Turbo gas mileage...
01-09-2009, 04:54 PM
#31
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I am saying they are not one and the same. I mean a boosted engine is more efficient in the point that you get more power per litre than NA. However they get worse mpg's. On the subies, they are both 2.5l and I'm sure maximized per their individual abilities equally. Again, name one factory vehicle with engines of the same litre where the FI gets better mpg's than the NA. On the turbo, correct it's not a restriction on the incoming flow but on the exhaust flow. Which is also bad. Both of my vehicles are FI and so of course I am a huge fan of them. Easy to mod with real success. Fun to drive. Just saying you are not getting better mpg's with them compared to NA with a tune. You may say an improvement if you tow and the engine has to work @ a lower rpm. As long as you stay out of boost. For me, it is better to tow in 3rd with little to no boost than 4th gear boosted. But because of my maggie I don't need to drop down to 2nd going up hills so my mileage towing has increased slightly.
01-09-2009, 04:57 PM
#32
Now that I beg to differ with you on...... Our Patented manifold design on the new L92 headed motors has proven to increase port velocity and fuel atomization. In other words, the supercharger is making the power and the manifold it is attached too is making the burn more efficient.
01-09-2009, 05:08 PM
#33
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What do you disagree with? I agree it is more efficient as far as power goes. Do you claim better mpg's over a NA engine with a tune though? Didn't you yourself say it was in the tune?
One more thing to think about. We are comparing engines of say an NA with 300hp to a FI with 400hp. If you want work done, you must use energy. I.E. fuel. If you want more power, you need more gas. A blower just pushes more air in, but you also need the same ratio of fuel in. So more air, more fuel. Now compare two cars say an NA V8 with 400hp and a FI V6 with 400hp. As most of the time you are not pushing 400hp around town the V6 is of course more efficient. Also the V6 has less moving parts and will most likely weigh less.
One more thing to think about. We are comparing engines of say an NA with 300hp to a FI with 400hp. If you want work done, you must use energy. I.E. fuel. If you want more power, you need more gas. A blower just pushes more air in, but you also need the same ratio of fuel in. So more air, more fuel. Now compare two cars say an NA V8 with 400hp and a FI V6 with 400hp. As most of the time you are not pushing 400hp around town the V6 is of course more efficient. Also the V6 has less moving parts and will most likely weigh less.
01-09-2009, 05:14 PM
#34
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.
01-09-2009, 05:21 PM
#36
when I am on the freeway cruising my motor makes less vaccum now with the turbo than it did NA. That tells me that there is more air available when the throttle opens. IE the motor doesn't have to work as hard to get the air thus it is more efficent. I'm not saying I think this is the sole reason for the increased gas mileage but I do think that it is a big factor.
01-09-2009, 05:22 PM
#37
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when I am on the freeway cruising my motor makes less vaccum now with the turbo than it did NA. That tells me that there is more air available when the throttle opens. IE the motor doesn't have to work as hard to get the air thus it is more efficent. I'm not saying I think this is the sole reason for the increased gas mileage but I do think that it is a big factor.
01-09-2009, 05:23 PM
#38
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01-09-2009, 05:25 PM
#39
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I wasn't going to bring it up, but since someone already did, let's talk efficiency of a turbo engine vs. an NA engine.
About 1/3 of the engine's energy goes to turning the crank. Another 1/3 is lost to heat (goes into the cooling system), and another 1/3 goes out the tailpipe. A turbo engine utilizes some of that otherwise lost energy, thus making it more efficient. As such, it has the ability to get better mpg's. Look at a big rig. They wouldn't be running turbos on them if they weren't efficient. 5-8mpg's of diesel for thousands of miles a week is a lot of coin.
About 1/3 of the engine's energy goes to turning the crank. Another 1/3 is lost to heat (goes into the cooling system), and another 1/3 goes out the tailpipe. A turbo engine utilizes some of that otherwise lost energy, thus making it more efficient. As such, it has the ability to get better mpg's. Look at a big rig. They wouldn't be running turbos on them if they weren't efficient. 5-8mpg's of diesel for thousands of miles a week is a lot of coin.
01-09-2009, 05:29 PM
#40
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They run turbos on those size engines because without turbo's the engines would need to be larger to produce the same amount of power needed to pull their load. Your statement is misleading. Smaller engines with blowers do get better mpg's than larger engines without with both producing the same power. But he had the same engine. Don't see an increase to mpg's adding a blower to the same engine.