hey I was woundering if I can put 100 octane will it mess with my tuning of the hondata? cause the tuning was done on 91 octane

 

well if its tuned for 91, why put in 100? it isn't going to give you any gains unless you car can adapt to that, i don't think it does though

so it might be wasteful to put 100 octane in there

 

the tuner has to make a whole other map for race gas. it changes the timing by using a higher octane, so i wouldn't use it until you get it tuned for it.

 

how does higher octane change ignition timing?

 

different octanes have different rates of burn speed

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ChrisRicketts &raquo;</TD></TR><TR><TD CLASS="quote">the tuner has to make a whole other map for race gas. it changes the timing by using a higher octane, so i wouldn't use it until you get it tuned for it.</TD></TR></TABLE>

No it does not. Higher octane has a slower burn therefore it allows you to advance your timing safely.

If you are tuned for 93 and run 100 you will be fine.

 

You have a wealth of knowlegde.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PrecisionH23a &raquo;</TD></TR><TR><TD CLASS="quote">

No it does not. Higher octane has a slower burn therefore it allows you to advance your timing safely.

If you are tuned for 93 and run 100 you will be fine.</TD></TR></TABLE>

ok, i stand corrected. but i don't see that running 100 is going to give you much profit other than decrease your chances of detonation a bit right?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ChrisRicketts &raquo;</TD></TR><TR><TD CLASS="quote">

ok, i stand corrected. but i don't see that running 100 is going to give you much profit other than decrease your chances of detonation a bit right?</TD></TR></TABLE>

Not always. Many times when a vehicle is tuned on street gas, just putting race fuel will give quite a noticable difference. Now remember, we are talking fully built cars. Just putting 100 or C16 into your stock or nearly stock car wont really do anything but waste money.

 

If the car was equipped with a knock sensor, wouldn't it advance the timing some if it were running higher octane?

 

the ecu controls timing.....just cuz you add some octane to slow down the burn speed doesnt mean the ecu is gonna know that there is any increase and change the timing.

 

Sure it would, in a way I think... On cars with knock sensors the ECU is always keeping the timing advanced to the point where it doesn't knock. If you add more octane, the ECU would advance the timing a little bit more since the fuel would be less prone to knocking, right?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by The_Head &raquo;</TD></TR><TR><TD CLASS="quote">Sure it would, in a way I think... On cars with knock sensors the ECU is always keeping the timing advanced to the point where it doesn't knock. If you add more octane, the ECU would advance the timing a little bit more since the fuel would be less prone to knocking, right?</TD></TR></TABLE>

not if you are OBD1 like most 4th gens are, timing is advanced manually.

and also, the other ecu's can advancing timing, but only by so much. some say putting more than 91 octane in 4th gens doesn't matter. in 5th gens, i know you can put a little higher but their still is a ceiling to where the octane doesn't matter and the ecu cannot compensate. i want to say in the 95 range but i'm sure someone will know the right answer.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by The_Head &raquo;</TD></TR><TR><TD CLASS="quote">Sure it would, in a way I think... On cars with knock sensors the ECU is always keeping the timing advanced to the point where it doesn't knock. If you add more octane, the ECU would advance the timing a little bit more since the fuel would be less prone to knocking, right?</TD></TR></TABLE>

If the car is not knocking with 93, it will run the exact same timing with a higher octane fuel.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by petern101 &raquo;</TD></TR><TR><TD CLASS="quote">

not if you are OBD1 like most 4th gens are, timing is advanced manually.

and also, the other ecu's can advancing timing, but only by so much. some say putting more than 91 octane in 4th gens doesn't matter. in 5th gens, i know you can put a little higher but their still is a ceiling to where the octane doesn't matter and the ecu cannot compensate. i want to say in the 95 range but i'm sure someone will know the right answer.</TD></TR></TABLE>

What you mean is you can set your BASE timing with obd1 and not obd2. It doesnt matter what obd you are, a knock sensor will always pull timing if it is programmed to when it senses detonation.

 

doesnt matter what octane you run.....as long as there is no knocking, there will be no timing adjustments made.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98vtec &raquo;</TD></TR><TR><TD CLASS="quote">doesnt matter what octane you run.....as long as there is no knocking, there will be no timing adjustments made.</TD></TR></TABLE>

short and simple answer.