Moving up to a 4" intake

[Houston Ben]

Hey all,
Just wondering, will I notice any difference between my stock intake upgrade to a 4" airaid UBI kit?? Ive seen the provided dyno sheets but im in the middle of making it and was just wondering if anyone thinks it really makes a difference (either way I have to make it due to a/c mount).

Thanks for entertaining my question.

Ben

[First c10]

Ben,
I installed a spectra 4" and my LTFT's became whacked out. Shawn had to do his magic in the tune and fixed it right up.
Oh the reason the LTFT's changed from stock was all the extra air volume.

[BR3W CITY]

On a GenIII with the regular MAF, you'll get the extra flow, but the difference won't be huge, as the maf's diameter limits the size no matter what tube you use. A short ram on a stock tune should be fine.

If you have a GenIV or are using a blade-style MAF, you'll run into erratic tuning issues. That maf has a sampling tube and expects certain volumes of air to meter.

Will you get "butt dyno" hp, probably not. You may notice a difference in sound.

I guess this is a good time to link a video. We switched my regular 4" short ram
"hot air" intake, for a longer intake and shielded intake box. Its still all based off of the ebay silverado intake kit, just with some work around it.

You Tube

[Hart_Rod]

Nice video J! Looks like you have the same type of workbench that I do....

Just general info to all, if you change anything on the air intake setup (size, shape, path, filter), the motor will need to be retuned. At a minimum, the MAF Calibration within the tune will need to be updated. Nearly all the calculations in the tune are based on the MAF Calibration. If it is wrong, it will affect your injectors, your idle, how the transmission shifts.

[Houston Ben]

Well....that sucks for me!! My tuner is an hour away!! I have a Gen IV 2011 5.3. Br3w, seeing you don't use one, do I need the MAF?? Damn, I thought this would be simple....

[Houston Ben]

BTW, here is the MAF I use

[BR3W CITY]

Originally Posted by Houston Ben

Well....that sucks for me!! My tuner is an hour away!! I have a Gen IV 2011 5.3. Br3w, seeing you don't use one, do I need the MAF?? Damn, I thought this would be simple....

My ECM doesn't use the GM OS anymore. Its a custom OS for speed density. You can totally do that, it just requires more advanced tuning. Its simple if you know what to do, but if your flying blind its a tedious evil b!tch.

Hart- I work out of 3 garages, none of which are permanently "mine". I NEED a freaking workshop table, but the truck is IN all the space I've got. So the truck becomes the workbench!

[Houston Ben]

Question, the vent on the passenger side that plugs into the intake tube, do I need it to go I to the tube or can I let it just vent?

Thanks!

[BR3W CITY]

Originally Posted by Houston Ben

Question, the vent on the passenger side that plugs into the intake tube, do I need it to go I to the tube or can I let it just vent?

Thanks!

I don't have one....is it a vacuum hose?

[Super73]

IMO the only benefit to a MAF is the ever so slight increase in accuracy between cells in the VE table.

In speed density mode (MAFless) the PCM averages between transitions. If you look at the screen shot I provided and look at MAP 70 and 75 and RPM's 1,600 and 2,000, the numbers look like this:

MAP - RPM - Value
70 -- 1,600 - 79
70 -- 2,000 - 82
75 -- 1,600 - 82
75 -- 2,000 - 86

Notice 70/2,000 and 75/1,600 are the same number. The motor is using the same amount of air for that MAP/RPM combination.

Now what happens at 1,700-1,900 for each MAP cell?
The PCM averages, so it would look like this:
MAP - RPM - Value
70 -- 1,600 - 79
70 -- 1,700 - 79.75
70 -- 1,800 - 80.5
70 -- 1,900 - 80.25
70 -- 2,000 - 82

It would do the same averaging for the changes in MAP for a set rpm.

Problem with that is a motors volumetric efficiency is not linear like the computer thinks. Through these mid cell transitions, AFR will be ever so slightly off from stoich provided you VE table is well dialed in.

Now, I feel the potential power benefits on a warmed up motor out way the down side of the MAF's ability to determine airflow more accurately through VE cell transitions than what was dialed in to the VE during a wideband tuning session.

For those about to try and jump on me again regarding elevation changes, O2's sure do a darn good job keeping you at stoich compensating with short trim fuel cells. Just saying..

[BR3W CITY]

Originally Posted by Super73

For those about to try and jump on me again regarding elevation changes, O2's sure do a darn good job keeping you at stoich compensating with short trim fuel cells. Just saying..

IF you keep 02's active for short term. There are differing opinions there. We ran 02 for short term and ran into issues with it. Tuned out better without them (after initial setup).

[Super73]

Brew,

I don't run narrow band O2's on my setup. The daily driver tunes I do with SD tune, I disable to lock in the VE, then re-enable NO2's. I have not had any issues with that.

[Houston Ben]

Yall are way over my head now!! lol. Well, got it in and it runs just a little rough but not bad. I will deff get it tuned later. I had to undo the wiring some to separate the pass. O2 from the MAF so I could move the MAF plug to the drivers side but that was no biggie. Now I just have to make the bay pretty and build an air box for the filter, thanks for all your input everyone.

[Houston Ben]

Don't know if this is a stupid question or not but can I drive it until I get it tuned again?

[Super73]

Unplug the maf see where the trims go. If it is +\- 10 then yes. But keep your foot out of it.

[Houston Ben]

Another question, does the crank case vent have to plug into the intake tube or can I leave it open?

[dayj1]

Originally Posted by Houston Ben

Another question, does the crank case vent have to plug into the intake tube or can I leave it open?

If you're talking about the PCV hose from the passenger's side valve cover, then yes. It has to be connected to a metered air source (i.e. after the MAF and before the TB). If you left it open to the atmosphere, you will have a huge vacuum leak.

[Houston Ben]

Thanks dayj, I will make hole and connect on Friday and see if that helps

[Houston Ben]

Another quick question, can I connect the PCV hose at the elbow by the TB or should I put it on the straight line area?

[Hart_Rod]

Originally Posted by Houston Ben

Another quick question, can I connect the PCV hose at the elbow by the TB or should I put it on the straight line area?

I would put it in the straight section, but it probably doesn't make that big of a difference.

[Houston Ben]

Thanks Hart Rod! Just need to go get a 90 fitting now.

[Hart_Rod]

Originally Posted by Houston Ben

Thanks Hart Rod! Just need to go get a 90 fitting now.

Brass fitting from the hardware store?

[Houston Ben]

Yup, actually from Auto Zone, worked like a champ! Running back to normal and is smooth again!! Thanks for all the help guys!