6.6 Gas L8T Engine Swap in 2015 Suburban

[adventurenali92]

Did somebody say cold start???

That’s a mean sounding burb! Great startup vid!

 

[blackelky]

Oh hell yeah

 

[Thrust]

Did somebody say cold start???

Did you get everything sorted out with the tune?

 

[L8T BURB]

Did you get everything sorted out with the tune?

We are still dialing in the tune. We have been able to eliminate ALL rich codes, and now are only getting a knock sensor code. My tuner is getting things so precise now that he's working on adjusting the sensitivity of the knock sensor. He said what happens is with these bigger engines that have modded exhaust, in my case, 6.6 swap with gutted cats, this causes some excessive vibration in the engine bay which the ECM may mistake for a knock. As of the last tune update we installed yesterday, I have logged around 100 miles with about 8 key cycles and no engine light as of now. Getting very close!!

The transmission is running hotter than I'd like. Temps here have been around 45 - 55 degrees, and trans seems to settle around 190-195. So I am going to "flip the pill" to see if that calms the trans temps down. This 6L90 is from a 2022 Silverado 2500, and GM decided to no longer have dipsticks on these transmissions. I am looking to add the OEM dipstick from the 2019 Silverado 2500. Searching Silverado HD forums suggests thats a fairly easy swap.

 

[fasteddy]

Cool swap! I've been looking at same with my 2016 Escalade as its starting to tick a little louder than I would like, even with DOD "tuned" off. GM sells a 6.6L long block and it should drop right in as the external points are all the same, even intake and exhaust. The work is the tune and accessory drive mods. But it bolts right up to the 6L80, which should handle the TQ which is similar to 6.2L. I would do a 6.2 crate, but GM doesn't sell those without DOD and the 6.6L runs on 87 octane too. Very cool swap! If your tune is in HPtuners please post it, so I can review...(LOL). Thanks and keep us updated.

 

[Trey Hardy]

Cool swap! I've been looking at same with my 2016 Escalade as its starting to tick a little louder than I would like, even with DOD "tuned" off. GM sells a 6.6L long block and it should drop right in as the external points are all the same, even intake and exhaust. The work is the tune and accessory drive mods. But it bolts right up to the 6L80, which should handle the TQ which is similar to 6.2L. I would do a 6.2 crate, but GM doesn't sell those without DOD and the 6.6L runs on 87 octane too. Very cool swap! If your tune is in HPtuners please post it, so I can review...(LOL). Thanks and keep us updated.

I second the tune I wonder how hard it would be to put one of these bad boys In my 07? Hmmm

 

[fasteddy]

I second the tune I wonder how hard it would be to put one of these bad boys In my 07? Hmmm

They are doing it. Mast and TSP offer the L8T with port injection options. Mast has one with a charger on it and 1000+ hp. All you need is 58x reluctor computer and a gen v intake with injector provisions. I think the tuning would be easier on the port injection. Don't know about the front accessory issues....

 

[B-train]

Bump....Any update for us @L8T BURB ?

 

[L8T BURB]

Man this thing has been a BLAST! I've honestly only floored it from a dead stop 5 times or so since I've had it back, and it makes me grin ear to ear each time. The torque that this 6.6 makes down low is just nuts!

The only real thing I'm looking to do differently is with the exhaust. During the swap, we decided to gut the stock 5.3 cats, as they didn't seem to be handling the new engine very well. Got the patented "rotten eggs" smell during the first drive after swap, so we gutted them which cleared that issue, but the raw fuel smell from the tailpipe is really becoming an aggravation to me.

I do have the cats/downpipes from the 6.6 that I believe I will have welded in this Spring. Likely just going to use the two upstream cats, and then maybe get 3 inch pipe custom ran after the cats to the back. Still unsure on a muffler, but possibly a flowmaster or magnaflow.

In the meantime, I have been doing an "RST conversion". At least that's what I'm calling it. Complete with color matched LTZ grill, black mirror caps, black badges, black D pillars, and RST rims. Also trimmed the lower valance to 3 inches. I will include pics below of the cosmetic mods. Be sure to like, comment, and subscribe to my YouTube channel. It's been VERY cold here, so I've been slow about posting new content lately but I'm looking to get back to it soon! Planning to get some full throttle runs for the next videos I'll be posting!

Youtube link: https://youtube.com/@L8T_BURB?si=4noRWfDzbbK78ckn

 

[adventurenali92]

Looking good! Are those non factory headlights? They look good.