ika667

Hey Everyone,

Question for you all, what's the deal with cold air intakes? I search the net and got a bunch of mixed feelings. Some say it does a difference, some say it don't. What do you guys think? Also, I got the same mixed feelings about performance chips and exhaust systems. If they are all crap, then how does one increase HP?

CrazyWJ242

well i've got one... heres what you need to understand about "cold air intakes" and how they work and why and why they may not.

#1 is the wonderful thing called vacuum
this is how much air the engine is trying to suck in while running... Engines are Air Pumps, (Air Intake and Exhaust system) if you have nasty restrictions in the system on either side, the vacuum wont operate efficiently (think of blocking the hose on your vacuum cleaner)

Alot of factory air intakes are very restrictive, so thats where a "cold air intake" would be beneficial.

#2 getting into the cold air aspect. basic thermodynamics indicate Hot Air Rises, (and of course heat coming from the engine, radiation and will heat up the air around the engine) so alot of these cold air intakes pipe down into a wheel well or behind a headlight and pull air that is not affected by the engine temperature.

Colder air is more Dense, offering significantly more combustion than warmer air, this can yeild more HP which is likely to be an efficient burn of the fuel used, not necessarily more fuel. (02 Sensors will adjust all of that for you)

#3 another thing to consider is actual length of the piping used, shorter piping will offer higher throttle response since theres less distance for air to travel from the Filter.

#4 Ram Air... this is a tricky one, "forcing" more air by having a nearly direct airflow to the engine with minimal restriction could yeild more power but i cant see how much more than an efficient "cold air intake"

#5 Forced Induction... this works right... how does it work, well your pumping the air into the engine, this causes less work for the engine itself, so it can pump out air more quickly... and thats our segway to the next one.

EXHAUST.

Simple Horsepower Mathmatics.
Air In + Air Out = Horsepower (not necessarily efficiency)

you know where your vacuum cleaner blows out all of the air... well if you block it all up, it'll barely suck anything in! (like it does with a dirty filter but more on that later) the flow in and out has to be somewhat equal to be efficient. so if you have a restrictive exhaust with a ton of bends you could be hurting more than your helping... and Im not going to get into tuned headers LOL but yeah theres alot you can do to get the most out of the exhaust)

where was I Ahh filters... the things most people complain about...

#1 K&N Filters suck as a filter. they'll let in more dirt than just about anything else out there...so thats where a bunch of grumpy old men will go on about it. paper filters are great filters but offer significantly lower flow rates... this may increase the vacuum again, which means its reducing the flow.

#2 these things will reduce low end torque... not necessarily true, you can set it up so you can have power where ever you want it in the power band really, its just alot of figuring out how your machine is running...

as far as tuners&chips go it'll only estimate so far, the best method is to dyno tune so you can see exactly how much and where you need it, its not something thats available on all jeeps...

As far as my Jeep goes, its got quite a few things going on for the power its making. and i'll cover that in a new post lol

CrazyWJ242

Ok i've got a 4.0L great engine, love the thing. theres a ton of work to do to it but...

you've got a 5.2L right... theres a couple things available for it... and ones practically free.


5.2L and 5.9L throttlebodies



basically using a Dremel to cut down the walls on the top of the throttle body, the walls are there to protect it... but why... its got a cover protecting it...

what does it do:
when your at partial to full throttle it'll actually be able to suck in extra air and bring it down into the engine, much less restriction. (then theres half shaft mods, countersunk screws and sharpening the plate that will yield more power)

Another thing you can do is put in a lower temperature thermostat... 180degrees is what most people will put in... I have the name crazy for a reason... i went 160 degrees... it kills MPG but its a real feel 10 hp there with the 160... again the lower engine temperature, colder denser air which burns more efficiently...

WJCraig

Today...went wheelin'...Pics in the pic section, for the poor Canadian Jeeper stuck in the south...

CrazyWJ242

you guys are going to make me want to tackle Uwharrie again sometime in the near future... 16 mile single track with bypasses for those without lockers and tons of lift... i hate going around the fun stuff lol

but its as good as it gets before heading all the way over to the mountains...

04WJGuy

Nothing like wheeling through the big cedars. Now I'm getting homesick.

ika667

Hey man just wanted to thank you for all your helpful info, that's a lot! Cheers!

CrazyWJ242

Yeah i realized about half way thru it was alot of info... but i think it its pretty understandable lol...

today i picked up a couple tires for the WJ, going to go mount and balance after supper.. im freaking starving... after that its finish up the onboard air project im just going to add a bit of oil now and then not have it automatically feed in...

04WJGuy

Mike did you check out the CB pics I posted?

CrazyWJ242

Yea i did, i think the one im looking at might be just a little bit bigger... i dunno, i probaby sit a little closer to the dash than you do, so it might be in the way for me... i might disconnect the F250's cobra and mock it up and see how it feels...

i like that its out of the way, so and the lights shouldn't be too bad down there... its looking like it could be the ticket...