I've been running the car on Optimax for the last few weeks, including the half day at Knockhill. My feelings are mixed, as I've noticed:

+Slight increase in power, but fuel economy remains unchanged
+Increase in pops and bangs through the exchaust
-Engine runs *rougher*

I'll give it another month, and if the running of the engine doesn't improve I'll desert the Optimax camp in favour of "normal" SUL.

What have you guys noticed?

 

Hi Miles,

Can't say I've noticed any performance change but it doesn't seem to be running rougher infact I have lost my small missfire when flooring it in third.

Fuel economy seems to have gone up aswell, managed to go to Glasgow and back on just less than one tank - works out at 30mpg I think.

Duncan..

 

I haven't noticed a great deal of difference, the car does seem to run a tiny bit smoother all round, although imagination could play a part. Don't think that the fuel economy has changed (90 miles of KH to a tank )

I did however get that regular misfire at KH, I think that both of you felt it, but that seems to have dissapeared again. So I'm not entirely convinced yet.

Stuart

[Edited by sasim - 7/28/2002 3:08:14 PM]

 

I've seen a huge difference. Problem is I put a SS DP on the car and then started using optimax so the optimax might be making the car noisier and pull harder through the rev range or it could be the downpipe

 

Been using Optimax exclusively for five weeks (600+ litres ) with no noticable improvement nor degradation over the SUL I used previously.

 

Just had my car serviced at Nobles in Penicuik - they said the feedback they had from a number of customers was that the 01 WRX does not like Optimax at all, and best to avoid it. Try SUL if I want, but most of their customers use regular unleaded.

I've been running mine on regular unleaded for the last 5000 miles, without any noticable problems. Is there a perceivable benefit using SUL or Optimax?

 

I've used Optimax for the past 4 or 5 tankfuls now.

Comments:

Engine feels slightly smoother. Not noticed any extra power over SUL. It's 4 - 5p per litre cheaper than SUL. No negative comments, but nothing really positive either.

Miles - I would give it a few more tankfuls to take advantage of the "cleaning" benefits of Optimax.

Then it would be worth trying a back to back test with SUL.

Quite often, you don't notice small improvements in power and smoothness, until you go back the way, and you notice the small decrease in power, and engine running slightly rougher.

John

 

im back to a tank of SUL since friday...
to me - the car feels smoother with SUL rather than optimax

or maybe its just colder when ive been driving

 

Do scoobs have knock sensors to retard the timing, and therefore get a bigger bang??

My Audi does but i aint really noticed any difference between SUL And optimax!

supposedly takes a few tankfulls to get the car to "learn" but it's more like a marketing ploy to me!

the performance gains as published in evo were so slight that i was very sceptical- could have been down to air temp, pressure, altitude etc etc

ta


foz