6.6 Gas L8T Engine Swap in 2015 Suburban

L8T BURB · Aug 22, 2024

RST Dana said:
But you almost put the escape in the Burban and never knows it there.

Good point! Thankfully I am used to driving smaller vehicles. I have had several Toyota Camrys and a Toyota Avalon in the past. They've been my favorite vehicles. I REALLY deviated from my norm with this Suburban lol!

What kept me from a Rav-4 was the price to get the features on my Escape would have cost nearly 8k more in a Rav-4. Plus Ford is running 0% for 36 months financing, and I was able to work the deal to 10% off MSRP. Felt like too good a deal to pass on.

Marky Dissod · Aug 22, 2024

L8T BURB said:
I would say that's a very fair statement. I would imagine more rear gear would get it up to speed with even less effort ...
but as for the impact that would have on MpG ...
I am not too sure as I have no experience with changing rear gearing and seeing the effects.

You said 'lug' before, which implies that the engine would prefer a few hundred more RpM.
I've seen 3.08 to be not quite enough,
whereas 3.42 or more gear would make the engine share more effort with the 6L80 / 6L90,
allowing even more time in the higher gears.

L8T BURB · Aug 22, 2024

Marky Dissod said:
You said 'lug' before, which implies that the engine would prefer a few hundred more RpM.
I've seen 3.08 to be not quite enough,
whereas 3.42 or more gear would make the engine share more effort with the 6L80 / 6L90,
allowing even more time in the higher gears.

100% agree. The engine is massive and I feel like it could easily stand more workload, especially if it would take some stress away from the transmission.

B-train · Aug 22, 2024

This has been a great thread! Thanks for all the information and learnings passed on. I totally feel you on the mpg. I drive a 2008 Denali for work now. 14.5 - 17 mpg gets old quickly on 900 mile trips.

I'm curious if anyone here has experience with the Chevy Equinox or GMC Terrain with the 1.6L diesel in them? I like my fullsize rig, but 32 - 50 mpg is pretty tempting. Plus, put it on a diet, remove the little blue emblem on the back, and then just run red fuel.....who's gonna check an equinox?

Good and bad experiences encouraged

TollKeeper · Aug 22, 2024

Start a new thread for the 1.6 Diesel.. I can tell you they are good down low, but run out of steam fairly quickly. They can be had for fairly cheap too.

the 18th letter · Aug 22, 2024

I wish I had many different options but there aren’t a lot of vehicles made for 6’8 300lbs guys out there. Whenever I see 5ft tall soccer moms climbing, (that’s what it looks like) out of one of these I giggle a childish giggle each time.

Bigburb3500 · Aug 22, 2024

This was such a great build thread! Not sure if you have seen my thread on my truck but I have a 3500 Suburban with a 6L90 and 4.10s, if I have to do any engine work and cannot afford a diesel conversion this looks like a PERFECT option. You did great work with the truck!

I feel you on the Toyota products. I have a 100 series LC that’s pushing 200k and it barely broken in. It finally had an “issue” where an OEM ignition coil went bad lol. Wife’s hybrid Lexus is going to have its brakes changed for the first time in 150k miles too. Hard to argue with hybrid tech and very surprised that the big three haven’t put it in their big vehicles. I know the F150 has a hybrid option and it gets mid 20s on mpg. I know GM did the half-assed attempt at a hybrid Yukon/Tahoe but these trucks are perfect for large hybrid systems. Low end torque + fuel benefits + towing benefits = perfect.

chevman88 · 2025-01-14T09:39:23-0500

@L8T BURB - would you mind DMing me who you worked with on your tune? Looking at doing the same to my '19 Yukon with a 10l80e and had some questions

B-train · 2025-01-14T15:13:04-0500

chevman88 said:
@L8T BURB - would you mind DMing me who you worked with on your tune? Looking at doing the same to my '19 Yukon with a 10l80e and had some questions

Another option you could do is get HP Tuners for yourself for about $600 with starter credits. Then, "test drive" any new HD pickup with a 6.6L, copy the ECM file, and then use it to modify your OEM file. It's a super easy process to copy and paste map values. And, you might find they aren't far off from what you have now.

I had contemplated that for my 2017 when I thought I needed $6500 of engine work done - lucked out with a $15 pushrod and oil change to be back on the road. But, HAD I needed to swap it to a 6.6L, that was my plan. I've played around with HP Tuners now for several months and it's pretty easy to use. More in-depth changes if you are looking to get crazy will need a good knowledge base and a dyno for best results. But, I'd be willing to wager that you could get great driveability right out of the box with a copied spark map.

What engine is in yours? If it's a 6.2L, then the exhaust will flow without any issues. A 5.3L may need some up sizing, but @L8T BURB will be able to fill in more info. I spoke with him in the past about this and he was super helpful.

chevman88 · 2025-01-14T15:38:07-0500

B-train said:
Another option you could do is get HP Tuners for yourself for about $600 with starter credits. Then, "test drive" any new HD pickup with a 6.6L, copy the ECM file, and then use it to modify your OEM file. It's a super easy process to copy and paste map values. And, you might find they aren't far off from what you have now.

I had contemplated that for my 2017 when I thought I needed $6500 of engine work done - lucked out with a $15 pushrod and oil change to be back on the road. But, HAD I needed to swap it to a 6.6L, that was my plan. I've played around with HP Tuners now for several months and it's pretty easy to use. More in-depth changes if you are looking to get crazy will need a good knowledge base and a dyno for best results. But, I'd be willing to wager that you could get great driveability right out of the box with a copied spark map.

What engine is in yours? If it's a 6.2L, then the exhaust will flow without any issues. A 5.3L may need some up sizing, but @L8T BURB will be able to fill in more info. I spoke with him in the past about this and he was super helpful.

It's a 6.2 with the 10l80. I just didn't know how integrated the transmission portion was in the tune and if whatever transmission I had mattered. I'm planning on keeping the 6.6 stock as it's the family grocery getter/tow vehicle. Wish I could get away with just the pushrod (ordered one before I scoped the lifter just in case) but no dice.

6.6 Gas L8T Engine Swap in 2015 Suburban

L8T BURB

Full Access Member

Marky Dissod

Full Access Member

L8T BURB

Full Access Member

B-train

Full Access Member

TollKeeper

Full Access Member

the 18th letter

Full Access Member

Bigburb3500

Full Access Member

chevman88

TYF Newbie

B-train

Full Access Member

chevman88

TYF Newbie

Similar threads

Forum statistics

Latest posts