Gas Milage

[nacho]

Hello Everybody. After installing a Subaru intake that I got for my Non-turbo baja. I saw that I got improvement in fuel economy in city driving. Not much though but it did help a little. Here is the run down. In the city I used to get 19 when I was running the engine hard like passing cars during lane changing etc. Now I get 20MPG doing this. When driving normally and not reving the engine hard I used to get 21 MPG. Now I get 23MPG. Later this week I will be taking a long trip and will post later. The intake is a little loud but I like the sound. The price is high and really don't know if it would be worth it. The intake cost me around $300. It would have gone on a WRX non-turbo though. It fit but there is little clearance from the filter to the fender. If you are not careful in the placement, it will make contact with the fender and make a strange rattle that will get annoying. I think it was well worth it to me though. I am interested to find out how I do on the highway.
Later,

[cliffhanger]

alll of my mods are fairly simple to do & bolt on -- I have:
Xcceleration TBE exhaust
Helix catless uppipe
Perrin lightweight crank pulley
VF-39 STI turbo
JDM STI TMIC
Walbro Fuel pump
remapped ECU
Perrin MBC @ 16#
ummm.. that's all I can remember.
like I said, I drive sane and get 22-24 MPG, but I could easily get much less if I drove like an idiot street racer. I've learned my lesson, racing is for the track! My next planned mod are perrin equal length headers and fuel rails - anyone have these?

Just curious why you have a MBC if you have a remapped ECU? What benefit are you getting from this compared to the ecu controlling boost on is own?

Ive been driving more city lately, and its been colder. But when i do get on it, it flows a LOT of fuel, so with a few full throttle merges combined with letting the car warm up a bit, and city driving, It really takes a toll on my mileage.

oops.. i was under the impression that the boost control acuator on the side of the turbo was what controlled the final boost, and that the ecu only controlled the m.a.p. signal and fuel cut. I dont actually know that much about imports and the like though, I am a primarily chevy guy. This is my first import and I love it! but it is learn as you go for me. If i can just have it controlled by the ecu, i will have to talk to the guy who ECUTEKed it for me and see what he set it at then. The mbc is just a throttle valve, i thought if you opened it up more, then it would allow more air pressure on the top of the diaphragm of the boost control actuator, hence the wastegate would open at a later boost. please clear me up, i dont mind being wrong, this is all just a learning experience for me... Thanks, and merry christmas! wow that was a lot of typing...

[Hawk296]

oops.. i was under the impression that the boost control acuator on the side of the turbo was what controlled the final boost, and that the ecu only controlled the m.a.p. signal and fuel cut. I dont actually know that much about imports and the like though, I am a primarily chevy guy. This is my first import and I love it! but it is learn as you go for me. If i can just have it controlled by the ecu, i will have to talk to the guy who ECUTEKed it for me and see what he set it at then. The mbc is just a throttle valve, i thought if you opened it up more, then it would allow more air pressure on the top of the diaphragm of the boost control actuator, hence the wastegate would open at a later boost. please clear me up, i dont mind being wrong, this is all just a learning experience for me... Thanks, and merry christmas! wow that was a lot of typing...

I was just asking becuase I was wondering if there was some advantage to running a MBC with a reflash.

The actuator on the turbo is what controls the boost ultimately but there is a electronic boost control solenoid in the passenger side fender area. You can find if if you follow the vacuum lines from the turbo wastegate actuator, It Ts and goes to the boost control solenoid. Basically the boost control solenoid stays closed to minimize boost ( Wastegate actuator pressure in my stock TD04 was around 4 PSI) This is good so that if the boost controller fails to operate you will have a mechanical default of around 4psi. To increase boost, the ECU tells the solenoid to open, which vents pressure from the wastegate line back into the intake (basically creates a leak) The advantage of using the stock solenoid (or the GM BCS) is that the ecu has a much more accurate control of boost.

Basically when your driving, the BCS will open to the initial wastegate duty cycle to try and maintain desired boost (all are in maps which ecutek tuners can change) the wastegate duty cycle will then modulate to control boost but will not go over the programmed max duty cycle. This also allows the ECU to use boost compensation tables to compensate for air density (altitude and temp).

If your car is running fine I wouldnt worry about it, especially if you had the ecutek guy tune with the MBC already in place. At 16PSI with a VF 39 you could probably achieve the same results without the MBC if you wanted to though.I was more or less wondering if you found some super cool secret that would give me a bazillion more HP.

[Kev M]

Update, past 3k now, and I suspect she's starting to loosen up a little.

However, I changed too many variables at once to know for sure yet.

Change to M1, added some air pressure to tires AND took a highway trip the past 2 days (but most of that was turnpike, running 75-85 mph. Averaged 25 mpg. Not bad with cold weather, high speeds and winter gas.

So I'm optimistic.

Kev

[jakub911]

Hello everyone, i'm new to the Baja community but a long time member of the Subaru community, i purchased at 2005 Black Turbo Baja Automatic in late late december from a dealership. i love the car i wanted to get one for along time now. But here is the kicker i've been averaging about 14.5 mpg with 90% city driving, if i get on the highway i get closer to 20. I already had the car checked out by a dealership and of course they said everything is "A ok", right know i'm working with Subaru USA to see what i can do because i think there is somthing wrong with the car, i just have to prove it. If anybody has any ideas or comments i would love to here them. Thank

p.s. they say that the midwest adds more ethonal during the winter and it has been really cold lately. But still i need help!!!!!

[bklynbaja]

[quote="jakub911"]Hello everyone, i'm new to the Baja community but a long time member of the Subaru community, i purchased at 2005 Black Turbo Baja Automatic in late late december from a dealership. i love the car i wanted to get one for along time now. But here is the kicker i've been averaging about 14.5 mpg with 90% city driving, if i get on the highway i get closer to 20. I already had the car checked out by a dealership and of course they said everything is "A ok", right know i'm working with Subaru USA to see what i can do because i think there is somthing wrong with the car, i just have to prove it. If anybody has any ideas or comments i would love to here them. Thank

I get about the same, anywhere from 250 to 300 a tank

[jakub911]

i never make it past 250 usually, where are you located

[bklynbaja]

New York City