Turbocharging? Vacuum? Too much thinking. Smart people unite

[pete c]

Originally Posted by oldtamiyaphile

Yes, but there's a middle ground. Running just barely any boost and staying out of enrichment.

At 50MPH my Fiat gets 70- 80MPG. My 2 ton van (diesel) gets 60+ MPG @45MPH.

So it's not all bad for turbos, but I'd say the amount of optimization that went into those engines is well beyond what a bolt on DIY kit would offer.

A diesel is a whole different story. A turbo increases power and mileage. Remember the difference. Power is controlled by fuel, not air. There is no 14/1 ratio to maintain. This is why basically every single diesel made today that makes more than 50 hp uses a turbo.

[Wiegraf]

Originally Posted by ksa8907

Turbos are ONLY used to increase power on gas engines.

By "pushing" more air into the engine the ecu will see a lean condition and increase fueling. Turbos are for reducing brake specific fuel consumption (more power per unit of fuel), not reducing fuel consumption.

I wasn't saying push MORE in.. i was saying less of the engine having to SUCK in and more of the exhaust spinning the turbo and PUSHING SOME air in...(not MORE..just some.. less effort on motot)


Both turbo and na cars are at same inHg for this conversation between me and you.. think we are gettin somewhere

[pete c]

Originally Posted by Wiegraf

You're thinking incorrectly...and maybe I am too...I'm just thinking a small turbo would "push" more air in rather then making engine suck.

Actually, his thinking is spot on.

You seem to have trouble understanding how a gasoline engine controls power output. If you are close to atmospheric pressure at the intake manifold, you are either running a NA engine at wide open throttle or a turbo engine at a lower throttle opening combined with boost. The result is high power output, which as he said will result in a much higher speed.

I think the problem may be that you are thinking in terms of engine efficiency, rather than fuel mileage. A turbo engine, running with some boost very well may have a higher "efficiency", the problem is, it also has way higher aero drag because it is pushing the vehicle at a high rate of speed.

[Wiegraf]

Originally Posted by pete c

Actually, his thinking is spot on.

You seem to have trouble understanding how a gasoline engine controls power output. If you are close to atmospheric pressure at the intake manifold, you are either running a NA engine at wide open throttle or a turbo engine at a lower throttle opening combined with boost. The result is high power output, which as he said will result in a much higher speed.

I think the problem may be that you are thinking in terms of engine efficiency, rather than fuel mileage. A turbo engine, running with some boost very well may have a higher "efficiency", the problem is, it also has way higher aero drag because it is pushing the vehicle at a high rate of speed.

Maybe I'm thinking efficiency will improve mph too much. And i was thinking lowèr inHg was just making it easier on motor. Makes sense though now.....

What about same inHg though.

[ksa8907]

So you're talking about reducing the pumping losses of a n/a gas engine, i.e. the vacuum. This will reduce fuel consumption but ONLY IF the amount of oxygen is not increased. This is why warm air intakes are good because they reduce the density of the air and thus the concentration of oxygen and then the ecu doesn't have to increase fueling (as much).

I'll say it again for emphasis, turbos only increase power in gasoline engines.

[Baltothewolf]

Ok I'm not even gonna bother reading the rest of the responses, but Turbocharged engines are more efficient than NA engines period. You are taking waste gas and turning it into power, and the engine doesn't have to work as hard to make the same amount of power. You are also adding back pressure in the exhaust which is another +1 for efficiency.

Im not going to argue with... Anyone about this. I have been beating this dead horse with people on these forums forever. I'm currently in the process of turbocharging my insight, and when I'm done, I'll post the efficiency gain results.

[Fingie]

well you get more torque. And i've owned NA and now a turbo celica all-trac, and the turbo sure is a bit lazier at the lower rpms (and drivetrain loss) but the twin-scroll turbo for sure makes up for it.

but i kinda want to swap a VVTI 3S-GTE from a caldina into my celica. And add water injection.


or some other toyota's turbo engine, would be cool to get a lighter but same hp engine for improved weight distribution. Maybe a 20V 4A-GE as a turbo XD

[oil pan 4]

Of the 3 not so old VW engines the 1.9d turbodiesel, 2.0L N/A and 1.8t turbo gas. The 1.8t got the worst milage and on top of the lower MPGs it needs more expensive premium gas.
In stock emissions compliant, corner cut, cookie cutter engines the turbo will get lower fuel milage.
To make a turbo gas engine get the best cruise mileage possible you need to make it act like the N/A engine as much as possible.
A turbo gas motor could be made to get better mileage than an N/A engine, but I wouldn't bother.
Another big thing for turbo gas motors is can it use regular gas?

[Baltothewolf]

Originally Posted by oil pan 4

Of the 3 not so old VW engines the 1.9d turbodiesel, 2.0L N/A and 1.8t turbo gas. The 1.8t got the worst milage and on top of the lower MPGs it needs more expensive premium gas.
In stock emissions compliant, corner cut, cookie cutter engines the turbo will get lower fuel milage.
To make a turbo gas engine get the best cruise mileage possible you need to make it act like the N/A engine as much as possible.
A turbo gas motor could be made to get better mileage than an N/A engine, but I wouldn't bother.
Another big thing for turbo gas motors is can it use regular gas?

Honda EarthDreams 1.5T can.

[Wiegraf]

Originally Posted by ksa8907

So you're talking about reducing the pumping losses of a n/a gas engine, i.e. the vacuum. This will reduce fuel consumption but ONLY IF the amount of oxygen is not increased. This is why warm air intakes are good because they reduce the density of the air and thus the concentration of oxygen and then the ecu doesn't have to increase fueling (as much).

I'll say it again for emphasis, turbos only increase power in gasoline engines.

Warm air intakes do it enough? Ok gotcha