2.7 Turbo 4 Fan Club

newdude · May 15, 2022

On 5/13/2022 at 11:16 AM, customboss said:

26.2 mpg with mixed 60-65 mph cruise speeds on highway is consistent with 91 octane fuels. 26.2 kept showing on 40 mile legs regardless of wind azimuth, downhill or uphill in lower velocity winds.

25 with 87 octane

24 with 85 octane

I did change out stock HD AC OEM air filter about 500 miles ago and MAF is free flowing to turbo. 27lbs/min at WOT test. Cruises at 3-4 lbs/in flow at speeds mentioned above.

I THINK from what I am reading the HO version will REQUIRE 91 octane or at least some dealers are claiming that from what I see in internet.

GM is still spec'ing 87 octane for the 2.7T HO. However, your MPG results point to the fact that a boosted DI engine loves the higher octanes and can benefit from it somewhat.

Ford has even proven this with its EcoBoost engines. They all run 87 all day long (except the 3.5 HO), but MPG (and obviously performance) gains are noted on premium.

Side note, my lease is up on my 2019 old body 5.3. 2.7T is on the short list, just waiting for one I want to come in at work. Looking forward to it, and contributing more real world data/info in the 2.7 Club.

Edited May 15, 2022 by newdude

Mike Borowski · May 15, 2022

18 minutes ago, newdude said:

GM is still spec'ing 87 octane for the 2.7T HO. However, your MPG results point to the fact that a boosted DI engine loves the higher octanes and can benefit from it somewhat.

Ford has even proven this with its EcoBoost engines. They all run 87 all day long (except the 3.5 HO), but MPG (and obviously performance) gains are noted on premium.

Side note, my lease is up on my 2019 old body 5.3. 2.7T is on the short list, just waiting for one I want to come in at work. Looking forward to it, and contributing more real world data/info in the 2.7 Club.

Do you think the OG 2.7 benefits from premium? I’m glad the HO is going to make this engine more popular, I’m a big fan of my 2020.

customboss · May 15, 2022

17 minutes ago, Mike Borowski said:

Do you think the OG 2.7 benefits from premium? I’m glad the HO is going to make this engine more popular, I’m a big fan of my 2020.

Not answering for newdude.

From my testing E15 88 octane may be ideal overall. Here in CO mountains it’s rated 87 octane. Going to do more testing.

KARNUT · May 15, 2022

I loved the E-85 option in my 14 GMC and using reg gas for trips. The break even for E-85 was a dollar some people claimed. Of course the 6.2 drivers didn’t mind paying the premium price for performance. In case of 2.7 most people want efficiency and performance. Leaning efficiency. If the people at GM offered tuning for multiple fuel usage with performance and or efficiency that would be a real plus. I remember many years ago the mustang svo had a switch for reg fuel or premium. Now wouldn’t that be something. While there’re at it a switch for cylinder deactivation would be nice. Choices what a concept.

Acpantera · May 16, 2022

On 5/14/2022 at 9:05 PM, David Bodine said:

Ok, well 20% of my usual 20.1mpg is 4 = 16 should be the mpg after towing my 3300 lbs. trailer. But is it was 11mpg. That is the Kansa trip. Last month my trip to Arkansa yielded 10mpg. I am going to have to accept that the 2.7 gets very poor gas mileage.

It is always going to take "X" amount of hp to pull a 3300lb trailer with the aerodynamics of a wet cinder block.

Back in the late 90's early 00's I had a soft sided 4 place snowmobile trailer, loaded with 4 sleds it was about 3500 lbs. I towed it all over with a Chevy Astro 2wd 4.3l v6 with a whopping 200hp. I routinely got 10 to 11 mpg. From time to time my two friends would trade places towing the trailer, one was a gm pick up 350 4x4 and the other was Ford f150 with a 302 2wd . All 3 vehicles got the same mpg within .5 mpg.

Their is no gasoline pickup towing that trailer ever going to do better than 12mpg on your same trip. 11 ain't bad at all with that weight and aerodynamic drag....darn physics.

newdude · May 16, 2022

21 hours ago, Mike Borowski said:

Do you think the OG 2.7 benefits from premium? I’m glad the HO is going to make this engine more popular, I’m a big fan of my 2020.

Going off of Customboss's report that I had quoted to, his 2022 is an LTD, so the non HO engine. His initial data seems to possibly support this benefit, but obviously as he mentions, more data will help. Expenses come to play here as well as 91/93 octane is roughly $0.70-$1.00 more/gal than 87.

HO or non HO, its impressive of GM to obtain and only require 87 octane.

the wanderer · May 16, 2022

11 hours ago, Acpantera said:

It is always going to take "X" amount of hp to pull a 3300lb trailer with the aerodynamics of a wet cinder block.

Back in the late 90's early 00's I had a soft sided 4 place snowmobile trailer, loaded with 4 sleds it was about 3500 lbs. I towed it all over with a Chevy Astro 2wd 4.3l v6 with a whopping 200hp. I routinely got 10 to 11 mpg. From time to time my two friends would trade places towing the trailer, one was a gm pick up 350 4x4 and the other was Ford f150 with a 302 2wd . All 3 vehicles got the same mpg within .5 mpg.

Their is no gasoline pickup towing that trailer ever going to do better than 12mpg on your same trip. 11 ain't bad at all with that weight and aerodynamic drag....darn physics.

I mostly agree with you, but one thing to keep in mind (in addition to computer MPG readings being "off"), is that when we're talking 10 mpg, an additional +/- 1 MPG is a difference of 10 percent. So when we talk about half to 1 mpg we don't think it means much but when we convert that to a percentage it can still be somewhat significant especially over long distances.

diyer2 · May 16, 2022

My 2 cents.

Lower elevations, 87 octane or higher. May make a difference.

Higher elevations 85 octane works.

Having lived in Colorado over 30 years and having tried higher octane fuels in many motors I believe there is no advantage. Just costs more.

If higher elevations needed higher octane we would have it. Scientists and engineers are smarter than most.

KARNUT · May 16, 2022

I put performance tunes in all my trucks requiring premium fuel. I would tune the transmission too. Of course working for a family business I didn’t pay for fuel it was written off. My 14 I left the engine alone with the E-85 option except for raising the shift points and RPM. And reducing TM. It amazing what is left on the table performance wise. With the ability for engine tuning for different fuel a boost for premium or E-85 should be a no brainer. I read review rags as soon as they’re available. Some manufacturers have those options.

ESierra · May 16, 2022

I've thought about putting in 89 into the 2.7T but anytime I get to the pump I seem to forget that I want to, since the prices are dramatically different. Even if I decide to, shouldn't I be on the light? If I'm not I guess I'm technically mixing 87/89

customboss · May 16, 2022

3 hours ago, diyer2 said:

My 2 cents.

Lower elevations, 87 octane or higher. May make a difference.

Higher elevations 85 octane works.

Having lived in Colorado over 30 years and having tried higher octane fuels in many motors I believe there is no advantage. Just costs more.

If higher elevations needed higher octane we would have it. Scientists and engineers are smarter than most.

I agree with you on naturally aspirated computer controlled DI engines.

The Trail Boss is Turbo charged so if you have a lead foot or tow you are gonna need more octane. That turbo can pump 22 PSI boost on the 2.7L.

I proved that running 85 octane here works fine but its retarding the timing significantly if I thump it.

87-88 seems a sweet spot for the L3B regardless of altitude.

Watch the engineering video in this thread that CAM shared. The lower octane allowance for higher elevations is from 1940's data. The states regulate that not the feds so its state by state and not proper data for modern engines.

I have a Honda electronic injection EU7000is generator I use for power outages here and it runs on 86 min but I boost it a bit with .68 of a gallon of VP racing fuel 94 octane no ethanol mixed with about 4.5 4.5 gallons CENEX 85 octane for cleaning and minor octane boosting but it runs on pump 85 fine.

If you supercharge or turbo charge and throttle it a lot you will need a bit more octane but NA engines even with VVT,DI, etc seem to do fine by my scanner.

customboss · May 16, 2022

2 hours ago, ESierra said:

I've thought about putting in 89 into the 2.7T but anytime I get to the pump I seem to forget that I want to, since the prices are dramatically different. Even if I decide to, shouldn't I be on the light? If I'm not I guess I'm technically mixing 87/89

Not sure what " on the light" means?

In Western NY I doubt 89 would help much unless you are towing or romping on it hard.

On timing ****** for mine I have seen -15 degrees and advance as far as 60 degrees. Using 87 or higher mixes gets me less negative range . 85 octane gets me less advance. 47 degrees was max on 85 octane here.

I don't WOT much but did to test with scanner dynamically.

I aim for 1500-2000 RPM because the thing has so much TQ its easy to accelerate at lower RPM.

I can say that the Amsoil OE 5w30 has shown my best MPG readings and my DIC is really spot on when checked against fill calculation. I think its more accurate than pump and temp at fill deltas. 0.1% MPG variations with fill looking more variable.

customboss · May 16, 2022

Why does the filter cancel out R-E-T-A-R-D for timing? PC much.....LOL

F-150stxguy · May 17, 2022

This is a great thread to read. I’ve caught up a few pages. I still have my older car I’m driving around and still haven’t pulled the trigger on the new 2.7 Chevy regular cab. I’ve been looking on the local lot but I doubt I’ll see one and probably have to custom order.

I have a hard time thinking I would be comfortable running 87 octane in the dead of summer in south west Texas. It regularly gets above 100 here in the summer. Granted, my truck will probably be living in Maine in a few years, I could see getting away with it up there in God’s country.

Anyhow, I would probably run 87 in winter and 89 in summer.

Id be very happy with some of the gas mileage you guys are reporting. I would be very interested in seeing what a 2wd regular cab could eek out.

About a month back I saw a bare bones Ford regular cab, 2wd with the 3.3 naturally aspirated 6 at the dealer. It was marked up a little but nothing extreme. I drove by the following day the ****ing thing was gone lol. What a crazy market we are in. I remember a few years ago up north I saw an F150 4x4 with the 3.5 naturally aspirated 6 sit on a dealers lot for a whole damn year, and the price was listed at 26,000. I’d jump on that right now.

Edited May 17, 2022 by F-150stxguy

customboss · May 17, 2022

"Id be very happy with some of the gas mileage you guys are reporting. I would be very interested in seeing what a 2wd regular cab could eek out. "

A member named COWBOY ordered one in Texas and I am betting that Grumpy Bear will be wanting one soon that will rival his 2015 Silverado 2WD that gets super MPG with a 4.3 V6.

Small tweeks can make a big difference.