GMT 900 motor vs '14 motor

[Ten7]

I'm currently driving a 2014 Tahoe for work, which has the older 5.3l / 6 speed / 3.42. GM website says it has 320 hp and 335 ft lbs, which I assume is the same as the 2010 silverado I had before the tahoe. The tahoe has decent power but its not overly impressive.

I'm close to ordering a 2015 Sierra and GM lists the new motors as 355 hp / 383 ft lbs. My question to the guys who went from an older 5.3 to a '14, how noticeable is the performance gain in HP and torque?

Thanks

[TJay74]

I went from a 2010 Sierra 5.3 to my 2014 6.2l. I test drove the 2014 5.3l and while it was noticeable that the power had been upped I still opted for the 6.2l since this is my only vehicle for some time until I can order a newer Vette.

[nibael]

the 5.3 is very powerful in the new truck. it's more efficent too. you'll notice a big difference.

[Savagecanuck1]

No big difference my 08 5.3 4.10 used the same amount of fuel as my 14 5.3 3.42.kinda disa pointing .maybe 1 mpg better on hwy when empty. Towing identical, both pigs.My gas bill last month was $800.All this new technology for little gain.

[SMiller]

I don't notice any power or mileage.

 

The old 5.3 was proven and simple, the new one is known for making the oil very dirty (direct injection) and being slightly louder (direct injection) time will tell but I assume these new motors will be as good as the last.

 

The 6.2 really rocks, the 5.3 seems to just be a wash.

[2017SierraSLT]

Test driving a pair of Ecotec 5.3's vs. my slightly modded and tuned '13 Vortec 5.3, mine would easily win a drag race. I think there is great potential there with the new ones, but I wasn't going like "wow" with the ones I drove.

[thetruck454]

I've driven both, the new 5.3 does come into its power band earlier in the rev range, but that's about the biggest difference I noticed

[Ten7]

No big difference my 08 5.3 4.10 used the same amount of fuel as my 14 5.3 3.42.kinda disa pointing .maybe 1 mpg better on hwy when empty. Towing identical, both pigs.My gas bill last month was $800.All this new technology for little gain.

 

If my google searches are accurate, an '08 5.3 produced 315 hp which is awful close to the 320 of my work tahoe. So you are saying that your 315 hp / 4.10 combo performs almost identical to your 355 hp / 3.42 combo in power and fuel economy? Do you notice any difference in power during normal commuting?

 

Ultimately this ^^ is what I'm trying to decide in my mind. That being, if I effectively lower the 3.42 gear ratio of a 2015 by running 33s or even 34s, will it perform at least as well as my current stock tahoe, or will it be even worse and leave me dissappointed? I wouldn't be overwhelmed with my current level of performance but I could live with it. If it is going to be worse, hunting for gears and kicking out of V4 all the time, then I will just order a max tow. I don't run a lot of interstate, maybe once a year, so I dont think gas mileage will suffer much with the 3.73s. But, it seems logical that a ~5% increase in tire size should at least be offset by an 11% increase in hp.

I'd love to have the 6.2l, but I'm pushing my budget as it is and I certainly don't want to be restricted to $$ premium fuel on top of it.

[Ltz73]

I had a 2009 Silverado 5.3 before my 2014 5.3 and my wife had a 2008 Tahoe 5.3 before her current car. I put 120,000 miles on my 2009 Silverado and we put 110,000 on her Tahoe (family wagon). I can tell you the difference in performance for me is overwhelmingly impressive with my 2014 Siverado. I have put over 12,000 miles on it in six months and I am still amazed at how much more power this truck feels like it has. Not to mention it is absolutely more refined, smoother, and quiter than my Mercedes e550 was.

[KMGZ400]

Test drove a few 14' 5.3's, ones with 3.08 and 3.42.. They are not overwhelmingly more powerful then the previous 5.3.. A little snappier definatley, but if you are dissapointed with the prev gen 5.3 you won't be much happier with this one... Something with a 6.2 or a diesel might be your best bet

[Ltz73]

Test drove a few 14' 5.3's, ones with 3.08 and 3.42.. They are not overwhelmingly more powerful then the previous 5.3.. A little snappier definatley, but if you are dissapointed with the prev gen 5.3 you won't be much happier with this one... Something with a 6.2 or a diesel might be your best bet

Maybe my last silverado and my wife's Tahoe were both turds maybe they were geared wrong I don't know. But I can assure you this truck performs overwhelmingly better in my opinion. Throttle response is night and day and this truck feels like it wants to go. When I jump on it I smoke the tires and it will run. My last a Silverado felt like it couldn't get out of its own way. Gas mileage on last truck was always between 14 to 16 mpg new truck is 19 to 22 mph, and this truck pulls my boat like a dream. I was hesitant to even get another chevy after those two, but one drive with this new motor and I was sold.

[Ten7]

Test drove a few 14' 5.3's, ones with 3.08 and 3.42.. They are not overwhelmingly more powerful then the previous 5.3.. A little snappier definatley, but if you are dissapointed with the prev gen 5.3 you won't be much happier with this one... Something with a 6.2 or a diesel might be your best bet

 

I'm not disappointed with the old 5.3 in stock form. It's no race car (its a truck after all) but its fine for what I do. But I will definitely go with larger tires on the new truck and I know that will effect its power. I just dont want my new truck to end up feeling weaker (due to the 33" tires) than my work vehicle. Another way of asking my question is, will the extra HP and torque at least cancel out the new tires?

 

My current personal truck is a '98 Ram with a 318 / 4 speed, now THAT is a turd. A whopping 230 hp and averages 11-12 mpg to boot. So anything will be an upgrade compared to the ram, but I put a lot of miles on my work truck and I dont want to jump in my new '15 at the end of the day and feel like it has less power than the 320 hp tahoe. I hope that makes sense?

Again, I'd love a 6.2 but it's not in my budget and a diesel sure as heck isnt. Nor could I justify it for what I do.

Thanks for all the opinions

[DanielAcosta]

 

I'm not disappointed with the old 5.3 in stock form. It's no race car (its a truck after all) but its fine for what I do. But I will definitely go with larger tires on the new truck and I know that will effect its power. I just dont want my new truck to end up feeling weaker (due to the 33" tires) than my work vehicle. Another way of asking my question is, will the extra HP and torque at least cancel out the new tires?

 

My current personal truck is a '98 Ram with a 318 / 4 speed, now THAT is a turd. A whopping 230 hp and averages 11-12 mpg to boot. So anything will be an upgrade compared to the ram, but I put a lot of miles on my work truck and I dont want to jump in my new '15 at the end of the day and feel like it has less power than the 320 hp tahoe. I hope that makes sense?

Again, I'd love a 6.2 but it's not in my budget and a diesel sure as heck isnt. Nor could I justify it for what I do.

Thanks for all the opinions

Definitely get the 3.42 or 3.73, not the 3.08 if you're going to upsize the tires. I also benefitted from adding a Hypertech to correct the speedometer and odometer from the oversize tires. Good luck with yours.

[Ten7]

Thanks. I wouldn't even consider the 3.08s for what I want.

[2017SierraSLT]

I was always confused why GM rated the GMT900 Suburban/Tahoe engines 5 HP more than the seemingly identical 1500 series truck engines. It had to be a tuning change if there was any change at all.