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Old 04-06-2013, 12:30 PM   #1
wrxhard
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Default Wrx hyper miler

As the title states, I want to dedicate this thread to mods that will increase fuel economy in our 2.0 wrx's. That being said...
Yes I know there are better platforms to get mileage
Yes I know it would be cheaper to buy a Prius
I know I bought a "sports" car with a turbo

And yet, I'm still making the thread. I like to tinker, and this gives me something to do. its about the challenge. Would/will i do all of these things to my car? maybe. will everybody be willing to? No, but its for good discussion and brings forth ideas that some havent thought of. There are mods out there that will give us better mileage while at the same time make the car mor fun to drive. Here are some of the ones I've thought of...

Engine:
Increase stroke - increases low end torque by increasing crankshaft leverage.
Increase compression - increases power over the entire rev range
Coatings - engine coatings make the engine more efficient, allowing you to get more power used per combustion event
Lightweight engine components - less power used to move the components translates to more power to move the vehicle
Mild port work - smooth small ports make for good high velocity air flow
El header - provides improved part throttle torque
Larger turbo - keeps you out of boost and larger turbine decreases pre-turbine back pressure
Smaller injectors - running higher base pressure in some cases gives better fuel atomization
Gapless rings - keep more pressure in the cylinder

Transmission/driveline:
Higher gearing - reduces rpm while cruising
Polishing gears - reduces friction
Cf drive shaft- lowers rotating mass
Light weight flywheel - lowers rotating mass
Synthetic oil - reduces friction

Wheels/tires/suspension:
Light wheel/tire combo - reduces rotating mass
Light weight brake discs - reduces rotating mass
Lower suspension - reduces drag

Exterior:
Fmic w/hood scoop delete - reduce drag
Front splitter - reduces drag
Wing delete - reduce drag
Cf body panels - reduce weight
Full length under tray - reduce drag
Diffuser - reduce drag

You will notice that almost all of these mods will also make your car faster or more fun to drive. Here's a few mor tips that won't necessarily do that...

Interior gut - reduce weight
Hard tires - reduce rolling resistance
Rwd conversion - reduce drivetrain losses from powering 2 extra wheels

I started this because everybody knows the stupid tips that are plastered everywhere, but we as enthusiasts have the opportunity to have our cake and eat it too. Not saying we'll be able to have 600 whp and 30 mpg, but I don't think 380whp and 33 mpg aren't reachable. If you have anything else to add, please do, I'll try to keep it all organized in this first post. As I find or think of things I'll add them too. Please help me make this a valuable resource to all of us. Keep in mind, going to extremes some of these things isn't always a good idea.
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Old 04-06-2013, 02:08 PM   #2
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Replace your glass with lightweight alternatives.
You could also put in a lighter wg spring.
Undersize your alternator.
Kill all powered accessories including drls
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Old 04-06-2013, 03:27 PM   #3
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You seriously listed ALL of that and didnt include to check or maintain a slightly higher tire pressure!?!?! Go micro polish your 5th gear or break your motor down for gap less rings... I'll check my tires and end up with the same mpg.
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Old 04-06-2013, 04:55 PM   #4
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Quote:
Originally Posted by wrxhard View Post
Increase compression - increases power over the entire rev range
Only if you're not limited by the knock resistance of the fuel. Note that any pump gas WRX is limited by the knock resistance of the fuel at WOT.

In our cars, increasing compression ratio will give a small bump to off-boost torque and fuel economy, but will reduce power by 2 to 3 times the % increase in MPG / off-boost torque.

If planning on running E85 exclusively, sure, yeah, bump the compression up to 10.5:1 if running racing boost levels or around 11.5 to 12:1 if your running street boost levels and get like 15% better MPGs and better power to boot... but on pump gas, it's a definite trade-off.
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Old 04-06-2013, 05:00 PM   #5
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Quote:
Originally Posted by wrxhard View Post
Higher gearing - reduces rpm while cruising
This depends on the road. I've demonstrated cases where 4th gets better mileage than 5th.

You seem to be approaching these with a "more is better" mentality, when for most designs there is an optimum.

Here is my gearing study:
http://forums.nasioc.com/forums/show....php?t=2000614

5th was better than 4th in most cases, but in cases of high load, where the turbo is creating pressure above ~0psig, 4th was better than 5th. So there is an optimum gearing for conditions... not to mention how expensive it is to get higher gearing than stock 5th.
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Old 04-06-2013, 06:06 PM   #6
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Originally Posted by corvallisbattery View Post
You seriously listed ALL of that and didnt include to check or maintain a slightly higher tire pressure!?!?! Go micro polish your 5th gear or break your motor down for gap less rings... I'll check my tires and end up with the same mpg.
I think you're missing the point of this thread. Read towards the bottom where I talk about the easy tips. You can find information like that everywhere. This is for more in depth things. I'm not suggesting you step over a dollar to pick up a dime, but if you're gonna rebuild with forged pistons, why not stroke it? *removed snarky comment*

Quote:
Originally Posted by Concillian View Post
Only if you're not limited by the knock resistance of the fuel. Note that any pump gas WRX is limited by the knock resistance of the fuel at WOT.

In our cars, increasing compression ratio will give a small bump to off-boost torque and fuel economy, but will reduce power by 2 to 3 times the % increase in MPG / off-boost torque.

If planning on running E85 exclusively, sure, yeah, bump the compression up to 10.5:1 if running racing boost levels or around 11.5 to 12:1 if your running street boost levels and get like 15% better MPGs and better power to boot... but on pump gas, it's a definite trade-off.
I realize that, but if you can take the pump gas trade off knowing kill mode will be an e85 tune anyways, why not? 10:1 should be able to go to 13-15 psi on a larger turbo on pump gas with a conservative tune.

Quote:
Originally Posted by Concillian View Post
This depends on the road. I've demonstrated cases where 4th gets better mileage than 5th.

You seem to be approaching these with a "more is better" mentality, when for most designs there is an optimum.

Here is my gearing study:
http://forums.nasioc.com/forums/show....php?t=2000614

5th was better than 4th in most cases, but in cases of high load, where the turbo is creating pressure above ~0psig, 4th was better than 5th. So there is an optimum gearing for conditions... not to mention how expensive it is to get higher gearing than stock 5th.
You also missed part of the thread, again towards the end where I talk about taking these things to an extreme isn't going to necessarily help.

Professwrx, thanks for the tips, I'll definitely add those when I get a chance!

Again, this is a more in depth discussion about increasing fuel efficiency, and I assumed (incorrectly) that because of the scope of this discussion, we can disregard the obvious "10 easy tips for fuel economy." This discussion also assumes the reader knows quite a bit about efficiencies of the car and all of its systems. I know it's nasioc, but seriously, lets try to make this a useful thread.
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Old 04-06-2013, 08:52 PM   #7
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this thread is hylarryous in the extreme

sell the wrx....buy a prius

done

stop screwin around with stupid...wont work

but it IS possible to get ~30mpg outta a 2.0 on the highway if you tune it yourself...and 26-27 in town...but that's too easy

isnt it??
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Old 04-06-2013, 08:55 PM   #8
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While I'm honored to have you **** in my thread, please inform me which ideas won't work.

I tell me the last time somebody got out of a Prius and said,"boy, that thing sure is fun to drive!"
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Old 04-07-2013, 12:33 AM   #9
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Quote:
Originally Posted by wrxhard View Post
While I'm honored to have you **** in my thread, please inform me which ideas won't work.

I tell me the last time somebody got out of a Prius and said,"boy, that thing sure is fun to drive!"
http://media.caranddriver.com/images...-s-429x262.jpg


and forget all the bs you are thinking about.....and 'hyper' anything with a wrx
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Old 04-07-2013, 09:11 AM   #10
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Really? Smaller injectors and higher base fuel pressure? Your kidding right?
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Old 04-07-2013, 09:44 AM   #11
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Diesel swap.
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Old 04-07-2013, 11:25 AM   #12
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Originally Posted by quazimoto View Post
Really? Smaller injectors and higher base fuel pressure? Your kidding right?
No, I'm not. ID's atomize the fuel better at higher pressures.
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Old 04-07-2013, 11:28 AM   #13
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Quote:
Originally Posted by Uncle Scotty View Post
http://media.caranddriver.com/images...-s-429x262.jpg


and forget all the bs you are thinking about.....and 'hyper' anything with a wrx
More valuable information. Thanks for stopping in.

Latentwagen, I like the diesel swap idea, that would make for an interesting project for sure!
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Old 04-08-2013, 01:29 PM   #14
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Quote:
Originally Posted by wrxhard View Post
No, I'm not. ID's atomize the fuel better at higher pressures.
So what would be so hard at just readjusting the openloop fueling tables and changing the closed loop fueling target? There is no need to change injectors or fuel pressure.You would be surprised on what a good professional ECU tune does for gas mileage. It's pretty moronic to suggest all that you have then bitch about people suggesting a Prius. Why did you buy a turbocharged car then genuis? For fuel economy? Really? Somebody forced you to buy a turbocharged Subaru?
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Old 04-08-2013, 02:06 PM   #15
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Quote:
Originally Posted by quazimoto View Post
So what would be so hard at just readjusting the openloop fueling tables and changing the closed loop fueling target? There is no need to change injectors or fuel pressure.You would be surprised on what a good professional ECU tune does for gas mileage. It's pretty moronic to suggest all that you have then bitch about people suggesting a Prius. Why did you buy a turbocharged car then genuis? For fuel economy? Really? Somebody forced you to buy a turbocharged Subaru?
I realize tuning helps a lot. What I'm getting at is a lot of small changes can add up to a big difference in economy. I know I don't have the perfect fuel economy car. Never said I did. In fact I stated that in the first post. The point of this thread is to pick people's brains about different mods that will help us get better economy, and hopefully make a more exciting car at the same time. I do get mad when the "just buy a Prius" comments come out because I'm not looking for a max effort mileage car. I want economy and fun. It can be had, it just takes more work. All the derogatory comments are derailing the thread from what it should be - informative and fun discussion. That's all it should be. I'm not gonna get all pissy and close the thread because of it, it's just annoying that it has to happen because I'm not looking to build an all out track car. Nasioc has always been this way, and I have expected it to turn into this, but hoped it wouldn't.
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Old 04-08-2013, 07:59 PM   #16
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i have a 2003 ,i just did a rebuild and put a bigger turbo on (16gxt) i have a stage 2 old cobb reflash and i've been getting 28-29 mpg .i believe this came from the bigger exhust in the turbo ...and the fact that i need bigger injectors to run any boost above 12psi. im hopeing when i put in the 750 cc injectors ,that the tuner can give me a good mpg tune for 0 boost and 2500-3100 rpms . and plenty of fuel for 18-19psi WOT running . if i could still get the 27mpg on the freeway ,and have 300+ horses at the flywheel i would be pretty happy with the car . i have a 105 ish mile roundtrip commute every day ,i've been able to get 430 mile out of a tank which gets me to and from work 4 days.of course some of this is how you drive.i watch the boost gauge and try to keep the vacuum as high as possiable when cruising ,drafting trucks ...and coasting when there is a big hill.and driving slower on the freeway. car only got @ 24-25 mpg before the rebuild.only thing i changed were fordged pistons,sti rods ,clover leaf porting of the combustion chambers,and silicon tubo inlet and outlet hoses.and had the rotating assembly balanced,heads rebuilt and surfaced ...im sure some of this helped too.seems like a 2 liter motor should get better milage when off boost .you would think tuners could give you the best of both worlds.some of the newer turbo cars are getting better mileage ,but i dont think they are making as much power either...guess you just have to feed the beast. these cars are geared pretty low too so im sure that hurts the mpg too.
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Old 04-08-2013, 08:29 PM   #17
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Quote:
Originally Posted by wrxhard View Post
More valuable information. Thanks for stopping in.

Latentwagen, I like the diesel swap idea, that would make for an interesting project for sure!
so the idea for any of this hyperstupid **** is to save $$$$ on gas....RIGHT????


so the expense of doing anything that costs a lot of $$$ to get 1 or 2mpg increase is, REALLY a waste of time....RIGHT???

so doing a diesel swap that would likely cost in excess of $5k would yeild you a return on the investment...when...EXACTLY???

new thread title should be:

hyperstupid things you can do to waste your time, effort and $$$ on trying to polish a turd



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Old 04-08-2013, 09:21 PM   #18
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Originally Posted by Uncle Scotty View Post

so the idea for any of this hyperstupid **** is to save $$$$ on gas....RIGHT????

so the expense of doing anything that costs a lot of $$$ to get 1 or 2mpg increase is, REALLY a waste of time....RIGHT???

so doing a diesel swap that would likely cost in excess of $5k would yeild you a return on the investment...when...EXACTLY???

new thread title should be:

hyperstupid things you can do to waste your time, effort and $$$ on trying to polish a turd



It's apparent you don't understand the concept. If you weren't so busy writing tens of thousands of internet posts you might stop and try to get some different concepts. It's not truly about the money savings. CLEARLY.

It's about chasing numbers. Same as the dyno or 1/4 mile.
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Old 04-08-2013, 10:12 PM   #19
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Quote:
Originally Posted by ProfessWRX View Post
It's apparent you don't understand the concept. If you weren't so busy writing tens of thousands of internet posts you might stop and try to get some different concepts. It's not truly about the money savings. CLEARLY.

It's about chasing numbers. Same as the dyno or 1/4 mile.
yeah...i know....idiots doing stupid things in the wrong vehicle for the wrong reasons

great......point made

http://img1.etsystatic.com/000/0/542....256778757.jpg
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Old 04-08-2013, 10:29 PM   #20
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I was getting 30+ mpg on my bugeye when I had stage 1 cobb and stock 205 sized tires.
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Old 04-08-2013, 10:42 PM   #21
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I was getting 30+ mpg on my bugeye when I had stage 1 cobb and stock 205 sized tires.
yeah.....all...ALL the 'hyper miler' mods have been posted here a LONG time ago

and it all boils down to a couple of things.....and tune and tires are the main thing...tires will make up to 3-4mpg difference....saw that on my car, no other changes.....lost 4mpg with new tires

my modded 02 wrx with a 16g on it would regularly get 27-28mpg on the road at 80-85mph.....and 30ish when i was on cruise at 70

but 'hypermiling' a turbo'd subaru ????



im gonna have a heart attack at this...OMG....hylarryous.....
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Old 04-08-2013, 10:45 PM   #22
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Uncle Scotty... I'm so happy you and I have found something in common... thinking this is absurd. Check your tire pressure... make sure your not running 9:1 AFR and enjoy!
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Old 04-08-2013, 10:45 PM   #23
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Quote:
Originally Posted by Uncle Scotty View Post

yeah.....all...ALL the 'hyper miler' mods have been posted here a LONG time ago

and it all boils down to a couple of things.....and tune and tires are the main thing

my modded 02 wrx with a 16g on it would regularly get 27-28mpg on the road at 80-85mph.....and 30ish when i was on cruise at 70

but 'hypermiling' a turbo'd subaru ????



im gonna have a heart attack at this...OMG....hylarryous.....
Then show the op the links.
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Old 04-08-2013, 10:59 PM   #24
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Originally Posted by ProfessWRX View Post
Then show the op the links.


yeah ****ing RIGHT.....d0000000d...it would take WEEKS of searching and trying to figure all that out.


no as in not as in way

cupcake wants to do his own searching and figuring it out...fine

no spoon feeding the cupcakes for me
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Old 04-08-2013, 11:05 PM   #25
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Originally Posted by Uncle Scotty View Post



yeah ****ing RIGHT.....d0000000d...it would take WEEKS of searching and trying to figure all that out.

no as in not as in way

cupcake wants to do his own searching and figuring it out...fine

no spoon feeding the cupcakes for me
So the info is out there. You can't find it, it's probably not in your 60,000+ posts primarily consisting of contentless material. op wants to compile it in a recent post. You want to continue to act like a grade schooler.

Is my running synopsis accurate?
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