Hi thanks for visiting my post, for the past 2 years I have been running 92 octane on my si and since the price is going up, I am trying to save some money. So I was wondering if anyone knows if Si's will be able to run on 89 octane without any problems? (My prelude is bare bone stock) Thank you for your help / advice .

 

I wouldnt do it. The engine is built to run on premium because the octane rating basically decides how early/late the gas detonates and the lower the octane rating the quicker it will burn so you might get early detonation or other issues. If you think about it its really not that much more maybe $4 at most a tank to fill up with premium instead of regular just do what the manufacturer says and it will save you money in the long run with repairs.

 

Premium!

 

Awesome, Thanks guys for your input.

 

you have an h23. You can run whatever octane you want.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98vtec &raquo;</TD></TR><TR><TD CLASS="quote">you have an h23. You can run whatever octane you want.</TD></TR></TABLE>

I agree. If you are not trying to get the absolute best performance out of your stock H23 then I would imagine mid-grade and regular will work just fine. The engine does have a knock sensor to retard the timing if any knocking does occur.

 

H23s require premium too. Ive run 89 in mine when I had one. Youll get good gas milage but it WILL ping in higher RPMs. If you use lower grade gas I wouldnt take it over 4K.