I used to own a 1995 Pontiac Firebird with a 3.8 (?) V6 and automatic transmission. No modifications and over 100K on the odometer. The car was given to me. On the highway I would average 30 mpg. Around town I didn't bother checking mpg because it was fun to occasionally get your foot into it. Here we are over 20 years later and most cars I see offered today get about 30 mpg highway. Do you think there is a Big Oil influence or is there a threshold on the mpg that technology can produce?
Weight. Most new cars are very heavy, laden with safety devices and electronics, not to mention options. Patrick
Modern cars also have to comply with far stricter emissions standards than their 90s equivalents. People also expect a lot more performance.
Fuel injection technology , ignition technology, computer technology have advanced so far in the past thirty years; Engine metallurgy and machining and coating processes, and oil technology have advanced as well. Older cars (Yes, those OLD cars from the 90's even!) are so outdated it isn't funny. Think about it: Those "High Tech" cars from the 90's are rapidly approaching THIRTY years old; most still used a DISTRIBUTOR based ignition, instead of sensor-based and computer programs. Our beloved V-8 cars aren't even twice that old...
Our '90 Reatta with the 3.8 and the 4 speed auto with the lock-up torque converter consistently got over 30mpg on the highway. Sometimes mid-30's. The old 3.8 was an amazing motor. Our supercharged Grand Prix GTP and our supercharged Riv didn't do quite as good but they sure had a lot more power!
If they would make motors that concentrate on torque at low rpm mileage would increase. But...the peak torque rpms keep going up while they keep adding gears in transmission and trying to run a motor with peak torque at 4000 rpm at 1800 rpm down the highway.
My Riviera got 32 MPG on a trip from NY to Norwalk, OH one year. Final drive on that car is about 2.05, 1600 RPM @ 60 MPH, at 2000 RPM, I'm doing close to 80 MPH. The engine currently has 184,000 miles on it. Mixed driving, it gets 23-24 MPG, amazing car, and it weighs about 3600 lbs.
My 2018 Outback is giving a steady 34 MPG the Electra is solid at 11 MPG Regardless - I know which one I prefer to drive Bob
A gas mileage standout for it’s size are the Roadmasters with the LT1. These cars will give you a solid 25-26 mpg on the highway. As mentioned earlier the 3.8 always gas notably high highway mileage, usually 30-32. Have had 8 3.8’s and could always count on that mileage. Another gas mileage consideration is gasoline used, season, etc.
So my thinking is that based on the 3.8's performance, fast forward 30+ years, we have not done much for the end user as far as mpg goes. It just seems odd that the numbers have not improved. Consider again, a what if scenario where you had a platform such as the 3.8 mated to a modern multi gear transmission and engine management system. One would think that numbers such as 40+ mpg could be achieved.
Hybrids have, but more in city type driving. When I was working for NYC Transit, my patrol car was a 2011 Toyota Camry 4 cylinder gas engine/electric hybrid. All of my driving was city type stop/go driving, and it routinely got mid 20's which I thought was pretty amazing. I checked mileage every time I fueled it up. Never got a highway MPG though. It was fast too. I was shocked the first time I floored it and both motors came into play.
Like I said....they produce motors with double overhead cams and rev to 6500....they add variable valve timing to compensate.....then try to gear it down for mph. If they built a gas motor like a diesel or gas boat motor and not even think of it revving beyond 4000 it could go down the hwy at 1400 at 70mph and get 40 mpg easy. But....engineers probably feel like dunces resorting to tractor technology.....
Bingo.. We have a winner here.. I have to run at least 3k rpm to keep a steady cruise speed in my POS Ram/Fiat work van. 8th and 9th gear are useless.
I have owned 3 82-84 Eldorados 4.1 engines .........they all gave me 28 mpg on the hwy and great handling in the snow
I had a 2013 GMC Sierra Z71 4wd w/5.3. It absolutely drove me crazy hunting for gears and downshifting 2 gears all the time. Literally, the minute that I heard you could order a 2016 Colorado with a diesel, I did. No test drive or anything. They weren't even out yet. It gets about 22mpg in the city and loafs along on the highway at 2000 rpm @ 70 and gets an easy 28-30mpg and no hunting for gears. Got 17mpg towing my 66 Skylark with it last yr to BG. Love it. Also have a 2000 Firebird w/ 3.8 5spd. Regularly got 30mpg on highway, with a best of 36 mpg with a good tailwind.
Next week Pat and I are gonna be taking off for a boat trip... I fully expect a full POINT SIX MPG (.6 !) out of two 454's (660 hp total) at a steady 2500 rpm (about 15-16 mph). After all, whats 100 gallons a day @ $4.30/gallon? THAT Riviera hardtop weighs a paltry 15,000 lbs and holds 220 gallons of fuel. Well worth every penny spent... ws
I bought a new Camaro SS 6 speed manual in 2010, took a trip to Montana in it and cruised about 75 mph most of the way traveling over 4 mountain passes. that car averaged over 30 mpg for the trip and I wasn't babying it. my 2018 Mustang will pull down right at 30 on the freeway at 70 mph and thats with a 460 horsepower engine in it. these new cars are amazing for the power they make and their ability to get good mileage
Right .....because they have the torque to loaf along....but if they built a smaller engine to produce max torque the mpg would be even better. 4cyl high rpm cars ....when you put 4 people in and some luggage mpg tanks....no torque..... I got 22 mpg with 5 people and loaded to the gills in my Roadmaster wagon with AC on and 75mph. My son followed in Honda Odyssey V6 with similar load and got 18mpg. And he was drafting me a lot of the time!
It sounds like the new 2.7 liter turbo 4 cylinder they are putting in the 2019 Silverado might be closer to what you're talking about. Peak torque from 1500 to 4000 rpm. https://media.chevrolet.com/media/u...ews/us/en/2018/may/0518--silverado-turbo.html It's a long stroke design tuned to make maximum torque where you need it.
