I seem to get more mpg when using SUL in my MY99 UK. However the cost of the SUL over the UL more or less makes it the same cost wise.

A thing I noticed in my scooby, is that when my car has about 2-3 litres of fuel left in the tank, the engine cuts off around 5000 revs in 1st and 2nd gear, as if to tell me that if I continue to drive like that, I will run out of petrol. Has this happened to anyone? As soon as I fill up past 5 litres the car is fine and will rev quite happily to the red line.

 

From new I've been running my UK MY00 on SUL. The big question is "am I wasting my time?" Is there much appreciable difference long term between running on Normal or Super (apart from the size of the whole in my wallet)? I know the car can run on either but I'd heard that performance was better on SUL.

 

I've tried and failed to notice any difference.

I guess it depends on how much mileage you drive. If the car is for playing with, then SUL. If you drive daily to commute then normal UL makes more sense.

(Flamesuit donned, awaiting backlash!)

 

Simon,

I've been running my MY00 on NUL but switched to SUL at the weekend. I have not really driven it much since but I did think that it was smoother and possibly picked up better as the turbo spools up! I'll let you know what the consumption is like afer a couple of fill ups.

I think the difference will be much more noticable in the summer when the increased temp starts having a much bigger effect (NUL detonates at a lower temp so is more prone in the summer).

Matt.

 

Simon,

I too have a MY00 and for the first 6 months or so ran it on normal UL. A couple of months ago I started to run in on SUL and after a couple of tankfulls (maybe it takes time for the ECU to learn??) I think the engine felt a little smoother (might be psychological though!!) but don't think there is any difference in performance.

 

MY00 run entirely on SUL, once NUL with octane booster (£7.50 for octane booster? can a recommend not buying it in Caithness, if you are going to that part of the world, buy some before hand and take it with you) I sit around the 15mpg mark, so if it improves fuel economy then I hate to think what I would get from NUL.
Never contemplated running it on NUL, was told by a dealer that it would make maybe 0.1sec difference to a lap on track, but no difference on the road.

 

I have used SUL for 90% of my 3 year ownership. I DO notice a difference in 'get up and go' when I ocassionally use NUL. Will be putting a full tank of SUL in tonight. I have found this difference more noticeable in our colder weather.
Car is a standard spec UK MY97. Infact, as seen in this month's EVO magazines 2nd hand guide to Impreza buying.

 

I have a MY00 and ran it on NUL for at least 7 months, partly because I thought that SUL would be a bit of a waste of money. How wrong I was!! Within a tankful of SUL, I definitly got a smoother engine and much better pick up from lower revs. And on a journey from Yorkshire to Somerset over christmas I got 289 miles on a tank of SUL, which quite frankly staggered me, as I wasn't driving like Miss Daisy!!!

So I would certainly recommend a move to SUL, and to be honest on a £40 fill up, it is only about £4 extra anyway!! Box of ****??

Jamie

 

I've run my own MY00 on SUL from new, have put NUL in on 2 occasions, shortly after buying it, then reset ECU with SUL back in it and on the Dales run in December coz I couldn't find any SUL.

The second time I haven't reset the ECU and it seems to be running fine again. I get 300 miles (at least) to a tank full, though I do very little "urban" driving if I can help it. I did seem to go through the tank of NUL a bit quicker, but I wasn't really keeping notes.

I see that the Subaru UK web site now says "95RON (minimum)" on the "what fuel does it use" in the specs for the Impreza turbo.

 

I have tried SUL definately no mpg gains and I can't say that I noticed any difference with the engine smoothness or power either.

Has anyone done back to back dyno testing on this phenomenon?

Mick

 

I average at least 280 miles on a tank - on a lot of occassions this is over 300 miles - thats on an sti 5 with a Link ECU - before I changed the ECU I was getting about 250 miles to a fill up

I use SUL and Octane booster £2.80 a fill up - cant remember name - just comes from Brighouse and is good

 

I have used SUL and Octane boost in my wrx for about a year now. I noticed a remarkble difference in it's smoothness through gear changes and it's over all performance.

I'm not bothered about mpg, I did not buy the car for that!!!!!!.

Here is something interesting for those of you who run on SUL. Have you ever had a "bad" tank of SUL?.
I have on a few occasions, due to going to a different garage than norm, I instantly went to my original garage and all was well again!!.
The reason I mention this is that on Saturday at the Autosport Show I had a long chat with the Nice man on the Millers stand.

We talked about their Octane boost, "which I already use along with Silkolene" and also their Track day Octane boost which gives it alot more UUUmmmppphhh.
Anyway we got onto petrol and SUL, he informed me that SUL has a shelf life of only 6 weeks due to the additive that is has added to it ( Cannot remember the name of it!!), thus this is probably why I have the odd bad tank of fuel!!!.

He did say that the best petrol stations to go to are on Motorways or very popular Big city garages who shift petrol damn quick.
He did say that buying it from the country and rural areas was not advised as there will not be the demand!!!.
Yet another reason why I have the odd bad tank of fuel, I live in a Rural area!!.

That's my tupeneth.

Muddy.