Yorkie

Has anyone tried normal 95RON in their UK STI MY02/3/4? According to the brochure it will take it okay. Is there any significant difference in performance over 97 SUL?

Yorkie

JohnD

iTrader: (5)

Although the STi in unmodified form will take 95 almost everyone plays safe and uses 97/98 You may find a small benefit from 97/98 as the ECU can use a tad more ignition advance and your engine is safer when you're giving it some on a hot day! Unless you do a big mileage where you'll see a financial benefit from using 95, the use of 97/98 should have been taken into account when considering such a car?
JohnD

billythekid

You might lose some performance and fuel economy as it will back off the ignition to a safe value.

However there is also the risk of det with low RON fuel, and I would not risk it - for the sake of 5p per l extra I would not gamble a fairly expensive engine.

s70rjw

iTrader: (2)

The extra MPG and smoothness more than make up for it.

Yorkie

I am not considering using it on a permanent basis I was thinking more along the lines of the imminent fuel shortages this week where SUL is getting a bit scarse near where I live ( both garages have run out of SUL). Also when I am out in the sticks and low on fuel is it safe to stick a couple of gallon of 95 into a part filled 97 tank?

Thanks for the advice so far...

Yorkie

Big Den

Well I've had 5 Impreza Turbos so far and have run them all on 95RON with no problems.

MY98 Turbo
RB5
Catalunya
STi 7
STi 8

Each to their own I suppose. None of the dealers used or the mechanics I've dealt with at those dealers have ever said there would be any issue with using 95RON and believe me I've had the conversation a good few times - 95RON V's Super U/L.

Den

FirebirdUK

I used to run my STi 8 on normal unleaded and never had any troubles...

In fact I didn't notice any difference between that and Optimax/Ultimate...

Leslie

You usually see the difference if you have a Knocklink.

Les

ru'

So, where's pslewis???

GrollySTI

I doubt you'd fit a knocklink to an unmodified UK car - so how would you know?

SB555

I agree with you to an extent but not so much for a type UK/Euro car unless its heavily modified.
In my previos MY00 Turbo I ran a full decat and quite ofter had to use 95 Ron and I never got any activity on the knocklink even when driving it hard.

Also had a Jap v4 sti and 95ron was a major no no.

Wannabe

Hi guys

I have an STi 8 with TSL 333 pack on it. i got caught short the other day and had to put Ultimate (97 ron) in it. i gave it some stick round a country road i know well and it performed like a dream.

the car is mapped for 98 ron fuel but i take it that this half tank wont have damaged my engine in any way would it?

bloody hope not

Sy

ALi-B

iTrader: (1)

Some slight additions need here (on Uk/euro spec car capeable of running on 95RON - NOT Jap imports, chipped/remapped/ppp etc etc):

The ignition retards for 95 RON...which gives a safety margin to reduce det.
The ignition advances for 97/98 RON...the safety margin is the same

Det is controlled by the retarded ignition timing so will be no worse.

(also fueling and air temp - which is calculated by the MAF...so if not modified and working OK..should be fine ).

JPS3290

I normally use 97 or Optimax but with living in the sticks have had to put 95 in occasionally and i can feel the difference. It doesn't pull anywhere near as good at 4000rpms on 95.

I just don't drive it hard if i had to use 95.

Craig Mac21

Well why does the PPP cert with my 05 sti tell you to run it on SUL 97 Only then?

Craig

Yorkie

I think that is something to do with the way the PPP is mapped. I had a MY02 PPP and ran it exclusively on SUL but it did say on the certificate that to get the best out of the package continuous use of SUL is recommended. I read that as NOT mandatory.

Yorkie

p.s. Out of curiosity and purely in the interests of science I will try 95 and report on any performance deficiencies