Hey folks,

I've got a 2009 Super with the following mods:
- LS6 Intake Manifold
- Cold Air Inductions Intake
- Tune
- Poly Mounts

I recently installed Doug Thorley Headers, a brand new O2 sensor (post header/pre-cat), and a full 3" exhaust and have not been re-tuned since.
Firstly, I must say it's much louder than I thought it would be, especially 2-3k rpms it manages to shake the interior with the borla pro-xs (that might be a mixture of loud + mounts though).

Anyways, I've idled the car a couple of times for probably 15-20 minutes, I've driven 15 and 10 mile trips respectively; I entirely expected the trims to be off but am just curious if it's indicative of anything else.

I am showing LTFT's in the negatives at pretty much any time between -4% and -10% (driving, idle, WOT, although I have to confirm WOT as I haven't done a whole lot of glancing while driving). I'd personally expect the car to add fuel and not remove fuel.

That being said, if the car had an exhaust or intake leak it would be reading very lean and adding fuel correct? I definitely hear ticking but I don't smell anything and the idle is rock solid. I'm thinking the ticking is just valvetrain noise being amplified by the thin headers as it's not significant. I am also assuming that my fuel trims would be in the opposite direction if there was an exhaust leak?

I'm going to re-check the torque on some of the hardware to make sure it's still tight; does anyone have any feedback or should I not worry and just wait for my re-tune?

Thanks,

Mike

 

Did you use the felpro gaskets? Or gm mls steelies

 

GM MLS steelies

 

Well, I found an exhaust leak where the rear header meets the crossover pipe.
I'm going to get a different style clamp for that and have it fixed.

The drone is freaking killing me though; I thought the Borla Pro XS were supposed to be quiet? Between 1700-2500 rpms it vibrates interior panels, my mirror, etc. The surprising part is I've got a resonator and cat as well..

 

To get of that drone you may have to install some Dynamat, or cheap Home Depot alternative. Should help with any rattles too.

 

I am shocked at how ridiculous it is considering that it is by no means obnoxiously loud. I am also considering what they call a hemholtz resonator

 

Resonator for the win

 

Whats the difference between that and the new resonator you used? This is what I purchased for when I do the exhaust, if ever lol. No idea if this will help at all.


http://www.ebay.com/itm/Gator-Glass-...FUbO7m&vxp=mtr

 

I've got a 14" resonator and a CAT as well; that's the part that makes it confusing.

A Hemholtz is pretty much a welded J pipe that is capped on the end. The theory behind it is you "tune" the length of it such that the sound waves at your drone rpm go in there, bounce off and come back and cancel out the drone frequencies; not sure how well it does or doesn't work.

Thanks for the link, I may consider adding that as a 2nd resonator if I can't get this thing tamed a bit. I suppose the poly mounts aren't helping all that much. I may also try some additional sound deadening (I already have some in the trunk for my subwoofer).

I'm getting an exhaust leak at the crossover/rear header fixed today and am hoping that will help quiet it down a little.

 

Well I've got the clamp replaced and the fuel trims seem to have settled down.
I can hear no ticking of any sort under moderate/light throttle. Under full throttle I can hear a slight one but I'm thinking this is the lifters.

I know when you rev the motor up significantly and it comes down you can hear the lifters much louder than before the headers. No more ticks or smells at idle.

 

Good job!. Now on to the steering wheel. Post some pics of that bad Buick too.