sensemagic

Hi folks,

I'm not going to start off an SUL vs Optimax debate - this has probably been done to death, with differing opinions.

I've been running my STI7 on Optimax since day 1, and am considering trying out non-Optimax SUL, to see how I find the difference (if any).

Will my ECU have learned anything about Optimax (like advancing the timing?) that could be unlearned by using normal SUL. Is it bad to alternate between the two fuels - will this confuse the ECU?

Thanks in advance,
Philip.

chrisp

IIRC the newer ecus should adjust almost immediately. If you are worried take it easy for a few miles after swapping.

scoobycar60

I dont care what people say my STI7 UK seems to run well on one tank of optimax, then rough on the next, no idea why, seems much more consistent on SUL never noticed power drop other than on what seems to be duff optimax then it runs badly, holds back and the throttle response gets jerky at low revs in a low gear.
Despite all the hype I've given up on optimax and stick SUL in mine, the car seems to like it better.

chrisp

Yep mine just seems better on Shell SUL (aka optimax) and OB. Try them both and stick to what you prefer.

Fizz

iTrader: (1)

My WRX was crap on SUL and brill on optimax... No have PPP it is excellent on both

scooby_jim

I tried Optimax, found little/no change in performance and my fuel economy went down!!! And that was coming from 95 RON unleaded.. Not worth the extra 4 - 5p per litre, thats for sure!! IMHO

MY02 WRX (no mods), so ECU should have automatically adjusted..

LG John

I've been using optimax since I got the scooby but just last night - in light of all the reports - I decided to fill up with SUL again to see if I have a preference. So far, (not done many miles) the performance does seem to have improved a little but maybe a little rougher. Will report back when I know more

MY99, TEK3, Decat.

PPPMAT

If you get a good tank of optimax, my car runs superb MY02+PPP. Had a bad tank last week though and it was awful. Esso/BP SUL not quite got the edge of optimax but is more consistent. I think it pays to run optimax but stick a tank of BP/Esso in it once in a while - seems to keep things in check for me

Ratman

For 6 months I ran my MY98 on Optimax at an average of 25.87 mpg. Then the local Shell Garage ran out, so I had to put in "Esso Superunleaded 98" at a similar price. I've kept with this for the last month now, but despite driving the same roads in the same style, my fuel consumption has dropped to 23.65 mpg. That's 8.6% less.

Not noticed any difference in performance otherwise.

That's just my experience.

Ratman
MY98 Wagon

Edcase

well i just had my car serviced after running in and I mentioned it was sluggish in 4th and 5th and he said maybe the ecu had been initialised on standard unleaded, so as I was using super it need reinitialising. He reset the Ecu, drove it around the block to reinitialise it and the difference is extremely noticeable.

steve77

I have used both Esso SU and Optimax and have found the following

When Esso SU is good it is better than Optimax, but when its bad its crap, sluggish, pinking etc.

Optimax always find that this is more consistant from tank to tank

Possible reason for this is where I buy optimax from there is a high turn over of cars filling up so there is less chance of water builing up in the forcourt tanks whereas where i Buy Esso from the turn over is much less

Anyway if your fuel runs poor just stick in a can of Fuchs Proboost that sorts it out every time

LG John

This sucks! There doesn't seem to be any set pattern with different users of different scoobys reporting different results!

steve77

Simple

Do you buy your beer from a pub that is empty or one that is full ?

Same for petrol. Your not telling me that companies such as BP/Shell/Esso etc don't consistemtly refine there fuel. I work in the chemical industry and you can control distillation processes very tightly and be consistent batch after batch after batch, so it has to be down to water in the forecourt tanks and nothing else. It is a common fact that oil companies regularly dip forecourt tanks to see what content the tank is water as they are allowed a tolerance for this.

As far as I am concerned this should be the end of the topic

LG John

So how can you tell which forecourts have low water levels and which ones don't?

Edcase

LOL @ saxo boy

SiPie

Kenny

In my experience,I have never had bad fuel from the ESSO station at Fairmilehead so that must have low water levels.

But the optipish at the Braids must be feckin soaking

steve77

You can't but if you read my responses properly what I am suggesting is to use a garage that you know has a high turnover of people filling up say on a busy main road, dual catrrage way etc

Less chance of water getting above the threshold then

Stueyb

My G/F used to work @ a shell station. they *know* when they have bad fuel, but they dont tell anyone and play ignorance when someone complains about the bad fuel (and they do, quite regularly)

Amanda-Jane

My dad and Granda both worked for Esso for many, many years and they would never put anything else in their cars. I used to always use Esso SUL in my cars too and never had a problem but in Hamilton there is not one Esso

AJ

LG John

Cool, I'll stick to the ESSO sipie suggested as its always very busy and has a massive turnover I think

SiPie

Well I'll no doubt see you there Kenny, as I just love visitng it nearly every 2nd feckin day