2.7t vs 5.3 vs 6.2 - Have I got this right? First post, my 22 TB 2.7t should land in a few weeks.

4banger · June 6, 2022

Sup GM fans, I ordered a 22 Custom TB with 2.7t h.o. early April and should land in a few weeks so wanted to join a forum for all the reasons a guys does with a new ride. I'm leaving a 2020 Jeep Gladiator behind as I tow a little cargo trailer camperized 4-season off-grid style a little too much and decided I needed some boost. Anyhow, wanted to run a few things by you guys and see if I got everything correct?

1st, I live at 4000' elevation, Calgary Alberta.

2nd, I understand naturally aspirated motors lose 3% power per 1000' elevation gain.

3rd, I understand boosted motors lose 0.05% power per 1000' elevation gain.

Having said that the compounding math every 1000' here's where I see these 3 motors shake out where I live at 4000'.

1. 2.7t - 309 hp/429 ft/lbs. (down 1 hp/1 ft/lb from sea level rating)

2. 5.3 - 314 hp/339 ft/lbs. (down 41 hp/44 ft/lb from sea level rating)

3. 6.2 - 372 hp/407 ft/lbs. (down 48 hp/53 ft/lb from sea level rating)

Am I missing anything so far before I add other analysis info I've put together?

mafd2 · June 6, 2022

Myself, I love a V8. I like the sound, feel and growl. I've always had V8's in all my trucks since my first new Silverado in 1985. I'm not a fan of a V6 or a 4 in a full size truck and is why I ordered my '22 Z71 refresh with a 5.3.

reeseb · June 6, 2022

"Myself, I love a V8. I like the sound, feel and growl. I've always had V8's in all my trucks since my first new Silverado in 1985. I'm not a fan of a V6 or a 4 in a full size truck and is why I ordered my '22 Z71 refresh with a 5.3."

I don't think that was what the OP was asking.

Edited June 6, 2022 by reeseb

reeseb · June 6, 2022

I have a friend with a masters degree in auto tech. I forwarded your question to him. His answer is below.

Yes. Altitude results in less oxygen. Your Baro sensor compensates for this altitude difference by adding less fuel.

mafd2 · June 6, 2022

58 minutes ago, reeseb said:

"Myself, I love a V8. I like the sound, feel and growl. I've always had V8's in all my trucks since my first new Silverado in 1985. I'm not a fan of a V6 or a 4 in a full size truck and is why I ordered my '22 Z71 refresh with a 5.3."

I don't think that was what the OP was asking.

Yes I understand just saying to me it's not worth the trade off of owing a 4 even if mpg.'s are better on a 4 and the elevation difference in H.P. etc.

calgator73 · June 6, 2022

2 hours ago, 4banger said:

Sup GM fans, I ordered a 22 Custom TB with 2.7t h.o. early April and should land in a few weeks so wanted to join a forum for all the reasons a guys does with a new ride. I'm leaving a 2020 Jeep Gladiator behind as I tow a little cargo trailer camperized 4-season off-grid style a little too much and decided I needed some boost. Anyhow, wanted to run a few things by you guys and see if I got everything correct?

1st, I live at 4000' elevation, Calgary Alberta.

2nd, I understand naturally aspirated motors lose 3% power per 1000' elevation gain.

3rd, I understand boosted motors lose 0.05% power per 1000' elevation gain.

Having said that the compounding math every 1000' here's where I see these 3 motors shake out where I live at 4000'.

1. 2.7t - 309 hp/429 ft/lbs. (down 1 hp/1 ft/lb from sea level rating)

2. 5.3 - 314 hp/339 ft/lbs. (down 41 hp/44 ft/lb from sea level rating)

3. 6.2 - 372 hp/407 ft/lbs. (down 48 hp/53 ft/lb from sea level rating)

Am I missing anything so far before I add other analysis info I've put together?

I think that's a fair assessment. TFL claims only a .36 second 0-60 time difference in the 6.2's favor at altitude. That lines up with your math in my opinion.

4banger · June 6, 2022

Currently driving the 2022 6.2 rental as my gladiator pentastar just about left us in the bush this past spring bear hunt so I've weighed it and getting a good feel for the difference in mileage and power before my 2.7 shows up. It's the long box gmc full load and at 5665 lbs with a full tank of gas and me not in it. Sure pulled our 3000 lb trailer home like it was nothing. I get the v8 sound thing but that's the only subjective win I can see so far and I'm too old to care about subjective anything anymore. Having said that there's no way I'll do aftermarket exhaust on the 4 banger with the spin whistle lol.

I guess the only other win I could see for the 6.2 or 5.3 is those low cylinder pressures of non boosted engines although engines built for cylinder pressure seem to be able to last just fine...ie; cummins and other diesels which run more cylinder pressure than the 2.7t. AND...the 2.7t was designed around the turbo so has the bottom end to handle said pressures, it also seems to have less hiccups (valve train) issues than the v8's presently also.

Next I see it weighs about the same as my pentastar so around 375 lbs I understand, or 160 less than the 5.3 which boost payload and towing but off-road in the soft stuff it's nice having a light front end that doesn't wanna sink away, which also translates into nimbler street handling as well. More wins for the little 4banger which is not really that little. It's a long stroke (more torque than hp) with 680 cc jugs and the 5.3 is a short stroke with 666 cc jugs...one just gets up to 22 psi boost and the other doesn't but compensates with twice as many jugs. The 2.7t can almost be thought of as half a 5.3 but boosted to make similar. Half the 5.3 would actually be 2664cc while the 2.7t is 2720cc. Just the long stroke with boost alone screams a lot more 'truck' engine to me if looking at it against the 5.3...I digress.

As for mileage, well if you're gonna climb a steep grade towing you'll burn the same amount of fuel as anything else gas if done in same timeframe as you need to make the power. As TFL did on ike with 5.3 and 2.7t both yanked ~7000 lbs up in 8 minutes and got 3.7 mpg to illustrate that fact. The 2.7t, as with many turbos for similar outputs against naturally aspirated motors, the consensus is ~13% overall better fuel economy which mostly seems to come from idling and low rpm duty as there's just less cylinders to feed a lot of the time but when it's making v8 power it will suck v8 gas...the smaller turbos just have more flexibility/versatility. I checked the fuelly.com averages for the 2.7t to the 5.3 and it's 12.6 l/100km vs 14.4 l/100km for 1.8 l/100km, for the USA folks that's 18.7 mpg vs 16.3 mpg or 1.4 mpg advantage for the turbski...funny that fully.com shows about 12.5% better overall.

When I look at how little power is lost at elevation this makes all the above look even better and better. On paper the 5.3 initially shows a 45 hp advantage (caveat - sea level) and 47 ft/lbs less torque...it's almost a dead wash between these two engines at sea level. The turbo runs more torque at lower rpm so for 'truck' duty would appear to make more sense. Then you add in 4000' elevation where I live and the turbo exponentially makes more sense, before I even tow into the mountains where I'll see 7000' passes and just where I live at 4000' the turbo shows I'll have 90 ft/lbs more torque and only 5 less hp than the 5.3. That's a big deal. That 90 ft/lbs will be lower rpm to boot. And climbing the big rocks at 7000' that gain is even bigger as the turbo only loses 1 more hp and 1 more ft/lb for 308/428 and the 5.3 drops to 287/309 for like 119 ft/lbs torque difference and 21 hp both advantage turbo.

This will be my first turbo motor and clearly I like to do research so will definitely find out the reality of it. I've driven plenty of fleet cummins turbo motors through the 90's and been in plenty of other turbos just never actually owned one. This motor looks to be the sleeper 1/2 ton truck motor for gas. Ford has a 2.7tt with same bore/stroke but smaller cylinders (449cc) and does 325 hp and 400 ft/lbs but more cylinders in a V vs inline, and 2 turbos...less 'truck' like preferred characteristics (more complex)...and Dodge(fca) is coming out with its hurricane engine to compete and it's a 3.0 liter inline 6 with 2 turbos also which is said to be 400 hp and 450 ft/lbs in standard output with 500 hp and 475 ft/lbs in h.o. versions. I didn't see bore/stroke on that one but it will be more ford/5.3 like, likely short stroke but at least it's inline which is a desirable trait, it's doing one turbo for each 3 cylinders. It does appear turbo is the future and digging into this I can sure see why. Will be fun to see how this plays out. I'm soaking in this 6.2 v8 right now and will definitely be able to compare to it. At my elevation I will have 22 ft/lbs more torque but 63 less hp so the 6.2 should pull away but the turbski may hit close off the line and still keep it closer than one may think. There's going to be a weight difference to offset also and reports seem to favour the turbo as funnest to drive around town...the numbers may be suggesting why that is.

4banger · June 6, 2022

14 minutes ago, calgator73 said:

I think that's a fair assessment. TFL claims only a .36 second 0-60 time difference in the 6.2's favor at altitude. That lines up with your math in my opinion.

Ya all the mathing I've been doing and researching seems to be correlating as well. I think this 2.7t from gm may be the sleeper dark horse engine for awhile until people catch on. I'm glad I prefer simple trims as I'm 100% drawn back to gm for this motor alone. They essentially built a modern 4bt cummins powered by gasoline. Granted it's the 2022 h.o. spec that really tweaked the nips...with new torque rating at 430 ft/lbs but there's no flies on the gen 1 2019-2021 turbo so far.

I don't think this will be the last we see in this direction either. I understand cummins is working on a gas powered version of it's 6.7 also...as they see that a lot of people want that torque style long stroke but refuse to go diesel to get it. They don't want to deal with def/complexity etc. So gm I think was crystal balling better than most with this 2.7, pretty much a vision of a perfect half ton truck motor in my head, I'm a huge fan of the 2v p-pump cummins motors and to see this gas offering from gm and it's got 3 years under it's belt winning to allow a gen 2 h.o. offering. Cripes...the original 5.9 cummins only had 400/410 ft/lbs torque...now this 2.7t has 430. Incredible imo.

Edited June 6, 2022 by 4banger

4banger · June 6, 2022

1 hour ago, mafd2 said:

Yes I understand just saying to me it's not worth the trade off of owing a 4 even if mpg.'s are better on a 4 and the elevation difference in H.P. etc.

how do you feel about the 4bt or 6bt cummins legendary work engines with million mile rebuild norms? yes the small block and LS v8's are legends and I love the shat out of them, car guys boost them to 1200 hp easily, gm is good at raising legends...well I'd prepare yourself for this 2.7t to become another gm legend, it will be swapped and crated a lot imo but it will take time, the mpg's don't mean a great deal to me either...but as a long time truck guy, torque is king, I don't give a flyin fart how it sounds, there's no trade off here, the torque is down low, like a diesel, this is a long stroke gas engine with power unaffected by elevation, just like a turbo diesel...I applaud gm but as with anything new it takes time to earn stripes and change old views, looks like this thing has earned it's stripes first 3 years so far, and...it's not little, it's the largest displacement 4 banger currently available in auto land, this is a big block 4 banger with a spin whistle lol