I can get super-unleaded for 3p p/litre cheaper than optimax - is there actually any other benefits to using Optimax over regular s/unleaded?

 

I have gone back to using super un-leaded and my car prefers it - less 'stuttery' than before.

My car is UK spec though - I'm not sure but I think the Jap models require higher octane so Optimax is meant to be better.

 

Optimax + booster

 

Here we go again !

My 10p's worth, all IMHO. UK99MY over 20,000 miles:-

- Definitely more consistent on BP SUL or Esso SUL than Optimax
- And yes, I did 11,000m exclusively on Optimax, and have
swapped around on the 9k since.

[Edited by Flat 4x4 - 11/29/2002 1:12:42 PM]

 

I've been told a lot of people say there car runs better on SUL and I must admit I'm tempted to switch back but given my specification I'm worried I'd get det with SUL.

TEK2.5 MY99, STI V intercooler, full scoobysport decat and a dawes at 1.25 bar - would it det with SUL?

 

Also gone back to SUL as optimax caused rough running. UK car also.

Sexy-Blue

Would hazard a guess that we probably bought optimax from the same filling station? Wonder if there's a trend here ?

 

Run on optimax and millers every fill up since it was introduced and not had any problems except the car responds better. Maybe because its an MY00 import RA.

I wouldnt go back to SUL unless I had to TBH.

 

No problems running optimax on my MY00 PPP'd UK car
Have not noticed any performance differences though as my car has always been run on SUL/Optimax from 7 miles on the clock

Tony

 

Saxo Boy : what bhp are you getting from yours at 1.2 bar. does it run sound like that ? how bigs the STI V i/cooler too. ??

 

Chrisp - still running an octane boost that makes as little as 1ron difference on optimax.....

Any point on a Standard Car ????

[Edited by dingy - 11/29/2002 2:09:27 PM]

 

I do find that Optimax makes more of a difference to the car if I put in the odd tank of SUL in the P1. Don't understand why, but it does.

Josh

 

Saxo, it won't det on SUL. But it will run better on Optimax than SUL IMHO.

 

CV = Calorific Value, the higher the CV the more power the fuel gives you.

Higher RON rating will reduce the likelihood for pre ignition (one form of det)

SUL has a higher CV than Optimax

Optimax has a higher RON rating than SUL

So it basically boils down to a choice between running a higher RON fuel or running a higher CV fuel.
Run more RON if you are worried about det (I'm not in my almost standard car)
Run higher CV if you want more power...

I'll fill up with optimax every now and again just to clean things out but for normal running I'll stick to SUL

 

Cheers John, I might experiment sometime to see the differences in smoothness, performance, consumption, etc - if I can be bothered

The STI V intercooler is the same size as the standard MY99 but has a better core. I had to turn the dawes down a little after fitting it so it obviously does something - more than anything I fitted for that little element of safety and the car does seem to have been more grunty (a little) since fitting it. Power wise similar cars get about 275bhp - JB would know better than me as he knows my car and knows what similar ones have achieved on the rollers. I'll be more interested in its 1/4 mile time when Crail opens for business in the spring

The way my car is running at the moment is really good IMO. Its got useful power from 3k rpm to the redline, is smooth and can still get useful economy (for a scooby) when your not enjoying it. The dawes adds a bit of brutality but I like that Through a tight c class road (the sort where you don't get out 3rd) I think it could really suprise some of the bigger turbo'd cars - that might get caught with their 'lag' knickers down. It would be immense if I got the TDO4L made into a hybrid that could hold full boost till the red line....drool!

 

well i strugle to find super or optimax so i put normal unleaded in and it's a uk my 98 i phoned subaru dealer and they said that it's fine to run on that uk model i think import it might not be the same i was sick of driving miles finding out they had sold out

 

What I'd like to know is how the local Esso garage, with their "Pricewatch" ads, can sell their SUL COSIDERABLY dearer than the Shell garage sells their Optimax. If you ask them, all you get is "We only price match on the same stuff, ours is better!"
AND there are only 2 garages in this blasted town that sell anything above unleaded!!! Grrrrr[img]images/smilies/mad.gif[/img] Alcazar
Edited because I forgot a: and it read as :madAlcazar LOL
Probably right too.

[Edited by alcazar - 11/29/2002 5:59:35 PM]

 

Have gone back to Esso SUL (by necessity at first) from Optimax. I am very pleased with how the car's running now - smoother when cold, better low-down torque, and pulling all the way to 7000.
MY99 UK car.

 

i have gone back to SUL too after my car was running really rough for the 1500 miles i done in it using optimax , my car is a jap 98 evo 5

 

Steve (dingy) yep its virtually standard, just exhuast mods its just seems to be better on optimax + millers than SUL + millers when it came out. I have been forced to use SUL + millers once or twice and it just didnt seem as smooth and pick up as well TBH. May all be in the mind, expecting it to be worst though . Just a habit now and my local garage to work is a Shell so it easy as well. I do have a Esso locally that sells SUL and cost difference is very small.

May try some of that NF stuff of yours just as a comparision to the millers.

Cheers

ChrisP

[Edited by chrisp - 11/29/2002 9:07:43 PM]

 

Mine loves the Sainsburys Super - 76p too!!

Pete

 

Chrisp, ive tried both CVL and NF and found the car to run better with NF! The power pickup is A LOT better and A LOT smoother. My vote goes to Optimax and NF. I didnt get a single bit of det while i was running my STI 6 Type R on it. Now i use Optimax only as i had Bob Rawle map the link ecu with it.

Cheers

Gez