What is this (exhaust pic)

It is a ploy to warm up your engine quicker.

HowStuffWorks "How Exhaust Heat Recovery and Recirculation Works"

 

My guess is catalytic converter. If that's what it is, then yes all the hoses are necessary. In general, they don't put parts on a car that are not necessary........for something.

 

agreed, i don't think they're necessary. just extra weight.

 

and too slow down the exhaust gases so the exhaust valves don't overheat

 

not if gas mileage is not a concern. If you bought the car to get gas mileage, it is perfect now.

 

You slow down the exhaust gasses to make their exit quieter and to prevent the exhaust valves from over-COOLING.
A slightly restricted exhaust keeps the exhaust ports on the engine at a more even temperature, slightly higher.

 

I wouldn't change anything but the axle back...

 

Wouldn't the catalytic converter restrict the exhaust gasses enough? I think that the muffler would just make it quieter.

 

Maybe. I don't know.
I don't think the CAT really provides much restriction.
If the gasses don't slow down, they don't quiet down either.

 

New catalytic converters only eat 4 to 9hp. Not nearly as bad as they used to be. Ps if you go straight pipe it'll be a mellow volume yet nasty rice sound. I tried it. Ended up getting a muffler and glad I did. I wanted to do mid pipe but figured a low in toque might hurt mpg. So went with just the axle back as 1 is easier to go back to stock and not much of anything Matters THAT MUCH that far down the exhaust system.

SGH-T889 ?

 

Yeah I hated the ricey rasp. With my intake and exhaust my mileage is the Same to slightly better

SGH-T889 ?

 

Did it? I would think that you would. I did some reading, and found that if you went "true" straight pipes (no catalytic converters, no muffler) it would hurt your performance/mpg. These engines are designed to have some back pressure, and I read that no back pressure would screw up the air/fuel mixture. Also some sources said that a performance muffler was better than straight pipes. I just don't know which would provide the most boost in mpg.

 

99.9% sure that is the exhaust heat recovery system. The cat is upstream from that.

Neither. Toyota didn't leave any MPGs on the table. Only thing I have seen that has a measurable difference is grill blocking in cooler weather.

 

The Prius does not have an Otto cycle engine, so old wives tales don't work. You can piss off your neighbors, but it is just louder, not better in any way.

In an Otto cycle engine the gasses are still expanding in the exhaust, in a Atkinson cycle engine the cylinder area when expanding is larger than when under compression, so the gases can expand more fully in the engine where it does work. (Not in the exhaust where it makes back pressure)

(best picture I can find is in German)

 

Hallo, my name is Tony from the Netherlands, I have only recently joined this wonderful forum.

Now, about this funny looking exhaust, it is used to warm the heater water of the Prius C.
wich is similarly as in my European version the Toyota Yaris Hybrid.
See the attached drawing.