rear mount turbo idea?

[njwrestler07]

I am looking to get a legacy right now, i would love the gt but the mpg is horrible on it, i know that i shouldn't complain about that but its going to be my commuter car. I was thinking of getting the 2.5i limited with manual transmission but had a crazy idea of maybe doing a rear mount turbo kit on it maybe next year. Is this possible to do?

[NJLGT]

almost anything is possible but it would be pretty expensive to fab up that kind of a system. Not worth it IMO, just get the GT if you want the turbo.

[burnout8488]

That would cost more than just getting a stock GT and buying the fuel for it...and probably get slightly worse gas mileage.

[njwrestler07]

how would it get worse? the rear mount turbo kits get better mpgs, and also sound amazing.

[Impulse]

What leads you to believe that rear mount turbo kits produce better mileage?

[njwrestler07]

for the fact that a know two people who have sts turbo kits, one on a ss trailblazer and one on a c5 Z06 and they both have seen a 2-5 mpg increase on both city and highway mileage

[weapon-x]

you want better gas mileage get a cobb and reprogram it for fuel eff.

[NJLGT]

for the fact that a know two people who have sts turbo kits, one on a ss trailblazer and one on a c5 Z06 and they both have seen a 2-5 mpg increase on both city and highway mileage

 

And this is a fact because they drove exactly the same %100 of the time before and after the install right? and of course you were in their cars the entire time to document this mysterious fuel saving turbo. :lol::lol::lol:

 

It's a simple fact, more air= more fuel on a properly working car, so if they drove 100% the same at the same temperatures and altitudes improved gas mileage would be impossible. The only way they could have improved gas mileage by installing turbo would be as stated they drove much more conservatively after the install, or they had something like bad spark plugs or a bad tune prior to the turbo, and were corrected or redone during the addition of the turbo.

[LosAngelesLGT]

I am looking to get a legacy right now, i would love the gt but the mpg is horrible on it, i know that i shouldn't complain about that but its going to be my commuter car. I was thinking of getting the 2.5i limited with manual transmission but had a crazy idea of maybe doing a rear mount turbo kit on it maybe next year. Is this possible to do?

 

If yuou are worried about mpg/frugality, tossing a turbo on an a n/a leggy is foolhardy.

[Impulse]

then they must not be stepping on it much, there is no thermodynamic way you can significantly increase power AND use less fuel than stock. search for a thread on this site where someone tabulated the costs to turbo a 2.5i. It turns out to be MUCH cheaper to dump the 2.5i and get a GT instead.

 

if you understand how turbos work, the farther away you get from the engine, the less efficient it becomes. this is why most turbos from the factory are mounted as close to the exhaust valves as possible. sure you might be able to do it, and it will be expensive, but it wouldnt be practical. You'd be better off with a supercharger: Impreza Supercharger

[njwrestler07]

yea, i might as well get the gt, whats the most you get on the highway, like 23 or 24?

[CapnJack]

I get between 26 and 30 mpg depending on time of year. Summer is near 30 and dead of winter is near 26mpg.

[Impulse]

I get between 26 and 30 mpg depending on time of year. Summer is near 30 and dead of winter is near 26mpg.

 

ditto, almost exactly same for me. 29-30 if i cruise at speed limit, 26-28 if i'm at 75-80. 1 mpg or so lower in the winter.

[RJS5689]

I need to figure out how to say this without sounding like a harsh jerkoff: You need to do your research into turbocharging and efficiency. To say the MPG on the GT sucks over a N/A is just laughable. The MPG difference is negligible between the two. Not to mention my buddy who drives his 2.5i pretty hard sees mileage as low as I do with my Spec.B. Manufactures are turning to forced induction more and more to gain better efficiency while still increasing power. If you need more concrete facts/evidence, I have a 15 page research paper I wrote for a persuasive writing class in college you can read. The paper explains why turbocharging is the true replacement for displacement and is actually a very economical way of increasing power. The key to keeping a turbocharger sipping on fuel is to stay out of boost! I'm sure you knew that though.

 

there is no thermodynamic way you can significantly increase power AND use less fuel than stock.

You may be talking just Subaru here, but Ford has actually done that. The new 3.5 EcoBoost makes 90 more HP than the N/A V6, but it still gets fuel economy that is several MPG better.

[Strizzy]

If I drive like a civilized person, I can push between 30-33 mpgs on the highway.

[ehsnils]

The fuel consumption depends on the weight of the right foot.

 

But a turbo engine of the same size as a NA engine can of course consume more fuel since it's force fed on air.

 

The turbo engine may be a bit less efficient during low rpms due to it's lower compression ratio, but the difference is small.

[ClimberDHexMods]

for the fact that a know two people who have sts turbo kits, one on a ss trailblazer and one on a c5 Z06 and they both have seen a 2-5 mpg increase on both city and highway mileage

 

Wow... pretty much every STi or LGT owner that goes bigger turbo gets better gas mileage anyways unless they get all born again race car driver. Have you thought through how a turbo kit can permit better mileage?

[ClimberDHexMods]

Why the heck are you looking at a Subaru if you want good gas mileage. It is not a hyper miler's car for sure.

[OmniEnder]

I get about 22 mixed driving... I need to take driving lesons from you people in the 30s.. i don't see how that is possible.

[underpowerd]

30s w/ the gt isn't really feasible, imho. back on the stock turbo, i found 28-29 hwy was possible on a flat road and a very surgical toe.

 

bigger turbo lets you be a little less surgical on the highway, but really only helps noticably in city driving, since it's easier to stay out of boost for the most part if you wish -- however, a lot of that is usually offset by fuel system upgrades and what becomes of mpg once you finally lay into it.

there's a reason why a giant turbo upgrade (or slapping a rear mount kit onto an n/a factory car) doesn't qualify you for a big 'green' tax credit

 

question: did those guys who added those kits tune for them? i suppose they could get more power with the same fuel by running their engines dangerously lean...

[njwrestler07]

im not going for something super great on gas, just something thats awd and something that i wont have to fill up ever 2 days and that is fun to drive. and how the hell are you getting close to 30 mpgs with the gt? there is no way

[dombek2k7]

I get about 22 mixed driving... I need to take driving lesons from you people in the 30s.. i don't see how that is possible.

yeah i second that.. im getting 21.6 right now on highway.. doing 70mph (stock lgt)

[BruceBruce]

i averaged 28 or 29mpg(i forget which one) on my recent snowboarding trip from san bernardino to san luis obispo. thats going 70-75 the whole way back. I avg 23-24mix normally. stock

[MAINIAC SPEC B]

The worst milage I ever got was 23. Around town in winter average 24, around town summer 25 and 30 on the highway with my 07 spec b. 55k and climbing.

[toreadorranger]

Yea I have no problem getting 26-27mpg on the highway. My worst tank yet on my car has been 20-21mpg Avg and that was before I went stage 1.