Been searching the forums for peoples thought on aftermarket intakes and two major point to make a worthwhile upgrade is to replace the resonator box infront of the throttle and the snorkle at the fender.

Then the whole tubing becomes debatable and lots of personal opinions come into play.

I was just wonder how restrictive the air resonator box was?

The snorkle you can see its restrictive by design for reducing flow, but the air box doesn't seem to be so.

 

Yes it is restrictive: Air Doc Performance Intake System H367

 

The intake resonator box does on a disrupt the flow by design, which helps to quiet motor noise, but not to a degree that effects performance.

For a rig with an otherwise stock AF system the OE air intake provides more air supply than the motor can effectively use, even at WOT which most folks never see.

I have yet to see any actual Dyno figures on the Hummer I5 that prove any gains. From a seat-of-the-pants perspective a high-flo intake will certainly sound different, but on stock smaller displacement motors they rarely show any actual significant gains.

 

The I5s respond very well to intakes. Better than most.

Every OEM intake made supplies enough air for the vehicle application's maximum motor displacement, Doh!

Just because OEM is adequate, does not mean it is efficient, effective, or delivering the best possible performance. The resonator box is a muffler in reverse, to quiet the intake noise so as not to scare grocery-getter soccer moms/dads when they hit the gas leaving the mall. OEM exhaust systems are also capable of expelling the maximum exhaust volume generated, but it doesn't mean they perform optimally either.



Here are some "actual I5 dyno numbers".
2007 bone stock in every respect 2007 3.7L Colorado with just and intake.


That's 2+ HP up every cylinder, which is better than many V8 trucks that may pick up 12-14HP (less than 2 HP per cylinder). When you actually test them, you actually know what happens, no need for speculation.

 

An intake is just one piece of the performance puzzle. Add a PCM tune, Efan conversion, CAT back exhaust, PP TB an I5s grow some serious ***** with plenty of low end torque.

 

4500-5500, in the old days that was redline. thank goodness we can run there now with nothing to worry about.,,xcept,,,
thats where the 8 horsepower comes in AND according to my new handy scanguage 2 trip computer i get about 4.3 miles per gallon ave!!

no, i dont want to run in 2nd gear to feel the "horses"!
just where is the lo-end tork??

in normal driving i dont think i ever hit 4000 rpm. only decent mileage is 2000-2500. above that you are less than 8 mpg. how about a mpg chart huh??
i think ill get one tomorrow

 

Well Tom, nobody needs an intake, but many want one.

I don't know about you, but when I've been following some old geezer in a camper with bicycles strapped on the back towing a boat on a 55 MPH two lane road for miles and miles at 42 MPH (with IN plates ), and openings to pass have been few and far between, I want to rap the throttle and see him get in the rear view mirror as a crappy memory ASAP.

 

you couldnt possibly pass him in a stock h3,that 10 hp at 4768rpm just barely makes it,,,ifn u catch a downhill stretch,yeah thats it

 

Why don't you go rag on every member who posts about their preferred mods with your senseless comments.

Personally I don't give a rat's butt about roof racks, HID light conversions, cha-cha 18-20" wheels, rubber band tires, chrome bling, sub woofers, head rest DVD players, light switch & diodes, fuzzy dice, and a whole bunch more stuff that other people do. The fact that you do not get it when it comes to performance mods is abundantly clear, and we know it is not your bag of tea.

You bought an Alpha after an I5, does it have more power? Why? Apparently you only need a horse drawn cart, or just a good pair of shoes, but you chose to move up in the power department. Is it more fun to drive? Or do you only use the first 242HP, or just the last 58?

 

Doc- Looks like any HP or TQ gains on your graph all the way up to 4500 rpms aren't very relevant. The appreciable gains fall between about 4500-5000 rpms which unfortunately are so high in the powerband that they are rarely encountered in most normal driving situations. Even when I engage passing gear in my H3, the RPM's rarely exceed 4000-4500 RPM even at WOT, unless I stand on it for longer than needed.

That being said, the gains you've shown at high RPMS are more than I anticipated, especially in torque. Thanks for posting


And I agree completely that to really see significant gains, the combination of intake, AF delivery, and exhaust upgrades need to be performed.