Cobb AccessPort "economy" setting

Hi everyone. I recently bought a new Legacy GT (I had a 1993 Impreza with 172,000 miles before) and am thinking about buying a Cobb AccessPort. I am interested in the extra power I could get out of it but after filling up my gas tank for the first time, I think I would be interested in giving the "economy" map a try too. I live in a hilly city and my work is probably less than three miles away so my gas milage going to and from work is pretty appalling. My only questions is how much of an increase in fuel efficiency could I get out of the AccessPort? Other posts about the AccessPort said that increases in gas milage were pretty minimal but I don't know if any of them gave the "economy" map a try. Any input?

-Brandon

Reply to
Brandon
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Perhaps the economy map would provide some marginal improvement in mileage, but this is not the purpose of the Accessport. It is for increasing performance on stock setups and to provide modified engine management for bolt-on upgrades. If saving gas is all you have in mind then I suggest you save your money. Besides, for what an Accessport will cost you can buy a lot of gas so it would take a very long time to conceivably break even.

Reply to
mulder

Agreed. The economy map sets the BOV pressure to zero. So it effectively disables the turbo. You still have to use 91 octane minimum (because the timing is so aggressive) so it will really only improve gas mileage on the highway and when it is hot out. But, because you are disabling the turbo, there is a warning against 'spirited' driving with the economy map. You can damage the engine. Turbocharged engines typically have a lower compression ratio than normally aspirated, and our scoobies are at between 8 and 8.2:1

Reply to
JD

A bit of correction here. It isn't possible to electronically "disable the turbo" and the BOV or actually BPV is not controlled by the ECU at all. You are thinking of the boost control solenoid, and the most that can be done with that is to reduce its duty cycle so it is always closed. This will reduce the maximum boost pressure to the wastegate setting which is probably around 7-8 psi (at least on the WRX it is). This would not result in engine damage, it would actually be safer, but there would be a loss of power. There may be other factors involved with what Cobb does in their economy map, I have not read their documentation.

Reply to
mulder

Right - if I bought an AccessPort, it would be for the performance gain, not the gas mileage. But being able to get some extra gas mileage at times would only sweeten the deal and make me a little more likely to poney up the $600+. I was just wondering if anyone had actually tried the economy map on Cobb's site and how much of an effect it had - in the city and on the highway. Anyone?

Reply to
Brandon

You could try simulating the effect of an 'economy' map by driving 2-3 tankfuls and NEVER revving over 4K.

Carl

Reply to
Carl 1 Lucky Texan

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Reply to
Bob H

The electronic boost control is set to 0 PSI. The turbo still spools but there is no pressure beyond the 100 KPa of normal atmospheric pressure. However, once the turbo spools, it is ambient and not in vacuum like an N/A car (off boost, at below 2000 RPM and no acceleration, an STi runs at around

56 KPa).

There is a warning from Cobb about the economy map; they say it because the timing advance is still very aggressive (close to 48 degrees on an STi), and no boost pressure. In open loop (ie. WOT) you will be dumping fuel in like it was turbocharged.

You still have to use 91 or better, and they warn against spirited driving. If this was not an issue, and it just reduced the power, they wouldn't need to warn anyone about anything.

Reply to
JD

Legacygt.com doesn't work. Double checked it; no DNS (Domain Name Service) on it with or without the 'www'. (fancy geektalk for "It's dead, Jim")

Reply to
nobody

Just loaded for me here is the USA.

Blair

Reply to
Blair Baucom

It works in Australia.

Here is a post from the forum

"Some people may have noticed an "expired domain" site up this morning. My registrar made a mistake in resetting my DNS when they renewed my domain for another 3 years, yesterday. They have corrected the mistake but DNS will still take a little time for some people to propigate. Sorry for the confusion."

-Tide

Reply to
sarahs choice

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