Tetra84

I searched the forums but couldnt find an answer quite relating to my question so.. Anyone know how much better a K&N air filter does for your preformance over a regular filter for your airbox on a 87-89 Carrera? Can you get alot more horsepower out of one? I mean, is it well worth the upgrade?

Thanks,
Paul

r911

figure on losing 5 hp

KCPSG

JMO but if you do a search on here and on Pelican you will see its a highly debated topic.

I have read alot on here saying that if you modify the stock airbox it will breath just as good as a K&N and then there are those who swear by the K&N. I personally think if for no other reason I would get the K&N to clean up the engine bay. I don't really think there is much of a performance difference. There is a sound difference though. It also makes it easier to access parts of your engine ..if you do your own work.

Tetra84

you mean if you just add a k&n filter into the existing airbox, or add some sort of cold air intake?

KCPSG

No... you replace the airbox and install the K&N directly on the AFM.

ron mcatee

I think there may be a cone replacement for the stock airbox, but don't know if it's a K&N. The replacement K&N for the stock airbox does not provide any additional room in the engine compartmaent because it is the same size as the factory filter. I used a K&N for about a year, but found it was letting too much dirty air into the airbox. The micron size of the K&N is larger and allows a lot more crud into the engine. that crud goes down the intake and doesn't help the engine any. Even though I cleaned it repeatedly, it was always dirty. I even bought an extra airbox cover and drilled the holes to allow more air to the engine. All is realized was more sound.....kind of like my 57 Vette used to sound with the carb cover off. I say stay with the stock stuff, but it's yours so do as you wish.

danoberer

I put a cone filter on my 89 targa a few years ago. Well worth the $ in my opinion. The sound is more throaty and it 'feels' like there is a little more power.

Steve Weiner-Rennsport Systems

FWIW,...The cone filters cost you about 5-6 HP, despite the nice sound. The factory airbox works FAR better.

K&N's flow more air than the OEM paper filter does after its been in there for a while (5K, or so). They do not filter as well as the OEM paper element so thats an individual choice.

KCPSG

I don't doubt Steve.However Mine was installed by PO and I do like how it opens up the engine compartment.

theiceman

Does the K and N being less restrictive allow more contamination into the engine , ie particles ? or is it the same flow just is nicer cosmeticaly ? just wondering because it does look sharp.

Tetra84

i dont really have any intention to change the airbox to a cone filter, but I have seen square filters from K&N that you can put in the airbox to replace the paper filter. Would this type of filter be any better or worse than the cone filter, or even regular paper filter?

tj willy

The thing about the having the airbox there is the air temperature. You def. want cooler air to produce more hp.

Also if you go K&N, be sure and keep it oiled as they direct. Some don't require oil, but I believe this is to aid in trapping some of the particles that would normally slip by due to the larger filtration holes.

You don't toss out the K&N's either (you probably know this). Just clean and reinsert. Saving you money in the long run and giving you the opportunity to KEEP clean(er) air to the engine without buying paper filters all the time.

(edit: I ran a conical in my Jeep and I have a standard K&N drop-in for the 87 Targa)

bgiere

I have tried both on sstock motor and a 3.2 with cams and exhaust mods...The stock motor had absolutely no discernable difference after 3 dyno pulls...The "massaged" engine gained about 2 HP and 1 ft. lb. of torque...That could even be temperature or operator error...I think all they do is let more dirt in...And it does show up in the wear numbers if you do a used oil analysis on a K&N equipped car...Keep your stock setup and change it regularly.

r911

IF you want some induction noise, search up the posts on drilling holes in the cover. P AG did this for a while - they called it the motor noise option or something.

There is no rational reason to replace the nice paper filter in your car with an oil media K&N. The risk of contaminating the thermal wires for the air flow sensor is significant, it lets in larger particles than the stock one, loses hp - at best, there is no increase ... you'd be better off with a carbon fiber cupholder.

I use a K&N myself but only because that is the only thing that works on my PMO carb setup - there are no paper filters for them.

JackOlsen

I have a K&N because the 3.6 swap doesn't leave enough room for the stock box. But everything I've read suggests (as Steve says) the K&N costs you horsepower, and is less effective at filtering engine-damagine contaminants. If I could get rid of it, I would.

Bringing in ambient-temp air makes sense on a water-cooled engine, but not on one with a huge blower moving massive amounts of cool air through the engine compartment at full throttle. I did tests with thermometers and then chucked the 'cool air intake' box I was designing. There is a temperature difference at idle and cruising, but it disappears when you get aggressive with your driving. A few percentage more horsepower isn't really worth fighting for when you're just cruising -- you can just push the accelerator a hair more. At full throttle, mods that extend the intake are just going to constrict the engine's ability to breathe.