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Registered
2003 XT
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11 Posts
Discussion Starter #1
I've now had my 2003 2.0 XT for just over a year and I love it apart from its thirst for unleaded. I have over the past month or so looked at just about all the alternatives

Discovery - drives like a tractor
Freelander Auto - Drives like a slug
Grand Vitara - Lacks Power
Passat 4Motion - Not bad but its a passat.
And the more sensible 2wd diesels - which would be the sensible choice but I drive a Forester now so I'm not into sensible choices.

So I am looking at how to make the Forester more affordable to run day to day. I live in the country doing around 12K a year mostly short journeys and on Byeways maybe 25% (nothing too exciting I have a Jimny for getting stuck). I average around 22 mpg with 24 being about the best out a tank and 18 the worst, or around 20p/mile

Anyway what I am thinking of is

HDI SBC-D-SE Boost Controller
LPG Conversion.

Any helpful comments on what I might expect as far as pence/mile etc greatfully received as I have decided I really like the Forester and want to keep it but I do need to convince my wiser, better looking and working other half.

Thanks
 

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Registered
99 UK S-turbo
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8,590 Posts
Using a boost controller (or manually blocking the pipe) to keep at actuator boost will save a few pence worth, easier to just not use the right foor as much!

Do you use super or 95, I find that using Tesco Super (typically only 2p/litre more than 95) I get about 5% better FE, so about a 3% saving. When I tried Tesco 99 and shell optimax I got worse FE and the car ran like a Bog o bones.

Simon
 

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JDM Foz [sold]
2016 Mercedes E220 AMG Auto
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4,389 Posts
boost controller worked for me. Still do motorway speeds and get 30mpg but as simon says keeping your foot off the loud pedal might work but I'm crap at that. What I would say is a boost guage is a must as without one how can you see how much boost is being produced and adjust your pressing of the loud pedal accordingly. Keeping the needle in the negative boost area works just as well.

The HDI boost controller is a nice piece of kit for the price. If you need a little extra boost on the motorway you just press the button to switch between low and high boost and you instantly get full boost ability and when you've overtaken that BMW that was in front of you you press the button again and hey preso low boost again.
 

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Registered
1997 T/tb
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511 Posts
Try using a lighter foot.

I average 26.5 !!

:biggrin::biggrin::biggrin:

Exactly the same.

i drove from portsmouth salisbury, then to the excel centre in london (Docklands)........... and back again on £40 of fuel

worked out at 26.5mpg with an online MPG calculator......... pretty crap really, but i do like the car!
 

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Registered
2008 GRB 20th anniversary 6 MT
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6,480 Posts
26mpg is the best I have seen in the FSTI but if you do short trips or drive in town it can go as low as 20mpg!
 

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Registered
2003 XT
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11 Posts
Discussion Starter #7
Thanks for the comments everyone. I like to think that I am quite light footed with the gas most of the time and this is giving me around 24 mpg so it looks like I could be better. I tend to try and keep the revs under 2k as I don't have a boost gauge, but I must admit that I'm not always very good at this because it is a Subaru and wants to be driven faster than a Nissan Micra.

What will the boost controller do for me and will I notice any difference in the drive ?

As far as LPG goes I am assuming that I will get 80% of Petrol MGP, at my 24 mpg this would equate to around 13 p/mile or equivalent to a diesel car doing 38 (better than my old xtrail). Is this a valid assumption ?

And I am using 95.
 

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Registered
2003 XT
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11 Posts
Discussion Starter #9
Thanks for that mykp but I am not sure what that does for me.

I assume that if you set the min boost setting at 8psi then this is the most boost that will be given at full throttle. Is the boost levels at lower revs equally affected ?

Sorry if I am being very dumb and thankyou for your help so far
 

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JDM Foz [sold]
2016 Mercedes E220 AMG Auto
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4,389 Posts
8psi is the maximum boost across the entire rev range. Your turbo wont be producing boost until about 3,000rpm (i'm sure others will give you the exact full boost rpm for your model).

Its difficult to explain but if you saw a boos gauge at work you'd get it. Below the 3000rpm there is boost but not much, the turbo needs to spin fast enough to produce full boost hence why it changes through the rpm range. a boost controller limits the amount of boost, therefore limiting the amount of petrol needed to produce power from this boost.

Now I am sure others will be jumping up and down and pointing, shouting rude words about the above description but this is a simplistic way of explaining boost. this is probably better but I cant be arsed reading it :D

Turbocharger - Wikipedia, the free encyclopedia
 

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Mad Englishman.
MY06 Forester STi 6MT
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4,158 Posts
Surely a "boost controller" will only be able to INCREASE the boost rather than reduce it below stock. Shouldn't the minumum always be the physical wastegate actuator open/closing pressure of around 0.68bar, unless you get a screwdriver in there....

(please be gentle)



(otherwise I'll send the ******* boys round and do you the **** over with a big ******* asterix :biggrin:)



Love and kisses on this fine and pleasant Friday night.

:biggrin:
 

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JDM Foz [sold]
2016 Mercedes E220 AMG Auto
Joined
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4,389 Posts
no it can be used to decrease the boost as well as they come with a different boost actuator which bleeds extra boost away. In fact on my hdi at 18psi and on full bore acceleration you can hear the boost actuator going "pssst, pssst, pssst, pssst" in rapid succession as it bleeds the extra boost away.
 

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Registered
2006 Forester STi
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157 Posts
Is it an Auto?

Mine can be as good as 30mpg(sane M/Way speeds)or as low as 9mpg(at The 'Ring:woohoo::woohoo:)

I average around 25ish normally

I would probably go for the LPG option or maybe think about having it re-mapped.



Pete
 

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Mad Englishman.
MY06 Forester STi 6MT
Joined
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4,158 Posts
no it can be used to decrease the boost as well as they come with a different boost actuator which bleeds extra boost away. In fact on my hdi at 18psi and on full bore acceleration you can hear the boost actuator going "pssst, pssst, pssst, pssst" in rapid succession as it bleeds the extra boost away.
Ahhh "different actuator" that explains it.



Lowest 20.6 mpg (including mapping runs), highest 32.6 mpg for reference.
 

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Smooshed FOTY 2011
2005 Lifted 2.5 XT 5-Speed MT Dual-Range
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5,813 Posts
What kind of jungle juice are you guys running over there that allows for 25-30mpg???

Over here, I start to tear up with joy if I manage 22......and that's RARE.

EDIT: Granted my roof basket and light bar certainly doesn't help either, but even before all that, I was still BARELY making 20.
 
A

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No boost controller on the planet can reduce the boost below stock..
If you put a small piece of pipe between the turbo and actuator it will be stock boost, the earliest time the turbo can possibly open the wastegate, so a boost controller can only match this or increase it.
Sometimes the phrase "stock boost can be confused with what the car came out of the factory with, if it's 0.8 bar then thats a controllled level of boost and not stock boost as mentioned with the pipe between turbo and wastegate.
Hope this makes sense :biggrin:
 

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Mad Englishman.
MY06 Forester STi 6MT
Joined
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4,158 Posts
No boost controller on the planet can reduce the boost below stock..
If you put a small piece of pipe between the turbo and actuator it will be stock boost, the earliest time the turbo can possibly open the wastegate, so a boost controller can only match this or increase it.
Sometimes the phrase "stock boost can be confused with what the car came out of the factory with, if it's 0.8 bar then thats a controllled level of boost and not stock boost as mentioned with the pipe between turbo and wastegate.
Hope this makes sense :biggrin:
To clarify for everyone then, mine runs at 0.68 bar with the AVC-R off. I am assuming this is wastegate actuator "physical stock" rather than the "stock map"...is what you're saying Andy.
 

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Registered
2004 Forester Sti 6 MT
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721 Posts
What kind of jungle juice are you guys running over there that allows for 25-30mpg???

Over here, I start to tear up with joy if I manage 22......and that's RARE.

EDIT: Granted my roof basket and light bar certainly doesn't help either, but even before all that, I was still BARELY making 20.

1 gal (Imp/UK) ≈ 4.546 litres ≈ 1.201 gal (US)

therefore

1 MPG (Imp/UK) ≈ 1 / 1.201 gal (US) ≈ 0.833 MPG (US)

Miles per gallon - Wikipedia, the free encyclopedia

and as mentioned before the octane rating is 95+
 
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