turbo/supercharging - Toyota Nation Forum : Toyota Car and Truck Forums

eishiba · 10-20-2009, 10:18 PM

Ok, so I know one can use a turbo charger to increase gas mileage. Is it possible to use it to increase gas mileage while a supercharger is being used to increase power? And Vise versa?

Ghostyman · 10-20-2009, 10:56 PM

Quote:

Originally Posted by eishiba

Ok, so I know one can use a turbo charger to increase gas mileage. Is it possible to use it to increase gas mileage while a supercharger is being used to increase power? And Vise versa?

How can a turbo increase mileage?

phatride4ever · 10-20-2009, 11:30 PM

Turbo and supercharger both make your mpg alot worse and you have to use a higher octane gas. Even if it did increase mpg, why would you spend thousands of dollars to get better gas?

***SCT*** · 10-20-2009, 11:49 PM

Turbo + Supercharger = MORE power than just having only one of either... thus consuming more gas, not less.

eage8 · 10-21-2009, 10:15 AM

well the theory is that you have more power so you don't have to use as much throttle to get places thus increasing gas mileage...

also a lot of times manufacturers say they increase gas mileage because you can have a smaller engine with the same amount of power. ie a turbo 1.6L will probably get better gas mileage than a 2.4L

eage8 · 10-21-2009, 10:20 AM

Quote:

Originally Posted by eishiba

Ok, so I know one can use a turbo charger to increase gas mileage. Is it possible to use it to increase gas mileage while a supercharger is being used to increase power? And Vise versa?

to answer your question, superchargers and turbochargers do the same thing in different ways. they are used for the same thing.

SuperRA · 10-21-2009, 10:50 AM

I think MPG is inversely related to the amount of power made no matter how its made i.e. boosting or displacement.

eage8 · 10-21-2009, 11:18 AM

Quote:

Originally Posted by SuperRA

I think MPG is inversely related to the amount of power made no matter how its made i.e. boosting or displacement.

then why do corvettes get like 28 mpg highway :-P

Flashmn · 10-21-2009, 11:48 AM

they have shit load of displacement, but they have tons of torque and hp compared to your less-than-milk carton engine

SuperRA · 10-21-2009, 11:52 AM

Quote:

Originally Posted by eage8

then why do corvettes get like 28 mpg highway :-P

That's a factor of the car's aerodynamics, weight, and the driver's light footedness. That figure was milked out with unreal driving conditions. If I had a vette, I wouldn't be getting 28MPG hehe.

I'm just kidding, of course my comment was a generalization, but it's mostly true for most cars out there.

eage8 · 10-21-2009, 11:58 AM

Quote:

Originally Posted by SuperRA

That's a factor of the car's aerodynamics, weight, and the driver's light footedness. That figure was milked out with unreal driving conditions. If I had a vette, I wouldn't be getting 28MPG hehe.

I'm just kidding, of course my comment was a generalization, but it's mostly true for most cars out there.

you'd be surprised I know a few people with vettes that get that reliably and a few with LS1s swapped into rx-7s that get that too. and a corvette is heavier than a corolla is (by almost 1000 lbs). They get that due to superior torque (which a super charger or turbo will give you) along with very long gearing in the top gears.

eage8 · 10-21-2009, 12:02 PM

all I'm saying is that it's very possible to increase both your hp and your gas mileage. it's an urban myth that they don't get along. a lot of the stuff they do to decrease emissions kills both.

an intake and a well designed exhaust should increase both along with a light weight flywheel and a standalone tuned properly.

Donald · 10-21-2009, 12:18 PM

There is a multitude of factors involved, many of which have been mentioned in this thread already.
The simple answer is that whenever manufacturers say they use boost to get better milage, it is by replacing a large engine with a smaller turbo/super charged one to move the same mass. The difference in milage is usually not very much.

A greater improvement in milage has been achieved by most manufacturers by improving breathing, fuel management, valve control.

To just install a supercharger/turbocharger on any engine will usually require that you increase your fuel delivery. As said before, if you are deciplined enough to keep you foot out of the tank, you might get better milage, because of the greater torque at a lower RPM, but that is not likely. The greater likelyhood is that because you have more power available to you, you will use it more = greater fuel consumption.

Ask the guys on here that have that have boosted their engines. They will tell you.

A supercharger is better for boosting torque at low to mid RPM ranges, and a turbo is better for boosting torque in the mid to upper ranges. Both will increase horse power, but the supercharger takes some of it back from the crankshaft, the turbo doesn't.

The supercharger supposedly gives you a more immediate response to throttle input, while the turbo (depending on it's size) will have a slighty longer delay in response (turbo lag)

If you are seriously interested in boosting your engine, I recommend a book called "maximum Boost" by a guy named Corky Bell

Flashmn · 10-21-2009, 12:35 PM

supercharger or turbocharger, doesnt really matter which is used, both can be sized accordingly for low or high rpm usage.

I'm one of those that dont believe in hp and mileage and for one simple reason, to get a certain amount of power (burning a quantity of air), you need to use a certain amount of fuel, thus you're always going to use more fuel.

But its misleading in a way and this is what alot of people dont get, because heres why. Take two cars, identical, except the other one has a turbocharger and 50hp more power than the other. They would get relatively similar mileage all the way from idle to the point that the turbocharger starts to create boost, now with the added air you need to add more fuel. So your mileage would go down, compared to the one without the turbocharger.

However HERE is where it all goes to shit. Now the two cars are going to shoot for 60mph/100kmh, the one with the turbocharger will hit 100kmh quicker than the guy without the turbocharger and can let off the gas and return to the idle map, while the one that doesnt have the added 50hp will have to stay longer in the WOT area of the map.

The consumed fuel could be calculated, but all in all, the turbocharged car will tend to drink more in normal use.

freakinbox · 10-21-2009, 03:34 PM

Well this might come into play with the turbo diesel jetta's. Yes yes someone is going to say diesel is different. In the end it still needs more fuel to run the turbo. But the turbo diesel usually gets better gas milage, espicially if you live in an area with hills. Why does it work like that? Because your average driver isn't reving the shit out of their car to get everywhere. So basically the turbo never completely spools up so is just more of a small boost, on top of that they used a fairly small turbo stock. I use it as an example because the jetta I had also had a 1.6 liter engine. So basically the smaller turbo give you less psi, spools up earlier so there is next to no turbo lag so you can keep the rpm down but still get benefits from it. In the end giving the car a bit extra to get around, such as getting onto the hwy, and not struggle or bog down going up hills.

A key point in milage that was messed up in older cars by the manufactures is that having an engine to small for the vehicle is just as harmful as having one that is to big. Example, the old trucks with straight 6's used more gas than the v8 counterparts.