Was your K&N Fuel Injection Performanc Kit Worth it?

Hiya folks. Today I find myself rather curious about the actual increase in performace attained by installing one of these K&N fuel injection performance kits. If anybody here has actually installed one I’d love to hear how satisfied you are. At first glance it looks like a nice little performance boost without spending a ton of money and it might even be an easy do it yourself project. I’m more likely to just pay somebody competant to install it though.

I know it’s not going to be like strapping a jet engine on to the roof and holding on for dear life. I’m just a little curious as to how much quicker you go from zero to sixty and how much easier it is to initiate a pass at highway speeds.

For the record I don’t race at traffic lights and I’ve only tested the top end of my car a couple times. I chickened out before the car did so it’s not like I really need any more performance. It’s just fun sometimes to punch it and giggle my ass off.

I don’t have any specific knowledge or experience with how well these work. I do have a general understanding of engine design and performance, and I’m skeptical that they perform as claimed.

Although it has the fancy name “fuel injection performance kit,” it’s essentially an air filter. The unalterable (practically speaking) limit on airflow into the engine is the throttle opening. This kit could only improve performance if the air filter was restricting flow to a level below what the throttle could admit. I am dubious that this is the case. As far as improving gas mileage, I can’t think of how an air filter could possibly do that (other than the obvious replace a very dirty filter with a new one - which would also improve performance).

Some of these filters get thrown away and replaced with conventional ones, due to the owner and/or mechanic not having in mind it’s meant to be cleaned and re-used. If that happens, it makes it a pretty expensive temporary filter. If it doesn’t happen, it needs to be cleaned at some point, which can be a pain in the neck. Paying a professional to clean it could offset any savings from its being permanent.

I’d be very surprised if they improve performance any more than chrome plated oil filler caps do.

I’m not a racer, but it was my understanding that better fuel injectors only helped when your stock injectors were INCAPABLE of injecting enough fuel for the amount of air in the engine. I would think this would only happen on forced induction cars.

I have often heard from ricers that replacing your intake, headers and exhaust with a better breathing/flowing units would noticably increase your gas mileage. I’ve even seen some of them claim they have empirically measured this. I’m skeptical, but i’ve heard it from enough seemingly intelligent people to give it a little credence. What do you think Gary T?

Correct, but note that the “fuel injection performance kit” has nothing to do with the injectors (and in fact, nothing to do with fuel injection per se) - it’s just an air filter, and in some cases perhaps its housing.

What you mention are the traditional first steps in performance improvement. The better breathing can improve efficiency which means better performance and better mileage. I doubt there’s as much to be gained with modern engine designs as with older carbureted systems, but I would expect improvement over stock for most cars.

Usually the first step was headers, as the exhaust manifold was typically the biggest obstacle to engine breathing. Next step was pipes/mufflers, which now can’t flow what gets through the headers. Next was carburetor (obsolete now, of course), or better yet intake manifold and carb. At this point it’s worth considering an air filter housing, if its intake area is restricting total flow.

When I checked the K&N site, it appeared that for some models the “kit” was just an air filter, but I imagine many (most?) include the filter and its housing. I have serious doubts that the kit alone would improve breathing on most designs, if any, as I would expect restricition in the exhaust and intake manifolds to be the primary limiting factors.

One caveat about performance modifications. Even in the old days, before electronic control systems (computers), it was possible to get into trouble. I recall that on Jaguar 6 cyl. engines, headers would scavenge the cylinders so well that the engine could run dangerously lean and burn valves. With modern systems, the possibility of unintended effects is quite a bit greater. Proceed with caution.

Thanks for the great input Gary T. Everything you said makes sense and I don’t want to waste my cash on a placeebo effect or worse yet damage the car. Maybe I’ll put the cash towards a performance driving course so I can get the most out of what my vehicle will already do. Or maybe just window tinting.

Wise words. Thanks again.