I've tried both in my ZTS and haven't noticed any difference in power or mpg. I think that the stock computer just isn't designed to take advantages of premium.

 

waste of money... only need to use Premium fuel is if you have Forced Induction or a Chip for the ECU....

btw, this should be moved to Team Tech....

btw,btw, I wanna be a Moderator!!!!!!

 

I run middle (whatever... 89?) because when I run 87 I get a CEL!

It solved my CEL problems for the first 5k miles, but it came back... Guess I gotta take it in.

 

87 all the way. The extra octane isn't needed, and could harm your engine.

 

Most gas stations buy 87 octane gas from wholesale companies that use additives and the quality is very poor. but companies like mobil and texaco must buy their own brand of premium gas.

If you live in an area that the temperture is in the 30's you may want to buy at least 91 octane gas since these cold tempertures will raise the level of alcohol in the gas and the octane potency will decrease.

I did notice my car running better with premium before I even started any modifications.

George

 

I used to use the cheap cheveron then one day I started using 91, I noticed a diffrence. Also my friend was telling me that if you have a pinging sound and you can feel it when you accelerate and stuff it's because you need to run better gas. I'll pay the extra 20 cents or what ever it is for 91 though!

 

Search in Zetec tuning as this issue has been discussed in depth. In short, your ignition timing was calculated with the burnrate of 87 octane in mind. Higher octane fuels contain longer hydrocabon chains which burn slower, leading to incomplete burn resulting in slightly lower fuel economy, lower power, and deposits that forum in the combustion chamber. These deposits can create hot spots that neccessitate the future use of high octane fuel (essentially you become a high octane junkie). If you want to run high octane fuel, you need to get a chip like the Diablo that advances the timing... otherwise you aren't so much throwing away money as you are damaging your engine. And it is federal law that all octane fuels (lowest to highest) contain detergents. The 'regular, super, and supreme' labels rather than octane ratings are just a marketing gimic to sell more expensive and profitable fuels.

[ 01-07-2002: Message edited by: Ducman69 ]</p>

 

Nothing but regular fuel for me. However, I only feed it with one brand "Mobil or Exxon, they are the same". I read an article before that by doing this, it's good for your car?

 

does not seem to make a difference in my car but running Sunoco gas over any other brand gives me an extra 5mpg and as much as 12 more[mpg] on the highway

 

I use 87 octane Citco gas at the 7-elevens around town. I researched the types of gasolines used by different Focus owners before I purchased my car and i saw, at the time, alot of people used Sunoco, Mobil or Citgo. I used Union 76 and Chevron gasolines before but they seemed to bog my car down.

 

in some magazine (either Motor Trend or C&D) about 2 months back, they did an experiment on cars in various categories, and they used a 4-cyl accord in which anything over 89 didnt do squat, and i believe in one of the cars (sorry for my forgetfulness) the higher octanes actually produced lower HP numbers... anyone remember this article? sorry the magazine is at work so i cant be more accurate heheh

 

Read the post in this thread about 2/3rds of the way down by CAJUN; the man knows his stuff.
http://www.teamfocaljet.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=2&t=004806

 

Moving to Focus Tuning

 

I have cams in my car, and race headers and stuff like that that give me 140 whp. Now some of my friends here said that I should be running Sonoco 94 just to prevent knocking or pinging.

Now, from what you guys are saying, I might be hindering performance since I don't have a chip yet?

No wonder I get NO GOOD, DISGUSTING gas mileage!

So what do you guys think? Go back to 89 maybe until I get the chip next month?

 

Unless you've changed the compression ratio or ignition timing in your car (cams, header, etc aren't doing that for you), you are essentially just increasing the volumetric efficiency... I don't see why you would want to run 94 with that.

Get some fuel system cleaner (remember to get the concentrate and put it in on an empty tank) and run the required octane. I'd still run 87, but if you are worried about extreme weather conditions or something, you could go with 89. Chip to advance your timing is a good idea though, and it'll help you pick up a little power since you don't mind paying for higher octane fuel. Might get rid of any flat spots in the engine too (sometimes manufacturers tune in a especially lean narrow RPM range for emissions and mileage considerations... felt like around 3K rpm on the stock car).

[ 01-08-2002: Message edited by: Ducman69 ]</p>

 

In the UK it's 95 octane or 98!

I worked with fuels in the past (Ph.D. chemist) and I say you should stick with higher quality fuels. They tend to put additives in that help clean the entire fuel / engine system, prevent corrosion and mop up water condensation etc, there's all sorts in there.

I don't know much about engines but as far as fuel and oil are concerned you get what you pay for! Try and use a well known brand.

 

DUCMAN69---Funny you should say that about the Flat spot, on my dyno chart, you can VERY CLEARLY see a flat spot at 3000rpm.

Hmmmmmm, I dunno what to do. I mean, I don't think the car will be knocking or pinging, I didn't do anything to the spark timming.

I think I will try it out, and use 89 Octane next time. That should be good right?

 

Jay, don't expect any results until after a few tanks have gone through the system. Make sure you get a couple good highway runs in as well.
Remember our fuel gets the formula adjusted based on the seasons as well. A bit more ethanol or whatever this time of year no matter what the octane rating. I'd go right back to the 87.

A

 

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>The 87 from the same company, ie, Mobil, would have the same detergents and additives as the 93.
<hr></blockquote>
By US federal law, this is true. I used to think the same thing, that hte additive packages were superior in their higher octane fuels. But HatchbackInBlack, I believe Alkemist was differentiating between the different manufacturers (Exxon vs SuperStop). Thats why he mentioned using a well known brand. I think thats right in that some of those no name crap gas stations really use poor bottom of the barrel fuels with subpaar containment and delivery facilities compared to the major stations (and I'm sure that Texaco additives might vary slightly compared to Shells and so forth).

BTW, I'm not sure if you are familiar with this but there are different measuring standards for octane in the US and Europe. There is RON (research octane number) and MON (motor octane number). In the US, the average of the two is taken (RON+MON/2... check it out as its usually written on the pump); so as an example the ROV 87 pump gas that we pick up at the station would be 82 MON and 92RON. I believe that in the UK, only a pure RON octane rating system is used. Your 98 RON octane is most likely very similar to our 93 RON+MON/2.
<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Although i am utterly unconcerned with the pinging, I<hr></blockquote>
You should be... pinging can cause serious long term engine fatigue, and in extreme cases engine failure (just see what happens when turbokits are operated with non-existent or non-functioning supplimental fuel systems).

If you are pinging, you need to either go to a higher octane fuel or have the timing scaled back a bit.

There are those octane boosters you can find everywhere. But I haven't heard from anyone that noted they actually worked well at increasing the octane rating. P-51 knows more about them, but from what I've read... they should be avoided. Plus, its only a temporary solution anyway.
<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>I think I will try it out, and use 89 Octane next time. That should be good right?<hr></blockquote>
I'd go back to 87 octane after flushing your system with the fuel injector cleaner I mentioned (not sure if it does much for the rest of the combustion chamber). If you aren't pinging with that octane, you've found the proper octane rating. If you are, put in 89 in the next time (your knock sensor will automatically retard the timing for that tank of gas if it notices knock... and you should be able to hear it just before and feel the slight power drain right after). I could see how it is possible to lightly ping with a lot of mods (even w/o timing or compression changes) if you lived in a really hot climate and had a non CAI. But as I was saying... go back to what the engine was designed for (87 octane) and if you have no problems then you've got what you need.

Saves money and overall better for performance.

[ 01-08-2002: Message edited by: Ducman69 ]</p>

 

Down in Turkey, the only unleaded fuel available is 94 (or 95, cannot remember exactly)

I believe this is the case through out Europe as Superchips claim to be optimised for "common europen high quality fuel" in their adds here...

And allmost all the companies (Shell, Bp, Opet, and locals) claim to have power and milage increasing additives (like VPover from shell, SuperX from BP, FullForce from Opet etc.)And they state up to %10 savings (which I had never personal vitnessed)

The only good gas I have found to work with my Focus is from a local company, PO...I guess they add exactly what's needed for local conditions.

 

Thanks Duc, I am almost Empty, and I will be sure to try going back to 87 Octane.

It is not warm here right now. about -4 degrees Celcius, I dunno what that is in Farenheit, Damn americans!

haha

So I will try it and see what happens. I do plan on getting the chip, so I will increase octane only then.

Thanks

 

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by Jays2000ZX3:
I am almost Empty<hr></blockquote>

Jay, You should try to keep your tank topped up this time of year as well to reduce condensation.

C to F: C*9/5+32=F (-4*9/5+32=24.8)

 

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by 2001 ZTS:


Jay, You should try to keep your tank topped up this time of year as well to reduce condensation.

C to F: C*9/5+32=F (-4*9/5+32=24.8)<hr></blockquote>

YEah, well, I am from the north, and it is usually REALLY cold up there so this little bit I am not really worried about my gas freezing.

AND I am switching back and forth in Octane levels, I mean, I don't want to put 87 in there, if there is a lot of 94 left. Ya know?

 

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by Jays2000ZX3:
I am not really worried about my gas freezing.
<hr></blockquote>

Thats not the problem. When you go from a warm humid garage out into the dry cold air, that 40+L of air in your gas tank has a lot of moisture in it which will condense each and every time you go through one of those warm to cold cycles. Just a few drops of water at a time can add up!

 

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by focalBlur:
does not seem to make a difference in my car but running Sunoco gas over any other brand gives me an extra 5mpg and as much as 12 more[mpg] on the highway<hr></blockquote>

So, if you're getting 28 mpg on Brand X you get 40 mpg on Sunoco? Come on, man.