Seemed to remember your name, was somebody else then.

I read the 330S's also needed the update as the Prodrive map was based on the original STi map.

Either way, I wouldn't run mine on 95ron.

Sounds like det caused by the low quality fuel.

There is an interesting safety feature in the hatch sti ecu in that if they see any proper det for a period of a second or so they will drop down from the std boost levels to running actuator duty.

Running 95 ron would cause that for definite. There really is a huge difference in what this uprated fuels do. Vpower as first choice and Tesco99 next choice, then Total excellium (not as good though) - all the rest are for splash and dash to the next proper petrol station.

What if you can't get any of those fuels
Are you saying that super unleaded is no good then?

Its not as good no. The guidance on the car is 98 Ron so anything less than that may be causing it it run less than at its best.

I definitely wouldn't run on 95 though.

putting 95 Ron in a 2008 STI (or 330s) is like lighting a fuse on a firework... only a matter of time...

As Dunc said, even some super unleaded's cause issues with the new engine...

Fast-Lad, I hope you've not done something expensive, and it's only the engine sensing too much det and going into safe mode... don't for god's sake tell em you put normal unleaded in it.... bye bye warranty...

Lads - here's the problem

In N.Ireland we don't have the luxury of such fuels as V Power & Tesco 99

BP Ultimate is widely available
Sainsburys SUL - limited availability unfortunately
There will be other variants of SUL
I suspect ultinately they are all from the same source though.

My opinion is you have 2 choices Shaun,

a: Run it like the old classic JDM imports, with octane booster in every tank

b: treat s# with a lot of respect, ie Stay away from it on warm summer days or avoid WOT in 5th (switch to s mode).

I'd certainly buy a knock sensor, so at least you know if things are getting noisy up front and can back off... then try some fuels out.... you never know, your map/engine combo may be safer than others.

Are the new cars really that sensitive in comparison?
I've had Impreza's since 1998
Current car MY05 spent 3.5 years of its life on Sainsburys SUL with PPP map
Last 1.5 years are still on Sainsburys SUL with Andy Forrest map.

The hypercast pistons just cannot cope with excessive DET.

A good mapper (AF for example) could remove any chance of DET by mapping it to Sainsbury's SUL?

Yeah - but bye bye warranty then :(

Out of interest what sort of pistons are in previous 2.5 models?
And I assume that 2.0 pistons are also different again?

Not sure what was in the 2007 car, but they were heavier certainly.. Subaru were trying to lighten and quieten the 2.5 so switched to these hypercast ones... On paper there is nothing "wrong" with these pistons, and as far as Subaru were concerned (and still are) they were an upgrade from the 2007 car... They just cannot cope as well against the extreme forces associated with DET, compounded by the OEM map a few have grenaded

The JDM are forged jobbies again, heavier, but stronger

I read with interest the comments about the fuel and mapping. How many comments are from those who know how to map engines or know for sure the engine is not designed to run on lower octane fuel? Is this hearsay information?..not a criticism just an observation? The fuel flap does state that only the high octane fuel should be used but is this too keep high performance or to stop engine damage? The power output levels for the car seem to be advertised by Subaru on the internet the same no matter where in the world where you are? In South Africa for example you can only get 95 octane in some garages, 93 is typical....the STI is available there but not the 330s. I do not see how the cars power output figures can be the same with the different octane fuels. Most modern engine management systems automatically compensate and drop the performance to protect the engine, surely Subaru would do this? The STI has been suffering the same piston damage as the 330s...see other posts.

correct Vince

The ecu can advance the ignition much more with a higher octane fuel, resulting in more power/torque. If it gets given bad fuel (be it lower octane or just a bad tank) then it'll pull back that advance to protect itself.. but in those moments the the car is in danger of damaging itself (until safe mode is enabled in extreme cases)

Didn't Top gear (or 5th) compare engine power levels between NUL and SUL? The average joe N/A engine made no difference, but the Subaru clocked an additional 35bhp?.. Now it may have lost 35bhp on 95 RON rather than gaining 35bhp on SUL...

I always understood that Subaru only recommend SUL to achieve optimum performance, but it was quite capable of running on NUL but with only performance loss.
Mines WRX PPP by the way, not 330s.
Says on fuel flap, SUL only a recommendation.

For the next owner to worry about :( although will probably never know of course!

TX.

Note to self, don't buy a 2nd hand performance car from SA :lol1:

TX.

After reading all this im so Glad i didnt get 1. I did ask the question of the STIs when i got my WRX-S and was told 95 would be ok,

But as one of the poster on here said, not all of us have the luxuary of having 97 98 ron fuel local, my nearest is 6 miles away, and i also travel the length of the UK so popping that stuff in all the time would be costly.

I still drool over the 330s and want my WRX to that kinda power, but hopfully that will be achievable without the crippling costs and sparseness of SUP

But im presuming most of u STI boys are using these cars as run arounds and not general business cars ?

be good to know what the cause of his lights are, is it all down to engine management then as to what the engine drinks ? I suppose if the octanes not there and the cars wanting more fire, its gonna throw a wobbler at somepoint.

I'm not sure how an STI, that has been run on 95 RON fuel from day one, actually copes with the DET.

In theory the advance will be so reigned in, the car will be producing 270bhp and similar torque.. maybe that keeps the DET in check?

If that's the case... why not just buy the WRXs and save yourself some cash

I suppose the danger period is if someone's been putting SUL in, and then switches to NUL without then kerbing the throttle enthusiasm.

330's would be in a worst position than STI I would have thought. Extra boost through midrange to get the extra power/torque. Not so bad at high rpm as boost is dropped to nearer the STI levels. The piston damage has been blamed on the rev limiter cutting the fuel from reading other posts... I do not know if this has been proven to be factually correct! A remap has apparently cured this but time will tell.

Hi All
Filled an almost empty tank on sunday with V power 98, same problem occured on monday night on my way home from work, spoke to the dealer, they will be picking the car up on friday morning, they have it booked in for the day to see what the problem is, will keep you posted. Hope they dont have it for long, love the power, My range rover sport feels like a tanker truck now :-)

If it's not the fuel then it could be the boost spiking.

Hi

Another Update :-) ....... Car was collected early Friday morning, had a call mid day from subaru stating that they have located the problem, A faulty solenoid not in stock but has been ordered and should arrive early next week.

The car was delivered back friday evening with an invoice as i had the bluetooth microphone fitted at the same time, at the bottom was a foc item

B16102AA380 - VALVE ASSEMBLY-DUTY

Im taking it that this was the faulty item ordered in, can any one shed some light on what this part exactly is.

It's your Boost control solenoid, your CEL was likely a overboost CEL.

Said this at the begining of the thread......

Just had the same problem with my astra diesel :( except I will probably get the part before you ;)

Pistons on the 2.5 sti's are all hypereuetic, from 2003 similar (but different design) were fitted to the 2ltr jdm sti's (stronger than the 2.5's) but they are cast, very strong but seceptable to det :( so the ecu's are better to compensate :D

Tony