3k rpm sounds?

Has anyone else noticed the sound the truck makes when you are pulling a load and cruising on the highway at about 3000 rpms when the motor is working hard? I tow a lot and i have been listening to the motor work and it definitely changes tone. It has a throaty sound to it. Im not worried about it at all i was just wondering if the truck was doing something different with the timing at that point or what. It almost sounds like some vacuum secondaries pulling open on a carburetor...

 

5.7 L Flexin! I want to say that’s probably the variable valve timing.

 

Yes I have noticed it too. Doin work son!

 

Yeah thats what is was assuming, i really like the sound though

 

Is your truck lifted? My 2nd gen made that similar sound whenever I towed heavyweights. I noticed it more when I lifted the truck 3:1.

 

When I accelerate, say at the onramp to the interstate, I try to keep it between 3 and 4k. That's where it sounds its best.

 

Yes i have a 3/1 with 275/65/20s. I have only found it to make the noise with it towing my box trailer. Which isn't too heavy just loads of wind resistance

 

Is it possible that it kicked to a lower gear because of the trailer? For some reason 3k does not always sound the same. 3k while accelerating sounds different than 3k cruizing, and likewise 3k in 5th gear sounds different than 3k in 3rd gear etc. This does not really answer your question of what is causing the different sound - just another comment - I have experienced different sounds at the same speed also.

 

Negative I believe it would be in fourth but it is when I’m on the highway about 70 mph

 

I’d say it’s a combination of the VVT and the fact that your throttle is in a different position the butterfly is open sucking in air so it sounds deep and throaty.

Think about it you can be at 5000 RPM barely touching the throttle if you’re holding that gear or you can be at 5000 RPM flooring it. It will sound different.

 

I don't pull anything! no matter what rpm I'm running ole girl is running beastmode I got CAI and straight pipes on her and she roares.

 

I noticed it too and figured it has to do with VVT activating based on load, etc...