DIY CAI stock intake mod

I looked for any DIY threads similar to what I did and could not find any.

Since I decided to tune my Denali going with EFI from MJ Engineering which I ordered yesterday.
I did my DIY intake mod which really woke up my engine.
Using K&N drop-in airfilter which I have had in since 2008.
I can only imagine how well it will run once I get the EFI AutoCal tuning.

I did this mod to my Dmax in 2008, it worked very good and the gains was similar to others that had Banks RamAir and S&B CAI intakes.
The Intake Ambient Temps dropped 20-25 degrees and the MAF g/s @ idle went from 26-28 to 40-42, using aFe ProGuard 7 drop-in airfilter.
Monitoring PID's using the Edge Insight on my Dmax.

The nice thing about doing this compared to buying a CAI you don't have to worry about MAF location issues.
Cost about $45-$50 for the K&N and about 2 hours labor.

Thanks for the write up, I'll have to give this a try.

Helidriver said:

Thanks for the write up, I'll have to give this a try.

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As far as seat of the pants testing this was more noticeable on my Yukon Denali than it was on my Dmax.
I used a combination of these tools depending on what was the easiest to use.
Remove the filter from the box when cutting and be careful when cutting around the foam seal.

looks similar to what i did! looks stock and its stealth! makes it possible to use the stock intake with my magnacharger and put my banks power intake in the bench :0

I was looking at my dmax and its open like that but on our denali its got a different edge that runs on fender with two opens that line up with two slots on the fender. Is the 03 denali a different box. Or did you just cut yours before pic and cut fender as well not scared to do either just wondering if mines different for any specific reason


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These are before and after on my 07.5 Dmax I also cut out the intake to match, the same as I did on my Denali.
As far as the 03 I don't know

One can't compare a Duramax to a gas engine, two different animals. Some could consider doing that on a light colored vehicle, but we see higher air temps with dark colored vehicles due to the fender being hotter.

JennaBear said:

One can't compare a Duramax to a gas engine, two different animals. Some could consider doing that on a light colored vehicle, but we see higher air temps with dark colored vehicles due to the fender being hotter.

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Considering the Denali and Dmax's air boxs are in the same location pulling from the inside passenger fender and both of my vehicles are BLACK.
So that theory does not play a part in this MOD, only the comfort inside the vehicle is affected.

Both of my vehicles IAT's are the with-in 2 degrees of the outside temps, with Phoenix Az hitting 115-122 in the summers and I'm getting these lower #'s then the color of the vehicle does NOT play a roll.
Besides the MAF g/s at idle was doubled on the Denali along with the IAT's and outside temps with-in 2 degrees.
If the vehicles color played a part in this then the IAT would be much higher than outside temps. They are not.
Plus there was a very noticeable gain in performance with this MOD over just having a K&N or even having a AirRaid Jr kit.
Without this MOD the IAT's was about 20 degrees hotter and the MAF g/s was 1/2 of what I have now.
And that was with only having a K&N OEM drop in which has been in for almost 6 years, cleaning every year.

My Denali MAF g/s at idle in park now is 8-9, my Dmax went from 26-28 to 40-42at idle in park the reason its higher is because its turbo powered.
If anyone thinks that more cooler airflow would not/will not help then I would have to question their knowledge on vehicles.
More air flow now you can add a little more fuel which equals more power.

Even my EFI tuner noticed a large increase in airflow, more than what he has seen and had to adjust for that in the tuning.
So I will have to dis-agree.
Beside I do know they are two different animals if anyone thought different they are fools.

Idle airflow is fixed on a gas engine. If you increased to 8-9g/sec, then your idle rpm had to increase. Diesel engines operate at wide open throttle, varying fuel for power creation. Gas engine utilize a very specific fuel flow for a given airflow. More air= more fuel= higher rpm.

Justin having tuned thousands of trucks of all colors in all environments in person and on dynos(including Phoenix last week) we can empirically state with complete confidence that, no intake will operate that close to ambient.

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---------- Post added at 11:41 AM ---------- Previous post was at 11:40 AM ----------

If you are seeing higher g/s then your throttle is open more.

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Well maybe you have not run into this yet, I have.
95 degrees outside temps, IAT 97 degrees.
Idle is the same, MAF g/s @ idle increased from 3-4 to 8-9.
Now I'm certainly not going to change anything, the Denali runs absolutely much better than it did before I did this mod even before I went EFI.
Besides this is not my first rodeo dealing with tuning, 35 years the real old school tuning days modifing the intakes and re-jetting the carburetor.
And now 10 years with this computer stuff.
The color of the vehicle has absolutely NO bearing on the intake temps, considering the air flow comes thru the fender under the vehicle.
If people want to listen to you, then it's there loss and they are missing a inexpensive way to have more power.
The next time your coming to Phoenix contact me I'll meet you anywhere and I'll prove you'all, that your very wrong.
How about we meet at CHUCKS SPEED & RV in Phx and we'll put my Denali on the Dyno so you can see for yourself.

FYI, any engine old school or computer if you can make more air flow available and give it a little more fuel it WILL run better and have more power.
If you contradict this then people should be real concerned, I've already got my EFI tuners,