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bdecker
05-02-2008, 12:26 PM
I'm considering installing a K&N Cold Air intake on my 6.0L Yukon. Given 13.5 MPG I'm getting now, if it returns the gas mileage returns advertised, it should pay for itself quick. I'm considering a series 63 or 77.

Does anyone have experience with these? Are there any downsides? Are the performance and mileage gains legitimate? How significant is the noise issue?

flipper
05-02-2008, 12:33 PM
I've put them in cars before, with little to no difference really. Or not much of a noticeable one. Maybe a little more power, but didn't notice much of a difference in MPG. As far as the noise, you don't really notice it until you stuff your foot in it. And what they advertise is in a perfect world, then stretched a little. Over all, I don't think they are really worth the price.

Carbon Dreams
05-02-2008, 12:53 PM
You cannot expect to open up one end and not the other. GM (OEM) exhaust systems are notoriously restrictive. Install a 3 inch pipe with a flowmaster along with a better intake, and you will likely see 2-3 mpg increase as well as more power. Hyperchip is also a good addition.

OhioX14
05-02-2008, 02:36 PM
If this is like the one my nephew put on his Acura it routed the intake down to a wheelwell. First big puddle he drove through sucked a bunch of water right down the intake. Car hasn't been the same since.

jraben8
05-02-2008, 03:07 PM
I wouldn't spend the money on it again unless you're doing exhaust too. Even then I'd be very pleasantly surprised if you see anymore than a 2 mpg increase...

Now, electric fans, that I'm thinking about instead of the clutch driven fan on the front of the motor.

Prostar Rich
05-02-2008, 03:36 PM
If this is like the one my nephew put on his Acura it routed the intake down to a wheelwell. First big puddle he drove through sucked a bunch of water right down the intake. Car hasn't been the same since.


This is an excellent point. You do not want to have an exposed filter on a daily driver. I am not sure if the K&N set up is like that but if it is I would not install on for fear of water being ingested into the engine.

Prostar Rich

jraben8
05-02-2008, 03:42 PM
The units for the trucks are made to sit and replace where the OEM airbox is located up above and in front of the wheel well generally behind the headlight.

FrankSchwab
05-02-2008, 03:45 PM
I guess I just don't understand thermodynamics.
Cold air intage? Sure, it should increase power - denser air, more atoms of fuel/air in the cylinders, more power. Better MPG? I just don't understand how - assuming that the carburetion or FI is putting a correct mixture into the cylinder, the power you get out of the engine is based on how much fuel is getting burned. All cold air gets you is more power for a given throttle setting, but you're burning the same number of hydrocarbons for the same power level..
I guess if hot air increases knocking, then cold air might allow the ECU to give you slightly more power from a given amount of gas by running a leaner mixture or more spark advance.

With the emphasis on CAFE (corporate average fuel economy) regulations, any manufacturer who could increase the average MPG of their trucks by 2 MPG would save tens of millions of dollars every year. Considering that the cost differential of doing this would be pennies for the manufacturer, simple capitalist economics would dictate that every manufacturer would have done this already. The fact that they haven't should tell you something about what their testing has uncovered.

/frank

jraben8
05-02-2008, 03:55 PM
Part of the problem with these is the fact that they are sucking in hot air from the motor anytime that you aren't moving say 15 mph or so.