Just wondering if this is possible cus the current petrol prices are killing me. Would fitting a manual boost controller work?

The reason I ask is because I use the scoob everyday for work, and would like to increase the economy in the week, and when im feeling flush, still have my performance.

 

You already have a manual boost controller........it's just under your right foot!

 

Normally aspirated Sport models are ****e on fuel economy too; it wont make a deal of difference Im afraid. As Pete says; tyring to drive off boost (easier on a TD05-equipped saloon) will help a little...

Simon

 

Am I right in thinking though that if less air is being forced in then the ecu wont force as much fuel in? In theory would no boost at all make the car into a sort of normally aspirated 2ltr ?

I drive mostly motorways so im not bothered about the loss of performance in the week, but still have it on tap.


Much appreciate it

 

Beat me too it, Thank you

 

why not just sell your car and buy one thats cheaper to run?

 

Erm, cus I dont want to?

 

oh, you should ask that question in general technical, you should be able to get the answer your after in there

 

erm, ok

 

Tried to drive off boost, its not as easy as it sounds. And cruising at 60mph on the M1 is absolute **** plus I hate being overtaken by 7.5 tonners, although I did manage 150 miles on half a tank

Do you not think the boost controller will increase the mpg a little, or even worth trying?

 

I've heard talk of an ECU that can take two maps (not sure if these are available for subarus). This would probably be the best way, having one map for economy and one map for performance.

 

http://www.ecutek.co.uk/products/mapswitch/

aha!

 

From website
How it Works

EcuTek have customised the function of the software in the ECU to allow dynamic switching between two sets of performance maps. Selection of the performance level via the car dashboard or DeltaDash determines a choice between two sets of boost control configurations within the ECU. One setting might be for a constant 0.5 bar (7 PSI) whilst the other might be 1.2 bar (17.5 PSI), tapering to 1 bar at the redline.


Wouldnt simply turning the valve on an MBC achieve the same effect?

 

Not something I would ever consider doing myself, as mentioned self control is probably the best option, but if you want to limit the boost to around 0.5 bar just connect the turbo outlet directly to the wastegate actuator with a bit of boost pipe. Bypasses the boost solenoid and ECU control so max boost is now regulated to the pressure that the wastegate normally opens at.

 

Aye

just run it off boost when you want to save petrol.

dont have a boost gauge?

dont take it above 3000rpm if your cars pretty standard.

MPG just went up for you

 

Thanks everyone for your replies.

I have a boost guage fitted but im not sure if its entirely accurate. At idle it the needle sits at about -0.6. And under throttle I dont think it goes above 0.8.

Does this sound normal for a standard UK Turbo my99?

 

I wouldn't say ****e. 34mpg on the motorway, dropping to 27/28 when giving it some throttle. 300 miles+ easy off a 50 litre tank.

 

the full boost for standard Uk, and wrx jap specs, is around .75 to .8bar. I think towards the 1999/2000 models it was slightly higher, 0.85maybe. And around -.6 - .7 on idle...sounds round about right.

As for fuel economy, the only real way to preserve it, is dont right foot it as much..... true, the more boost you use, the more fuel you use. .............im noit sure the reverse is totally true, as you get to negative numbers.

Why is it, when you ask for advice on here regarding fuel, you get braindead answers 'if you can afford to run it - sell it', Likewise if thats the most constructive thing you can add to the forum, why bother coming on it....... not all of us have vast bank accounts, but we love our scoobs, on what limited resources we have. Im in the same boat my friend. Ive got a my93, because thats what i can afford. I cant afford a brand new one, so i havent got one.

An MBC wont make much, if any difference, as previously stated, you have a boost controller, which you can control, its just linked by the ecu to your right foot.

I find driving at 65mph gives me my best fuel economy - around 350km/ per tank (40ltr tank)

Hope that helps.


Frank

 

Surely the cost of a man boost controller means you will have to own the car for a good while, whilst driving it slowly everywhere, to even get your money back. I had a sport that around town ave 25/26 mpg. The turbo is ave 22/23 its not worth it just take your time. Unless of course your feelin flush and you fancy a natty gadjet!

 

Keep it below 3000rpm and it'll never go above 0.5 bar

You could put a switch on the purge solonoid to disconnect it, which will limit it to about 6psi ...you'll need a 2 way switch and switch it to a load resistor to prevent a Check engine light.

But the above could all be achieved by careful use of the right foot.

 

Thanks everyone for the positive replies, especially redwrx I dont want to ever sell my scoob, not until its had its day, or its F**ked. Which ever first.

Ali-b I like your idea on a switch, tell me more..........ie How the bloody hell I do it lol


Ive read on here about people turning the actuator push rod to make the it more effective against the wastegate, does this mean turning the opposite way to loosen it would let the wastgate open early, thus allowing no boost.

Not sure im keen on this idea as it would be a pain in the **** to keep having to remove the heat shield everytime I want a blast.

The quest continues...................

 

agreed

flog it and leave the scoobys to all us rich folk

 

bollocks
you do not know your jap specs

 

Im not even gonna comment on how much of a pr**k that statement makes you sound.

Nothing to contribute? Then leave it out ffs !

 

Go on then enlighten us oh wise one.

 

I normally get around 22mpg with my normal driving.... hell it's an impreza !!
Today I drove to Birmingham/Wolverhampton, it was a pea souper this morning, so 60-65mph was the speed I set. I was totally not in the mood for speed on the way home....max was about 85mph, but mostly 75mph.

I'm not down to 1/4 tank and i've 280 miles on the clock, I won't make a habit of this mind

But, i don't see the point in doing big motorway miles on an Impreza, you are better off getting a car suited to that type of driving.

MY03 STiUK PPP BTW.

 

You could get one from here- http://www.armval.co.uk/products.htm

(its the £75 one 2nd from the bottom)

OR

You could just join the turbo outlet nipple straight to the turbo actuator,which will give you 0.5bar(bypassing the boost solenoid)

 

Ahh thank you, I now understand why an MBC wouldn't work. Even if the MBC was set to the lowest setting then it would just be the same as not having it at all and the 'normal' pressure from the turbo would still be going through.

So im thinking now the other approach, something to adjust how much pressure the wastegate can withhold. A sort of quick adjustment of the actuator arm maybe? ?

Oh and I dont want to get rid of the scoob, so stop posting stuff like "Get a cheaper car" and stupid comments like that. This post has never been called " Shall I get rid of my scoob cus I cant afford it" So please leave it out.

 

I wouldnt bother adjusting the wastegate-even with the boost level as low as 0.5 bar you will get better fuel economy-the power difference between .5 and .8(std level) is very noticable-IMO due to having a low compression ratio engine,if you had any lower level of boost(.5) you would have to rev the **** off it to get anywhere ,which would totally defeat the object of the matter.

Gary.

 

Cheers Gary

After looking under the bonnet this morning ive noticed that the pipe comin from the turbo splits into to two. One continues onto the wastegate actuator and the other im pressuming goes the boost solenoid?

Should I just take the boost solenoid pipe off and bung up the open ends?