Do you mean the Denali XL?
Or do you mean the Denali short wheel base?
The MTX Thunderform doesen't fit the Denali XL because it is a long wheel base, and the factory space for the rear mounted hidden subwoofer is constrained by the cubby hole directly above the sub. Since this cubby hole is formed into the factory rear quarter panel plastic trim, it is impossible to look stealth, or look factory, but cutting the entire quarter panel out. MTX never offered a Thunderform for the Denali XL, Yukon XL, Suburban, nor the Cadillac ESV.
The MTX Thunderform DOES fit the short wheelbase Denali, even though you may have read that it doesn't. The unit actually does, but to install it requires moving the Denali amp that is in the way.
The factory BOSE amplifier is the
key difference between the Tahoe / Yukon short wheel base, versus the Denali / Escalade short wheel base. In the Tahoe and Yukon, the amplifier is located up front behind the glove box in the 2000-2002 models. However, in the Denali / Escalade of the same '00-'02 years of the GMT800 body style, the luxury amplifier is larger, and is located in the rear of the vehicle,
on top of the factory Bose sub..
The fact that this Denali amp needs to be relocated to fit the MTX Thunderform is most likely the reason why you may have read that it doesn't work in the Denali.
However, remember that cubby hole I mentioned earlier? The cubby in the Suburban and Denali XL that is directly on top of the factory sub in the long wheel base vehicles? The cubby hole that gets in the way of installing an enclosure with enough internal volume to support a 10" driver?
Well, in the short wheel base Denali, as well as the Tahoe and Yukon, the factory cubby hole is more forward over the rear wheel well, instead of on top of the factory subwoofer, where the amp in the Denali is. Therfore, if you take the rear factory amp in the Denali that is on top of the sub, and move it INSIDE the cubby hole that is on top of the wheel well, then the MTX Thunderform will fit perfectly in the Denali.
When you move the amp forward, just swivel it around 180 degrees, so that the plugs into the amp essentially stay in the same general location. Fortunately, the Bose amp electrical connectors are all on only one side of the amp, not two. So by pivoting the amp around 180 degrees, no extensions of any wire harness is needed.
A TYF member named Jeff did exactly this. His user name is JustPlayInn. Here are some photos he took of his installion of an MTX Thunderform into his short wheel base Denali:
BEFORE, with Factory Bose Sub, and Factory Bose Y91 LUXURY Amp on top:
View attachment 166024
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BARE, after factory sub and amp and bracket all removed. NOTICE the GM OEM "Dynamat Extreme" installed at the factory directly behind where the subwoofer mounts (on the gas filling port bump in of the sheet metal):
View attachment 166025
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BOOM, with the MTX Thunderform 10" hidden blast box in place, fitting perfectly in the Denali short wheel base (Jeff installed a Polk Audio driver instead of going with the MTX driver)... only the factory amp is MIA:
View attachment 166026
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BAM, with the Bose factory amplifier cleverly swung around 180 degrees so as to maintain the factory wiring harness lengths, with a connector port hole drilled in the aft end of the cubby hole, and the stock amp fitted perfectly in place:
View attachment 166027
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BONE stock look after the job is complete:
View attachment 166028
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Photo credit: All photos from "JustPlayInn" (Jeff), and this was his installation as well.
Like I said in a previous post, if I had a short wheel base, Denali or otherwise, I'd be inclined to go with the MTX Thunderform. You can get it as a bare box and put in your own driver, or as a loaded box, with the MTX driver, or as a full package deal with the box, the driver, and the amp for the sub built in. This latter fully packaged version is what I would do personally, because there is a lot of value in a pre engineered solution. Having to find a place to hide yet another amplifier is something I'd rather avoid, so why not get one built into the box itself?
