K&N Air System opinions please...

[Poe1983]

I'm not really a big mod guy. I love my truck the way it is. But if there was ever anything I've considered to do on it it's putting a K&N system on it. Basically what I want to know is would I get at least an extra MPG out of it? And what could I expect performance wise? Consider the fact that I have absolutely no other mods on the truck. Answers are greatly appreciated :cool2:

 

[Black Dog]

Nah, I don't think you'll see a gain like that, maybe lucky enough to see 1/2 a mpg. When I put mine on I did think I saw 1 mpg, but then later it was gone, back to normal. I think the extra flow causes it to run lean, burning less gas, but then in time the computer adjusts it out to make it a normal mix. So could end up burning more, except for the following: You will probably see better responsiveness, and maybe a slight gain in power, causing a sensitive throttle foot to go a little easier on the pedal to get the same results as before. I did feel that it was breathing better and more responsive. Also, you can hear it growl when you accelerate (because the silencing bladders are gone), it's cool but it also gets overridden if you add an exhaust. Just make sure whatever system you get is a sealed off "cold air" box, as the factory one already is and you don't want to sacrifice that benefit. Bottom line though is the apple is higher on the tree than it used to be, but there's still a small amount of benefit to it with a good system.

 

[Stargazer]

I've never heard of intakes improving MPG significantly, but was wondering if the 17.5 HP gain that K&N advertises for their FIPK was realistic or not.

If there was a gain like that, I'd probably see my MPG go down .

 

[TN Tahoe]

I've never heard of intakes improving MPG significantly, but was wondering if the 17.5 HP gain that K&N advertises for their FIPK was realistic or not.

If there was a gain like that, I'd probably see my MPG go down .

If you look at K&N dyno testing chart the 17.5 HP gain is at the top of the RPM band which means unless your going to keep your foot on the floor most of the time your not going to feel the gain in HP.. so much for MPG..

 

[73shark]

If you look close at the OEM stock system, you can see that it is already a CAI w/ a fairly now restrictive tube. The only difference I noticed w/ the GM CAI was a slight increase in induction noise at WOT. Not much tho as the stock system was pretty loud.

 

[Poe1983]

Nah, I don't think you'll see a gain like that, maybe lucky enough to see 1/2 a mpg. When I put mine on I did think I saw 1 mpg, but then later it was gone, back to normal. I think the extra flow causes it to run lean, burning less gas, but then in time the computer adjusts it out to make it a normal mix. So could end up burning more, except for the following: You will probably see better responsiveness, and maybe a slight gain in power, causing a sensitive throttle foot to go a little easier on the pedal to get the same results as before. I did feel that it was breathing better and more responsive. Also, you can hear it growl when you accelerate (because the silencing bladders are gone), it's cool but it also gets overridden if you add an exhaust. Just make sure whatever system you get is a sealed off "cold air" box, as the factory one already is and you don't want to sacrifice that benefit. Bottom line though is the apple is higher on the tree than it used to be, but there's still a small amount of benefit to it with a good system.

I figured the 1mpg was a stretch. For a truck that has no mods, and I have no plans for any mods, what kind of intake system do you think would best suit me if I'm looking for a little easier acceleration with just a bit more horsepower?

 

[Dr. Overkill]

I figured the 1mpg was a stretch. For a truck that has no mods, and I have no plans for any mods, what kind of intake system do you think would best suit me if I'm looking for a little easier acceleration with just a bit more horsepower?

Don't do it for power or MPG because you're probably not going to get it, as others have posted. Even Truckin magazine once, surprisingly, said that much of the HP gained after installing one particular intake was eliminated after logging some miles on the truck (they did two dyno pulls). The computer will compensate.

If you do an intake, do it because you like the sound or because you don't want to be filling up the landfills with disposable air filters every X miles or just because it's kewl. But don't expect meaningful performance gains.

I don't know if K&N makes a true cold air FIPK. Mine certainly isn't. Sure, it sorta seals against the hood insulator, but the ends of the box also stop short of the inner fender by 3+ inches, allowing only hot engine air into the intake. I'm planning to box in their box and seal it against the fender so it will draw only cooler air rather than hot engine air. Maybe I'll see that magical HP or MPG then

_dennis

 

[Black Dog]

I figured the 1mpg was a stretch. For a truck that has no mods, and I have no plans for any mods, what kind of intake system do you think would best suit me if I'm looking for a little easier acceleration with just a bit more horsepower?

I think as a stand alone mod it is what it is, but I believe that when you add other mods the combination of them all can add up to an effective package. So having the CAI could help the exhaust, ignition, tuning mods reach their full potential. That's really why I got it, so with exhaust and a tune, etc. I can try to make it optimized and not have one end or the other restricting the potential.

Anyway, I can only endorse the GM Performance because the way it looks and fits is excellent. Not sure but I heard it was made by either Airraid or AEM, two other good quality systems. And then there is Volant, which is like upper crust in bling, fit and finish- expensive like the GM. I don't think K&N is anything to write home about like they used to be, I think it's not a true "CAI" in most cases, and try to avoid oiled elements if you can. I think if it's just slightly over oiled it can interfere with the air metering.

 

[Black Dog]

And yeah, they all say 15 or 20 HP, but like said above it's at friggin redline, a place you should try to avoid in a heavy rig. I want low end power, low to midrange torque!

 

[Dr. Overkill]

So having the CAI could help the exhaust, ignition, tuning mods reach their full potential. That's really why I got it, so with exhaust and a tune, etc. I can try to make it optimized and not have one end or the other restricting the potential.

Actually, there's another good point. If the rest of the system is restricted, it doesn't matter if you open up just one end. It won't necessarily breath better unless flow along the entire pipeline from start to finish is improved. Vortec and later heads breath pretty well, and the OEM exhaust manifold breaths pretty well (although ditching mine for headers had to shed at least 40 lbs!). But you might consider high flow cats and a decent cat-back to help open it up on the other end. Regardless, I still think the computer is going to adjust to these changes and diminish gains to some extent.

What cracks me up is seeing the import racerboys with big ol' fart cannons clamped onto tiny pea shooter exhausts--I hope they don't think this actually increases flow :smilielol:

 

[KSEngineer]

MPG Mod Report

I'm not really a big mod guy. I love my truck the way it is. But if there was ever anything I've considered to do on it it's putting a K&N system on it. Basically what I want to know is would I get at least an extra MPG out of it? And what could I expect performance wise? Consider the fact that I have absolutely no other mods on the truck. Answers are greatly appreciated :cool2:

I have a 08 Tahoe purchased in Oct 07 currently with 23,000 miles. Up until +/- 5000 miles I was averaging 17 to 18 mpg driving 65 to 80 mph with the stock setup. I wanted to stay in the good graces of GM and enjoy some hp and mpg gain so I went had the dealership install a "touring" exhaust and a cold air intake. I averaged 14.5 mpg for the next 15,000 miles until I changed the cold air intake back to stock. I am now back to getting 350 miles plus before the filling up and getting 16.5 to 17 mpg + mostly hightway miles. I am convinced that the mods cost me fuel economy. I had a good discussion with a mechanic that made sense to me that basically observed the the mass air flow sensor causes fuel to be injected into the engine to achieve a air/fuel ratio. The more air the more fuel...... The intake did have a drone at 70 mph plus that was noticeable that has gone away since I switched back to the stock intake. If you are after performance I would consider intake and exhaust mods and would go one step farther considering a custom tune. If you are after mpg I would leave it stock and enjoy the gm factory tune and keep your foot out of it............based on my experience after mpg I wish I had left it all stock.

 

[73shark]

While the logic is good, wouldn't more fuel and air create more power and thereby allow less throttle to maintain same speed? Seems like it would be a wash to me.

 

[Black Dog]

While the logic is good, wouldn't more fuel and air create more power and thereby allow less throttle to maintain same speed? Seems like it would be a wash to me.

Exactly what I was trying to say. Methinks someone's gas foot was maybe making a few adjustments of its own, in the other direction...

 

[KSEngineer]

While the logic is good, wouldn't more fuel and air create more power and thereby allow less throttle to maintain same speed? Seems like it would be a wash to me.

I use cruise control. I agree with your thoughts and the logic and logged 15,000 miles trying to prove you correct (to myself) but I have convinced myself that while cruising at the same speed and rpm with the CAI it was letting more air through the engine thus using more gas. Maybe a custom tune would adjust the computer to regain or even gain fuel economy with the custom setup. With the stock tune in my truck it was costing me money in mpg. I did not want to adjust the factory tune for warranty issues. I have even played with folding my side mirrors in while on the highway to reduce drag and run with the ac compressor off. I don't want to come off sounding like I am over the top anal about fuel economy but I have payed attention to fuel economy with the miles I drive.

 

[Black Dog]

It sounds like you have payed attention, and I was clowning around with my comment above. I tell you though, when I did mine, I too noticed an mpg gain at first, I was stoked that it was so noticeable. Then sure enough, it adjusted down to nothing. But I never noticed a negative drop though; but then it wasn't long after before I added the exhaust too. With that added, it still looks like the same as before. I gotta admit though that if you put the stocker back on and noticed an increase, that's a test I haven't been able to experience. So, sorry if my comment put you down.

 

[KSEngineer]

It sounds like you have payed attention, and I was clowning around with my comment above. I tell you though, when I did mine, I too noticed an mpg gain at first, I was stoked that it was so noticeable. Then sure enough, it adjusted down to nothing. But I never noticed a negative drop though; but then it wasn't long after before I added the exhaust too. With that added, it still looks like the same as before. I gotta admit though that if you put the stocker back on and noticed an increase, that's a test I haven't been able to experience. So, sorry if my comment put you down.

I didn't take your comments the wrong way. I think the computer and each individual engine could have a slightly different outcome. If I didn't drive so many miles I wouldn't have bothered switching back. I feel that I have fairly good data because I run full tanks of gas out of my truck on the highway. I didn't mix a lot of in town driving with highway miles together for the comparision. We didn't buy these things for fuel economy anyway. If it were just a weekend toy I would have a supercharger on it.