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Discussion Starter #1 (Edited)
2016 EBPP with 54k miles, bone stock motor. New block and head with 1k miles accrued so far. Both before and after the new motor, my display has always said I average about 23.x mpg. I do about 65 highway, 35 city. I was expecting around 25-26 mpg, but figured the 3.55 gears aren't doing me any favors there and I've been "breaking" in the block so I'm varying rpm quite frequently and not necessary focused on mpg. Now that I'm past that period, I'm driving more normal, but still not impressed by the mpg. I drove about an hour yesterday, all freeway, and intentionally kept it around 65-75 tops. That yielded me a max of 27.8 mpg over the course of the trip.

I've seen plenty of people in other posts saying they're getting 30-35+ mpg during highway driving...are these people driving 50 on the highway or what am I missing here? Are these motors really that finicky or are they really all over the board?

I very rarely see boost as well, it's not like I have a heavy foot. The only thing I know was affecting it was it was 100+ degrees and of course the a/c was on. I'd expect a couple mpg increase in better weather with no a/c on, so maybe I need to wait for cooler weather before I start complaining...lol
 

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Why did you replace the block and head?

My 2015 PP Auto has been bone stock for 5 years and I consistently see 20-22 with county driving and my wife 25-26 with country/city/highway commute. I just recently updated a bunch of parts and ordered Rev-x tuner but haven't tuned it yet.
 

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I get every bit of 35-38mpg with my 3.31 sometimes thouth it’s only 30-33 I think varying gas quality and weather conditions.

You should definitely get 30 all day long highway

I lose mpg after I floor it a lot but average cruise is high
 

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Discussion Starter #5
Why did you replace the block and head?

My 2015 PP Auto has been bone stock for 5 years and I consistently see 20-22 with county driving and my wife 25-26 with country/city/highway commute. I just recently updated a bunch of parts and ordered Rev-x tuner but haven't tuned it yet.
Blown head gasket. Dealer replaced it all under warranty, so I'll take it.

What do you mean by county driving? 25-26 is what I was really expecting for mixed. Maybe I'll see that once the weather cools down and I don't have a/c on all the time. Just picked up a Cobb AP as well, worst case scenario I can run the "economy" map for long trips.
 

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Discussion Starter #6
I’m getting 30 mpg running 65 to 85 mph.
What rpm are showing at those speeds? I know the 3.55s aren't helping me, but they're not significantly different than 3.31. At 80mph, I'm at 2500 rpm. At 70, I'm around 2000 IIRC.
 

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Discussion Starter #7
I get every bit of 35-38mpg with my 3.31 sometimes thouth it’s only 30-33 I think varying gas quality and weather conditions.

You should definitely get 30 all day long highway

I lose mpg after I floor it a lot but average cruise is high
What would you say is the difference between the times you're seeing 35-38 and 30-31? That's quite a difference. Is that weather dependent by chance? I'm thinking I'll pick up a couple mpg max with cooler weather and a/c off, but that's quite a spread you're seeing.
 

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2016 EBPP with 54k miles, bone stock motor. New block and head with 1k miles accrued so far. Both before and after the new motor, my display has always said I average about 23.x mpg. I do about 65 highway, 35 city. I was expecting around 25-26 mpg, but figured the 3.55 gears aren't doing me any favors there and I've been "breaking" in the block so I'm varying rpm quite frequently and not necessary focused on mpg. Now that I'm past that period, I'm driving more normal, but still not impressed by the mpg. I drove about an hour yesterday, all freeway, and intentionally kept it around 65-75 tops. That yielded me a max of 27.8 mpg over the course of the trip.

I've seen plenty of people in other posts saying they're getting 30-35+ mpg during highway driving...are these people driving 50 on the highway or what am I missing here? Are these motors really that finicky or are they really all over the board?

I very rarely see boost as well, it's not like I have a heavy foot. The only thing I know was affecting it was it was 100+ degrees and of course the a/c was on. I'd expect a couple mpg increase in better weather with no a/c on, so maybe I need to wait for cooler weather before I start complaining...lol
Ever since I've been tuned running the NX2 turbo I've seen my highway MPG plateau around 27-28 MPG. The estimated 30 MPG assume you are bone stock and drive like grandma. I'm not expecting to get phenomenal fuel economy but 28 MPG with my setup is still pretty good.
 

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I don’t go above 70mph (65 to 70) is our highway here and I don’t speed lol, I get 30-33 or so sams club, but costco’ man! Goes straight to 35+

I was max at 35 before I got a catted downpipe and full exhaust (downpipe 3 inch into dual 2.5 exhaust) after that, I gained another 10%

But I’m not tuned for it, my car just seems to compensate on its own just fine. But the freer flowing exhaust added the 10%

I’m on ford perf tune and intercooler 3.31 rear
 

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“A10, so 3.15 Rear, at 75 mph, dead on 2K rpm“
A10 here also, try 80 and see if shifts again and also indicates 2K. I’m not sure about this but I don’t think it shifts into 10th until about 90 ?
 

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Discussion Starter #13
Well crap, I forgot about the 10 speed autos lol. Totally different ball game. I'm 6 speed manual with 3.55s. I have no doubt the A10 is one of the main reasons I've seen wildly different mpg results in other posts as well.

I've always been told, and heard, that Costco gas is trash as well. Interesting seeing those results between the two.
 

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Discussion Starter #15
Well let me rephrase haha, not necessarily trash, just not recommended if the life of your motor depends on the octane listed. I would run it all day in a n/a stock car, just not a boosted motor that's been tuned for 91+ (we only have 91 in CA).
 

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Blown head gasket. Dealer replaced it all under warranty, so I'll take it.

What do you mean by county driving? 25-26 is what I was really expecting for mixed. Maybe I'll see that once the weather cools down and I don't have a/c on all the time. Just picked up a Cobb AP as well, worst case scenario I can run the "economy" map for long trips.
I meant country driving but county is also accurate as I mostly drive around the local county roads which are all country roads :). In my area there are many country roads that are wide open with minimal traffic and minimal traffic lights so there isn't a lot of stop and go. I rarely drive on a highway but get up to highway speeds in the country and top out between 70-80 mph. I work from home and when I leave my community and hit the main road I do 0-80 MPH pulls and drive in sport mode locally.

My wife commutes to the city and drives on the highway and city for short distances (5 miles highway and a couple miles of city) with most of her commute on country roads as well.

What psi are you running cold? Mine are set at 32.
 

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In my HPP i get between 22/26 city/highway. My highway speed is always between 70-80. The roads here are all up and down, never any flat ground for more than a mile.

When i drive my wifes 18 A10 i get 30+ all day
 

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See here Costco and sams sell this

87 octane $2.00
93 octane $2.15

That’s it

I use 93. Other stations are like 70 cents more for 93. But 87 is same as shell etc
 

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“A10, so 3.15 Rear, at 75 mph, dead on 2K rpm“
A10 here also, try 80 and see if shifts again and also indicates 2K. I’m not sure about this but I don’t think it shifts into 10th until about 90 ?
My comment was running in D. I’ve never seen 10th in S, so you may be right about the 90 mph.

If Magneto is driving secondary country roads at 50-55 mph, fuel economy will pretty much be maxed out. One of the reasons they picked the double nickel during the early 70s fuel crisis; it’s the sweet spot for economy vs. speed. Modern engines have mitigated that substantially but physics apply no matter what.
 

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Discussion Starter #20
I meant country driving but county is also accurate as I mostly drive around the local county roads which are all country roads :). In my area there are many country roads that are wide open with minimal traffic and minimal traffic lights so there isn't a lot of stop and go. I rarely drive on a highway but get up to highway speeds in the country and top out between 70-80 mph. I work from home and when I leave my community and hit the main road I do 0-80 MPH pulls and drive in sport mode locally.

My wife commutes to the city and drives on the highway and city for short distances (5 miles highway and a couple miles of city) with most of her commute on country roads as well.

What psi are you running cold? Mine are set at 32.
Oh ok gotcha, yeah I don't see many roads like that in my normal commute and trips. They are nice when I find them though.

I honestly haven't messed with the pressure since they were installed, so they were around 39 hot when I've checked before, but recently I think they've all settled down to mid 35s. Definitely not a low tire pressure problem haha
 
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