In need of some guru experience

thehorizontalbob · August 7, 2015

First of all, hello all! I'm obviously new here and am excited to become a part of the community and not only learn but also offer insight where and when I can! Anyway, on to my first question.

So I finally decided to start upgrading my truck and bought a K&N intake, Edge Evolution CTS Programmer and am going to modify the exhaust. Pretty standard stuff, but it's a start...Also, I apologize if this specific subject has been beaten to the ground, I just can't seem to find an answer.

My question, however, is that after I installed the intake today the truck sounds much better, but only under load and it's variable at best. It'll sound very throaty when I punch it but quiets down on its own even during acceleration, is this normal? Part of the variable valve timing? Is my truck wonky? Also, I deleted the resonator and fabbed in a straight pipe, left the flapper and muffler. The truck sounds literally no different, except when I punch it, it sounds wispy and there are no deeper exhaust tones than stock. Is this normal? It's been fairly disappointing so far, I'm hoping there's some setting somewhere I can change to get my truck to sound like the ones on YouTube supposedly running the same setup. Any help would be greatly appreciated!!

Spurshot · August 7, 2015

The noise from the intake system on your truck is from what is called reversion. It's a product of the intake charge starting and stopping due to the opening and closing of the intake valves.

I found this article that makes an attempt to explain it. http://www.hotrod.com/how-to/engine/ctrp-1008-intake-reversion/

There are literally pulses of the intake air that back up in the intake manifold, duct and air filter box. On a old engine I built in the 70s with individual runners and Weber carburetor throttles for each cylinder/port, you could see the reversion in the form of atomized fuel backing up out of the velocity stacks on the carburetors.

The noise tends to get weaker with higher rpm. I think it's due to a higher frequency shift.

thehorizontalbob · August 7, 2015

I gotcha, that makes sense...It was so weird to hear a deep throaty acceleration and then right in the middle of it, it crapped out. I thought I broke something, haha. Thanks for the info, it definitely helped!

SILVER SLED · August 7, 2015

I don't have the scientific explanation as above, but my MIT intake tube does the same thing. Light to mod acc and it makes noise, then reaches a certain rpm than is quiet.

Good to know about the resonator only delete being too quiet. I guess I'm just gonna hack off the muffler and leave the resonator.

Roader · August 7, 2015

No reason to worry about the VVT. I have it on my camaro and glad its there since it helps bring torque in sooner. I know its new to a lot of people but after 5 years ive had 0 issues with it.

crushNchowda · August 8, 2015

What engine do you have? 4.3, 5.3, or 6.2? If you have the 6.2 a catback exhaust won't do much, may help slightly on the 5.3 if it's larger diameter same goes for 4.3....but really not much on either

On most. Any. Gm small block equipped vehicle the 2 best things you can do for power are long tube headers and a dyno tune (a good cold air intake like you already have as well)

That would get you anywhere from 20-40hp to the wheels depending on application

thehorizontalbob · August 15, 2015

Gotcha. Thanks for the great advice. I have the 5.3 in my truck with a k&n intake and an Edge Evolution CTS programmer at the moment.

Bvonscott · August 15, 2015

I have the full Airaid system on my truck. It is quiet at idle and light throttle, but any medium to full throttle it gets loud and mean sounding until I let off. No issues with pulsating frequencies.