Turbo gas mileage...
01-09-2009, 02:36 PM
#21
I did a test a little while ago that might interest some of you.
I freshened up my motor about 6 months ago and left the turbo system off for the first month or so. Once I got the tuning dialed in NA I used the data logger on HP tuners to do a simple gas mileage test. I set the logger up to read the amount of fuel in the tank. This is much more accurate than using the stock guage. I then wrote down the current mileage on the truck. I drove on the freeway at 70 mph for about 30 minutes then recorded the mileage and fuel level again. I got about 16.8 MPG. I then turned around and headed back home and did the test again. This time I got about 17.2 MPG. That's an average of 17 MPG. Not bad for a healthy 6.0.
Then I installed the turbo system and did the same test. No joke I jumped up to 23 MPG! Granted this was strictly freeway driving with no boost involved but it was still a huge increase. This is what I love about a turbo. I can drive all day long without boost getting great gas mileage then when it comes time to have some fun I can do that too!
I would love to have more people do some testing like this and post up their results.
I freshened up my motor about 6 months ago and left the turbo system off for the first month or so. Once I got the tuning dialed in NA I used the data logger on HP tuners to do a simple gas mileage test. I set the logger up to read the amount of fuel in the tank. This is much more accurate than using the stock guage. I then wrote down the current mileage on the truck. I drove on the freeway at 70 mph for about 30 minutes then recorded the mileage and fuel level again. I got about 16.8 MPG. I then turned around and headed back home and did the test again. This time I got about 17.2 MPG. That's an average of 17 MPG. Not bad for a healthy 6.0.
Then I installed the turbo system and did the same test. No joke I jumped up to 23 MPG! Granted this was strictly freeway driving with no boost involved but it was still a huge increase. This is what I love about a turbo. I can drive all day long without boost getting great gas mileage then when it comes time to have some fun I can do that too!
I would love to have more people do some testing like this and post up their results.
01-09-2009, 02:42 PM
#22
I did have one customer tell me he picked up a few miles per gallon over stock. I think becuase you do not have to put the same amount of load on the engine with a turbo to get things moving. I know my test truck will get to speed easier with the turbo then without. just a thought.
01-09-2009, 02:48 PM
#24
Sure you can.
I can only speak of my combination.
When driving the truck with no turbo of corse I do not see boost, but I have to put my foot into harder to get up to speed.
But with the turbo on there I can feel the truck accellerate faster and still show NO boost in the intake.
I personally have never done a mileage comparison, its pointless for me.
I can only speak of my combination.
When driving the truck with no turbo of corse I do not see boost, but I have to put my foot into harder to get up to speed.
But with the turbo on there I can feel the truck accellerate faster and still show NO boost in the intake.
I personally have never done a mileage comparison, its pointless for me.
01-09-2009, 03:01 PM
#25
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well lets look at the points brought up so far - the turbo is not sitting still while your driving at a steady speed. A turbo produces boost according to load, so even at a steady throttle input the turbo increases and decreases speed depending on that load. That alters the engine's efficiency which has alot to do with fuel economy, so if 2 identical trucks were traveling down the road side-by-side at a constant throttle position and one truck has a turbo you will have an increase of efficiency in the turbo truck's engine as load increases (due to aerodynamics or elevation change). Not the most scientific reply but I too have seen fuel mileage increases when converting a non-turbo vehicle. Volvo and other car manufacturers are looking more closely at turbocharging as a way to increase engine efficiency (fuel mileage).
01-09-2009, 03:06 PM
#26
well lets look at the points brought up so far - the turbo is not sitting still while your driving at a steady speed. A turbo produces boost according to load, so even at a steady throttle input the turbo increases and decreases speed depending on that load. That alters the engine's efficiency which has alot to do with fuel economy, so if 2 identical trucks were traveling down the road side-by-side at a constant throttle position and one truck has a turbo you will have an increase of efficiency in the turbo truck's engine as load increases (due to aerodynamics or elevation change). Not the most scientific reply but I too have seen fuel mileage increases when converting a non-turbo vehicle. Volvo and other car manufacturers are looking more closely at turbocharging as a way to increase engine efficiency (fuel mileage).
01-09-2009, 03:08 PM
#27
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I did see a substantial increase in steady state mpg while set to cruise when I had the 5.3. No idea why and really don't care...maybe the ZO6 cam or the tune, though it was alot richer. Maybe it was magic. And of course an increase in performance. 10.39 stock to 7.64 with turbo and mods. FWIW, this is my only experience with FI. Probably do a TVS on my next truck...I just gotta know.
01-09-2009, 03:33 PM
#28
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well lets look at the points brought up so far - the turbo is not sitting still while your driving at a steady speed. A turbo produces boost according to load, so even at a steady throttle input the turbo increases and decreases speed depending on that load. That alters the engine's efficiency which has alot to do with fuel economy, so if 2 identical trucks were traveling down the road side-by-side at a constant throttle position and one truck has a turbo you will have an increase of efficiency in the turbo truck's engine as load increases (due to aerodynamics or elevation change). Not the most scientific reply but I too have seen fuel mileage increases when converting a non-turbo vehicle. Volvo and other car manufacturers are looking more closely at turbocharging as a way to increase engine efficiency (fuel mileage).
Also one more point. Just because you are not over atmospheric pressure it does not mean that the blower (either turbo or super) is not forcing air into the engine. Engines naturally run at some vacuum as the atmosphere is trying to push air in. I mean, it is an air pump. So even though you are not above atmospheric pressure you can be boosting the engine. I believe if you are FI you rarely see no "boosted levels" above what an NA engine would see.
Last edited by Prime Power; 01-09-2009 at 03:56 PM.
01-09-2009, 04:40 PM
#29
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Prime - you are comparing apples to apartment buildings. What does the n/a Suby and turbo Suby have in common other that the name? different compression, different cubic inch, different injectors, different tune, different power, etc. As to your comment "You will get less mpg as you have a restriction to air flow unless boosted." the turbo is not sitting still, it is spinning. And the exhaust pressure is driving the turbo not the air going to the engine. Therefore at speed and with "some" load the turbo is now spinning faster than the air rushing into the compressor and therefore "increasing" the engines ability to "breathe".... improving engine efficiency.. Your saying mileage isn't a product of efficiency?
01-09-2009, 04:47 PM
#30
I am saying that in the case of the STS and most turbos the large percentage of the MPG gains are coming from the tuning........PERIOD. At cruising speeds that turbo wheel is just free spinning, there is NO way that it could POSSIBLY move ANY air without impeller tip speed (or rpm).....and it is NOT going to get there without load.