dean23

acetone helps the fuels tension area spread out, so it can fully combust easier. works well for some cars and not otheres. but wondering what its like in a rotary... but if i keep under 15mpg im in trouble...

chinkst3r

iTrader: (5)

lol dean ur telling me, i just replaced my o2, and filled and i got 15 exact... =( sucks, and i commute everywhere, so i travel atleast 2-4 hrs on the road a day

RotaMan99

What type of roads do you drive on? Residential, city, or highway?

chinkst3r

iTrader: (5)

i drive all over, my work and school are about 5-10 mins from the freeways, and my house is 15 mins from the freeways... however, after reinstalling the o2 sensor i've noticed a difference in how the engine reacts to the gas pedal, and i seem to be getting good mileage*knocks on wood**three times* so far im at about 220 miles and still got a little left in the tank, barely above the double bar E

RotaMan99

You have a T2 right?

jgrts20

aha I get 200 miles per tank city and my car runs fine. I really dont know what to tell ya.............WE GET SHITTY GAS MILEAGE. I really dont know how some of you guys say your getting 350-400 miles per tank. That like what a new car gets and our cars are definately not new. My 1st gen was worst and it was running a holley 4-barrel carbuator, so I consider myself lucky getting 200.

RotaMan99

IF I filled my tank and drove in the city every day. I would get about the same. The city, because you are in stop and go traffic all the time you are not getting a high millage vs Rpm ratio. Think of it this way. On the highway at 2500 rpm, I do about 55mph. If im in the city at 2500 rpm for any reason I may only be doing around 35mph. It gets worse when you are crawling in low gears at rpms you would normally get high millage at when on the highway.

Obveously it also depends on how hard you run the motor.

One thing I do that I notice really helps, is I only fill my tank half way so Im not hauling the extra weight around. I get better MPG this way. Get more for your money.

chinkst3r

iTrader: (5)

lol, yahz i got T2, but i hardly boost cause im so concerned about the mileage... oh wellz i guess haha thanks for all the help guys

s4Lt

I would imagine this to be false cuz when I was NA I would run 87 octane and then tried 91 and the car loved it, better throttle response and burns better, also cleans better. After a while of 91 I tried 87 and car hated it, was all sluggish as hell. Almost all manuals will say 87 octane even the corvettes. You will have a shittier MPG but your engine will perform better and stay cleaner.

so-mars

thnx

had no idea exhaust leak would kill fuel economy so much

RotaMan99

False False and False.

91 doesn't burn cleaner nor does it burn better. Everyone thinks of higher octane fuel as cleaner, better fuel but does not understand what its real use is.

The higher the octane, the more heat it will take to ignite but it has the same explosive power as 87 octane depending on the AFR you run. The rating is usually called anti-knock rating or Resistance to detonation rating. This is so you can run much hotter combustion temps and compression, which leads to hotter combustion temps, with a lower chance of pre-ignition and detonation. Thats all higher octane is good at.

I highly doubt it increased your throttle responce, this would all be in your head. Take it to the track and you will run slower with higher octane in an N/A then with lower octane.

Do a tune up, tune your timing and adjust your fuel and your engine will run a LOT better on 87 then it ever will with a higher octane.

And how the hell can a fuel, CLEAN? 91 does not clean better nor does ANY FUEL. If your thinking of using 91 to degrease parts, well thats a difference story. Burning it in an engine that is not design for 91 could cause excessive carbon build up.

To further understand Octane Ratings. Please read this
http://en.wikipedia.org/wiki/Octane_rating

Please don't post that information again

RotaMan99

To correct my self here. Higher octane fuels have more explosive power/energy, then lower octane fuels. At difference AFRs you will get different BTU outputs.

RotaMan99

haha, your welcome. I did not know it either untill it happend to me and I was wondering why my fuel millage dropped so rapidly. I then though to my self....The exhaust leak is right after the O2 sensor..... DING DING DING. I felt really stupid after I realized that.

s4Lt

Yeah what ever dude, its not "in my head" like I said, Ive back and forth and I had much better performance with 91 then 87, I was telling my friend with his 5.0 Mustang the same **** you just told me and then I decided to try the 91, bigger/stronger combustion = more power, a c4 bomb will give out more output power and do more damage then a hand grenade. Bigger explosions/more powerful explosions = more power.

RotaMan99

A little from the link I just told you to look at.

A common myth amongst petrol consumers is that adding a higher octane fuel to a vehicle's engine will increase its performance and/or lessen its fuel consumption; this is false—engines perform best when using fuel with the octane rating they were designed for and any increase in performance by using a fuel with a different octane rating is minimal or even imaginary

Obveously it was on different days you filled up so the air temp, whether it was colder or warmer could have put this thought into your head.

I have also put 91 in only because I hit the wrong button the pump, filled up with 91 instead of 87. My car never ran so slow in its life, not counting the time it was running on one rotor.

Why do you think Turbo guys like running on 87 or the lowest octane they can safely? Its because it takes less energy to ignite the fast burning fuel. Why not just run 100 octane all day? Would you run 100 if it was available at the pump stations? Higher octane fuels have more POTENTIAL energy IF your engine is designed for it.

I just realized I didn't use the word potential when I corrected my self 2 posts ago.

The higher octane fuels also burn slower.

Different material inside plus a lot bigger. Wrong compairison. We are dealing with the same amount of fuel just a different octane rating.

RotaMan99

I guess the last link was to long for you to read. Here is another.

http://theserviceadvisor.com/octane.htm

and another

http://www.bajajusa.com/High%20Octane.htm

and another

http://www.wisegeek.com/what-is-high-octane-fuel.htm

All basically saying the same thing. Why should your so called knowledge be any different?

RotaMan99

Is that your white T2? If so have you done any mods to it? Increased boost at all? If so may have also been why you felt a gain. I did not realize you had a T2 if its yours.

Still, you need to keep in mind what high octane is used for and how it works. Don't blurt stuff around saying stuff like, it burns better, cleaner and gives you more power.

s4Lt

I didn't read it cuz I didn't feel like wasting my time. No its not my white 7, and btw, the same amount of c4 as a grenade c4 wins hands down. SO the comparison is valid.

I don't even read half of what you say so you're wasting your own time lol.

TehMonkay

iTrader: (-1)

:: Waits for RETed to own the n00b on higher octane fuel::

CarzArKoo1

saving gas, changing spark plugs work, how many plugs do we have? for 13B, is pretty much easy to acess right?

so-mars

my car runs better with uhh 93 ? 91? i cant even remember what the shell ultra premium is or whatever. it has additives in it that clean out the engine i dunno what kind of retards you are talking about running cleaner when its actually cleaning while running because of detergents.

and also by your own words if you tune your car differently for your gas then you get higher performance.

and im sure like 90% of you here are delusional weed smoking alcoholics who slept with your sisters when you were younger so yeh. heh.

probably took auto shop in high school to work on cleaning the mud off your truck and failed out of community college too heh

s4Lt

word, I think. Not quite sure what you wrote there, I think Shell has 93.
Are you agreeing with me?
LOL

RotaMan99

Alright, so for now on we should tell everyone to buy 91 or higher octane fuel because it automatically burns better, cleans better, burns cleaner and give you instant power.

Learn something everyday....

And to the post about shell gasoline. They do use additives but its not octane specific. Higher octane by itself will not clean better, burn cleaner and give you instant power.

My argument here is from when he said that 91 cleans better. Its not the fuel its the additives the fuel stations put in after the fuel is dumped into the tanks.

As long as your engine needs it. In a stock or semi modified N/A, you would not be able to get 91 to burn better then 87 and get more power. In a T2 there is a better chance because of the high compression numbers from boost.

I don't exactly know where you intended to go with this?

Rx7TyreBurna

iTrader: (1)

Well, interesting reading.... someone should fill there car with some 91 octane and take it to the dyno, and then have a can of 87 there, and drain all the 91 out after a run, and then fill with 87 and dyno. I am guessing that the numbers will be a little off.

87 octane does burn better in our cars then 91 octane. Higher octane ratings are suggested for higher compression motors, or turbo motors because the can create higher compression. Higher compression being 10:1 +.

I fill with 87 octane, used to be hardcore 91 octane, but then after reading, and running some tests, like I said above, it turns out the 87 was better FOR MY SETUP. Now if you are running a turbo with a ton of boost, stick to higher octanes, if you are running some insane compression rotors, also stick to the higher octane. But, for mostly stock RX-7s. Or even pretty modified, 87 ftw.

It really doesn't make a difference to me if anyone else is paying more for their gas and losing a couple HP.

As for gas being clean. There are gases that have less detergents in them. Shell uses the most. But you can get 87 octane from them and get the same number of detergents as buying their 91. I usually fill with their 87, because then I am getting the number I need and the detergents to keep my injectors clean.

But, to the OP, I had this same problem. It ended up that I had two leaks. One was a worn out FI line coming from the fuel filter. The other was my PD.

So, I would suggest checking your PD and all your fuel lines. Sounds like a small leak somewhere to me.

Also, I am getting 20-24 mixed driving now.

RotaMan99

Same here, I just don't like it when some make false statements they are trying to argue is true. Good post btw.

I had to replace my metal fuel lines from the tank to the engine with SS ones. I replaced all the fuel lines on the engine as well. Made some SS lines that go under the intake manifold so I have no rubber lines rubbing on anything creating a possibility for a leak.