Roojai

Just bought a MY94 WRX wagon. Want to get a scoobyecu but until I do, am I alright using optimax on it's own, or even normal unleaded, or do I have to use octane booster for safety??

M0NEY

you dont have to use octane booster.

Optimax is fine

Roojai

cheers

neilswrx

disagree as imports are mapped for 100ron uk cars would be ok ,optimax is approx 95-97 ron see other threads relating to this .
i know of at least one car not far from me that was run on normal unleaded ,now no piston as it,s melted i would seriously use octane booster or super unleaded if you can get it on a import

RRH

WRXs det the same as STi's do.

Maybe not to the same degree, but it happens all the same.

You can buy a lot of £2.50 bottles of miller OB for the cost of a new engine. Think of it as insurance.

RRH

neilswrx, not sure if you misread the thread m8, but optimax has a higher octane rating than SUL, ie 98.something(ish)

Scoobsterboy

Not correct, Optimax is rated at 98ron and super unleaded is 97ron Also BP Ultimate is 97ron. At the very least you should be running on optimax. NF Octane booster will add the extra ron to bring you closer to the 100ron which jap cars are mapped for.

Bob Rawle

You should use equiv of 100 ron to be safe.

Optimax is 98.6

Do not use Ultimate on its own.

bob

RRH

here's a question for you- slightly off thread but relevant none the less.

given an avergae size impreza fuel tank, will a bottle of Miller OB increase a tank of Optimax to the magic 100?

also, how much more potent is millers CVL?

cheers guys,
simon

sti-spec-a

Optimax is 98.6RON
My WRX MY95 has been fine for the past year at standard boost when ran on Opimax alone
Now its running way above std (20psi) the Knocklink was showing occasional yellows at 5000rpm Now it has Booster as well,NO knocklink activity and the car pulls that wee bit harder

Cheers Grant

sti-spec-a

RRH ..... yes it will take the octane number over the magic 100

Cheers Grant

Scoobsterboy

Is it legal to use octane booster for road use? If it is why can't we get 100ron from the petrol pump??

sti-spec-a

AFAIK its legal to use,legal buffs on here will confirm/deny

"If it is why can't we get 100ron from the petrol pump??"
its not economically viable for Esso,Shell,BP and the likes to sell 100RN on the forecourts when 99.99% of cars in the UK are mapped for 95 RON If the UK cars that were mapped for 95 RON started running on 100RON they would be popping and banging all over the place ..............
You can buy 100 RON straight from the major fuel distributers but its dear,very dear about £2.00 a litre Greersport used to run the JUN skyline(Jeremy Clarkson DVD) on ELF turbomax which was 102RON

A good idea would be for 1 of the major fuel players to start selling 100RON at the pump The would get the business of every import user in the land It doesnt cost extra to turn 95 into 100 the petrol is taken from a higher point in the "Refractional distilation process" It all comes from crude oil petrol,diesel,race fuel etc etc
A petition would be a good idea if you got every import Japcar driver to write to Shell,Esso etc then they might relise a good idea when they see one .... or maybe not

Cheers Grant

Roojai

So, Where can I get Millers octane booster from. £2.50 sounds good. In Halfords it's almost £5 for STP octane booster, a bit much for me.

RRH

graham goode racing, demon tweeks- loads of places do it. don't know a lot about the STP stuff except it's sounds expensive.....

M0NEY

Its usual crap mate.

Ive put normal unleaded in mine before when no optimax or SUL was availiable and was fine.

When imports used to come over in the beginning, people used to run normal unleaded with just resetting the ecu and none of them went bang.

M0NEY

And a piston going wrong cause of using Normal unleaded is the biggest load of rubbish ive heard.

Piston just went on a sti5 (a mates). Was it because of normal unleaded. Nope. Its cause he was ragging the sh*t out of it

Autocar

Never heard of det then EXPERT.

neilswrx

if its the biggest load of of rubbish then why are the majority of jap import owners told to run either superunleaded or add octane booster ?
maybe the piston went because he was running it like s--t but have you personally seen the state of it ,it,s in aberdeen ?
well the garage up here is laughing like **** as he was told to use either option and didn,t bother as he thought he knew better
i,ve only taken the majority view here to use optimax plus booster or super so take or leave it at your own risk but as far as i,m concerned the biggest load of rubbish is to think you know better without even asking someone who knows and i,ve asked various scooby owners/scoobynet etc.
each to their own choice

M0NEY

Autocar - thats correct. Ive put normal unleaded in mine and the car doesnt det. Thats before it was modified. Have you ever heard of det or do you just read on the web

Neilswrx - please tell me who says to add octane booster???

I havent seen the piston - but you will never know if it was becuase he used normal unleaded or if he thrashed it. I blew a piston on mine and thats after it was being mapped. It wasnt due to fuel as right fuel was being used, even the mapper wasnt 100% why it went? You cant say why a piston goes

The last sentence cracked me up. Im not saying i know better than alot of scooby owners. Been around scoobys for the past 8 years and was at one of the dealerships when they first started coming over in the country and everyone was playing about with fords. lol

Im just saying - from when they first started coming over, normal unleaded was used and the ecu was just resetted.

All my opinion of course

sti-spec-a

Sometmes you can use normal unleaded if you just occasionally blat the throttle,run std boost and the engine spends most of its life off boost
Before i met Bill Greer i ran my first WRX on 95 RON without any problems for about 10 months
I look on using Opti + booster as an insurance Its cheaper than a rebuild

Cheers Grant

RetroR

Been reading this thread with interest as I have just bought a import myself and have been wondering about this.

I have the a 95 wagon though (220hp?) totally standard bar a H&S backbox and I was wondering if running just on Optimax would be ok.


Dave

greasemonkey

Maybe, maybe not. The lower the octane rating of the fuel you run, the more likely it is to det, and the more it dets, the more likely it is to eat itself.

The way to be sure is to fit a KnockLink. That way, if it dets, you'll know, and you can back out of the throttle PDQ - hopefully before damage is done.

Until/unless you have a KnockLink, the safe approach is to use Optimax plus at least enough booster to get the fuel up to the 100 RON or so the car will be expecting. You could skip it, sure, and save yourself a few quid every time you fill up, but is it worth it when the potential consequence is an expensive engine rebuild? At end of day it's easy for Money to be blasé about it, as it won't be his car that suffers if you follow his advice and find it's wrong.

Caution is always a worthwhile approach, even if it costs a little more.

M0NEY

Very true Greasemonkey about knocklink

Like i said, its all my opinion and based on cars that were worked on.

As you can see grant didnt have probs with his.

I only said all this cause reading crap about booster is a must and being told using normal unleaded will blow the engine (crap)

As indicated in my first post, with optimax you will be fine (no need for booster).

Booster is better used when you have a remap with more mods. With my spec, i was told i could gain another 20bhp if i had remap with booster

Jay m A

iTrader: (2)

To answer the original question, for peace of mind I'd run on Optimax minimum, and not do top speed runs / rag it off the lights until your ScoobyECU turns up. And order a knocklink.

I'm sure being new to Scooby ownership thats hard to do.

Its currently what I'm doing, waiting for the knocklink, ScoobyECU etc. I've even got Exhausts/filters/turbo hoses and Dawes sitting in the garage waiting to go on, but not untill I can monitor everything

Hurry up Pavlo LOL

greasemonkey

Sorry M0NEY, but as a sweeping generalisation, that's bollocks, and like I said, it won't be you picking up the tab if your advice proves to be inaccurate, will it? Both the last two JDM cars I had detted their heads off when driven hard with Optimax alone, and thus I daresay others will as well.

As stated earlier, using booster, even if unnecessarily, is by far the preferable approach to not using it, and picking up the bill for a rebuild further down the line. Yes, there are other things that can cause engine failures, but this is an easily avoidable risk.

If you have a KnockLink, and thus know your car doesn't det when you run on Opti alone, sure, go for your life. Without a KnockLink however, using booster should, IMO, be considered worthwhile risk prevention.

M0NEY

Yep ran optimax all the time with no knocklink.

Got a knocklink and run optimax and still no det when driven hard.

Most of the scoobs ive ever driven or met dont use booster and have never had a rebuilt. Are you saying you used just optimax and had a rebuilt?

Were your JDM cars completely standard to with just optimax?

Also, depends how hard your driving that will blow up and engine. Ive seen many scoobs on here with sti's running booster and driven hard they still blew it up!

Scoobs are quick cars, but if everyone thinks you can jump in and race the hell out of them 24/7, then they will be expecting a rebuild. lol

greasemonkey

Lucky. As mentioned above, some do, some don't, and until you know yours doesn't, the safe option is to use booster to minimise any risk.

No, I'm saying that the only times I tried Opti alone, the KnockLinks lit up like Christmas trees.

At the time we're talking, both would have been bog standard.

Of course. Don't you think that suggesting to a new owner that his car will be fine on Opti, without knowing how hard he drives, is a tad irresponsible?

There are plenty of reasons why these engines fail. What we're talking here is an issue of minimising risk. At end of day, if you run the right oil, change it the right way, have the car maintained to the correct standards, and run the right fuel, you are at less risk of something going wrong. Agree or disagree?

I don't think anyone on this thread has said that, have they? As said, this is a simple case of common sense and risk control.

adpd

I have an imported WRX (running pretty standard), and have a KnockLink fitted.

Above 5000 rpm I get occasional det.

I only put in Optimax (now 80.9p per litre the sods!)

Thus, I now change gears at around 4,500 rpm until I can get a ScoobyECU.

It is risky blasting your car around on fuel that is not right for the car.

Granby

iTrader: (5)

While i'm no expert i think the outcome of all this is you could use just normal unleaded or optimax and if you drive slowly and don't hammer it you should be OK (but who's buys a scooby to take it easy) but if you use the power that is available you would be safer to use a octane booster