Ok well as you can tell i have D15B with no aftermarket fuel setup all stock.. Well, the guy who I bought the motor off of always used 93 octane and changed his fuel filter like once every 5-6 months or something he said. Also, he said that there was never any problems with the fuel or any of that... Well I've had motor in my car about 10 months, and I've always used 89 "mid grade", so the other day I took my car out to races and i used 93, thinking that "okay well dude before me always used it, its basically stock motor, besides few boltons, whats the damage"... Well now that I've upgraded, the rpms are no longer at 700-850 now more towards 900-1000 on idle.. Car runs perfect, just a little up on rpm's... Switching from 93 to 89 wouldnt harm me in anyway right? Also, are there power differences on diff grades of fuel on basically stock motors..?? And what sort of upgrades should you look into before upgrading?? "fuel pump, rail, injectors, ect... followed by a good tune i suppose, right"?

 

Hey man I have the same engine you have right now. As for your question on running the lower grade fuel there should be no problems. I have a Crx w/about 180,000 mi on it taken to the track a couple of times and ran the snot out of it when i commuted... There is no reason why you should have to use high test. I run 93 in my mustang BC it has higher fuel compression to avoid knocking. There is no real power gain unless the car is built for higher compression. As for your stock motor upgrades... You have a fuel injected carb or dpfi. Just get a new engine, a cheap ZC swap would do nicely no big swaps and start putting on those "upgrades" then.

 

You won't gain or lose anything by running a higher or lower octane. In a way that I can explain, octane is just a number that tells you at what temperature the gas will ignite. High compression NA or turbo applications usually require the use of high octane gas to prevent knocking/pre-det

There's no extra power or anything like that. When I was NA I did run the shell V Power because it was supposed to help clean out the fuel system, but I really couldn't tell any difference.

To run a different octane you don't have to upgrade anything. Fuel pump, rail, and injectors just allow your motor to get more fuel. Since you're mostly stock you don't need more fuel, so your stock fuel system is fine.

 

with higher octane gas, you have the potential to make more power, but only through tuning.

 

Tuning like ECU wise, or tuning motor wise..?? Or tuning motor wise then tuned w/ a Hondata/Uberdata/Crome type of chip..??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM_SOHC &raquo;</TD></TR><TR><TD CLASS="quote">Tuning like ECU wise, or tuning motor wise..?? Or tuning motor wise then tuned w/ a Hondata/Uberdata/Crome type of chip..??</TD></TR></TABLE>

With a stock motor there is no need to run 93, even with the best tune and ignition advanced as far as it can go. There is just no power there.

On a built motor it will make more "power" because you can advance your ignition more without worrying about pre-detnation.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nota-eg &raquo;</TD></TR><TR><TD CLASS="quote">You won't gain or lose anything by running a higher or lower octane. In a way that I can explain, octane is just a number that tells you at what temperature the gas will ignite. High compression NA or turbo applications usually require the use of high octane gas to prevent knocking/pre-det

There's no extra power or anything like that. When I was NA I did run the shell V Power because it was supposed to help clean out the fuel system, but I really couldn't tell any difference.

To run a different octane you don't have to upgrade anything. Fuel pump, rail, and injectors just allow your motor to get more fuel. Since you're mostly stock you don't need more fuel, so your stock fuel system is fine.</TD></TR></TABLE>You will most likely lose a little gas mileage with the higher octane gas.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by amckee &raquo;</TD></TR><TR><TD CLASS="quote">You will most likely lose a little gas mileage with the higher octane gas.</TD></TR></TABLE>
seemed to me like my gas mileage was a lot better using 93.... i switched back to 89 an now it seems like im starting to have issues...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by amckee &raquo;</TD></TR><TR><TD CLASS="quote">You will most likely lose a little gas mileage with the higher octane gas.</TD></TR></TABLE>

Yes, i would like an explanation on how in the hell you would lose gas mileage with higher octane. I was going to be a tool and flame you but im waiting to see why you said what you said.

Octane does have the potential to give you better HP/ gas mileage. Most people say that it only works if you have tuning, i.e. if you use a gsr motor that requires 91 octane you will lose power if you use 89 but not in reverse if you use 91 and you have a d16y8 motor. I know for sure that my d16y8 got about 2mpg more on avg when i used 91 vs 87. As far as octane, i would think that you would gain power, no matter what engine you have because the car could adjust the air/fuel ratio. As far as the amount of gain, that is determined by tuning.

 

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

Yes, i would like an explanation on how in the hell you would lose gas mileage with higher octane. I was going to be a tool and flame you but im waiting to see why you said what you said.

Octane does have the potential to give you better HP/ gas mileage. Most people say that it only works if you have tuning, i.e. if you use a gsr motor that requires 91 octane you will lose power if you use 89 but not in reverse if you use 91 and you have a d16y8 motor. I know for sure that my d16y8 got about 2mpg more on avg when i used 91 vs 87. As far as octane, i would think that you would gain power, no matter what engine you have because the car could adjust the air/fuel ratio. As far as the amount of gain, that is determined by tuning.</TD></TR></TABLE>


Your 2mpg variances are not evidence to warrant the use of a higher octance fuel. You could have lost or gained these changes from weather, driving differences, ect...

As stated above octane is a measure of the fuel resistance to detonation and on a stock d-series you will not, I repeat, will not see any improvements except the extra lightness you will feel in your wallet.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 97ShLude &raquo;</TD></TR><TR><TD CLASS="quote">


Your 2mpg variances are not evidence to warrant the use of a higher octance fuel. You could have lost or gained these changes from weather, driving differences, ect...

As stated above octane is a measure of the fuel resistance to detonation and on a stock d-series you will not, I repeat, will not see any improvements except the extra lightness you will feel in your wallet.</TD></TR></TABLE> WELL SAID

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 97ShLude &raquo;</TD></TR><TR><TD CLASS="quote">Your 2mpg variances are not evidence to warrant the use of a higher octance fuel. You could have lost or gained these changes from weather, driving differences, ect...

As stated above octane is a measure of the fuel resistance to detonation and on a stock d-series you will not, I repeat, will not see any improvements except the extra lightness you will feel in your wallet.</TD></TR></TABLE>

well said, except it was over the course of a couple months, switching back and forth between 87 and 91 while driving spirited and driving like a grandma for x amount of miles per tank. Basically, I ALWAYS gained 2 mpg so thanks for trying to make it seem like an issue of circumstance, but it wasn't and i made sure i drove the same. I wasnt turboed but i wasnt stock either.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FuNkDrSpOt &raquo;</TD></TR><TR><TD CLASS="quote">Yes, i would like an explanation on how in the hell you would lose gas mileage with higher octane. I was going to be a tool and flame you but im waiting to see why you said what you said.

Octane does have the potential to give you better HP/ gas mileage. Most people say that it only works if you have tuning, i.e. if you use a gsr motor that requires 91 octane you will lose power if you use 89 but not in reverse if you use 91 and you have a d16y8 motor. I know for sure that my d16y8 got about 2mpg more on avg when i used 91 vs 87. As far as octane, i would think that you would gain power, no matter what engine you have because the car could adjust the air/fuel ratio. As far as the amount of gain, that is determined by tuning.</TD></TR></TABLE>My personal experience is opposite of yours. I got about two miles per gallon less with the higher octane gas. Maybe my personal experience is less valid than yours.