Hi Guys and gals,

I was thinking as I was driving around the other night wondering how do you adjust a map for a lower or higher RON fuel ?

To me it seems like you must just map lower spec due to less RON which means easier det. ie: How come someone can take a JDM STI7 which is meant to run on 100RON and map it for 98RON while at the same time increasing the BHP ? Does the decat zorst play a role in this ? Surely just upping the boost, timming, etc requires more RON. I know I really don't have a clue about these things I am just curious for a little insight.

Obviously there is not a 'variable' in the maps for 'RON FUEL USED' so really when someone says they are mapping your car for 98 RON or a lower RON fuel they mean that they are adjusting other parameters to account for the lower RON....what are these paramaters ?

Any help on this would be appreciated...trying to learn as much as I can about my car :D

Cheers,
Ray

For lower octane you retard timing, add more fuel and reduce boost. But any one of the three can also work. Depends on how much lower the octane is.

For a given octane there are a few sweet combos of timing, fuelling and boost. You can usually get more power even on lower octane by increasing boost and retarding timing. But you can go too far with the boost for the octane and you just cause high EGTs and end up with really retarded timing. Then you have no more power and just a less safe map.

Thanks John,

So I guess to really extract more power from a already high strung JDM STI-7 that is running on 98RON vs. the ideal 100RON you would first need to perform a decat (to help EGT's so you could up the boost) as the timing will have to be retarded to adjust for lower fuel ?

Obvioulsy you can do other things such as front mount etc...

One thing I don't understand is that my JDM STI7, (fully decatted but not remmaped yet, in the process :D ) runs very sweet(from what I can tell and I think you have seen my deltadash logs as well) and VERY RICH on regular 98 RON. I always have postive knock correction etc etc.... in other words it almost looks like my car was designed to run on 98 RON, or maybe I would be getting even more positive knock correction with better fuel and hence more power ? Why is it running so rich and so much advance if it is running on 98 RON when it should be 100 RON ? I don't use octane booster as I can't seem to find the good stuff here or in the USA. The best I can get is Super 104+ booster which is only like 1/2 a RON point when added to 98 RON gas.



Cheers,
Ray :D

[Edited by Razor2001 - 3/14/2003 1:14:33 PM]

bttt :D