Gas mileage? You guys check?

We've got that oxygenated junk over here, too - oh, wait! Is April 1st the cut-off date?? (In NJ, they only do it for the winter.) I gotta check. Maybe that's why my car has felt so ballsy lately; it hates that oxygenated junk.

 

35 on the honda, or the 3rd gen?

 

Because I run base timing at 13* and do not run a stock prom and I run rpm levels much higher than stock producing power up top where a stock motor will not.

With and advanced motor timing, you will gain low end power but can suffer up top in the rpm range and drop off from poor octanefuel detoning too quickly. I can not run the camaro on 87 fuel, it runs like crap up top.

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This is in my '89 Chev truck- same load each way

Gas mileage results from Orange, CA to Parker, AZ (243 miles)
I used 25.5 gallons of Calif 91 Octane = 9.5MPG

From Parker back to Orange but diverting trough Indio-Palm Springs area to visit a friend 9 miles longer on Arizona 91 octane fuel. (252 miles) I used 19.5 gallons = 12.9 mpg

There was also much more traffic coming home that cause much more variance of speeds than going out.

This Calif oxygenated fuel is crap. Gallon for gallon it burns cleaner, but you have to use more of it to go the same distance. Ultimately, everyone is poluting more and buying more fuel- another political snowjob.

 

To also add another note, The only car I own that will run decent on 87oct fuel is my 77 ElCamino.
Fact is-

It is getting better gas mileage on 91oct than it is on 87oct Calif fuel so the slightly more expensive fuel is worth it in the long run.
I'm thinking the higher octane fuel has more % of Xylene added to increase octane which results in less % of oxgenates and crap that can be added.

 

mines not doing to well. Rockers knocking, exhaust leak, miss-matched plug wires still.

I did the 5sp swap, and I'm running 3.23's rather then needed 3.42's. I have to rev the car quite well to get it to take off.

I have not done actual numbers, but I'm guessing mid teens in town. No highway.

 

the difference in gas mileage between 87 and 93 is not tangible...

it's all rumor and whatnot... started to raise demand for something that is rediculously over-priced.

use it if you need it... but a car that is meant for 87 uses 87, no exception... no point in putting in higher.

if it's designed to use 87 and it's pinging, you have a bad sensor somewhere.

 

well i live in hot, sunny florida and do high speed city driving(0-60-0 constantly). i was gettin about 18mpg before i put on a little magnet clamp my friend designed and over three tank went up to 23.5 to 24. not bad as far as im concerned

 

just so you know those magnets are placebos... they don't really work.

at least you didn't pay for it... you didn't specify either way, but I would have to assume that you didn't...

 

ya, .5mpg better sounds kinda like its in your head, but explain how that magnet works, I've never heard of it

 

I know all about the magnet thing... the makers claim it 'Aligns' the atoms in the fuel, so it burns more efficiently...

bunch of crap...

plus he is claiming it went from 18 mpg, to 24 mpg... not just a 0.5mpg increase.

 

I like to play it safe so I fill up once I get to a quarter tank when on hiway. Small towns are pretty spread apart so I do city and hiway speeds so on the average I get 300 miles per 11 gallons of fuel. Around 25 - 29 mpg. Lol if it ever dips down into the teens then it better be fast by then.

 

Did you read what I wrote about California fuels? You do not face this problem nor have you ever experiences oxygenated fuels.

My car does not have any bad sensors. Everything on it is top notch AC Delco sensors that are all withing 2 years old and maintains and checked frequently. This car is in top notch shape, this car is producing power in a higher rpm range than intended and I doubt anyone else here in Calif running this crappy fuel makes power up top like I am. Years back this car ran fine on 87oct fuel and it was and older motor and electronics yet the fuel was never oxygenated back then. Plus it did not make power as high. It always was able to twist to 5500 rpms but lacked power after 4000 rpms and took a long pointless time to get to 5500. It now runs mostly between 4k and 5500 only when I drive it hard and it WILL NOT run on 87 octane at those rpms- it flattens out in power with 87, but not with 91. ANything over 91 is pointless and makes no power difference because the compression and timing is not fit for any manditory octane increase further- more octane would be a waste of money and minutely be reducing power due to slower combustion time.

It is not knocking up top with the 87, but is on the edge of knocking enough that the power is dropping where the slower burning 91 is keeping the advanced timing a tad more on the downstroke- its a very fine line that is esily felt but not heard. I would love to know if the computer is picking up the knock recordings from the 87oct at high rpms at all. When I bump the timing to 14* advance from 13*, it WILL knock at top end on 87 and flattens out on 91.

 

well we do have winter and summer fuel mixtures here in Texas...

I was saying gas mileage-wise, you could never tell the difference between 87 and 93...

higher-octane fuel does nothing for a stock motor... in normal situations.

 

And I will repeat that I am gettng better mileage definately in every car I own with the 91 octane Calif fuel over the 87 octane Calif fuel.

My quote from above:
-----------------------
I'm thinking the higher octane fuel has more % of Xylene added to increase octane which results in less % of oxgenates and crap that can be added.
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Its that higher percentage of BTU making substance that makes the higher octane fuel more powerful than the weaker 87oct fuel.
The companies used to put different crap into the fuel other than Toulene and Xylene that would increase BTU combustion force of the fuel(Toulene and Xylene are processed derivitives of crude oil and are what are added back into gasoline in pecentages of one or any combination of both to give the gasoline its octane rating, not overall BTU rating) Now they have gone the way here in Calif of mostly detergents and oxygenates because of the enviromental wackos. Our octane ratings are the same as the rest of the country but our BTU output on 87oct compared to your Texas BTU output is lower due to lack of other BTU creating additives here in Calif. We are getting worse mileage and ultimately using more gallons of gasoline to go the same distance. It is BS.

 

well I would think that the gasoline producers would have to meet some sort of minimum specification for the 87 fuel.. because so many vehicles were designed to work on it... if they started make the fuel crappy, (and I know how cali is full of wacko's,) it seems that they would be breaking a law, because that 87 would be damaging your engine.

sue 'em

 

believe what u want about the magnets....results r results. its basically the same process they use on rocket fuel before launching to gain maximum burn. every car its been on has gained at least 10-20% better fuel economy. it align for a more efficient burn and breaks apart the carbon for lower emission and less build up in ur valves and injectors. if uve never tried it then u cant really say it doesnt work. science is science

 

might as well toss your money in the garbage...

ANY money you spent on this was a total waste

I shouldn't have had to show that web site to anyone, because its friggin' common sense that this isn't possible

gotta use your head... c'mon.. if putting a little magnet on your car would improve gas mileage, then EVERY manufacturer would put one on their cars... especially right now with gas prices

/obvious

 

I love how they always tell you to stay within some speed range (usually the speed limit) and that that will save gas.

 

well u go on and believe what u wanna believe. i used it and noticed a difference. no other changes. just because it seems unlikely doesnt mean it doesnt work. any small improvement is better than nothing. and just because one product may not work, others may work due to the power of magnets and the polarity used. u dont know everything and until uve actually done any research and studies and tests u dont really know if it works or not

 

You can tell yourself what you need to feel good about your purchase... I'm just telling you the facts.

IF that product worked... it would be on EVERY vehicle... EVER.

simple as that...

plus there are VERY reliable sources that say those don't work...

have you tried the go-fast pills you put in the gas tank? increases your 1/4 mile time by 2 seconds! -- saw it on an infommerical... same place you probably saw that "Magic Magnet" or whatever it's called.

hey camaro_junkie... there IS an optimum speed for good gas mileage... but it's actually MUCH lower than the highway speed limit.... of course it depends on the aerodynamics of the vehicle, but its about 35-50mph.... ours is probably about 45mph for optimum MPG.

 

Oh I know there's an optimum speed for a car for good gas mileage. It's just funny that they tell all these people with much different cars, much different aerodynamics, much different gearing, etc. that the optimum speed is X. It's not the same for every car obviously.

 

yup, and it's also MUCH lower than the speed limit..

I can say though, that on my car I get nearly the same gas mileage at 70mph, that I get at 90mph...

plus I get there a lot faster

 

actually doesn't oxigniated fuel if anything give you more power?

though at a good hit to gas mileage?

 

you guys are right though about how speed for one car is different for another on optimum gas mileage

my rx7 it was around 75-80mph or so I'm assuming... it's the fastest I have gone one a steady trip and managed a good 30mpg where hwy I normally only get around 25 or so doing around 65-70


the honda being as aerodynamic as a brick I have no idea yet what the best range is but it never has dipped below 30mpg yet

 

nah, the rx7 wouldn't be much different than the thirdgens...

its about 40-50 for pretty much ALL vehicles...

I'm not saying you don't get amazing gas mileage at high speeds... just that you would get better at the 40-50mph range...

 

I disagree

first off EVERY car is different as far as what rpm range they are most efficient at. second gearing makes a big difference. aerodynamics is also a decent part of this


but if your 40-50mph is correct for most efficient fuel usage why is it my best was seen at 75-80mpg?

at 65 it was down to around 25
at 50mph I can get on avg aroudnd 23-25
but yet at that 75-80mph it put me right at 30mpg


I do have a few ideas as to why this is though
for one aerodynamics, and being at 75-80mph puts me closer to the more efficient rpm range

 

Went to San Diego and Back from Santa Clarita on Sunday and put on 320 miles exactly. I filled up yesterday just to find out the milage and turns out I got 31.2 mpg. pretty freakin' good.

 

no matter how aerodynamic the rx7 is, it shouldn't get better gas mileage at 80mph than 50mph... (which I don't think is much more aerodynamic than a 3rdgen firebird, if at all)

once you reach the point where there is a measureable wind resistance, the force starts increasing exponentially with your speed...

I think it must have been a fluke that you got 30 at 80mph... are you sure you don't get 30 at lower speeds as well?

most people never drive that slow so they don't even know what kind of mpg they would get at that speed.

-- I didn't read this page until just now... but here is another source of information

"Cruise at a constant speed
While driving on lesser trafficked roads, you get maximum fuel efficiency while cruising at 50 - 60 km/h. Driving faster increases the air drag and you burn more fuel. At higher speeds you can burn as much as 30% excess fuel over your cars optimum speed."
http://www.cybersteering.com/tgmain/tgt/smm.html

http://www.cartalk.com/content/colum...cember/12.html

everything in these articles I've heard elsewhere, and I've even been told this by someone in the airforce who helped design airplanes...

even so, I welcome your comments, and I'm particularly confused at how you get higher gas mileage at higher speeds...

maybe if you were following a car at 10ft away at that speed, you were reducing drag...


honestly, I'll NEVER find out what mileage I get at sub-air resistance speeds, because I NEVER go that slow...

 

if he only noted that sort of mileage one time, he could have had a significant tail wind on that particular day. this would cause the wind drag to be decreased enough. im not sure how much of a difference it would make tho. also if he is in the upper end of the rpm range at 50-60mph and then shifts at around 70 to a cruising rpm this could cause a significant change in fuel economy, especially with an enfine as small as the wankel

 

well we have to assume we are in the same gear at 50mph, as 80mph... and that the TCC is locked, or its a manual transmission.

 

with the aerodynamics the Cd of this car with the optional aero kit is .28 which if I remember right the firebird at best is around .32-.34, also remember not only Cd but frontal area. you cars have quite a bit bigger front end then what I have, Quite a bit more which is going to give more resistance to wind as well.

as far as your 40-50mph thing at 40 I'm in 4th gear I can try to put it into 5th but chances are ANY throttle at all and I lug it
at 50 I'm in 5th yes but the rpms are still a little low for being in the most efficient spot of the rpm range

I used to drive to work day in day out 50-55mph and was getting around 24-25mpg on that trip

that time I got 40mpg wasn't my first trip doing as such
avg gas mileage came out to around 30mpg that includes there and the trip back a few different times at those speeds. so don't think it was a fluke.

but I have done it both ways

the slower speeds driving to work. the faster trip during my once a year trip to the sand dunes with the family and a trip to the same general area to either see some friends or take some friends out to the dunes.

faster speed always did better.

sad thing though the best trip was without having a TPS on my car at all. but I will admit that one migh of been a fluke but still the rest avg to 30

though I wil be honest she gehts crap for gas mileage right now. have a leak near the fuel rail so I am spraying fuel bad... enough that I can't get the car at any higher rpms then an idle or else I lose fuel pressure

 

I dunno, maybe it has to do with how small the motor is in the rx7, but in every other car I've driven in, you get better mpg at lower speeds... and common sense agrees with me

I'm still curious as to how your car gets more efficient at higher RPMS?

My car can output more POWER at a certain RPM, but if I was driving around all day at 3600-4200 RPM, I'd get 15mpg... no matter how fast I was going.

 

look here for information regarding fuel economy and how speed is related. You can also look up what our cars are rated to get...92 RS 3.1 is rated for 27mpg.

Just an fyi... http://www.fueleconomy.gov/

 

the manual 3.1 gets LESS MPG than an automatic?

another reason autos are superior

 

as far as speed goes with gas mileage
lets say your driving alonge at 30mph and you using .5 lbs of gas an hour
and then lets say your now driving along at 60mph and you are using .7lbs of gas an hour


lets say you do a steady 600mph trip at each speed
the first way you do it at 30mph will take you 20 hours to get there and you will burn 10 gallons of gas
the second way you do it at 60mph will take you 10 hours to get there and you only use 7 gallons of gas to do it
so doing some math here that comes to 60mpg on the first trip and 85 mpg on the second trip

yes I know there is no way yet cars are going to do this but I was using the numbers as referece just to make the point

at faster speeds while you might burn more fuel for a given amount of time the amount of time it takes you to get somewhere is shorter

like lets say gas usage stayed at 1lb an hour no matter the speed. the faster you get there the better off you are. but in reality we know thats not true to go faster you need to use a little more throttle but the amount of throttle increase isn't twice the amount. ie going 60mph vs 30 mph doesn't mean twice the throttle it could only mean maybe 1.5 times more throttle.


as far as more efficient at higher rpms the rotary motors lack low end. part of it is motor design also part port design.
at lower speeds I don't have the port velocity to promote good efficiency from scaveging and such. at higher rpms the port velicty goes up which helps aid scaveging and with the throttle open a little more both add up to a little less pumping losses. but like everything there is a limit if I go too much throttle or two high of rpms I will lose
kidna like with going to fast or two slow you lose gas mileage there
there is a little window though getting the best gas mileage out ofeach of them though

 

Well, I should be getting 17mpg (city) according to those EPA numbers and I'm more or less right on target, so that's good to know. It is weird that the auto gets better efficiency than the manual.

As far as rx7speed getting better gas mileage at higher rpms, I only know the basics of the Wankel, but I'm sure the efficiency characteristics are much different than traditional gas engines.

 

I get about 18 MPG on the TTA - I was hoping for better then my L98, but boost is just too fun...

 

5 if I`m easy on it .....but it goes like hell!

 

geez a 477 I envy you. think I can borrow it some day? I have a 2000lb car I would like to shoehorn that baby into

 

yup the rotary must be completely different regarding rpm and gas useage (if that is possible)

because in a normal gasoline/deisel engine, you get BETTER gas mileage at lower rpms

and at speeds at 50 or lower mph.

 

was a double post and I tried to delete it


won't allow me so this the mods can clean up if they want but hey I tried

 

not really that different

any motor has an efficient point on it. if you try to drive a car around at 1200rpms in 5th gear your not going to get **** for gas mileage even more so a car that has no power at that rpm


generally cars are most efficient at their torque peak though
and with more efficiency your using less fuel to make the same amont of power just again can't go too far like anything in life


but right now my car just had the best gas mileage of it's life

something like infinite gas mileage
went 20 miles without using a drop of gas :-)

 

also as far as speed goes I donno
again I say depends on the car my celica which was a piston motor got good gas mileage at around 60 mph or so

the ls1 f-bod or vette gets best gas mileage above 50 mph

it all depends on many things. aerodynamics gearing, where the motor is most efficient at

 

if ur is a 3rd gen rx-7 they were all twin turbos i believe and would probably be more efficient as the turbos kick in and start really blowing the air in

 

interesting... in other countries the rx7 continued from 97 to 2000...

 

take a look here... at the very bottom it lists the rx7 twin turbo gas mileage at differing speeds....

shows it gets better mileage at slower speeds...WEIRD

 

if the guy says he gets better gas mileage at higher speed why cant u just take his word for it? or do u always have to be right and wont believe anything other than what uve been told?

 

how many times are you going to quote that
even though I told you it wasn't fitting of my mazda

 

I'm simply pointing out that with all cars the optimum speed efficiency is between like 35-50mph, not 70-80mph.

just defending my original argument with information, nothing else.

even if you own an rx7.

get over it. it was offered as advice that a slower speed would achieve higher MPG. Someone thought differently, and I gave them cold-hard facts.

take it or leave it.

 

your cold hard facts are not cold hard facts with ALL cars

mine has shown that

many trips to work in the 50mph range netted lower gas mileage then the many trips I have made in the 75-80mph range

again multiple trips both speeds
both ways include too and from so unless I was getting a tail wind only when going at 75-80mph BOTH TO AND FROM it seems my car doesn't meet your cold hard facts.

again another car that I'm sure doesn't quite live up to your cold hard facts but I admit I have no experience with it
6spd ls1 f-body or vette. hard to use that 6th gear when only doing 50mph


your advice I would say is welcome but when you claim cold hard facts when given information about another car that I HAVE SEENN WITH MY OWN EYES and many others have had the same experience with other then me which go agains't your COLD HARD FACTs don't claim them as cold hard facts


you wrong by saying ALL cars
take it or leave it


btw you didn't have that bit of information in there when I quoted you you had something else listed which is what I quoted

and now that I noticed that a few other things I would like to add. the turbo car is quite a bit different then the rx7 I own.
for one they have two turbos which much larger injectors and a different style of air flow, way different port timing as well as port sizes, compression differences rotor weights, other acceceries attached to the motor, differences between a car that is stock vs non stock, gear ratio differences, how tall the tires are and wide they are (rotating mass as well as friction from the tires rotating) the whole intake and exhuast setup, different cars for the most part. I mean two complete different cars. worse then comparing a l03 vs a l98. EVERYTHING is different on that car then it is on mine. I mean EVERYTHING. well except the alternator since I'm using a fd alternator.

just to give you an idea of the port timing differences (not counting my aux ports. best way I can describe them is think vtec)
Primary intake (Part throttle/cruise)
IO 32° ATDC
IC 40° ABDC
Secondary intake (Part to full throttle)
IO 32° ATDC
IC 30° ABDC
EO 71° BBDC
EC 48° ATDC

and for the car you quoted
io ATDC 45
ic ABDC 50
secondary
io ATDC 32
ic ABDC 50
Exhaust port position
eo BBDC 75
ec STDC 48


but again your cold hard facts are wrong from what I have witnessed first hand and what others have witnessed in riding with me or even driving my car themself. and again this being both ways I doubt I'm going to catch a tail wind everytime going both to and from the place at higher speeds.

so next time BEFORE you spout them as cold hard facts experience make sure your right cause in this case your wrong.


I'm not trying to be an *** and if I seem that way I'm sorry kinda tired right now and it doesn't sit well with ppl stating things as true and fact when it's not and when it seems as though you are trying to make me out to be a lier when I'm not.



btw I think it is time for bed