What costs more in the mileage department?

[ryu_haneda]

I've always debated going turbo on whatever car I drive. My only problem is that turbos usually need much higher octane (91 is a minimum, so at minimum I'd be getting premium gasoline from that point forward).

I currently have an NA motor that's supposed to get something like 15-17 city and 25-27 or so highway.

What happens if I go with a 2.0L WRX powerplant swap? At that point I'll be using premium gas for life. Is there any benefit in the mileage department?

Second question - if that doesn't work out, how 'bout a motor swap from an H6 (or even an NA Tribeca motor)? Do those require premium gas too? Any savings in mileage?

Thanks for your time. I was definitely curious. Later!

[SilentRacer]

Turbo engines not only run on premium but they are terrible on gas. H6 can run on regular but its still not as fuel efficient as a 4 cyl.

[Reason]

Turbo engines not only run on premium but they are terrible on gas. H6 can run on regular but its still not as fuel efficient as a 4 cyl.

That is true, but I wonder if it would be better in a lighter car. The newer engine will be more efficient than whats in there now. If you aren't heavy on the foot the WRX wouldn't be so bad either. It all depends on how you drive.

[dodik]

if you mate H6 to 5mt your highway mpg will be around 30 at best, city around 18. and youll have a car that fills solid.

[deadlydave]

If you can keep your car out of boost, it's not too bad. The size of your grin is directly proportional to the amount of fuel you're using though.

Turbo spooled = :grin:
Turbo spooling = :neutral:
Out of Boost = :-(

[MCarp22]

Most subarus get about the same mileage, N/A, turbo, H6, whatever. According to the EPA estimates, it's only approximately another $200 a year for a premium fuel fed '02 WRX vs a '98 Legacy GT.

[SilentRacer]

If you can keep your car out of boost, it's not too bad. The size of your grin is directly proportional to the amount of fuel you're using though.


Because people buy wrxs to keep them out of boost right? :roll:

[deadlydave]

If you can keep your car out of boost, it's not too bad. The size of your grin is directly proportional to the amount of fuel you're using though.


Because people buy wrxs to keep them out of boost right? :roll:

Lol, no. They bought wrx's to mod them, then have me hand their asses to them with a 12 year old 2.2 Legacy at autocross. :smile:

I don't drive conservitively for most highway driving, but drive like a grandma in town. Usually because I'm stuck behind one.

[ryu_haneda]

Sounds like a case for contentment, then...

The 2.5GT has a decent 165hp engine (more like 120 or less at the wheels, I know :grin:). Honestly if I could, I think I'd like to try an H6 swap (or something NA from a Tribeca).

In terms of what I'm REALLY going to do, I think I'm just going to enjoy NA power for as long as I can. Besides that... I got a remanufactured 2.5 put in my car last September and it still purrs. I like the manic top-end noise it makes when I really get on the throttle (around 5-6k rpms). Is that a "torquey" noise?

Oh, by the way, Mrs. Subaru says hi. She drives the 2000 Outback. Later!

[Reason]

The 2.5GT has a decent 165hp engine (more like 120 or less at the wheels, I know :grin:).

Yea right, try less. I dynoed mine and got 117 whp. I had light weight crank pulley, short ram and a cat back. Stock may be around 95-105 whp.

[ryu_haneda]

The 2.5GT has a decent 165hp engine (more like 120 or less at the wheels, I know :grin:).

Yea right, try less. I dynoed mine and got 117 whp. I had light weight crank pulley, short ram and a cat back. Stock may be around 95-105 whp.

Haha! Let's hear it for drivetrain loss! :grin: It's all good, I'd rather have better inclement weather traction anyway.

[Sarra]

Swap in a VW TDI motor, and a really simplistic RWD transmission. Pull unnecessary parts from the front of the car, install, and voila, you can go 500 miles on a tank of Diesel. Plus, you can go 450 miles on a tank of Diesel while flooring it around town. 150 BHP and 300 torque, can't beat it. :wink:

I would do a 2.0 WRX swap, though, if I were you. Keep out of boost for good gas milage.

And, you don't really have to run premium, it just runs better and happier with premium. :-)

[deadlydave]

the 2 Litre wrx engine, at least in stock form, needs the premium. Goldstein Subaru put 87 in it and it was knocking and running like crap.

[Sarra]

the 2 Litre wrx engine, at least in stock form, needs the premium. Goldstein Subaru put 87 in it and it was knocking and running like crap.

Which year motor? Just curious.

I suppose the ECU could be more picky about fuel rating depending on motor. I know that the 3.0's run okay on 87, but only for a while. After so many miles, things start to protest.

Speaking of gas, I mistakenly put $20 of 82 octane gas in my Dad's T100. I thought the motor would explode! Luckily, I limped to a local Shell station and filled it up with premium. It still was knocking after that, but not to the point of having to get it towed.

[deadlydave]

His is a 2003, I believe. It's a bugeye, not sure on the exact year. He said he thought the banging and shaking were because he was a noob to the 5-speed. :lol: Freakin' Goldstein.

[ryu_haneda]

In the final analysis, then, I guess it's just a question of me deciding to go with NA power and 87 gas for price, period. Any european car, american car with front-wheel drive, or hybrid/turbodiesel would blow a Subaru Legacy out of the water, mileage wise.

I may yet get a turbo... just not gonna be soon. (If I'm really dreaming here, I could wait until Subaru decides to create a turbodiesel or hybrid motor, and then think about popping that in my car to help with mileage and the environment.)

Honestly though, I'm happy with what I have. On to maintenance!

[SammyDaFish]

My old NA 2.2 got about 27mpg. I put a turbo on it, up to 33-34 (tuned with a smt6) Turbo cars generally get better mileage as the design is more efficient under load. The problem is you get addicted to the fun that comes with pressing down your right foot and waste it all.

With the increase in gas prices the difference between 87 and 93 octane gas generally has remained the same. Therefore you're paying less to get premium than you had in the past. When gas was $2.00 /gal, premium was $2.30 (15% more). Now that gas is $3.05 /gal, premium is $3.35 /gal (11% more) ... so the dollar value you pay extra for premium is actually less.



High compression turbo motors own all on the street :)

[Huffer]

Turbos with variable valve mechanisms paired with the right base engine will outperform NA engines in many respects... but the tuning has to be just right.
Factory tunes are rich, to compensate for the variabilities in all types of gasoline and also the differences in altitude as well.

However, for pure reliability, the less moving parts you have, the more reliable the car is going to be over the long run.

Which is better, 45mpg and hard to keep running, or 30mpg and never dies?
:lol:

[SammyDaFish]

put an old subaru 3 cylinder in there..... 60mpg but doesn't go up hills :)

[rougeben83]

[quote="ryu_haneda":wtitxdei]

The 2.5GT has a decent 165hp engine (more like 120 or less at the wheels, I know :grin:).

Yea right, try less. I dynoed mine and got 117 whp. I had light weight crank pulley, short ram and a cat back. Stock may be around 95-105 whp.

Haha! Let's hear it for drivetrain loss! :grin: It's all good, I'd rather have better inclement weather traction anyway.[/quote:wtitxdei]

It's also what dyno you use. The mustang dynos give like 90-100whp, and something like a dynojet will give you 100-110whp on a stock ej25.

That's why it's more helpful to use the dyno (the same dyno) to measure improvements from upgrades vs. as concrete data to base general concepts about any particular engine...

[Reason]

[quote="ryu_haneda":wk2nv4hl]

The 2.5GT has a decent 165hp engine (more like 120 or less at the wheels, I know :grin:).

Yea right, try less. I dynoed mine and got 117 whp. I had light weight crank pulley, short ram and a cat back. Stock may be around 95-105 whp.

Haha! Let's hear it for drivetrain loss! :grin: It's all good, I'd rather have better inclement weather traction anyway.

It's also what dyno you use. The mustang dynos give like 90-100whp, and something like a dynojet will give you 100-110whp on a stock ej25.

That's why it's more helpful to use the dyno (the same dyno) to measure improvements from upgrades vs. as concrete data to base general concepts about any particular engine...[/quote:wk2nv4hl]

Mine was done on a dynojet, I don't think the numbers will be far off with a mustang dyno. But you will get larger numbers on a dynapack.

[strat81]

if you do highway driving, most of the time cruising you will be out of boost... my wrx gets good mileage on the highway and so so around town. nothing any worse than the legacy wagon i had got.

now, if you're into it alot, then yea, you're gonna burn through gas.

keep in mind too that premium per fill up is only really a few bucks more. (it all depends on how you look at it long term vs. short term)

[Numbchux]

I'm disappointed in the 5 people that voted wrong...

the stock 2.2l N/A will ALWAYS outperform the others in mileage. regardless of the cost of the gas to fill them up (which will always be more with the others, obviously)


more air = more fuel. be it via a turbo, or extra cylinders. the wrx motor only has a slight advantage in displacement, but being low compression, will require more throttle to put out the same hp require for cruising.


btw....all H6s are N/A. and the Tribeca's got the same 6-cyl that the outbacks of the same year got.


another thing to think about. running an EZ30R (tribeca/outback motor) in a swapped car means standalone ECU (immobilizer = no stock ECU). and only the Link Plus G3 can run the EZ30R with fully-functional AVCS (which is the only way the 30R could get decent mileage). but that's a $2k+ ECU, and will need extensive tuning work.

BUT, on the plus side....with a standalone, you *might* be able to write a map that would allow you to sacrifice some peak performance to allow you to safely run lower octane fuel.....

[strat81]

i had problems getting 250 miles out of a tank in my wagon... even before i put the a/t's on it. car had a tuneup and everything, ej22, auto.

wrx pulls 320ish on a tank with mixed highway/city driving with a bit of romping in there for good measure.

[Rockgod]

If I'm really dreaming here, I could wait until Subaru decides to create a turbodiesel or hybrid motor

Actually they have. They haven't gotten around to releasing it yet.

http://www.worldcarfans.com/4070308.001 ... rbo-diesel (http://www.worldcarfans.com/4070308.001/subaru-boxer-turbo-diesel)

http://news.windingroad.com/countriesma ... to-market/ (http://news.windingroad.com/countriesmarkets/euro/subarus-diesel-likely-to-beat-its-hybrid-to-market/)

[ryu_haneda]

A turbodiesel would REALLY make use of the hoodscoop. :)

On the other hand, an electric hybrid would make worse power, but be better on emissions. ...or would it? I mean, what happens when the battery eventually dies down the road? What kinds of disposal policies come into play for dead hybrid batteries?

[deadlydave]

A turbodiesel would REALLY make use of the hoodscoop. :)

On the other hand, an electric hybrid would make worse power, but be better on emissions. ...or would it? I mean, what happens when the battery eventually dies down the road? What kinds of disposal policies come into play for dead hybrid batteries?

The civic hybrid has more peak horsepower than the regular Civic EX. I'm still waiting to see what the disposal policies look like.

[Jedi Taxi]

I'm pretty sure the 1.8L impreza is probably the best fuel economy wise, but slow as hell...

[MCarp22]

the stock 2.2l N/A will ALWAYS outperform the others in mileage.

But only by like 1mpg. If it was like 10mpg it'd be a lot more justified.