Intake for Liberty's

[02libby]

I have read that is does not benefit the Liberty to install a cold air intake on the 3.7 liter. Has anyone installed one and seen gains in mpg? It seems the stock one would be restrictive as to where the snorkel brings air into the engine (smashed into the hood). Just wondering. Looking how to get better mileage out of my Liberty.

 

[JJsKJ]

I have read that is does not benefit the Liberty to install a cold air intake on the 3.7 liter. Has anyone installed one and seen gains in mpg? It seems the stock one would be restrictive as to where the snorkel brings air into the engine (smashed into the hood). Just wondering. Looking how to get better mileage out of my Liberty.

The cost of an aftermarket intake is hard to gain back in mpg. You would be better off just putting that money into new plugs more often and keeping the maintenance up. The factory air box flows a lot of air, more than the 3.7L can use and it also picks up cold air at the edge of the hood where an aftermarket intake would pick it up underhood where the heat is. Just toss a fresh Wix filter in occasionally and drive w/ a light foot and keep the tire pressure up and that is about as good as you can do for better mileage on a KJ.

 

[CRD4Liberty]

That's just it, you've heard enough aftermarket spin that it "seems" that the stock unit couldn't possibly be good. The fact is it's a very well designed unit, and so are the intakes on a lot of other rigs out there. In the old days we changed filter, carb,intake manifold and matched the ports to get more usable power. Now they just want to change a little plumbing that they charge you up the hindend for, and it's supposed to do the same thing. Well it's bullpucky. Today manufactures have to produce a unit that gets good power AND fuel mileage, the people and the government requires it, back in the old days we didn't concern ourselves with mpg when gas was 37 cents a gallon. 4WD&SUV mag got 2.5 mpg better mileage on their modified Liberty after a exhaust and intake change.
Now just tell me how long you'd have to drive your rig to make up the $500+ price tag at the pump. They dynoed a whole 4 ft lb more torque and about a whole 2 hp difference. Sounds spendy for what you get to me.

 

[indieaz]

I'm not going to pretend to be some master engineer - but I"ve got some experience building high performance engines. And I will tell you that the air intake and exhaust systems on the liberty are more than adequate for the 3.7l engine we have. The money you will waste on exhaust and air intake are not going to be worth it. Not to mention the downside of a "cold air intake" system on this vehicle - which is that you don't want one when you drive through puddles etc. The best thing you can do for fuel economy is to be light on your gas pedal and keep the RPMs low.

 

[02libby]

noted... thanks for all of the info. I will keep the intake the same. 2.5 mpg difference and 4 more ft lbs of torque are definatly not worth the time and $.

 

[indieaz]

4WD&SUV mag got 2.5 mpg better mileage on their modified Liberty after a exhaust and intake change.

In my opinion their test is pretty much invalidated. I'm wondering how many miles they drove to test that 2.5mpg difference. Did the same driver drive the vehicle...was the weather identical? Probably none of hte above. I can get 2.5mpg difference in my liberty between me and my wife driving it...and nearly that much depending on how hot/cold it is and humidity level changing the intake charge air density.

The real thing that makes me question that 2.5mpg improvement is the 4 lb-ft of torque they got on the dyno. Generally speaking you can dyno the same identical vehicle 4-5 times in a row and your results will vary by as much as 1-2% each run. Basically they spent $500...and the reality is they probably got next to nothing in return.