BryanC

(Edited cos I found the link...)

You can do an ECU reset yourself - it's fairly easy - I've done it myself.

There's a couple of weird shaped plugs under the steering wheel, usually taped up to keep them out of the way.

I don't remember *exactly* what you have to do - but it bascially involved plugging these things together, pushing the accel, turning on the engine, driving for a bit, then stopping, and disconnecting it all.

I *think* there's a link to how to do this somewhere on motec's aussie web site... There's one somewhere anyway.

http://www.wrx.org.au/tech/#ecu_reset

Bry

[Edited by BryanC - 5/3/2002 12:48:30 PM]

chrisp

Last thing I was told by my local UK dealer workshop manager back in 98 when I picked my first scoob up was to always put in SUL and only run NUL if I needed to and try not to run very high revs with NUL in. So in three years and two scoobs the only time NUL was used was during the fuel blockages and then I took it really easy anyway.

The car has an adaptive ECU and will retard the ignition on lower grade fuel and advance on better fuel, simple .


*** corners better on SUL as well

[Edited by chrisp - 5/3/2002 1:41:16 PM]

Ex-Bitten Hero

I ran for a while on SUL, and had a power curve like this. (Look at run 2). The point to note is that power tails off from 5500rpm and vanishes above about 6200rpm.

I then changed to Optimax and ran it for several tankfuls (after an ECU reset), and had it rolling roaded again. Identical power figures (255bhp first time, 254bhp second time) but it held 250+bhp from 5400-6800rpm. This backed up what I'd felt on the road anyway.

So for me, no overall increase in power, but markedly better top end.

Torque is up a bit too - assuming that torque is proportional to boost in the main torque region (2700-4000rpm say). I saw around 18psi (peak) 17.5psi (held) on SUL, now I occasionally see 19psi (peak) 18psi (held). MY00 PPP, no Dawes (who needs it with boost like that? And with the boost gauge confirmed as accurate too ).

And it sounds quieter too - had to go back to NUL for half a tankful (thank you, Wales ) and the difference was noticeable...

Interestingly, mine doesn't like Optimax + Millers Octane Booster - feels quieter but slower so went back to Optimax .

Just my observations over the last year...

Cheers
Richard

[Edited by Ex-Bitten Hero - 5/3/2002 8:13:32 PM]

Jon1T

I've switched between Optimax and normal u/l a few times now, and although the car is 'smoother' I haven't noticed any tangible increase in performance anywhere in the rev range. Are we all deluding ourselves that Optimax increases performance - has anyone got a Dyno graph comparing torque curves and bhp between Optimax and u/l?

Neil Smalley

This months Evo mag did a 3000 mile before and after test of Optimax on I think a Civic type R, Jag XKR and BMW M roadster.

carl

See this month's Evo.

Surprisingly, none of the test cars reported a reduction in fuel consumption -- I reckon I get about 10% better economy on Optimax.

Then if I switch back to NUL the better economy continues for a few tankfuls -- I suspect it's because the Optimax has cleaned the valves.

YMMV

chrisp

I have a mate with a 206GTI and he noticed a huge difference and a mate with a classic porsche which was knocking slightly on 95 its very happy on optimax. I run my import on optimax basically cause I dont want a big bill for a rebuilt engine. I am assuming you have a UK model otherwise running 95 is seriously bad news.

Jon1T

I'll buy Evo and have a look - I've got a EU import MY02 - but I'm really trying to find out if anyone has round any noticable difference with Scoobs running Optimax (Jap spec cars excepted) - I've never noticed any difference in using the 2 and wonder if we're paying extra for stuff we don't really need. Subaru quote the WRX's 215bhp fig using 95 RON petrol, so I don't see the prob with running normal u/l and paying 3p per litre less (and let's face it those 3p's add up, even for those on pslewis style average national wages!)

ian_sadler

Jon,

Don't forget that when changing fuel grades the ECU will take time to relearn and adjust boost etc. with out a reset.

I dont think one tank is enough time.

Ian

Dizzy

I thought the MY01/2's relearnt v quickly

ChrisB

True Dizzy.

I had my MY99 UK serviced and the dealer reset the ECU with Optimax in. 1st time I pulled away from a roundabout afterwards I was gob smacked - pull like an absolute nutter compared to before.

carl

Advice from Bob Rawle was that (IIRC) MY93-96 ish needed an ECU reset, 97-98 learnt over a few tanks, 99-00 learnt over about 40 miles, 01 onwards work in realtime (i.e. learn instantly)

Dennisi

Do you have to ask for an ECU reset as I use Optimax all the time but unsure if this has been done...?? I dont know if the person b4 me used it but it was serviced 3 weeks ago, would it have been done then do you think?

Den

SimonEvoExtreme

Ralliart UK in Dudley did back to back tests on a RR using 2 different cars. From one they got 5 bhp increase, the other 4.

stephen30

I've noticed a diffrence in my Sport. Let's say at 4k revs in fifth, he car is 5 mph faster than on nul fuel. And it works proportionately too. I have, for reasosns too long to go into, run on half and half and saw a 2.5 mph increase. Also, feels better though the ears too but this is the only actual place I have a demonstratable example.

Steve

carl

Huh? Road speed is directly related to engine speed by the gear ratios, final drive ratio and the circumference of the tyres? The engine turns 4000 times in a minute, the wheels turn some fixed fraction of that. Putting different fuel in won't change that (unless you've spilt some on the clutch plates or on the tyres )

stephen30

Really? Why is the car faster then? definately a non techie.

Steve

SL2

Even if you had 1000bhp, at 4k in 5th gear you still would be doing the same speed.

stephen30

Must be something else then such as more wind, goin up a hill or somethin on the first measurement.

Steve

carl

Speedometer error I assume. The speedometer's driven by a coiled spring and a cable so there's plenty of scope for different results each time.

Boost II

iTrader: (1)

I wonder if this stuff is like the Emperor's new cloths. I'm not 100% convinced I can tell much difference between 97/95 RON fuel. Sometimes the different feeling you get between different tanks of the same grade fuel can seem fairly dramatic. Definately the weather makes a difference- there are just too many variables. As for assessing fuel economy - who ever goes through exactly the same movements of throttle and brake for a whole tank? I see at least 10% variations in fuel economy given the same grade of fuel and similar driving style.

Generally I like to see reproducible figures, measurements and statistics rather than how the car "feels."

carl

Have you read this month's Evo? They compare in-gear acceleration times (I presume using the Datron GPS kit). There are a couple of times (out of the 30 or so recorded) that are 0.1s *more* with Optimax which I can't believe, so I reckon +/-0.1s is the amount of noise in the data. Even accounting for this, some of the in-gear times are a second quicker

scoobypig

I reckon some cars like it, some don't.
My wrx(ppp) goes like hell on sul or sul/optimax mix but now I've been running just optimax for a while it doesn't seem as eager.
I know there are so many variables but I'm not alone in thinking my car likes ordinary sul more.

Jon1T

I take it there are no comparitive dyno runs out there then....but what I'm really getting at, is are we all wasting our money for something that costs more but delivers no real benefit. I don't beleive that for EU or UK cars running 95 Ron is an 'engine wear' issue, because Subaru would be open to massive litigation if they didn't produce a car that ran fine on 95 Ron as this is more or less 'standard' everywhere. So apart from people 'feeling' a slight difference, has anyone got any hard data to show that running a Scoob on Optimax has demonstratable benfits? Otherwise we can stop using it.....

mutant_matt

Jon,

Prodrive quote two differet power figures for the MY01> PPP. One for 95RON and one for 98RON (can't find the figures now but I'm sure someone will provide them).

That would imply that they have dyno'd with both and found normal Super gives more power than Normal Unleaded. So at the very least, Optimax should give as good results as Super (which is better than NUL) and more than likely better than Super.

FWIW, I think that Optimax in my UK car makes a fair amount of difference to the smoothness and drivablility of the car and I've had some good dyno results. Unfortunatley, I can't compare to NUL has I have no figures for that. I did have to put some NUL in it recently (breifly) and was surprised to find the engine seems to run really roughly - placiebo(sp?) or not, I don't know?

Matt

Kempo

Surely if it prevents the engine from detting then regardless of whether YOU feel the difference it has to be a good thing???

I would certainly feel the difference to my wallet if the engine goes bang on a nice hot summers day. But, I have actually felt a benefit from running Optimax, I was getting *unusual* power delivery, particularly in 1st gear which has gone since always using Optimax - saying that, I would defy anyone who can spot (with the naked foot ) an increase of say 5 - 6 bhp that Optimax *may* provide.

I will continue to pay my money and make my choice.

Paul UK95 (264 bhp )

SimonEvoExtreme

Jon
I take it you didn't read my post above about the dyno tests on Optimax.

4-5 bhp and 0.1 secs on accelaration seem about right although I agree that 0.1 could easily be noise.

What I find strange is that everybody is staring a gift horse in the mouth. Optimax is a minimum 98.2 ron while other SUL is 97. And Optimax tends to be cheaper, or at least where I buy it. Tough choice.....not!

If you regularly swap fuels, I suspect that you won't notice that much difference because most manufacturers ECU's have some sort of "learning" capability and this will only confuse it. In addition, if your average fuel for a few years is 97 ron, then even a month on Optimax won't make a lot of difference. What you need to do is to reset the ECU. I know this can be done on the Evo just by disconecting the battery for a while but i dont know about the Scooby.

Jon1T

Matt- I agree - sometimes I noticed the car ran more smoothly on Optimax when I filled up, but also though so when its filled up with normal u/l!! But no difference in performance - and I'm only talking about a bog standard MY01, so may be diffent story for higher mileage/older Scoobs. I just don't like the thought of paying for a perceived benefit, with no hard evidence to back up the claims......

chrisp

http://www.scoobynet.co.uk/bbs/threa...threadid=91867

Pays ya money takes ya chance

Jon1T

Simon - yes read it! I take it that was on Evo - can you run those on 95Ron??? Crisp I take your point, but Subaru quote the new age bhp figs based on 95Ron so I don't accept running MY01 on 95Ron alone will cause engine damage. I 'm not trying to be lairy, I'm just trying to find out if Optimax really does have any performance benefits for MY01/02 scoobs