Jump to content
SAU Community

Recommended Posts

Taken from: http://www.leesracing.com/articles/a1.html

Research Octane Number (RON)

is measured under mild conditions and is more important in controlling part throttle knock.

Motor Octane Number (MON)

is measured under more severe conditions and is most important for octane satisfaction at wide open throttle.

Anti-Knock Index (AKI)

is the average of the RON and MON. This is the number posted on the retail gasoline pumps normally indicating 87, 89, or 92 octane. Racing gasoline have AKI's from 100 to 118

Taken from Wikipedia: http://en.wikipedia.org/wiki/Octane_rating

The most common type of octane rating worldwide is the Research Octane Number (RON).

Edited by MintR33
  • Replies 42
  • Created
  • Last Reply

Top Posters In This Topic

It's up to your car to tell you which fuel it's gonna like best.

For example, i run Caltex Vortex 98 and BP Ultimate. The car runs like a dream on BP but its halfway across the city for me to get a tank, so it doesnt see it much.

Caltex Vortex it runs fine on, no complaints, the knock sensor never shows knock when giving it a bootfull.

Shell Optimax however has given me some cases of knock when booting... alot of people say that optimax is good to reduce knock and shit but i guess it all depends on your car, because it didnt reduce knock on mine.

So just try a fresh tank of them all and decide for yourself.

It's up to your car to tell you which fuel it's gonna like best.

For example, i run Caltex Vortex 98 and BP Ultimate. The car runs like a dream on BP but its halfway across the city for me to get a tank, so it doesnt see it much.

Caltex Vortex it runs fine on, no complaints, the knock sensor never shows knock when giving it a bootfull.

Shell Optimax however has given me some cases of knock when booting... alot of people say that optimax is good to reduce knock and shit but i guess it all depends on your car, because it didnt reduce knock on mine.

So just try a fresh tank of them all and decide for yourself.

Hi Justin, where are you located?

:P cheers :dry:

always used bp ultimate around my local, could feel a difference and per tank of gas got further on avg, real numbers

filled in parra @ teh wooly's station as was getting onto empty line thanx to misses picking me up an not gassing up ^^ best tank of fuel ever, best price was packed cuase tehy sell cheaper than everywhere. the fact that shite loads of fuel goes through, "fresher" fuel maybe, less time swishing in tanks with the added station mixers ? eh eitehr way, went the furthest ever, like freakishly better, no a single frigging nock and 200k's to less than half tank, when i get 300k's on avg per tank.

97 s2 stocker with cat back, mod suspension and a quickshift kit

you mean this link??

http://www.skylinesaustralia.com/forums/in...treme&st=20

From SydneyKid

"A/F ratios are based on weight, not volume, hence the need for specific gravity of the fuels.

Moving on...............we have a new project car, an R33GTST that is in need of some TLC. One of the recent upgrades was a Power FC. As most people are aware, the default ignition maps are a little advanced for Optimax, Ultimate or Vortex 98. Not as bad as they used to be for 95 ron fuels, but still a tad. Obviously I will tune it properly eventually , but we have a few mods to go yet and I don’t have the time to tune it multiple times. So the idea was to stick the Power FC in and run it on the default maps for a couple of weeks. On Optimax and Ultimate (didn’t try Vortex) it was reaching knock of 60+ up our usual test hill in 4th gear as logged on the datalogit. The dash warning was also flashing frequently, as it is set for 60, in normal day to day driving around. When the tank was just about empty this week, we filled it up with Optimax Extreme (@ 5 cents a litre more than Optimax). Several runs up the hill and we are not seeing knock over 10. And zero dash warnings in 3 days of normal driving.

Now that is very worthwhile, there is not enough Optimix Extreme around yet for me to tune it exclusively for 100 ron, but it sure will be a useful for the odd track day or run down the ¼.

I will monitor the effects of the ethanol on the fuel lines, o’rings and seals over the next few weeks. The injectors and fuel pump will have to come out shortly so I will check their condition as well. I am not anticipating any problems, but it is still worth checking.

cheers:)"

Hi Justin, where are you located?

;) cheers :happy:

Hey SK,

I'm in Canberra. I havent tried Optimax extreme or whatever the ethanol one is, but the optimax 98RON. I filled up a popular servo in my area so i'm going to assume it was pretty fresh.

I found it strange that i saw knock with it when all i've heard people say is that it will reduce knock.

If your car is stock I see no reason why you cant use any 98 RON fuels. If its modded then probably BP Ultimate is good.

My car is stock I mainly buy Optimax when I have 4 cent discount vouchers from Coles and BI LO or get Ultimate. I run Ultimate every second or third tank anyway.

I also use Mobile 8000 Synergy but very rare.

220-250k's to a FULL tank is doing well on bp ultimate, vortex 98 from popular stations seems the go 400+k's, stuff al back fires and much less overfueling like my car isnt running on the safe map, there are no popular bp servo's in sydneys west, everyone goes the cheaper fuel proly why i can get decent vortex, 4c off aye.

anyways the vortex "seems" to drive better,

thats real odd.......

whats the difference between vortex and ultimate performance wise....anyone tried?

im gonna fill up my next tank with vortex...ill see how it goes

well I tried most high octane fuels in my r33, such as Mobil premium, Optimax, Ultimate, And i felt that when i startyed using Vortex98 my car ran alot better, more perfromance, more km's out of a tank, and alot less backfire(hardly any at all). I would strongly reccommend Vortex, but by the looks alot of different people cars run better on a range of fuels. My advise would be to try them all! see how you go.

Yeh bro just put fawken good old leaded in there she be right. Car might cough and fart bit ay heh but she be right, then just chuck bit of supercheap carby cleaner through intake every 500k's or so car should run sweet. >_<

Todays prices i think our only choices is to use the 98 octane. I havent noticed difference between BP and vortex

Edited by siiick

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Did this end up working? Did you take some pictures?
    • And finally, the front lower mount. It was doubly weird. Firstly, the lower mount is held in with a bracket that has 3 bolts (it also acts as the steering lock stop), and then a nut on the shock lower mount itself. So, remove the 3x 14mm head bolts , then the 17mm nut that holds the shock in. From there, you can't actually remove the shock from the lower mount bolt (took me a while to work that out....) Sadly I don't have a pic of the other side, but the swaybar mounts to the same bolt that holds the shock in. You need to push that swaybar mount/bolt back so the shock can be pulled out past the lower control arm.  In this pic you can see the bolt partly pushed back, but it had to go further than that to release the shock. Once the shock is out, putting the new one in is "reverse of disassembly". Put the top of the shock through at least one hole and put a nut on loosely to hold it in place. Put the lower end in place and push the swaybar mount / shock bolt back in place, then loosely attach the other 2 top nuts. Bolt the bracket back in place with the 14mm head bolts and finally put the nut onto the lower bolt. Done....you have new suspension on your v37!
    • And now to the front.  No pics of the 3 nuts holding the front struts on, they are easy to spot. Undo 2 and leave the closest one on loosely. Underneath we have to deal with the wiring again, but this time its worse because the plug is behind the guard liner. You'll have to decide how much of the guard liner to remove, I undid the lower liner's top, inside and lower clips, but didn't pull it full off the guard. Same issue undoing the plug as at the rear, you need to firmly push the release clip from below while equally firmly gripping the plug body and pulling it out of  the socket. I used my fancy electrical disconnect pliers to get in there There is also one clip for the wiring, unlike at the rear I could not get behind it so just had to lever it up and out.....not in great condition to re-use in future.
    • Onto the rear lower shock mount. It's worth starting with a decent degrease to remove 10+ years of road grime, and perhaps also spray a penetrating oil on the shock lower nut. Don't forget to include the shock wiring and plug in the clean.... Deal with the wiring first; you need to release 2 clips where the wiring goes into the bracket (use long nose pliers behind the bracket to compress the clip so you can reuse it), and the rubber mount slides out, then release the plug.  I found it very hard to unplug, from underneath you can compress the tab with a screwdriver or similar, and gently but firmly pull the plug out of the socket (regular pliers may help but don't put too much pressure on the plastic. The lower mount is straightforward, 17mm nut and you can pull the shock out. As I wasn't putting a standard shock back in, I gave the car side wiring socket a generous gob of dialectric grease to keep crap out in the future. Putting the new shock in is straightforward, feed it into at least 1 of the bolt holes at the top and reach around to put a nut on it to hold it up. Then put on the other 2 top nuts loosely and put the shock onto the lower mounting bolt (you may need to lift the hub a little if the new shock is shorter). Tighten the lower nut and 3 upper nuts and you are done. In my case the BC Racing shocks came assembled for the fronts, but the rears needed to re-use the factory strut tops. For that you need spring compressors to take the pressure off the top nut (they are compressed enough when the spring can move between the top and bottom spring seats. Then a 17mm ring spanner to undo the nut while using an 8mm open spanner to stop the shaft turning (or, if you are really lucky you might get it off with a rattle gun).
    • You will now be able to lift the parcel shelf trim enough to get to the shock cover bolts; if you need to full remove the parcel shelf trim for some reason you also remove the escutcheons around the rear seat release and you will have to unplug the high stop light wiring from the boot. Next up is removal of the bracket; 6 nuts and a bolt Good news, you've finally got to the strut top! Remove the dust cover and the 3 shock mount nuts (perhaps leave 1 on lightly for now....) Same on the other side, but easier now you've done it all before
×
×
  • Create New...