To be honest ... the Ford Ecoboost 3.5 vs ...

[Homer1959]

I just got back from a 1000km  trip through the mountains of Côte-Nord, Quebec. It's incredibly hilly there! I was towing my 35-foot, 7,775 lb travel trailer for the first time with my new Sierra HD 6.6 gas. Before this, I was driving an 2014 F150 3.5 EcoBoost.

 

First impressions: wow, the comfort is 10 times better, and the handling is vastly superior. Fuel consumption seems about the same, maybe a bit more, though it's hard to judge on those kinds of roads.

 

Power-wise, I'm not entirely sure the 6.6 pulls much more than my former 3.5 EcoBoost. I'll have a better idea on our Texas trip in two months. That 3.5 pulled hard and didn’t make much more noise than the 6.6 it  the 6.6 definitely lets you know it’s working.

 

I never drove the F150 in Côte-Nord, so I can’t compare the under-the-hood noise on those hills. But after 4000km, I can confidently say the 3.5 felt as strong as the 6.6, or at least very close, which surprised me. That said, I’m very pleased with my new 2025 HD2500 SLE. No oil consumption and no issues with the 10L90 so far. This trip and the weather were a real test to see if the 6.6 would guzzle oil, and I’m happy to report it’s not an oilaholic!

 

[CRApex]

21 minutes ago, Homer1959 said:

I just got back from a 1000km  trip through the mountains of Côte-Nord, Quebec. It's incredibly hilly there! I was towing my 35-foot, 7,775 lb travel trailer for the first time with my new Sierra HD 6.6 gas. Before this, I was driving an 2014 F150 3.5 EcoBoost.

 

First impressions: wow, the comfort is 10 times better, and the handling is vastly superior. Fuel consumption seems about the same, maybe a bit more, though it's hard to judge on those kinds of roads.

 

Power-wise, I'm not entirely sure the 6.6 pulls much more than my former 3.5 EcoBoost. I'll have a better idea on our Texas trip in two months. That 3.5 pulled hard and didn’t make much more noise than the 6.6 it  the 6.6 definitely lets you know it’s working.

 

I never drove the F150 in Côte-Nord, so I can’t compare the under-the-hood noise on those hills. But after 4000km, I can confidently say the 3.5 felt as strong as the 6.6, or at least very close, which surprised me. That said, I’m very pleased with my new 2025 HD2500 SLE. No oil consumption and no issues with the 10L90 so far. This trip and the weather were a real test to see if the 6.6 would guzzle oil, and I’m happy to report it’s not an oilaholic!

 

The 3.5 can create HP and torque but will not come close to outliving that 6.6.  

[UWSkier]

Ecoboost will maul the 6.6L in the hills, then need a complete teardown in 60k miles.  The 6.6L is a stout engine, but it's underwhelming power-wise.

[Homer1959]

I agree my confidence was always shaky with the 3.5 but luckily it serves me well for 10 years.maybe the lack of horsepower is a reason why we can expect greater reliability ? Time will tell i Guess

Edited August 31, 2025 by Homer1959

[Epsilon Plus]

The L8T is classic GM malaise wrapped around a package that could decimate the competition.

 

Always sub par in stock form. Always a world beater with the proper hands modding it. Look no further than GMs own L8P crate engine with a itty bitty baby cam and some 91 octane

 

That's a 30.4% increase in horsepower and 17% increase in torque from barely opening the valves a touch more/longer and taking the brakes off the tune.

 

The reality is the L8T is designed solely for fleet reliability and fuel mileage, just like the previous 6.0 was. Add in terrible throttle response and a lack luster safe overly rich classic GM tune, and this truck is a dog.

 

Tuning is probably my next big spend. Just a throttle modifier makes this thing feel like a different engine.

[Pryme]

Yeah the 6.6 gas is not fast. Unloaded I can say for sure my old 16 tundra was quicker. But I don’t care about that in a truck. I like this truck more and it’s certainly way more heavy duty. 

[Homer1959]

Dont take me wrong guys, i dont miss my F150 at all, i was just a bit disappointed by the engine power, maybe my expectations were too high ? Anyway i love my truck i dont regret it at all , 

[Homer1959]

Btw i wonder if anyone drove an f250 with the 7.3 gaz and can share how they compare power wise under load 

[jake111]

On 8/31/2025 at 8:14 AM, Homer1959 said:

... no issues with the 10L90 so far. ...

 

10L1000 I'm sure for a 2500HD...

[rjgvt]

After having 3 GMC 1500's with the 5.3 in a row, not sure what's not to like with the 2500HD. My last 1500 had a GVWR of 7200 lbs and payload of 1775 lbs. I kept stuff in the truck under the rear seat and in the bed with a cap on it like I do with all of my trucks. I took a load of firewood to camp with the 1500. I had 2 jet sleds full, a plastic concrete mixing tub full and the very back of the bed stacked up some. I'm pretty sure I was close to overloaded if not over. I was glad to get there and unload the firewood. 

 

Fast forward to my current truck, a 2500HD AT4. With the stuff from my last 1500 in my 2500, 2 people and mostly full gas tank, it weighs around 1000lbs over curb weight. The difference is that I have around 2200lbs left of payload. I don't need a race truck but what's not to like?

[Pryme]

23 hours ago, Homer1959 said:

Dont take me wrong guys, i dont miss my F150 at all, i was just a bit disappointed by the engine power, maybe my expectations were too high ? Anyway i love my truck i dont regret it at all , 

You have to realize a 2500hd is about 7200lbs vs a 1500 or 150 is what, about 5500lbs? Put about 1700lbs in the bed of a half ton and see what happens to the seat of the pants feel. 

[newdude]

On 8/31/2025 at 9:22 PM, Homer1959 said:

Dont take me wrong guys, i dont miss my F150 at all, i was just a bit disappointed by the engine power, maybe my expectations were too high ? Anyway i love my truck i dont regret it at all , 

 

 

A GM crew cab gas HD weighs 7200-7400lbs.  Doesn't help lol.  The previous generation HD gas crew was maybe 6600-6800lbs?  But was a dog with the last version of the L96 6.0.  So the continued weight gain from enlarging these trucks for capabilities has its negatives for sure.  The L8T 6.6 gas in a 2007-2010 generation truck would rip.  401hp 464tq in a 5800lbs truck?  That's a current 6.2 1500 in terms of performance.

[Chuck FB]

Keep in mind the F 150 homer referred to is not a current rated 3.5 as they were not pushing as much power out of them back then. Assuming I found the correct specs for that year, here they are. Its the magic of the turbo that gives the high torque across the rpm range and creates a great pulling engine and certainly for the small size of the engine. But its all that power out of a small package that puts a lot of stress on it when pushed and I've seen various comments from those that live in Colorado seeing a Ford F150 sitting on the side of one of the major grades with a trailer behind and blew the engine, I get the impression it earned the name Eco Boom 

 

Also the weight of an HD truck is perhaps 2000 pounds more than a half ton, that weight takes power to move which reduces performance. However that is the very reason its a more stable platform to tow with because of its stiffer stronger heavier build and running 10 ply tires.

 

The current 3.5, is that around 400 hp and 500 lb-ft of torque ?

 

2014 F150 EcoBoost Specs 

Engine Specs: 3.5L EcoBoost V6 Twin-turbocharged and Direct Injected Design 365 horsepower @ 5500rpm 420lb-ft of torque @ 2500rpm

 

 

[Chuck FB]

55 minutes ago, newdude said:

 

 

A GM crew cab gas HD weighs 7200-7400lbs.  Doesn't help lol.  The previous generation HD gas crew was maybe 6600-6800lbs?  But was a dog with the last version of the L96 6.0.  So the continued weight gain from enlarging these trucks for capabilities has its negatives for sure.  The L8T 6.6 gas in a 2007-2010 generation truck would rip.  401hp 464tq in a 5800lbs truck?  That's a current 6.2 1500 in terms of performance.

I was typing my last post as you were posting, yup weight kills performance ... I mean who ever saw a marathon runner that was wider than they were tall LOL. Like you said the current HD, mine is just about 7700 lb curb where as my friends chev 1/2 refresh with the longest box on the crew cab and also a HC trim with the 6.2, I believe his is somewhere in the 5500 to 5600 range, mine is at least 2000 lb over that and less power to boot and certainly pushes more air, gee who would win in a race.  

Edited September 2, 2025 by Chuck FB

[Homer1959]

Im not full-time stupid  I know the truck is heavier, stronger, and built with bigger, more solid components than my former F150. However, engine power-wise, in terms of HP versus torque, it’s about the same, which makes it amazing to see what two little fans spinning fast can accomplish.

 

The Ecoboom  , as Chuck mentioned, had its fair share of problems, but how many millions are out on the road?

 

A V8 is a V8, and the 6.6 should be much more solid and reliable. Comparing 213 versus 400 cubic inches for essentially the same HP and torque should be easily manageable.

 

Ecoboost first generation  213 cubic inches 360 HP 420 LB-FT of torque

 L8T                                   400 Cubic Inches   401  HP 464 LB-FT of torque and sounds much better at the tail pipe

 

401/464 is plenty , my first towing experience with my Sierra was on a fairly difficult road  and doesnt represent what I am use to drive on with my former truck. Ill be able to really compared apple to apple in November on my way to McAllen Tx leaving from Montreal qc. I cant wait for that trip, in this super confortable truck ... 

 

Edited September 2, 2025 by Homer1959