Air Filter Question

If there was a significant benefit to using these after market filters, one would think Ferrari would install them at the factory. The cost differential is miniscule.

One added concern is warranty. If they can trace a failure to use of a different filter no warranty.

Considering the above why bother?

 

I total agree with ROB on this!
I have had 15 HP more on my 308 GTSi QV with the K&N filter
and now on my `91 Testarossa also +15HP with the K&N.
And yes of course we all change our oil 1-2 times a year.
I don`t know any F.-driver who does not change his oil at least once a year.

So to me: It worth it to pay more for the K&N
You hear (sucking noise;-) and feel it between 3.000-6.000 rpm`s

Wolfarossa
FORZA FERRARI

 

I used to use K&N filters until I read about the increased dirt that is alllowed into the engine. A few more HP is not worth the risk to the engine of a road car when you consider the cost of Ferrari repairs. In a race car, it may be worth it, but what good does a few extra HP do the your day to day driving of your Ferrari ?

 

Is there an increase in the HP of the 360 Stradale (or standard 360) using K & N? Where can you purchase the air filters? Web site?

 

How can an after market air filter give you an extra 15 HP over the factory filter. If I was an Ferrari engineer, this would be like free HP from no where. How are these cars tested for the increase in HP, it just seem to good to be true ??

John

 

There are a couple of reasons why a K&N would produce more horsepower as I am finding out from my dyno time (see numerous tech threads). Not only does it change the flow characteristics, but at least in carb cars can change the relative mixture strength as well.
My personal guess only - The porosity of the filter affects the vacuum seen by carbutetors, so a car that is Air/Fuel right on with a paper filter will actually lean a little with the K&N. Ergo, to take advantage of more flow from the K&N, would up my main jet a hair.
Kjet cars will show an increase in hp as the flow sensor is downstream of the filter; you would get less resistance to flow (at a given throttle setting) from the filter and the A/F would still be on.
And of course, I could be completely wrong.
best
rt

 

I would love to see a real- life dyno comparison between a stock filter and a K&N on a 308. I've heard these numbers before, but until I see real results , I'm still somewhat skeptical of that big an increase. Does anyone know of an actual reference where this comparison was done? If it's true, I'll buy one!

 

Forza,#48, October 03

Carobu Engineering dyno test of a carb 308 with stock, K&N and no filter lid (open stacks)..
stock: 229.54 @6700
K&N: 227.15 @6700
no lid: 227.64 @6800

hth
rt

 

Originally Posted by nberry
"If there was a significant benefit to using these after market filters, one would think Ferrari would install them at the factory."

Originally Posted by john328
"How can an after market air filter give you an extra 15 HP over the factory filter. If I was an Ferrari engineer, this would be like free HP from no where. How are these cars tested for the increase in HP, it just seem to good to be true ??"


Engineering, like everything else, is a series of trade offs. K&N sells an increase in HP, the trade off is long term engine durability. No problem for them, it's YOUR engine. not theirs.

Ferrari has other factors to consider. It's THEIR problem if the engine fails while in factory stock condition. By law they have to maintain low emissions levels over a long period of time/mileage. They also have to warrant that all the emissions related parts are durable and/or routinely serviced. Also in most markets they have to muffle the intake as part of noise level laws. K&N doesn't have those concerns.

 

On those figures, why would one use a K & N?
Rob, where did your 10-15HP come from?
Or does K & N only give an advantage with FI?

 

I run a stock air filter for the dirt reasons, 5,10,15 HP will not change the performance of my car at the track (its driver limited right now).

This year I changed the oil 8 times (9 if you include the major that is now under way). Why? Aside from the 18K miles I put on the car, I change the oil after 2 track days and the car was on the track 18 days this year.

I also went through 4 sets of brake pads and a set of rotors 2 sets of tires, and a lot of race gas. But, hey, thats why we own these cars; so we can use them as intended!

 

I have a K&n on my 308qv, maybe a couple of hp"s, but 15?

 

Jmillard308, the reason the carb 308 loses hp with the K&N is that the stock jetting is already slightly lean...adding the low restriction filter leans it out more....to take advantage of the K&N's better flow, one would need to richen the main jets slightly.

FI compensates for the better flow automatically by the air sensor plate, which automatically meters more fuel when it senses more air passing it. I think the HP gains with K&N are not automatic, and can be even car specific, that is not ALL 328's will gain 10hp as Rob's has.

 

I highly doubt the horsepower gains that K&N claims to achieve. I have had them in my cars and have not noticed any real increase in power or throttle response. If they do add power at all, it is too small to realize. Besides for allowing larger dirt particles into the engine, they also have their oil used to trap dirt, get sucked in and coated onto the Mass Airflow sensor wires in today's newer cars. This causes a fault and an engine code resulting in a limp mode in some of the more sophisticated engine managment systems (cutting power). I would recommend to stick with the stock filters.