Would I need a higher octane gas for aftermart headers?
Edmond Kwok
I have a 1990 Integra which I want to install a DC Stainless
Headers into. Everything on the car is stock and the only aftermart part
will be the headers (so far). I was wondering if I would need to use a
higher octane gasoline after I put in the new headers, or would it be ok
to just continue using my 87 octane Arco. If I need a higher octane, how
much higher?
One of my friends say i *might* need a higher octane but another
friend says since I didn't change the chip that I wouldn't need a higher
octane gas.
I would appreciate any tips, suggestions, and/or advice since I
would not like to find out from a knocking engine. Thank you in advance.
-Edmond (edk...@ucdavis.edu)
Fok Tommy
No... You don't need to change the gas you are using at the moment..
UNless you changed the slip/compression ratio of the engine than your car
require a higher octane rating gasoline
Edmond Kwok (ez06...@boris.ucdavis.edu) wrote:
: I have a 1990 Integra which I want to install a DC Stainless
--
===================================
| Tommy Fok |
| E-Mail : 4t...@Qlink.Queensu.Ca |
| Phone : (613)547-4477 |
| Fax : (905)420-0283 |
===================================
Just go for your ultimate goal and
Never look back, causes you'll always
regret it once you fail to suceed!
Just Ask
You should be able to use the same gas. Your engine isn't going to knock
just because you added a header.
It will run leaner though, so check your plugs in a few thousand miles, you
may have to richen up the fuel mixture.
The only time you would need to go to a higher octane fuel, would be if you
increased compression.
Most people think higher octane gas makes you go faster and your car makes
more power using it.
Not true ! Octane is the resistance to burning. Higher octane fuel is
harder to burn, therefore reducing preignition,
but it has the same BTU's ( British Thermal Units ) as low octane fuel.
They both put out the same amount of heat.
I have a Honda CBR F2 with 12:1 Compression, and I use 87 Octane fuel/ Your
Integra probably has 9.0:1 or less compression,
so don't waste your money on high octane fuel. Besides, the gas stations
make 45 cents a gallon profit on 92 octane fuel, and only
15 cents on 87
Edmond Kwok <ez06...@boris.ucdavis.edu> wrote in article
<560jdq$s...@mark.ucdavis.edu>...
Jim Edwards
Edmond Kwok <ez06...@boris.ucdavis.edu> wrote in article
<560jdq$s...@mark.ucdavis.edu>...
> I have a 1990 Integra which I want to install a DC Stainless
> Headers into. Everything on the car is stock and the only aftermart part
> will be the headers (so far). I was wondering if I would need to use a
> higher octane gasoline after I put in the new headers, or would it be ok
> to just continue using my 87 octane Arco. If I need a higher octane, how
> much higher?
> One of my friends say i *might* need a higher octane but another
> friend says since I didn't change the chip that I wouldn't need a higher
> octane gas.
> I would appreciate any tips, suggestions, and/or advice since I
> would not like to find out from a knocking engine. Thank you in advance.
>
>
> -Edmond (edk...@ucdavis.edu)
Nope! better off to use the highest octane gas anyways, its better for the
car, causes less engine pinging, and gets you better performance.
Jim
Mike Kohlbrenner
Jim Edwards wrote:
>
> ... better off to use the highest octane gas anyways, its better for the
> car, causes less engine pinging, and gets you better performance.
With all due respect, this is one of the most common myths about
cars. The best octane to use is the MINIMUM required to prevent
preignition/knock/ping. Anything more is a waste of money and
anything significantly more can actually give lower performance.
--
Mike Kohlbrenner
<kohl...@an.hp.com>
Steven Joseph Mastroyin
In article <01bbcdc5$881130e0$253b...@jime.cycor.ca> "Jim Edwards" <ji...@cycor.ca> writes:
>
>
>Edmond Kwok <ez06...@boris.ucdavis.edu> wrote in article
I can't answer Edmond's question, but...
>Nope! better off to use the highest octane gas anyways, its better for the
>car, causes less engine pinging, and gets you better performance.
>
>Jim
C'mon, Jim, do you work for an oil company or something?
Higher octane gas is not necessarily better for the car. It certainly
isn't so much better that buying higher octane is worth the price.
Higher octane will case less knocking (I assume that's what you mean by
pinging), and that is it's main selling point. However, unless your car
is actually knocking with the lower octane, it is unnecessary to use
higher octane.
As for better performance - this, my friends, is hogwash. Any better
performance in a typical engine will be caused by Placebo effect and
nothing else. (i.e. "Hey! I put expensive gas in my car, so now it
MUST run better!) A higher octane makes fuel burn *less* efficiently.
This is the exact reason why it stops knocking. If you have an engine
that is not knocking and you are using a higher octane, you may actually
see a decrease in performance.
Steve
Gordon Sleigh
Jim Edwards (ji...@cycor.ca) wrote:
: Edmond Kwok <ez06...@boris.ucdavis.edu> wrote in article
: <560jdq$s...@mark.ucdavis.edu>...
: > One of my friends say i *might* need a higher octane but another
: > friend says since I didn't change the chip that I wouldn't need a higher
: > octane gas.
: > I would appreciate any tips, suggestions, and/or advice since I
: > would not like to find out from a knocking engine. Thank you in advance.
: Nope! better off to use the highest octane gas anyways, its better for the
: car, causes less engine pinging, and gets you better performance.
Thats not COMPLETELY true I don't think. I've been told numerous times that
using above the reccomended octane for your car is a needless expense.
I'm by no means an expert though. (:
Does the owners manual of your '90 Integra say to use 87? My '89 says to
use 91. I'd think the 2nd Generations would want the same.
--
/ exISIS/AtCon/HookUp Communications - Internet Services - 902.429.5419 \
[|) 1989 Acura Integra RS: Pioneer - JL Audio - Sony - Alpine - Fosgate (|]
\ www.isisnet.com/sleigh/caraudio - An object at rest cannot be stopped /
edward tadlock
>>>>> "SJM" == Steven Joseph Mastroyin <ste...@wpi.WPI.EDU> writes:
In article <56fqaa$l...@bigboote.WPI.EDU> ste...@wpi.WPI.EDU (Steven Joseph Mastroyin) writes:
SJM> In article <01bbcdc5$881130e0$253b...@jime.cycor.ca> "Jim Edwards" <ji...@cycor.ca> writes:
>>
>>
>> Edmond Kwok <ez06...@boris.ucdavis.edu> wrote in article
SJM> I can't answer Edmond's question, but...
>> Nope! better off to use the highest octane gas anyways, its better for the
>> car, causes less engine pinging, and gets you better performance.
>>
>> Jim
SJM> C'mon, Jim, do you work for an oil company or something?
SJM> Higher octane gas is not necessarily better for the car. It certainly
SJM> isn't so much better that buying higher octane is worth the price.
That depends, If you have a high compression engine, it may
well require high octane to prevent detonation. Based on your
theory I could take a $50,000 race motor and run it on plain
old 87 octane unleaded.
SJM> Higher octane will case less knocking (I assume that's what you mean by
SJM> pinging), and that is it's main selling point. However, unless your car
SJM> is actually knocking with the lower octane, it is unnecessary to use
SJM> higher octane.
True.
SJM> As for better performance - this, my friends, is hogwash. Any better
SJM> performance in a typical engine will be caused by Placebo effect and
SJM> nothing else. (i.e. "Hey! I put expensive gas in my car, so now it
SJM> MUST run better!) A higher octane makes fuel burn *less* efficiently.
SJM> This is the exact reason why it stops knocking. If you have an engine
Higher octane prevents detonation which is one cause of
knocking. Improper timing is another cause, and higher octane
my fix some of the symptoms of that, but not the cause.
As far as burning less efficiently than stoichiometric (about
13:1) I'm not sure the octane of the gas makes any difference
as long as it meets the minimum requirements. Timing, valve
size, combustion chamber shapes, compression ratio, etc
all affect the burn rate and burn efficiency of the fuel.
A few years back Circle Track did a good technical study
of gasoline, it might help answer some questions.
**************************************
These are my opinions, not those of TI
***************************************
Dennis Z Kuo
Gordon Sleigh (gsl...@isisnet.com) wrote:
: Does the owners manual of your '90 Integra say to use 87? My '89 says to
Gordon, the owner's manual of my '88 Integra says to use 87 octane. I
found the old Integra catalog recently and noted that it says to use 87
octane, too. I've been using 87 octane forever and the car runs fine. I
don't think they changed the engine for the '89 model year, did they?
1590 cc in-line four, 118 hp @ 6500 rpm, 103 lbs-ft torque @ 5500 rpm...
BTW, I thought all non-VTEC Integra engines used 87 octane.
--
Dennis Kuo | University of Pennsylvania
ku...@mail.med.upenn.edu | School of Medicine, Class of '97
"A bear in his natural habitat...a Studebaker."--Fozzie Bear
home page occasionally running at http://mail.med.upenn.edu/~kuod
Chuck Tomlinson
On 9 Nov 1996 00:31:54 GMT, Edmond Kwok wrote...
>
> I have a 1990 Integra which I want to install a DC Stainless
>Headers into. Everything on the car is stock and the only aftermart part
>will be the headers (so far). I was wondering if I would need to use a
>higher octane gasoline after I put in the new headers, or would it be ok
>to just continue using my 87 octane Arco. If I need a higher octane, how
>much higher?
It's possible that the headers will increase airflow through the engine
enough to lean out the mixture at full throttle. This could increase
combustion chamber temps enough to cause knocking.
I'm assuming here that the Integra uses speed-density fuel injection (no
airflow sensor), which generally won't compensate for changes in full
throttle volumetric efficiency. Hopefully someone will correct me if I'm
wrong about this.
If your engine has a knock sensor *and* the headers make the engine want
to knock with 87 octane, the computer will detect knock before you can.
It will reduce spark advance (reducing power as well), but you won't be
able to tell.
Unless you can rig up a way to let you know when the computer is retarding
the spark timing to avoid knock, your best bet might be doing a
performance comparison between regular and premium (e.g. time from idle to
redline in 3rd gear at full throttle).
OTOH, if your engine does _not_ have a knock sensor, just run the car on
87 with the headers. If it knocks, try a higher octane.
--
__
___| |____ Chuck Tomlinson <toml...@ix.netcom.com>
/___LT-1___/ Mouse Power!
|__| '94 Vette Z07/ZF6, '89 Mustang LX5.0L/T5
Gordon Sleigh
Dennis Z Kuo (ku...@mail.med.upenn.edu) wrote:
: Gordon Sleigh (gsl...@isisnet.com) wrote:
: : Does the owners manual of your '90 Integra say to use 87? My '89 says to
: : use 91. I'd think the 2nd Generations would want the same.
: Gordon, the owner's manual of my '88 Integra says to use 87 octane. I
: found the old Integra catalog recently and noted that it says to use 87
: octane, too. I've been using 87 octane forever and the car runs fine. I
: don't think they changed the engine for the '89 model year, did they?
: 1590 cc in-line four, 118 hp @ 6500 rpm, 103 lbs-ft torque @ 5500 rpm...
I know they changed the engine from 112hp (Or was it 114?) to 118hp in '88
but I don't think there was any change between '88 and '89. Especially with
'89 being the last year for the 1st Gen Integra.
I've got my owners manual right here... I quote:
'Your engine is designed to operate on gasoline with 91 Research Octane
Number or higher.'
I was using 87 for a while and noticing some knocking. So I switched up and
the engine seemed to perform much better. (I also cleaned the injectors for
the first time since I bought the car (6 months ago. God knows how long ago
the previous owner did it, if at all) so that might have contributed to the
performance increase too, but the knocks went away.
: BTW, I thought all non-VTEC Integra engines used 87 octane.
Quite possible, but not mine according to my book. (:
I've got a Canadian Integra. I can't see there being any difference there,
but who knows?
Anyone else know the details on this discrepancy?
Dennis Z Kuo
Gordon Sleigh (gsl...@isisnet.com) wrote:
: Dennis Z Kuo (ku...@mail.med.upenn.edu) wrote:
: : Gordon, the owner's manual of my '88 Integra says to use 87 octane.
: I've got my owners manual right here... I quote:
: 'Your engine is designed to operate on gasoline with 91 Research Octane
: Number or higher.'
(snip)
: I've got a Canadian Integra. I can't see there being any difference there,
: but who knows?
I think I may have stumbled across something, Gordon. My manual actually
recommends _86_ octane or higher, but on page 43, it says "The pump
octane number is an average of the Research (R) octane and Motor (M)
octane numbers." The catalog states 87 unleaded regular, but indicates
<R+M/2) after the 87. I have no idea what the difference between
research and motor octane numbers are...anyone care to fill me in? Do
they follow different octane ratings in Canada?
Mike Kohlbrenner
Gordon Sleigh wrote:
>
> I've got my owners manual right here... I quote:
> 'Your engine is designed to operate on gasoline with 91 Research Octane
> Number or higher.'
> I've got a Canadian Integra. I can't see there being any difference there,
> but who knows?
>
It is good that you quoted the manual, because it very simply
shows the source of the discrepancy. Research Octane Number (RON)
is only one measure of Octane that is used. Motor Octane Number
(MON) is the other. It's merely a difference in the conditions of
the testing. RON always comes out 6-10 "units" higher than MON.
In the U.S., "octane" is "Pump" octane, which is the average of
RON and MON. Every pump in the U.S., as far as I know, has
"R+M/2" on it.
If in Canada, you pump gas from pumps that list RON, your 91 is
close to U.S. 87. So, there really isn't a discrepancy. Just
a different measure.
Now, what gets interesting, is that in high compression, high
rpm engines, the "more important" number is RON. And the
realities of gasoline refining are that the "spread" in the
RON and MON ratings are not consistent. That is why I said
6-10 units above. One batch of 87 R+M/2 may have a 90 RON,
while another batch may have a 92 RON. The two batches will
behave differently in an engine requiring 91 RON.
This is likely one of the reasons that certain companies have
"better" 87 octane gas than others or they have "more consistent"
87 octane gas than others. It is not anyone's imagination,
necessarily, it may be this R+M/2 thing.
--
Mike Kohlbrenner
<kohl...@an.hp.com>
Mike Kohlbrenner
edward tadlock wrote:
>
...
> As far as burning less efficiently than stoichiometric (about
> 13:1) I'm not sure the octane of the gas makes any difference
> as long as it meets the minimum requirements. Timing, valve
> size, combustion chamber shapes, compression ratio, etc
> all affect the burn rate and burn efficiency of the fuel.
I think the point being made was that high octane gas is high octane
gas because it is not as "explosive". The flame front in the
fuel/air mixture in the cylinder propagates more slowly with a
high octane fuel. Thus, unless you advance the timing to
compensate for this, you will not be building pressure inside
the cylinder quickly enough for the most efficient transfer of
energy to the piston/crank.
--
Mike Kohlbrenner
<kohl...@an.hp.com>
edward tadlock
>>>>> "MK" == Mike Kohlbrenner <NoJun...@My.Mailbox.Thank.You> writes:
In article <328CD8...@My.Mailbox.Thank.You> Mike Kohlbrenner <NoJun...@My.Mailbox.Thank.You> writes:
MK> edward tadlock wrote:
>>
MK> ...
>> As far as burning less efficiently than stoichiometric (about
>> 13:1) I'm not sure the octane of the gas makes any difference
>> as long as it meets the minimum requirements. Timing, valve
>> size, combustion chamber shapes, compression ratio, etc
>> all affect the burn rate and burn efficiency of the fuel.
MK> I think the point being made was that high octane gas is high octane
MK> gas because it is not as "explosive". The flame front in the
MK> fuel/air mixture in the cylinder propagates more slowly with a
MK> high octane fuel. Thus, unless you advance the timing to
MK> compensate for this, you will not be building pressure inside
MK> the cylinder quickly enough for the most efficient transfer of
MK> energy to the piston/crank.
I think we are talking about two different things here. I was
discussing "most efficient", you are discussing "most
powerful". These two may or may not be the same in a engine.
My point is that the whole DESIGN of the engine makes a
difference as to whether higher octane fuel has advantages.
So, unless the owners manual specifies it, you are probably
actually wasting money. (Now can someone tell me why
SuperUnleaded costs 10-15 cents/gal. more? Is it that
much different from regular unleaded to justify the price?)
Advancing the timing gives more power, but brings with it
the chance of knocking and detonation, so you would have
to use a less "explosive" gasoline that burns slower. So
I think your explantion is right on in that area.
Ed
*********************************************
My thoughts, not TIs
*********************************************
Young Song
In article <01bbcdc5$881130e0$253b...@jime.cycor.ca>, "Jim Edwards" <ji...@cycor.ca> wrote:
=Nope! better off to use the highest octane gas anyways, its better for the
=car, causes less engine pinging, and gets you better performance.
=
=Jim
=
Wrong. If the car runs without pinging with 87 octane fuel, you can't
"reduce" pinging further from a "zero" level... Higher octane doesn't mean you
get more horsepower if your engine wasn't built for it. My civic is built for
87 octane fuel and it runs just fine with it. There is absolutely no added
smoothness or power by purchasing higher priced 92 octane fuel. A car will
only benefit from 92 octane if it pings to begin with. If it doesn't, you
can't improve on that.
Young Song
University of San Francisco, School of Law
http://www.slip.net/~ysong
"Happiness is the full use of your powers along the lines of excellence" JFK
Young Song
In article <56h0h7$k...@dfw-ixnews8.ix.netcom.com>, toml...@ix.netcom.com (Chuck Tomlinson) wrote:
=On 9 Nov 1996 00:31:54 GMT, Edmond Kwok wrote...
=>
=> I have a 1990 Integra which I want to install a DC Stainless
=>Headers into. Everything on the car is stock and the only aftermart part
=>will be the headers (so far). I was wondering if I would need to use a
=>higher octane gasoline after I put in the new headers, or would it be ok
=>to just continue using my 87 octane Arco. If I need a higher octane, how
=>much higher?
=
=It's possible that the headers will increase airflow through the engine
=enough to lean out the mixture at full throttle. This could increase
=combustion chamber temps enough to cause knocking.
I doubt the airflow is increased by the addition of just a header (this is a
four banger so you only have ONE header not headerS). If the restrictive
air intake and the little exhaust and mufflers are still stock, then the
increased diameter from the exhaust manifold to the catalytic converter will
not result in much difference... Once you've got a better intake and exhaust,
then the car will circulate higher volumes of air.
=
David K.
Young Song wrote:
<snip>
> Wrong. If the car runs without pinging with 87 octane fuel, you can't
> "reduce" pinging further from a "zero" level... Higher octane doesn't mean you
> get more horsepower if your engine wasn't built for it. My civic is built for
> 87 octane fuel and it runs just fine with it. There is absolutely no added
> smoothness or power by purchasing higher priced 92 octane fuel. A car will
> only benefit from 92 octane if it pings to begin with. If it doesn't, you
> can't improve on that.
>
> Young Song
> University of San Francisco, School of Law
> http://www.slip.net/~ysong
I agree. My 96 Accord was idling roughly using Chevron 89 octane and my
mechanic (Honda specialist) recommended switching to 87 octane. Believe
it or not, the car idles fine now!
--
Dave airk...@ix.netcom.com http://www.geocities.com/colosseum/1750
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Tom
What's the recommended octane for a 1992 Prelude S model? (lost my
manual)
Tom
J. Forbes
>Young Song wrote:
><snip>
>> Wrong. If the car runs without pinging with 87 octane fuel, you can't
>> "reduce" pinging further from a "zero" level... Higher octane doesn't mean you
>> get more horsepower if your engine wasn't built for it. My civic is built for
>> 87 octane fuel and it runs just fine with it. There is absolutely no added
>> smoothness or power by purchasing higher priced 92 octane fuel. A car will
>> only benefit from 92 octane if it pings to begin with. If it doesn't, you
>> can't improve on that.
In a car with a knock sensor, which automatically retards ignition timing at
the first inaudible hint of pinging, you can get better performance with
higher octane fuel-if the compression is high enough to need it-even if you
never hear pinging with the lower octane fuel.
Jim
--------------------------------------------------------------------
Jim and Janet Forbes jfo...@primenet.com
Sierra Vista, AZ URL= http://www.primenet.com/~jforbes
--------------------------------------------------------------------
Adam Frix
In article <jforbes.49...@primenet.com>, jfo...@primenet.com (J.
Forbes) wrote:
> In article <328FB5...@ix.netcom.com> "David K."
<airk...@ix.netcom.com> writes:
> >> only benefit from 92 octane if it pings to begin with. If it doesn't, you
> >> can't improve on that.
>
> In a car with a knock sensor, which automatically retards ignition timing at
> the first inaudible hint of pinging, you can get better performance with
> higher octane fuel-if the compression is high enough to need it-even if you
> never hear pinging with the lower octane fuel.
Right. But every car, even those with knock sensors, come with
recommendations regarding octane ratings. Every car manufacturer
specifies certain octane fuels with all its vehicles.
If you stick with the mfrs. recommendation--and what idiot buys a car and
never reads the manual?--then the knock sensor issue never comes up unless
and until you're forced to use bad or lower octane gas, or the combustion
chambers crap up.
Aloha,
--Adam--
David K.
Adam Frix wrote:
<snip>
> If you stick with the mfrs. recommendation--and what idiot buys a car and
> never reads the manual?--then the knock sensor issue never comes up unless
> and until you're forced to use bad or lower octane gas, or the combustion
> chambers crap up.
>
> Aloha,
> --Adam--
The 96 Accord calls for 86+ octane.
-----BEGIN PGP PUBLIC KEY BLOCK-----
Steven Huang
Funny. I have a 86 Accord lx-i. The owner's manual said
to use 86 octane. I tried using 92 octane and it will give me big
forward thrust when I changed from P to D4 at high idle speeds.
By using lower octane, this problem is much better. I rather
save my money now by buying 89 octane at AAMOCO. Lower octane
is actually better. High octane are for cars with lots of
horsepower (i.e. Ferrari) Just my opinion
Adam Frix
> is actually better. High octane are for cars with lots of
> horsepower (i.e. Ferrari)
High octane is not for "lots of horsepower". High octane is for engines
with high compression ratios and other design elements which might cause
preignition or knock.
Actually, high octane is for engines where the manufacturer specifies high
octane. That's all.
It's true that high compression ratios tend to correllate with higher
horsepower, but there are many, many other elements that can affect that
relationship to where it's not applicable. Let's take Honda vs.
Oldsmobile: the Integra GS-R makes 170 bhp, and probably requires high
octane fuel. The 94 Oldsmobile Cutlass with the 3.4 liter V6 makes 210
bhp, and doesn't ask for anything beyond 89 octane, possibly 87 octane.
210bhp vs. 170bhp, and the 170bhp requires the higher octane fuel. So
"lots of horsepower" isn't the issue.
Aloha,
--Adam--
Gary Derian
-- High octane only means that the fuel is hard to ignite. That way,
compression can be higher without detonation. A spark has enough energy to
ignite almost any octane.
<gde...@cybergate.net>
Gary Derian aka Vega Man
I know I'm nuts but I have 3 Vegas: L-4, V-6, V-8
edward tadlock <tad...@bosch.dseg.ti.com> wrote in article
<TADLOCK.96...@bosch.dseg.ti.com>...
Allen Madding
Danno wrote:
>
> I have a 1984 Camaro with a 2.8L V-6 which I run on the lowest octane
> fuel I can find... When I'm at home, I use farm grade unleaded fuel (85
> octane unleaded, RAW), and when I have to fill up at the pump, I only
> run 87 octane... If I put anything higher than 89 octane, my car LOOSES
> performance AND mileage. I don't quite understand it, but if my car
> likes cheap fuel, I'm not going to complain.
>
> Oh, and I get MUCH more power out of a lower octane fuel.
>
> Danno
This would be due to the low compression of the motor and the colder
spark plug being used. The higher the Octane the harder it is to ignite
the fuel. Higher octane fuels are used for higher compression engines to
prevent pre detination which results in burnt pistons and valves and the
like.
Allen
Danno
I have a 1984 Camaro with a 2.8L V-6 which I run on the lowest octane
fuel I can find... When I'm at home, I use farm grade unleaded fuel (85
octane unleaded, RAW), and when I have to fill up at the pump, I only
run 87 octane... If I put anything higher than 89 octane, my car LOOSES
performance AND mileage. I don't quite understand it, but if my car
likes cheap fuel, I'm not going to complain.
Oh, and I get MUCH more power out of a lower octane fuel.
Danno
David Floyd
In article <3294C0...@worldnet.att.net>, Allen Madding
<t.a.m...@worldnet.att.net> wrote:
* Danno wrote:
* >
* > I have a 1984 Camaro with a 2.8L V-6 which I run on the lowest octane
* > fuel I can find... When I'm at home, I use farm grade unleaded fuel (85
* > octane unleaded, RAW)
* > Danno
*
* This would be due to the low compression of the motor and the colder
* spark plug being used. The higher the Octane the harder it is to ignite
* the fuel. Higher octane fuels are used for higher compression engines to
* prevent pre detination which results in burnt pistons and valves and the
* like.
* Allen
Allen;
Exactly. I put 87 in my cars, but my motorcycle REQUIRES 94+. It is a
900cc flat twin running at a compression ratio of about 9.5, with one plug
per 450cc pot. Farm fuel would result in predetonating the engine to
death in short order. I throw octane booster in the tank in the summer
just for good measure. Some folks swear by 100 octane aviation fuel.
--
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
David Floyd
1974 R90/6 -- "Narrenschiff"
Pawtucket, RI Be a Clean Livin' Man,
With a Rope in your Hand!
dfl...@ids.net - Bob Roberts
dfl...@binah.cc.brandeis.edu
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
P. J. Remner
In a previous article, fall...@hacker.com (Just Ask) says:
>Most people think higher octane gas makes you go faster and your car makes
>more power using it.
>Not true ! Octane is the resistance to burning. Higher octane fuel is
>harder to burn, therefore reducing preignition,
*BUT* - if you car has electronic ignition and a knock sensor, the
computer *might* be programmed to run the ignition timing as advanced
as the fuel can take it. Higher octane fuel means more advance can
be utilized, and more advance means more power and economy!
I have seen some cars actually run cheaper, on a cents-per-mile scale,
on $1.50 premium versus $1.30 regular, simply because the computer took
advantage of the higher octane.
I did a similar thing on my non-computer car by simply knocking the
distributor a little advanced. Idled really smooth, made shitloads
of power, but I didn't see any mileage gains because I kept putting
my foot in the secondaries and enjoying the added power!
--
The "." in addresses is a delimiter just like a decimal. It's a POINT!
"Divine intervention is... unlikely." Worf sez:
- the Doctor of the Voyager "Assimilate *THIS*!"
Pat Beal
dfl...@ids.net (David Floyd) wrote:
>Allen;
>Exactly. I put 87 in my cars, but my motorcycle REQUIRES 94+. It is a
>900cc flat twin running at a compression ratio of about 9.5, with one plug
>per 450cc pot.
>1974 R90/6 -- "Narrenschiff"
Are you running a modified engine? I seem to remember that the R90s ran a 9.5
to 1 compression ratio and the R90/6 ran 9.0 to 1.
When leaded premium started to disappear, popular modifications included
thicker base gaskets to reduce compression and dual plugs to improve flame
front propagation.
Patrick J. Beal
Supervisor/Systems and Support Services
The University of Illinois at Chicago Publications and Mail Services
Voice: 312-996-8648 E-mail: pat...@uic.edu Fax: 312-413-1167
MidNight RamBler
On 24 Nov 1996 14:26:20 GMT, P. J. Remner <aj...@cleveland.Freenet.Edu> wrote:
>
>In a previous article, fall...@hacker.com (Just Ask) says:
>
>>Most people think higher octane gas makes you go faster and your car makes
>>more power using it.
>>Not true ! Octane is the resistance to burning. Higher octane fuel is
>>harder to burn, therefore reducing preignition,
>
>*BUT* - if you car has electronic ignition and a knock sensor, the
>computer *might* be programmed to run the ignition timing as advanced
>as the fuel can take it. Higher octane fuel means more advance can
>be utilized, and more advance means more power and economy!
>
I agree with P.J. First let's clarify what higher octane means.
Higher octane, means more resistance to the *fuel vapors* self igniting ,
before piston reaches the highest "point".
Higher compression and higher temps require higher octanes.
Now like PJ said if your car has a knock sensor, you may be better off using
higher octane since ---read PJ---.
If OTOH there's no knock sensor , it's almost certain that you can benefit of
higher octane since you can manualy advance timing(knock sensor can't be
bypassed "conventionally" as far as I know). Just rotate dist cap counter
clockwise - if memory serves - and see when pinging/knocking occurs. Then
go back one degree or so.
I *have seen* one CRX vtec doing 21 degr. without problems. The performance
gain was really something ... makes you jealous..
Besides , since knocking/pinging is *not* always easy to isolate , it's best
you spend a little extra and be sure there's not even the slightest engine
damage done , than spending more later.
I'm posting another article on how to check for pinging..
When I find the time, I'll post my story and hope someone finds me a solution.
It's about a CRX vtec '91 pinging/knocking for the past 3.5 years for no appa
rent reason..:(((
Also , as soon as I find it, I'll post a *GREAT* article on "everything there's
to know about gas" ,I came across 2 years ago.
Stay tuned.....
This message is [31;1m [5mPOWERED by HONDA [0m
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Allen Madding
> Actually, high octane is for engines where the manufacturer specifies high
> octane. That's all.
>
OR engines that have been modified to have a substantially higher than
stock compression ratio.
Allen