to 6,500rpm and a redline at 7,000, but upgraded drivetrains with carbon fibre pushrods and lightened and balanced titanium everything can push the revs up to 9,000 (which is insane for a pushrod designed in the 40s). However the 1275cc unit can't really go that far because the stroke is a tad long. The 1098cc unit is a fairer bet for high-revving engines.

back to the subject of air filters, there should be a book in the aisle of whereever you're getting a filter from that will list the year, model, and engine type of your car and that will tell you which oil, fuel, and air filters you need. probably spark plugs too.

I searched K&N's website and found a filter that will fit my car, (98 civic), and a local place carries them according to their site.

Are these things pretty straight forward to install?

very straightforward.

pull off the cover with whatever bolts/screws/clips that are holding it there

remove old filter

clean out any debris (there shouldnt be any)

put in new filter, making sure the rubber around the edges seats well (usually doesnt have to be perfect, the cover will generally seal it on)

screw/bolt/clip cover back on.

A K&N won't provide any noticeable performance gains. If you do notice a performance gain, it's probably just your brain thinking "I just paid $80 for a frickin air filter, I'm gonna pretend like I got 20hp out of it."

I use whatever paper filter is available at the time.

They have done testing and I've seen results suggestion that an AC-Delco filter performs better then a K&N.

.-FSB-.

You'd be an idiot to think that an airfilter could ever give you 20hp. More like 5-10 hp and that's with proper ram pipes/stacks to suit. Maybe 15 if you had a decent flowed intake manifold. And all that stuff only really has an effect if you've got a half-decent exhaust system.

Personally I did notice the performance gains just from fitting a K&N filter and richer needles in the carbs. I fitted a sports exhaust first and then the sports intake. But I did rebuild my engine at the same time which almost definitely had a much larger effect on hp than a cheapish (only £70 which is $35usd) air filter, even though that air filter and ram pipe combination is the best for the twin carbs I have.

What? doesn't that sign mean pounds? If it does, you're way, way off.

Oh, and you may also notice a difference from an old dirty ass paper filter as well.

lol. Yes sorry, a dollar is half a pound, not the other way around. 140 dollars for a cheapish airfilter.

Ahhh i forgot about weight reduction. Its a lot more beleivable. I was just going off compartive times for much larger cars, such as muslce cars, so the horsepower wont directly convert, there may be many differences. (Eg: auto, less wind resistance problems). i can definitely see it running 14, mid to low. I think 13s would be possible but I dont really know.