Do you guys recommend a K&N air filter for a stock L98 engine? Will I notice any difference in power? Seems they cost around $85.00.😲 Or will a basic filter have same result?

 

Hi there. I have one on my car but it still has the factory air intake cover with the restrictive air vents. The only thing I noticed is a little deeper sound with WOT. If you are running a K&N with the modified opening you might gain a little hp but pinot worth $85. Mine was already installed when I bought the car.

That's my $.02.

Ted

 

IMO the K&N filter is all about optics. But, I have seen research that proves improved performance and research proving that it doesn't add performance. I would guess any minimal gain would occur at WOT for a sustained amount of time and that is unrealistic for the street.

 

I use the K&N air filters because they are re-usable and have been "quality" parts. They work and perform well and being able to wash them occasionally is a plus to me. Are they worth $85? That is a personal choice as you can buy quite a few air filters for $85. I use them in most of my cars and RV because I have had many years of good service out of the K&N filters. I am frequently amazed at the volume of crap they filter out and hold until they are washed.

The one thing you need to be careful of is to not over-oil them after being cleaned. I have heard of problems due to the excess oil getting on important parts and causing them to fail. The MAF sensor on my C4 is probably the most likely part that could be hurt by over oiling the filter. It just takes a very light coating of the special oil to get the best performance out of the air filter.

I have used K&N air filters for over 40 years and will probably continue using them as the standard in my Corvettes and the rest of my fleet.

 

I have opened up the air box and tried the K & N filter and the stock filter. There is very little if any difference between the two so I would say don’t waste your money

 

Somewhere on YouTube a guy took a C4 Corvette filter and set up a test system for measuring the air volume. He modified the airbox versus the stock airbox used a K&N filter versus a paper filter and found out that the standard airbox gave 125% air that the engine needed without any mods. Therefore leave the standard one alone and buy paper ones. I would just change them every eight or 10,000 miles or once a year.

 

I just use the stock paper ones.

 

I just removed my airbox to repair the broken studs and mount on top of the radiator housing. Some jamoke had put two giant bolts with nuts in place of the correct mounting studs and I could not get them off (rusted) without drilling them. I bought a pair of the correct mounting studs and screw caps, but I had to do some work to get them to fit snug because the mounting holes were very enlarged. While I had the airbox put I checked the filter to make sure it was brand new (good to go) and noticed the loose black plastic air flap just lying underneath the box.

I pulled it out and cleaned it and vacuumed the surrounding areas that had some leaves and debris and put it back the way I found it. I assume it just lays in there and somehow directs air flow into the front of the air box? Also, I wanted to advise members that when you remove the vented airbox cover to replace your filter, make sure you put it back with the louvers in the correct position. They are angled a certain way so air from the plastic air dam from below directs air up into the airbox cover. If you install the vents the other way I think you might disrupt the air flow.

Thanks,

Ted

 

In a lot of cases I've seen a clean stock filter perform equal to most all "expensive" aftermarket filters. K&N has been demonstrated several times to not filter nearly as well as most other options but, is reusable and that is it's draw. Mine came with it on it. It shrank over the years. K&N replaced it no questions asked so I'll continue to use it. I would not, and do not, run one on my daily for the oiling issues above with MAF sensors on new cars. I do lube it properly but it always seems to seep some oil out regardless. I don't not like the product as it does work and is quality. It has it's place. I just would save the money as for most people with the way they drive these cars, a filter is a once in a lifetime of ownership change...

 

On my 90 the combination of K&N, cut out air box and air foil in the throttle body made mine a lot more throaty and snappy/responsive, not sure if I got any actual horses from it but I'm happy with the setup.

 

I have run the K&N in a couple Corvettes . In between the hazzle of cleaning I had a nice clean stock AC filter to install while waiting for the K&N to dry. I removed the K&N from my 91 ZR1 and currently running a stock AC . Marc Haibeck built the engine in my car. When he runs the car on a chassis dyno for h.p. and torque numbers it's done with no filter at all. This is the least restrictive . He's tested clean new factory style filters verses a filter with some mileage . A clean new OE filter is worth only a few h.p. loss over no filter. Many say the K&N allows fine dust and dirt that a factory OEM doesn't. I've seen videos from motorcycle engine builders showing bikes run with K&N filters and the pistons and liners had lots of scratches . They recommended not running a K&N on their builds . I live in Southern Pennsylvania lots of farm land and fields all around . I decided a few h.p. loss isn't worth the possibility of not trapping dust , sand , etc . There are other filters that claim to be better than the K&N like the green ones that seem to trap more particles than the K&Ns material . Is it really worth the few ponies ? If I remove the spare tire , tire carrier, brackets , jack and handle I would gain all that back and more .

I just reviewed Haibecks website. He tested a combination he built on a ZR1. It made 419 h.p. @ the wheels with a ported air box no filter . Then he ran the same car with an OEM AC Delco air filter with 500 miles on it . The power loss was 3.2 h.p. . The filter was an older gold or yellowed AC Delco element . He's tested the new white element Delco made in China and power loss is the same .

Weight reduction on a 400 h.p. ZR1 that weighs 3500 lbs is for every 8.75 lbs removed its like adding 1 h.p. . The spare tire alone is 37 lbs . I haven't had a flat in any of my Corvettes ever .

 

That's actually a splash guard. It keeps water from getting into the filter box.

It installs like this...

 

K&N filters in general have some pro's and cons. Yes they let more air pass. But that rarely equals more power. The factory did a very good job of making an air box and a paper filter that will pass more than enough air to feed your engine. The pro of the cotton gauze wire filters like a K&N are, they are washable. They also deal with water much better than a paper filter. The cons are they do not filter as well as paper. Also they are more expensive in the short run. I've run them for years in ATV's that will go through mud. I use an oiled foam wrap over them to help add filtration for on dusty roads. I also used one on my LS swapped 84 because I needed a universal cone style filter to make it work.(Not a factory air box).

So if you want a washable filter and you don't live on a dusty road then I say go for it. But don't get one to gain power. That's what cams are for.

 

Thank you for posting the information on the air intake "deflector" but I think it would decrease air flow a ton if that is in fact how it should be installed. I'll have to remove the front portion of my air filter box and see if it will fit that way. It is pretty thick ABS plastic that doesn't bend too well. I don't recall seeing the attaching clips on either side of the deflector to hold it in place. Mine was literally laying underneath my air box.

BTW, it sound like we have numerous members on here running K&N filters. I would just recommend the spray type oiling kit from K&N that comes with the cleaner pump spray and aerosol spray oil. All you have to do is lightly mist the oil spray after the filter has been cleaned and dried completely. I've used them on at least two vehicles in the past with no MAF issues.

Good luck!!

Ted

 

I've always thought the same. It seems only logical that it would indeed restrict the flow of air a great deal when installed ''correctly.''

But that's how it gets installed. So they say.

Here's a previous thread on it...

https://www.corvetteforum.com/forums...installed.html

There's also a link to a Mid America pdf in that thread with installation instructions. Though the pictures in the pdf are crumby.

A lot of people just toss em. It's not like many folks are really driving through standing water or making a habit driving these cars in the rain anyway.

 

I wouldn't bother with a K&N air filter. The last time I ordered from Rock Auto, I got some Pro A/C-Delco air filters. They are like the regular air filters, but there is a foam piece on the top.

 

No....it's a waste of money. End of story, full stop......Just get an open air lid and factory filter. Do NOT waste your money on one.