russell hayward

Did a little monitoring today :-

Peak 1.3 bar

Hold 1.1 bar ish

until 6,000 RPM when it gradually reduces to 0.7 as you approach the redline ?

Anyone else had this ?

I am running 95 RON at the moment, so this may be the answer.

Thanks

Russell

Dave T-S

Russell

I would strongly advise you do NOT run a STi7 UK on 95 RON!

There have apparently been a number of STi UK engines let go, no point in encouraging it!

Re boost tailing off at 6000 rpm, the fuel normally leans out at around this figure, and boost follows suit.

[Edited by Dave T-S - 4/19/2002 7:40:30 PM]

russell hayward

Well yes normally I would use super, but as most of the time I am just cruising up and down the motorway there seems little point.

Today was the first time I had really given it any throttle.

Will try Super on next fill up and see what happens with the boost then. Does yours tail off loke that ?

If the engine lets go then more fool the Dealer and Subaru for saying it will run on 95 RON !

Dave T-S

Well, actually the manual says you should use 98 RON, but 95 will do at a pinch - and will detract from performance and driveability.

I go out of my way to put Optimax or at least SUL in ours.

Your engine however, not mine......

Deep Singh

Not particularly confidence inspiring to hear UK STi engines are already popping.

russell hayward

FUEL GRADE 95 RON UNLEADED (MIN)

Cut and pasted from the STI specs on the Subaru website.

I think I will ring them to see what the Official line really is.

I was under the impression that the car would run quite happily on the grade, albeit it runs better on Super/Optomax.

As for the manual, surely that doesnt take into account the UK ECU mods ?

Russ

Dave T-S

Russell

With a UK car, you get a UK relevant manual. The JDM ones want 100 RON.

I make a 12 mile or so detour to put Optimax in as it is average 98.6 RON as opposed to 97 RON for most other SUL.

If I could get 100 RON I would stick that in - it's called insurance, and not taking chances.

PS - re your first post - peak and held boost is only really relevant under load in 5th/6th gears, so no I don't have a reading at 6000rpm

[Edited by Dave T-S - 4/20/2002 5:49:35 PM]

russell hayward

Dave

Says 98 in the manual, but 95 if not available.

I was speaking to Mike about this and he recommended Optimax of course, as the car goes much better on this fuel.

Anyway, just filled up with 97 RON and chucked some booster in for good measure. Only drove 0.4 miles back home and the car still cold, but low down response seems miles better already.

Out for a longer run later.

The car is loosening up noticeably now (1700 miles), gearbox included.

Fitz

Although running on Optimax is app 4p-5p dearer per litre, when running it in my previous car and also the guy at work with his RS2
both realised slightly better fuel economy from it, in that we both noticed a slightly increased tank range. Nothing scientific, just
noticable. So although paying more you would appear to get some back in improved economy which could well be as a result of the
engine working more efficiently at the prescribed RON rating it was designed to run on.

Still running in my STi so can't comment on that as yet....
Chris

russell hayward

While I understand your logic, in 5 years of Scoob ownership and logging every fill up, with 4 different cars, I can't reach the same conclusion.

You may be right, but a much bigger factor is how far you press the throttle. You also can't really compare like for like journeys, because they will always be different.

Back to the STI and 95/97 RON. Last fill up was Super+Booster. The car is now much more responsive under 4k, when cold( which was really bad) and when hot. Throttle response is better, and the turbo is spooling up about 500 rpm sooner now. Over 4k, doesn't really feel any quicker and the boost is behaving in the same way.

Now up to 1900 miles, so hopefully things will keep improving as the engine loosens.

Anyone noticed the strange noises the OEM tyres make when cornering with any conviction ? Bit like a whooshing sound. Very bizarre.

Have to say the transition from cruise to WOT is not very smooth compared to the other cars I have had. As the boost builds, the car can feel almost hesitant at times. Anyone else noticed this ?

Russ

chuckster

I had that on my MY01 WRX, and loads of people had it on the MY00..put it down to an engineered flat spot which corresponds to the noise emmission test RPM - PPP tuned it out on the MY00/WRX...
I sold the car instead as I thought it tedious LOL
Chuck

russell hayward

Well, that could be it. It seems to be better on 97 RON but not completely, and still nowhere near as smooth from low revs as my P1.

Also had a couple of instances where cruising in 6th. When I applied the throttle, car only gave about 0.5 bar of boost. Put this down to the 95 RON fuel I had in there at the time, as it hasn't done it since.

Thinking about it, the Demo I drove had a really bad hesitiation once or twice coming back on the throttle. Again this car was running 95 RON. I reported it to the chaps at the dealer as it was that bad.

Hopefully the PPP may help matters, as you say Chuck.

Russ

Numptie

I thought about posting about the 95 / SUL issue a while back but decided it'd probably already been done to death and I'd missed it.

It seems to me that the advertising (brochure + website) say 95 is ok.

The manual and sticker inside the filler flap contradict this however.

One of the reasons I bought the car was that I was sick of always having to hunt around for SUL when I had the E6 (small point though - I'm still delighted with it ).

Should someone be pulled up on this or do I have the wrong end of the stick ?

[Edited by Numptie - 4/24/2002 1:34:27 PM]

russell hayward

My impression was 95 was perfectly OK and my Dealer backed this up.

I had assumed the ECU was specifically mapped for this. However, it appears this may not be correct.

The car is much better on 97 RON so I will stick with this where possible. Like you, ease of use was an issue, as I am using the car as an everyday mode of transport.

Had similar issue with the P1 when it was released. The Subaru website was actually wrong stating 95 was OK, and I think they changed it eventually. You can use it in an emergency but the car will det leading to inevitable results.

carpet

why not find a mate who owns an airfield and stick aviation fuel in ( 100 RON !! ) and its cheaper than from ESSO etc ... ??

I have a mate whos dad has an airfield ( not that ive put this sort of stuff in my car tho ! would work out at about 60 odd p per litre ( so v much cheaper !! )

Pooder

I noticed a huge difference when I changed from SUL to optimax on my 98 turbo. If Lancaster in Sevenoaks ever get round to supplying my STI(on order for 5 months now)I will not run it on anything but optimax.

russell hayward

Tried Optimax in the STI. Not any difference to 97RON as far as I can tell. May be a little more eager at high revs, but nothing major.