Guys can you help, I have had my UK turbo now for nearly 3 years but have never run her on optimax (dealer said it was ok to use SUL) I was just wondering if I started to use optimax would I notice a differance in performance she is a 98 model with center decat, my question is would it harm my car in any way.
Cheers
Colin

 

Yes, you'll notice it; no, it won't harm it.

 

Thanks Tel, I've got half a tank of Sul at the moment is it ok to mix it?
Cheers
Colin

[Edited by Scoob99 - 10/14/2003 10:50:01 AM]

 

Yup you can mix it but you may not notice the same amount of difference as you would with just optimax.. i'd say its best to wait till its nearly empty then fill up with optimax..
optimax won't harm your engine infact it'll help protect it...

Franko

 

Yep, go nuts!

 

Cheers Guys!!!!!!!!!!!

 

Ive only recently switched from SUL to optimax as i can get SUL cheaper round here,but im sticking to optimax now.Ive defo noticed a differance.

 

Col as my car is virtually the same spec as Yours I can say, I didn't notice any difference.

Ran it on NUL for about 15 months, then SUL, then Optimax, and I have to say that it doesn't feel noticably different and has had more than enough optimax to re-learn by now.

Do get slightly better fuel economy from the optimax though when pottering about to from work etc.

 

Cheers Paul

 

Do a ECU reset as well as optimax, as the ECU will have learnt to cope with NUL so it will continue to retard the timing by the same amount even with Optimax.

Just disconnect the battery for a while and when you start it up again it will start to learn to use optimax, you will DEFINITELY notice the difference

 

I only really noticed the difference when I was forced to fill up with normal unleaded (having run Optimax for about 10 tanks). Definite (subjective!) drop in performance.

 

Agree with you all I have a MY00ppp and filled up with a tank of optimax - car felt more spritely than just SUL. Have re-filled with SUL and peformance drop is noticeable - never felt this in my old 93WRX but then again I always used loads of O.B just to be safe.

I shall be refilling with Optimax I think

 

yOU SHOULD GET THE SAME AS MOST NOVAS, 3 TO 400 MORE BHP.

HE HE

 

So from what you are saying diconnect the battery for how long?? then I should notice a differance?
Cheers
Colin

 

If you disconnect the battery (just remove the +ve terminal) for an hour or 2, the ECU will forget the accumulated information from all the fuel (good and bad) that you have been using. The theory is that it will have adjusted to the worst fuel you have been using and will take many tankfuls (if ever) to readjust to Optimax. By resetting, it will start to learn immediately the best timing for Optimax when you start up after the reset.

Check out the SIDC FAQ (http://www.sidc.co.uk/faq.htm) where theres more info

 

Hang on a second...is the question that you would notice a difference using optimax compared to SUL (assuming you did what your dealer said)?

To be honest I can't tell the difference - if anything SUL seems to make it run that wee bit smoother. The car is too rapid anyway to notice any real difference.

I did read somewhere that anything above 97 ron makes buggerall difference on a uk car, although I would like someone to verify that...

 

MY my 2000 uk seems to run smoother on optimax and has a slightly lower engine note, Dont know about performance. But my garage mechanics reckon you'll get a little xtra oomph out of it, though obviously only a teeny bit.

Cal

 

What difference in performance and power you'll get between SUL and Optimax is more likely to be a placebo effect - so very little, if any. Only way to know is for someone to fill the car with either SUL or Optimax at different intervals (without you knowing) and see if you can spot the difference.

I doubt you'd spot it on pure performance. More likely to spot a smoother or rougher running engine than any extra BHP.

What I have noticed is that my car activates my knocklink much more often on something like BP SUL than it has ever done running Optimax.

So, I would say the benefit may be a greater protection from detonation running Optimax than SUL, but you'd need to have a Knocklink and it may vary from car to car.

It made me realise that I should stick to Optimax on my car anyway.

Stefan

 

Without a doubt, optimax performs better than 95 Ron normal unleaded.
However the differnce is very small but if we were to have 100 ron over here and you compared that to our 95 ron then you would notice the difference indeed.
As my car is jap spec Optimax is a must and add some NF Race formula to that and it just gets better.
If running on a higher octane was a load of rubbish then why do they sell so much octane boosters.
Putting a higher ron fuel in a car that is configured in such a way to take and use the benefits of the purer 100 ron fuel simply outway a car configured to run on 95 ron.
This explains a little why the jap spec is faster than UK.
The ECU is programmed from the outset to make the most of 100 ron where as UK spec is configured for 95.
You aint gunna get 100BHP+ from it but it wont hurt your car either so i would recomend it.

[Edited by DJ WATTS - 10/17/2003 1:52:57 AM]