Ecu

[Markturbo]

I have read people on the forum saying about running the tubby on the wrong petrol to fill it with optimax then reset the ecu could some one tell me how to do this cheers

[DeusMR2]

fill up with optimax and run through it a bit to get rid of any old crappy petrol.

with the engine up to normal temperature, switch off, open up the engine bay and the fuse box near the coolant cap.

disconnect the ECU fuse for about 2 minutes and then plug it back in

drive away and drive like you just stole it so the ecu can learn to full boost again, car may run rough for a little while, but after its relearnt everything it'll be all good

[BLOODUK]

So how much bhp would you lose from saying using SUPER unleaded to optimax if say its only 3bhp does it matter , ive been using super unleaded its still <I thought I could get past the swearing filter - what a sad muppet I am eh?>ing fast.

[DeusMR2]

you would lose quite a lot of bhp, much more than 3bhp, if youre using crap petrol (normal unleaded stuff). Super unleaded has slightly better results but whenever i used it my 2 always goes into safe mode. With optimax or bp ultimate my stock guage always rises to the + mark, if i were using normal unleaded or super unleaded then the needle stops about 3/4 of the way and you can feel a noticable loss of power. This happens around 5500rpm in 3rd gear with your foot all the way down. Generally they run better on optimax even when not boosting (less rough and more rev happy). This may differ across the country though but as far as I know everyone here with a tubby claims either optimax or bp ultimate or both are the best fuels. note also that rev 1 and 2 are more sensitive to lesser petrol than rev3s.

-edit forgot to mention that optimax and ultimate give better fuel economy since more of it is being burnt unlike with normal or super unleaded where a lot of is wasted (unburnt and chucked out the exhaust) in safe mode boosting. The better fuel economy is definately noticable, not "theoretical". So the extra cost of better petrol is balanced by better fuel economy, course this depends on how far away you live from a Shell or bp station!

[BLOODUK]

To be honest ive never noticed a difference in performance from super unleaded - optimax , apart from hear say from members has there been some official results done?

My stock guage goes to the + as normal :hokus-pokus:

[RichB]

You *should* run a turbo MR2 on 97+ RON fuel to avoid detonation. It's not about BHP increases. In the long run your engine will suffer if you do not use a higher octane fuel. (and yes, it will not perform as well either).

[BLOODUK]

Yes but apart from hear say wheres the proof? , show me some proof of a car not doing so well on super unleaded compared to optimax!

:bookworm:

BP ultimate = 97 RON

Super unleaded = 97 RON

Optimax = 98 Ron

To go from 97 ron to 98 ron you wouldnt even notice a difference , the only VERY slight difference is fuel economy but unless your trashing the car every day you wouldnt notice a difference if at all.

[RichB]

Optimax is NOT rated at anything like that - in the eyes of the law it is standard unleaded petrol, so it only has to meet the requirements for 95RON. That's below even supermarkets' Super Unleaded. Maybe while it's still in the refinery it starts life as 98+, but on the way to the forecourts it fizzles out rapidly, and waiting in the underground tanks (that might not seal 100% the inert gas they're supposed to contain) doesn't stop the loss of the lighter ingredients (responsible for the octane uplift). And that's before it gets into your own tank. Shell doesn't trust the fuel to exceed 95RON in the random checks of Customs&Excise - I don't see why anyone else should trust it to. In the Optimax forum their 'expert' admitted to Optimax having a guaranteed MON value of 86, which is just over the legal minimum (85MON). According to Shell, a typical MON value would be around 87, but that would be pot luck. Therefore at worst, Optimax (AKI=90.5) will be slightly better than bog-standard supermarket unleaded (AKI = 90)

Here is an embarassing shrinkage of the Optimax hype (from ASA):

http://www.asa.org.uk/adjudications/show_a...ications_id=all

[RichB]

Oh, and you don't need to reset and MR2 ECU, cycling the ignition is good enough!

[BLOODUK]

Therefore at worst, Optimax (AKI=90.5) will be slightly better than bog-standard supermarket unleaded (AKI = 90)

eeek

[BLOODUK]

Oh, and you don't need to reset and MR2 ECU, cycling the ignition is good enough!

As i thought , i think its just hearsay from other members that causes people to do things with the ecu because of petrol .... personally im staying with Super unleaded and if i cant get that which would be unusual ill go optimax. Aslong people arnt sticking normal unleaded in there shouldnt be a problem ;)

edit: thanks for taking the time to fill me in with this info !