As you may recall I've been experimenting with SUL/Optimax. I recently put a tank of optimax back in and hated it...considered getting a pipe, bucket and a packet of 'XXX' mints to get that sh1te out of there! I then stuck SUL back in and it was all round.

However, as it happens I was with John Banks today in fairly cold conditions and from looking at the delta-dash he knew what fuel I was running (SUL) as it was more prone to det - he noticed this without us discussing fuel at all.

All this seems to confirm what was said in the previous thread that whilst SUL will give you more power the compromise is that its more prone to det. I'm now running fractionally less boost than what I could probably run with Optimax but it still faster IMO than what it would be at the higher boost.

Basically IMHO:

If det is a problem then use optimax.

If your not so close to the det limit then use SUL.

If you want the best from your car use SUL with an octaine booster so that you get lots of power and good det resistance.

If your a cheap git use supermarket 95 RON or cooking fat

Hope these findings are of some use to someone

 

http://www.scoobynet.co.uk/bbs/threa...hreadID=159066

Those are the first findings for those that are totally

 

thanks for this kenny

SUL and OB it is for me then

also glad to hear that optimax is 'safe'

 

No probs phil My test have not been particularly scientific and have depended a lot on how the car feels. The car didn't det on SUL but it was a little closer to it. As always, if your car runs like a bag of sh1te on a fuel that mines likes then maybe its not for you.

I would point out my car runs far smoother on optimax......but its boring

 

Saxo boy,

Interesting test, but how did you notice the car detting? Did you have det cans on?

 

It wasn't detting on SUL....John has previously set up my car on Optimax on a far warmer day than yesterday. When we were out with the laptop plugged in he hummed and asked what fuel I had in. The car wasn't detting on the SUL but it was pulling the ignition timing more than it did with the Optimax. Without me telling him John knew what fuel I was running just by the delta-dash logs.

I don't use octaine booster but will continue to use SUL. If I have any track/crail days or know that I'll be booting it in hot weather (a summer subaru meet for example) then I'd fire in some OB to be super-safe.

 

Knock retard was from 0.5 to 3.5 degrees coming onto boost - with Optimax previously there was none.

You would be better reducing your boost Kenny if you attended a meet in the summer. My recommendation as per my website is about 16.5 PSI. Retarding the ignition more is not going to work - will just raise the EGTs, and it is already rich. Excessive boost on the small turbo is the issue.

I still say you need a knocklink with your setup. And preferably a TD05

[Edited by john banks - 12/29/2002 12:56:13 PM]

 

Understood John. I usually don't push the car for long anyway. My typical back road jaunts will involve a ratio of 1 minute of hardcore driving to every 2 minutes of slow cruising to allow the brakes and turbo to cool down. I'm a big ***** really

Re: TDO5! I've seen a few of these crop up in 'for sale' every now and again....what is if I bought one what is involved (costs) in getting it to fit an MY99? What turbo do you have john?

 

Speak to Mark Aigin at www.lateralperformance.co.uk about a front entry TD05 conversion, or maybe Andy F would do one for you - you'd have to see if he was up for it, after all he has popularised it (although Pat had done it previously). They are about £500-600 I gather including a second hand but rebuilt TD05 with all new bearings, seals etc. My turbo is an MD304 VF hybrid, but the cost would be double that. Personally I would strongly consider the TD05 and I will be interested to see how it compares to my turbo when a good friend gets his TD05 on.

In addition you would need an uprated fuel pump, fuel pressure regulator and a knocklink. About another £350. You could also convert to a 3 port solenoid for about another £40 for more reliable and better boost control.

Plus fitting of the bits (about 4 hours labour at Star performance), and remapping.

With your STi intercooler and pipework you would probably end up with about another 20% power on top of what you have now, which is probably about 20% on top of standard.

You wouldn't race hot hatches after that

[Edited by john banks - 12/29/2002 2:37:59 PM]

 

Cheers for that John....I'll add this thread to my favourites cause it'll be quite some time before I've saved up for that little lot

 

Sorry, I am a young car fan, as many regulars may know by know? I know very little about fuels. What exactley is SUL and where is it available?

Ian

P.S. Please don't tell me it is standard unleaded or summit like that because i will feel really thick!

 

super unleaded..!

Dan

 

Shell un-leaded but use optimax

 

Cheers

 

sul = Super Un-Leaded

 

Wow, where did this thread come from A few months on and I still swear by SUL over Optimax although I might put and tank of Optimax in soon for cleaning purposes

 

getting the maximum power from a fuel means running as close to det as possible. SUL is lower octane and will det quicker, you could probably replicate the power increase with octimax by increasing the advance on the plot to take account of the slower flame front, and releace a few more bhp. Is a few bhp worth the risk?????????????????????

 

Thanks for all that Kenny-interesting and useful.

Les

 

John B - my secs reads up to 11 degrees of knock retardation at WOT in 1st /2nd from the ecu, from seeing the values you've just posted, is that really bad???

 

Postive knock correction is advance, and a good thing on a new age car, you expect it to be doing this.

 

phew

I got very worried for a second there, I'm glad your answer was so swift

Knocklink goes in later this week hopefully.

cheers

 

Just to confirm - so if I see negative degrees then i need to back off? Also what is a really low lambda reading, out of interest? IE where you'd start worrying.