which gas do you really need to put in. 87 or 89, its a pure stock car with nothing done to it.

 

regular.
no need to put high octain in a stock car

 

87 octane or 85 in denver type elevations. anything higher than 87 is a waste ans will reduce power output

 

Not to be a thread *****, but how come you will lose power by putting in a hight octane?

 

Per the owner's manual on my '99 LX sedan, page 156:

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Gasoline
Your Honda is designed to operate on unleaded gasoline with a pump octane number of 86 or higher. Use of a lower octane gasoline can cause a persistent, heavy metallic rapping noise in the engine that can lead to mechanical damage...</TD></TR></TABLE>

 

higher octane fuel is more resistant to detonation and burns slower so one has to adjust the timing approperiately. The J30a lacks a knock sensor and the I4 cannot use it to advance the timing when you put in higher octane fuel.