whats the highest compression you can go on 89oct.?
 

i have a turbo civic(which takes 91oct or higher) 91oct is highest oct. pump gas in ca.(atleast where im at). Im kinda leaning towards all motor for my obd-1 crx with a d16z6.....but i dont want 3 cars(also have another f.i. car) that all run on 91oct with the price of fuel.

im wanna build a mild all motor z6
(zc pistons,z6 rods, arp rod bolts and head bolts, i have dual springs already, spring's,and a cam) maybe spray nitrious(not in near future) when i race.

also i know a good tune is important.


so roughly how high of compression could that motor safely handle on 89 oct?

(also the car will be daily driven to work maybe 20 miles round trip)

Re: whats the highest compression you can go on 89oct.? (hatchinprogress)
 

ttt

Re: whats the highest compression you can go on 89oct.? (hatchinprogress)
 

Well you could run super high compression on 89, but you'd have to take out so much timing to keep the motor from pinging under load, it would defeat the purpose of high compression altogether.

To answer your question, I'm going to throw my opininon out there and say 11.0:1. It depends on alot more stuff though, you know?

91 costs only 5% more than 89 here. *shrugs*

Re: whats the highest compression you can go on 89oct.? (The_Head)
 

the highest to run on pump gas w/o a tune i would say 11:1 cr. or 10.8 to stay within stock numbers CTR/ITR.

Re: whats the highest compression you can go on 89oct.? (hatchinprogress)
 

have you ever consider keep one car stock?

Re: whats the highest compression you can go on 89oct.? (Turbo9Nut)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Turbo9Nut &raquo;</TD></TR><TR><TD CLASS="quote">have you ever consider keep one car stock? </TD></TR></TABLE> yeah thats what my beater is for (stock '91 dx) https://honda-tech.com/forums/images...es/emsmile.gif

I run a bit over 11.5:1 on basically 90 octane, so I would hazard to guesstimate 11:1 is doable on 89, but you will not be able to run full stock timing.

My $0.02

Re: (X2BOARD)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by X2BOARD &raquo;</TD></TR><TR><TD CLASS="quote">I run a bit over 11.5:1 on basically 90 octane, so I would hazard to guesstimate 11:1 is doable on 89, but you will not be able to run full stock timing.

My $0.02</TD></TR></TABLE>about how much should i retard the timing?

I meant with stock timing at least... 11:1

with a d16A6 head and d15b2 (flat PM3 pistons coming out of the deck about .028") i ran 87 octane, full timing and as lean as 18:1 air fuel ratio without audible knock in any gear. it was around 10.2:1 compression and i could be in 5th going like 40mph at 1500, hold it in full throttle and still no marbles in a coffe can. it had exceptional low rpm torque. just the pistons, valvejob, some porting, kamikaze header and 2" exh.

if i were you, id try the PM3's first.

Re: (mike_belben@yahoo.com)
 

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

if i were you, id try the PM3's first. </TD></TR></TABLE>but i allready have a set of zc pistons (came from my dohc zc, so there free)

PM3's are in every 1.5L dx and civic STD from 88-95. theyre pretty free as well, and i personally feel your results concerning minimal octane will be better.

Re: (mike_belben@yahoo.com)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mike_belben@yahoo.com &raquo;</TD></TR><TR><TD CLASS="quote">PM3's are in every 1.5L dx and civic STD from 88-95. theyre pretty free as well, and i personally feel your results concerning minimal octane will be better.</TD></TR></TABLE>hmm thinks for the info https://honda-tech.com/forums/images/smilies/emthup.gif

Re: whats the highest compression you can go on 89oct.? (hatchinprogress)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hatchinprogress &raquo;</TD></TR><TR><TD CLASS="quote">i have a turbo civic(which takes 91oct or higher) 91oct is highest oct. pump gas in ca.(atleast where im at). Im kinda leaning towards all motor for my obd-1 crx with a d16z6.....but i dont want 3 cars(also have another f.i. car) that all run on 91oct with the price of fuel.

im wanna build a mild all motor z6
(zc pistons,z6 rods, arp rod bolts and head bolts, i have dual springs already, spring's,and a cam) maybe spray nitrious(not in near future) when i race.

also i know a good tune is important.


so roughly how high of compression could that motor safely handle on 89 oct?

(also the car will be daily driven to work maybe 20 miles round trip)</TD></TR></TABLE>

Static compression ratio is not directly related to what Octane fuel is required. A higher static compression ratio engine will need more intake cam duration so the point of the intake valve closing is later thus reducing the effective compression ratio to about 8:1, which is about the limit for 89 Octane.