6.6 Gas L8T Engine Swap in 2015 Suburban

[strutaeng]

Awesome! Thanks for the update!

I do see the 6.6 L8T being a good swap candidate for other vehicles down the road: great power and torque, compact, and bolts up to pretty much anything it seems. Prices should become more affordable as they build more of them.

I think this thread has a happy ending...

 

[k_arnold72]

All that said, I picked up a 2024 Ford Escape Hybrid 2 weeks ago. Averaging 42 MPG...

But how many smiles per gallon?

 

[L8T BURB]

But how many smiles per gallon?

This may be an unpopular opinion here, but I will try to map out my feelings on this.

The Suburban was fun to drive, a killer looking vehicle... however I had grown such a feeling of resentment towards the vehicle. Realizing that despite it being a unique build, at the end of the day, I had $35,000 (cost of vehicle purchase plus repairs) tied up in a vehicle that booked for $9000.

Each day driving it, I would think about how I would handle another mechanical failure. I had reached the point where I knew that if I had any sort of mechanical failure, I'd be ready to drive the thing off a cliff. Having no peace of mind of any warranty was causing me more stress than it probably should have.

My 2 vehicles before the Suburban were a 2020 Toyota Avalon Hybrid XSE and a 2022 Toyota Camry Hybrid XSE. Moving to the Suburban was a gut check for gas mileage, but became a soul searching event once the camshaft grenaded just 2 months into ownership.

That said, being back in a new vehicle with factory warranty getting over 40MPG is my happy place. I will never say anyone is crazy for owning one of these vehicles, but in my case, with the amount of driving I do, the Escape Hybrid is about as perfect a fit as I could get. I understand comparing a 2024 Escape ST to a 2015 Suburban LT isn't exactly apples to apples, but I am happy with my choice.

So to answer your question... I would say 42 smiles per gallon!

 

[Geotrash]

This may be an unpopular opinion here, but I will try to map out my feelings on this.

The Suburban was fun to drive, a killer looking vehicle... however I had grown such a feeling of resentment towards the vehicle. Realizing that despite it being a unique build, at the end of the day, I had $35,000 (cost of vehicle purchase plus repairs) tied up in a vehicle that booked for $9000.

Each day driving it, I would think about how I would handle another mechanical failure. I had reached the point where I knew that if I had any sort of mechanical failure, I'd be ready to drive the thing off a cliff. Having no peace of mind of any warranty was causing me more stress than it probably should have.

My 2 vehicles before the Suburban were a 2020 Toyota Avalon Hybrid XSE and a 2022 Toyota Camry Hybrid XSE. Moving to the Suburban was a gut check for gas mileage, but became a soul searching event once the camshaft grenaded just 2 months into ownership.

That said, being back in a new vehicle with factory warranty getting over 40MPG is my happy place. I will never say anyone is crazy for owning one of these vehicles, but in my case, with the amount of driving I do, the Escape Hybrid is about as perfect a fit as I could get. I understand comparing a 2024 Escape ST to a 2015 Suburban LT isn't exactly apples to apples, but I am happy with my choice.

So to answer your question... I would say 42 smiles per gallon!

Being happy with a choice that works for you is what it's all about, and a 6.6L Suburban is probably not the right choice for a big commute every day. And I totally get feeling resentment toward a vehicle that let you down so soon into your ownership of it. But you taught us all how to do something we didn't know was possible, so thank you for the education, good sir!

My 2012 started having oil pressure problems in the first week in the middle of a ski trip and I had to change oil in the parking lot of a condo in the bitter cold to try to get it squared away. But she got us all home, and somehow we bonded through the experience. She's never let me down since, and now it's tip-top and I'd drive it anywhere.

For me, there is something about keeping a car for a looooong time that I like. I drove an Isuzu Rodeo for 300K, when most of them died at half that mileage. I just loved keeping it going. Don't know why.

 

[Tonyrodz]

This may be an unpopular opinion here, but I will try to map out my feelings on this.

The Suburban was fun to drive, a killer looking vehicle... however I had grown such a feeling of resentment towards the vehicle. Realizing that despite it being a unique build, at the end of the day, I had $35,000 (cost of vehicle purchase plus repairs) tied up in a vehicle that booked for $9000.

Each day driving it, I would think about how I would handle another mechanical failure. I had reached the point where I knew that if I had any sort of mechanical failure, I'd be ready to drive the thing off a cliff. Having no peace of mind of any warranty was causing me more stress than it probably should have.

My 2 vehicles before the Suburban were a 2020 Toyota Avalon Hybrid XSE and a 2022 Toyota Camry Hybrid XSE. Moving to the Suburban was a gut check for gas mileage, but became a soul searching event once the camshaft grenaded just 2 months into ownership.

That said, being back in a new vehicle with factory warranty getting over 40MPG is my happy place. I will never say anyone is crazy for owning one of these vehicles, but in my case, with the amount of driving I do, the Escape Hybrid is about as perfect a fit as I could get. I understand comparing a 2024 Escape ST to a 2015 Suburban LT isn't exactly apples to apples, but I am happy with my choice.

So to answer your question... I would say 42 smiles per gallon!

Did you get close to what you wanted when it sold? You usually never get what you put into a project, but sometimes you can come close when it's special enough.

 

[Marky Dissod]

@L8T BURB, what was the fuel economy like with the L8T?

 

[L8T BURB]

@L8T BURB, what was the fuel economy like with the L8T?

On interstate and state roads 55MPH it did good. I could occasionally get it to 25-26 MPG if I ran 55MPH and REALLY focused on hypermiling. It took a lot of work. Average for 70MPH interstate travel is around 21MPG.

In town is a TOTALLY different story. I was seeing around 13MPG in town driving. With school starting back up, I was driving a LOT of in town trips taking kids to/from sports practices and games, so I was deeply rooted in that 13MPG range for the past several weeks. Fueling up for $85 once a week was getting old FAST.

I did a calculation at one point with a true MPG average and it was around 16.5 MPG total - thats mix of city and interstate travel. The thing just lugs so bad in town that it tanks the MPG. Tons of torque for effortless accelerations, but it felt like all I did was put fuel in it.

I figured it up and if I was to keep the Suburban for 100,000 miles vs. the Escape Hybrid for 100,000 miles, it was set to cost me something like $15,000 less in fuel costs on the Escape. This is also assuming no repairs to the Suburban which I know is a completely unreasonable expectation. Keep in mind that I have the Ford Protect Premium ESP that is essentially a bumper to bumper warranty for 7yr/100k miles. So if I actually keep the Escape that long, its essentially a guaranteed no repair cost ownership experience.

 

[Marky Dissod]

On interstate and state roads 55MpH it did good.
I could occasionally get it to 25-26 MpG if I ran 55MpH and REALLY focused on hypermiling. It took a lot of work.
Average for 70MpH interstate travel is around 21MpG.

In town is a TOTALLY different story. I was seeing around 13MpG in town driving.
With school starting back up, I was driving a LOT of in town trips taking kids to/from sports practices and games,
so I was deeply rooted in that 13MpG range for the past several weeks. Fueling up for $85 once a week was getting old FAST.

I did a calculation at one point with a true MPG average and it was around 16.5 MpG total -
that's a mix of city and interstate travel.

The thing just lugs so bad in town that it tanks the MpG.

For now, would you mind if I focused on the last sentence (click to expand)?
If memory serves, 3.08 & 6L90?
By 'lugs so bad in town', are you implying that more axle gear would help improve city / metro / urban MpG?
(I'm admittedly eager to infer it, but thought I should check with real experience.)

 

[RST Dana]

On interstate and state roads 55MPH it did good. I could occasionally get it to 25-26 MPG if I ran 55MPH and REALLY focused on hypermiling. It took a lot of work. Average for 70MPH interstate travel is around 21MPG.

In town is a TOTALLY different story. I was seeing around 13MPG in town driving. With school starting back up, I was driving a LOT of in town trips taking kids to/from sports practices and games, so I was deeply rooted in that 13MPG range for the past several weeks. Fueling up for $85 once a week was getting old FAST.

I did a calculation at one point with a true MPG average and it was around 16.5 MPG total - thats mix of city and interstate travel. The thing just lugs so bad in town that it tanks the MPG. Tons of torque for effortless accelerations, but it felt like all I did was put fuel in it.

I figured it up and if I was to keep the Suburban for 100,000 miles vs. the Escape Hybrid for 100,000 miles, it was set to cost me something like $15,000 less in fuel costs on the Escape. This is also assuming no repairs to the Suburban which I know is a completely unreasonable expectation. Keep in mind that I have the Ford Protect Premium ESP that is essentially a bumper to bumper warranty for 7yr/100k miles. So if I actually keep the Escape that long, its essentially a guaranteed no repair cost ownership experience.

But you can almost put the escape in the Burban and never knows it there.

 

[L8T BURB]

For now, would you mind if I focused on the last sentence (click to expand)?
If memory serves, 3.08 & 6L90?
By 'lugs so bad in town', are you implying that more axle gear would help improve city / metro / urban MpG?
(I'm admittedly eager to infer it, but thought I should check with real experience.)

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.