H3 Performance Intake Systems
Joined: Apr 2006
Posts: 7,253
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RE: H3 Hummer Performance Intakes Systems
not to knock the product but I don't understand....the airbox is the most restrictive part of the stock system. Air goes from the airbox to the MAF then to tophat....by keeping the stock airbox you are keeping the amount of air to the MAF the same...so the computer will not recurve the air/fuel mixture to make more power. It may smooth out the airflow but won't pull more air because the stock airbox just wont allow it...this has been tested extensively by chevy high performance in the past...I just don't understand.
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Super Moderator
Joined: Jul 2007
Posts: 13,098
From: Boat Town USA MI
RE: H3 Hummer Performance Intakes Systems
Yep, into the fender IK.
The factory set up is a plastic moulded tube within like a sleve/bushing that then slides into the air filter box. The factory intake snorkel is appx 6" long and less than 2.7" inside diameter and has that padded flange up against the inner fender. From the outside it looks a lot bigger than it is?
I repalced that with a 3.5" I.D. to 3.0" I.D. funnel shaped snorkel to open it up some. Not rocket science, but more air is better. See what I mean, measuring tape is at the inlet side:
Pic of the AirDocIntake snorkel that replaces the restrictive stock tube.
The factory set up is a plastic moulded tube within like a sleve/bushing that then slides into the air filter box. The factory intake snorkel is appx 6" long and less than 2.7" inside diameter and has that padded flange up against the inner fender. From the outside it looks a lot bigger than it is?
I repalced that with a 3.5" I.D. to 3.0" I.D. funnel shaped snorkel to open it up some. Not rocket science, but more air is better. See what I mean, measuring tape is at the inlet side:
Pic of the AirDocIntake snorkel that replaces the restrictive stock tube.
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Joined: Nov 2007
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RE: H3 Hummer Performance Intakes Systems
Not to be party pooper, but the resonater assembly was removed thereby eliminating a source of air to reduce hesitation/starvation and noisein relation to your foot. The revalence to velocity/vacuum then had to be maintained buy opening up another source of air to compensate for the removal of the original source. The filter box is not nescessary your restriction but a noise reduction and heat/moisture barrier. Your Paper filter is the restriction and piping. If you put a vacuum gauge on a stock setup(around or after the resonater)and measure it, and then put it on the modified setup (in the same area of your first measurement)you should see the difference in the rise rateand the speed to which is rises and desends according to your throttle input. Plus your NA engine has a max cfm requirement at WOT once that is reached it doen't matter regarding the opening.I could beCOMPLETELYWRONG here, but I base it on experienceand the basic commonality in all oem vehicles.
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Joined: Jul 2007
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From: Boat Town USA MI
RE: H3 Hummer Performance Intakes Systems
You lost me Gunny? This is ridiculously simple.
The resonator box can't prevent starvation when in the H3 system because the air within it cannot move to the throttle body without air entering the intake system. Example, take a straw, hold it perpendicular to the horizon, suck water in it, put your finger on top, the water will not leave the straw until your finger is removed from the top!
The faster air can enter the system, the lower probability of starvation. Starvation probability with a 3.5 or 3.7 liter with a 3.5" I.D. intake pipe is irrelevent because the total air volume wihtin the system at idle is more than the engine can conbust. WOT results in a LARGER volume of air through the AirDocIntake than the stock system with resonator box can possibly provide because the stock intake snorkel to the air filter box is less than 2.7" I.D. and the numerous obstructions within the stock system (ie. the stock accordian intake hoses and resonator box) create drag/obsticals to the intake flow. It is like porting and polishing a intakerunners in a head,smooth the head of any obstructions or burs, air flows faster, motor makes more power.
In other words, that is why AirDocs have a 3.5" pipe instead of the 3" tube used by the competition.
The resonator box can't prevent starvation when in the H3 system because the air within it cannot move to the throttle body without air entering the intake system. Example, take a straw, hold it perpendicular to the horizon, suck water in it, put your finger on top, the water will not leave the straw until your finger is removed from the top!
The faster air can enter the system, the lower probability of starvation. Starvation probability with a 3.5 or 3.7 liter with a 3.5" I.D. intake pipe is irrelevent because the total air volume wihtin the system at idle is more than the engine can conbust. WOT results in a LARGER volume of air through the AirDocIntake than the stock system with resonator box can possibly provide because the stock intake snorkel to the air filter box is less than 2.7" I.D. and the numerous obstructions within the stock system (ie. the stock accordian intake hoses and resonator box) create drag/obsticals to the intake flow. It is like porting and polishing a intakerunners in a head,smooth the head of any obstructions or burs, air flows faster, motor makes more power.
In other words, that is why AirDocs have a 3.5" pipe instead of the 3" tube used by the competition.
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Joined: Jul 2006
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RE: H3 Hummer Performance Intakes Systems
My first "normal" driving condition(s) results are in as far as Mileage goes.
242.1 Miles - roughly 50/50 highway and stop/go driving
14.25 Gallons - 87 octane
MPG - 17 (16.989)
I had the car off when I filled it, andwith the lasttwo tanks used the same pump at slow speed with auto cut-off. I know it's not any kind of scientific testing method, but it's all I have for ya right now.
Considering the circumstances, I think in my situation 17 MPG is decent. I'm trying to do all highway miles now starting today, with no stop-and-go since I'm working some early/late hours and haven't hit traffic. I'll see if it goes up at all by the weekend.
242.1 Miles - roughly 50/50 highway and stop/go driving
14.25 Gallons - 87 octane
MPG - 17 (16.989)
I had the car off when I filled it, andwith the lasttwo tanks used the same pump at slow speed with auto cut-off. I know it's not any kind of scientific testing method, but it's all I have for ya right now.
Considering the circumstances, I think in my situation 17 MPG is decent. I'm trying to do all highway miles now starting today, with no stop-and-go since I'm working some early/late hours and haven't hit traffic. I'll see if it goes up at all by the weekend.
Senior Member
Joined: Nov 2007
Posts: 312
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RE: H3 Hummer Performance Intakes Systems
ORIGINAL: Doc Olds
You lost me Gunny? This is ridiculously simple.
The resonator box can't prevent starvation when in the H3 system because the air within it cannot move to the throttle body without air entering the intake system. Example, take a straw, hold it perpendicular to the horizon, suck water in it, put your finger on top, the water will not leave the straw until your finger is removed from the top!
The faster air can enter the system, the lower probability of starvation. Starvation probability with a 3.5 or 3.7 liter with a 3.5" I.D. intake pipe is irrelevent because the total air volume wihtin the system at idle is more than the engine can conbust. WOT results in a LARGER volume of air through the AirDocIntake than the stock system with resonator box can possibly provide because the stock intake snorkel to the air filter box is less than 2.7" I.D. and the numerous obstructions within the stock system (ie. the stock accordian intake hoses and resonator box) create drag/obsticals to the intake flow. It is like porting and polishing a intakerunners in a head,smooth the head of any obstructions or burs, air flows faster, motor makes more power.
In other words, that is why AirDocs have a 3.5" pipe instead of the 3" tube used by the competition.
You lost me Gunny? This is ridiculously simple.
The resonator box can't prevent starvation when in the H3 system because the air within it cannot move to the throttle body without air entering the intake system. Example, take a straw, hold it perpendicular to the horizon, suck water in it, put your finger on top, the water will not leave the straw until your finger is removed from the top!
The faster air can enter the system, the lower probability of starvation. Starvation probability with a 3.5 or 3.7 liter with a 3.5" I.D. intake pipe is irrelevent because the total air volume wihtin the system at idle is more than the engine can conbust. WOT results in a LARGER volume of air through the AirDocIntake than the stock system with resonator box can possibly provide because the stock intake snorkel to the air filter box is less than 2.7" I.D. and the numerous obstructions within the stock system (ie. the stock accordian intake hoses and resonator box) create drag/obsticals to the intake flow. It is like porting and polishing a intakerunners in a head,smooth the head of any obstructions or burs, air flows faster, motor makes more power.
In other words, that is why AirDocs have a 3.5" pipe instead of the 3" tube used by the competition.
Finger = Throttle Body
I know it is ridiculously simple, and I bet your results in the 6-8hp to the wheels,though in some ways it is not. Don't get me wrong here your system is the results of logical analysis and basic refinement and I am not arguing that and it looks real good compared to whats out there. I was just noting on IK's comment. But you have to consider all of the computer power put into its original design to meet apeasment of the "common" man/consumer and gov't standards and regulations.
Now we have to come up with a MAS upgrade. I can't wait to get out of here to be homw tinkering in my garage.
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Joined: Jul 2007
Posts: 13,098
From: Boat Town USA MI
RE: H3 Hummer Performance Intakes Systems
Alright, now I understand Gunny. Doh! [&o] MAS upgrade, also which nobody has for the 3 yet. You be very careful over there my friend, and I look forward to you getting back here to tinkerso we candiscuss what you come up with!!!! Thank you once again GunnyRet!
I am also aware that part of the improvement I myself have been able to extract on my own 3 is because I have a PCM tune from PCMforless. This is why I enlisted an impartial (completely stock 07 Auto Trans) H3 owner....Gunner....to test for me with no other mods. Anybody is free to ask Gunner questions, I'm sure he will honestly answer them from what he has observed, and measured with the ScanGuageII and mileage data since the AirDocIntake install. That crazy Texan has recorded every gallon of gas consumed by his 3 and the MPGs it has achieved since ownership.
Well, Gunner does have some nice meaty tires, but otherwise his drivetrain and components are stock. [&o]
I am also aware that part of the improvement I myself have been able to extract on my own 3 is because I have a PCM tune from PCMforless. This is why I enlisted an impartial (completely stock 07 Auto Trans) H3 owner....Gunner....to test for me with no other mods. Anybody is free to ask Gunner questions, I'm sure he will honestly answer them from what he has observed, and measured with the ScanGuageII and mileage data since the AirDocIntake install. That crazy Texan has recorded every gallon of gas consumed by his 3 and the MPGs it has achieved since ownership.
Well, Gunner does have some nice meaty tires, but otherwise his drivetrain and components are stock. [&o]