New Member from Illinois 2011 Yukon Denali, love it but where is the power?

[OR VietVet]

What octane fuel does the owner's manual ask for?

 

[intheburbs]

I was looking at an S&B cai. Will a better muffler help, or do I need to run a true double exhaust? What about a tuner?

Don't waste your money on an intake. The stock box works just fine.

A tune will help for sure - you can dial out some of the Torque Management. That will improve throttle response.

Are you running premium gas?

 

[diesel_dave]

What altitude do you live at? If you're anywhere close to sea level, 87 octane is almost certainly your issue. Engine is probably pulling a lot of timing to counter knock. I live at ~5k feet so I can get away with 89 which is mid-range where I live.

 

[swathdiver]

I typically run 87 through it.

You're destroying your engine dude. Broken rings and pistons are in your future. Run 91 or 93 or E85.

Low octane swill is why your high performance, high compression engine is running like crap. No wonder why you blew out your manifolds.

I forgot to add that it is AWD. Is there an automatic ride adjustment on this? I hear something making noises in the back when it is sitting.

She has air ride shocks out back with a compressor to keep the truck leveled.

 

[jdwood1111]

I just bought a 2011 denali AWD a few months ago and I think its quite quick for a 6k vehicle. Just took it down and back to FL (see my other thread and into thread). The plugs and wires were already done before I bought the truck and then I did the following all at the same time but I definitely noticed a difference overall:
Airaid intake tube - added a lot sound and noise but not much noticeable performance
cleaned the throttle body
cleaned MAF
AEM dry air filter
Changed front and rear diff fluids, seem to "glide/roll" a little better although was pretty good before
flushed power steering fluid and maybe I thought it turned a little easier
Significant difference from just 89 octane to 91 or 93 so I can't imagine running 87. The truck runs smoother, idles better, more performance and better mileage. Not great on my pocket but I have to get past that.

As noted above, the noise in rear near the gas tank fill port is the air compressor keeping the truck level.

Working on a tire issue and some hose replacements shortly.

 

[Fless]

What altitude do you live at? If you're anywhere close to sea level, 87 octane is almost certainly your issue. Engine is probably pulling a lot of timing to counter knock. I live at ~5k feet so I can get away with 89 which is mid-range where I live.

You'd be hard pressed to find an altitude in the Land of Lincoln that is over 1,000' AMSL. They are few and far between, and most land is around 600-700 ft AMSL.

 

[Familyman2112]

You're destroying your engine dude. Broken rings and pistons are in your future. Run 91 or 93 or E85.

Low octane swill is why your high performance, high compression engine is running like crap. No wonder why you blew out your manifolds.



She has air ride shocks out back with a compressor to keep the truck leveled.

This is my first E85 vehicle. I just assumed E85 would be worse for my engine. Is that not really the case? I am contemplating throwing a couple gallons of racing fuel in with the next fill up, just to peak the octane at around 93.

 

[Doubeleive]

This is my first E85 vehicle. I just assumed E85 would be worse for my engine. Is that not really the case? I am contemplating throwing a couple gallons of racing fuel in with the next fill up, just to peak the octane at around 93.

if it is the short wheel base you should have slightly more power than mine does simply because of less weight.

 

[Geotrash]

where are you located?

It's in the thread title. Illinois.

 

[Doubeleive]

It's in the thread title. Illinois.

ya I saw that and edited it, i was thinking if he was near anyone a comparison could be done or something, maybe there is some undiagnosed issue going on