Sounds awesome!! :D

Im running a stock tbss muffler on mine and just love the way the high flow stockers sound :)

Nice! I couldn't read the dyno number. Was it 361? Did you upgrade your injectors? If not, what was the idc at wot?

I like the sound too when you mash the pedal. Only problem is that it is a tad too loud @ WOT.
I am going to try to experiment with installing a second muffler and a cutout.
that way when I am just cruising around, exhaust is running through two mufflers, when I want the performance, I can bypass the second muffler.
But this needs to wait 'till next month as I will be out of town for a while.

The way this particular dyno is set up, a stock 07-08 Denali is getting about 280AWHP SAE corrected with smoothing set at 5.

The 361 you saw was uncorrected. Below is the Dyno sheet with SAE correction and smoothing at 5.

Attachment 145292

The pull was on 4th gear and the guy did not run it to 6100 which is my current shift point. If he had, it would have dynoed about 10 hp higher.

I am still waiting for the final tune from BBP. Hopefully Justin can tweak a few more ponies out of it.

I am on stock injectors as Justin told me for my current mods, they will be fine.
Unfortunately, I did not log the duty cycle. I will try to log it when I revisit the dyno after I get the final tune.

Nice. I'm putting a set of milled and mildly ported 799's, a cam, and injectors, on my LQ4 soon and expect similar results. So how does it drive?

Well, my choice of mods was made with an eye towards adding a blower sometime in the (hopefully not too distant) future and I did not want to redo-repurchase the same items twice.
Hence, the 1 7/8 instead of 1 3/4, and my choice of cam.
Both do not do much down low. As you can see from the dyno graph, power really starts to come on around 3800 to 3900 rpm.
When its hits, it's like a bat out of hell. It pulls hard to the shift point.

Below that rpm point, it drives like a normal Denali does, which is no bad thing as most of my day to day driving is in that range and the truck seems to maintain its gas milage.

What the graphs and numbers don't show is the Black Bear tune to my 6L80!
The improvement there is beyond description. It's like a totally new gearbox. Gone is the hesitation and the pause before downshifting. Gone is the half hour (:)) it takes to shift.
The truck actually jumps ahead during shifts, without slamming gears or hard shifts.
Brilliant!

Your Denali sounds awesome and your ideas are similar to what I want to do to mine.

Can you tell me what the off road y pipe does.? Does it replace the catalytic convertors.? Does the engine warning light stay on.? I'm up in Vancouver Canada and we have mandatory emission tests every two years up here and I'd need to pass but wouldn't mind detuning it at test time.

Also the cam - you say it doesn't make much difference at low RPM - I'd like more pull off the line and was even thinking of lower gears and a high stall. What do you think about streetability.? I too am going to drive it regularly.

The offroad Y-pipe would be the same as ARH's regular Y-pipe, but without the cats. Either way, you'll need a tune or the Check Engine light will come on. Would look like this picture for a GMT900 chassis. This picture shows cats.

Attachment 121746

As far as what is required to pass your emissions test, I don't really know. Maybe if you post up your location in Canada, other members local to you can offer some help.

Thank you AK.

I am in Vancouver, BC. Our emissions check is called AirCare and they just seem to plug in and check the electronics on newer vehicles. They don't actually hook up to the exhaust.

Maybe a tune would pass aircare..?

Any Vancouverites on the board with modified LS engines.?

what car or tuck or suv you got??

what did you cam