2500HD Front Air Dam

[Icutmetl]

I get it; there’s probably a small fuel mileage penalty that comes with removing your front air dam.

 

Beyond that, are there any drawbacks? Will the airflow direct more road grime up into the engine compartment? Did the 2WD trucks come with a shorter one that the 4X4 guys could use?

[redwngr]

You've probably read GM's comments in the OM, but they post this caution in the section about off-road driving: (and they do suggest removing it for 'off-road')

 

"Operating the vehicle for extended periods without the front
fascia lower air dam installed can cause improper airflow to the
engine. Reattach the front fascia air dam after off-road driving. "

 

 

Don't know it they are concerned about dirt/debris or if they think the change reduces airflow thru the radiator.  

 

 

Here's the rest of it:

 

Before Driving Off-Road
. Have all necessary maintenance and service work completed.
. Fuel the vehicle, fill fluid levels, and check inflation pressure in all tires, including the spare, if equipped.
. Read all the information about four-wheel-drive vehicles in this manual.
. Remove any underbody air deflector, if equipped.

....Re-attach the air deflector after off-road driving.
. Know the local laws that apply to off-road driving.

 

To gain more ground clearance if needed, it may be necessary to remove the front fascia lower air dam, if equipped. However, driving without the air dam reduces fuel economy.

 

 

 

 

 

[Icutmetl]

29 minutes ago, redwngr said:

You've probably read GM's comments in the OM, but they post this caution in the section about off-road driving: (and they do suggest removing it for 'off-road')

 

"Operating the vehicle for extended periods without the front
fascia lower air dam installed can cause improper airflow to the
engine. Reattach the front fascia air dam after off-road driving. "

 

 

Don't know it they are concerned about dirt/debris or if they think the change reduces airflow thru the radiator.  

 

 

Here's the rest of it:

 

Before Driving Off-Road
. Have all necessary maintenance and service work completed.
. Fuel the vehicle, fill fluid levels, and check inflation pressure in all tires, including the spare, if equipped.
. Read all the information about four-wheel-drive vehicles in this manual.
. Remove any underbody air deflector, if equipped.

....Re-attach the air deflector after off-road driving.
. Know the local laws that apply to off-road driving.

 

To gain more ground clearance if needed, it may be necessary to remove the front fascia lower air dam, if equipped. However, driving without the air dam reduces fuel economy.

 

 

 

 

 

I did, but was wondering about real world feedback. I’ve never read about anybody that’s had any issues from “reduced airflow,” not saying it’s not valid, I just haven’t read about it.

[crankman]

I didnt see any difference after removal of mine in 2015. I towed before and after removal and kept track of temps, never saw anything. 

 

[gearheadesw]

When I modified mine, it came out funny...

[i82much]

Thermal is a big factor in towing.  I read comments from a gm engineer stating that the big benefit of the 4.10 axle is that it allows an earlier upshift into 3rd gear on steep grades, thus REDUCING engine rpm and helping the engine stay cool on a long pull.

 

These trucks have fantastic cooling capabilities, but if I removed my air dam I would be just a little more attentive to engine and trans temps if I did any serious towing.  I am 99% sure you will be fine and 100% sure it is worth paying a little extra attention.

[Cosmic Charlie]

5 hours ago, i82much said:

Thermal is a big factor in towing.  I read comments from a gm engineer stating that the big benefit of the 4.10 axle is that it allows an earlier upshift into 3rd gear on steep grades, thus REDUCING engine rpm and helping the engine stay cool on a long pull.

 

These trucks have fantastic cooling capabilities, but if I removed my air dam I would be just a little more attentive to engine and trans temps if I did any serious towing.  I am 99% sure you will be fine and 100% sure it is worth paying a little extra attention.

allows earlier UPSHIFT ? would make the RMP's higher ?

 

YES ?

[i82much]

28 minutes ago, Cosmic Charlie said:

allows earlier UPSHIFT ? would make the RMP's higher ?

 

YES ?

assume a 4.10 truck and a 3.73 truck are pulling a grade at 45 mph with a heavy load.  3.73 truck might be in second gear, 4.10 might upshift to third and be at a lower RPM.

[i82much]

32 minutes ago, Cosmic Charlie said:

allows earlier UPSHIFT ? would make the RMP's higher ?

 

YES ?

https://www.forconstructionpros.com/trucks/trucks-accessories/article/10288893/select-the-correct-pickup-axle-ratio

 

“At first glance, you think a 3.73 isn't going to do that much for you vs. a 4.10," says Martuch. "It really comes down to what gear selection you have pulling that grade. That 3.73 vs. a 4.10 has a huge impact on engine rpm because you are selecting second gear with a 3.73 to pull the grade, but you can hit third gear with a 4.10. Your engine speed is down about 1,000 rpm lower, so temperatures under hood are going to be significantly lower."

[Icutmetl]

How on earth did this topic morph from a question regarding front air dams into a discussion on gear ratios and shift points?

[i82much]

4 minutes ago, Icutmetl said:

How on earth did this topic morph from a question regarding front air dams into a discussion on gear ratios and shift points?

because thermal.

[i82much]

i saw elevated engine temps when towing with a jeep wrangler after removing the air dam.  the problem is that the fan can pull way more air from below if you remove it, which means you have less air going through radiator.

 

probably gotta really be pushing it hard with an hd truck to have an issue, but keep it in mind.

[Icutmetl]

48 minutes ago, i82much said:

i saw elevated engine temps when towing with a jeep wrangler after removing the air dam.  the problem is that the fan can pull way more air from below if you remove it, which means you have less air going through radiator.

 

probably gotta really be pushing it hard with an hd truck to have an issue, but keep it in mind.

I’d think so too...