borinquen7

iTrader: (1)

Well with gas prices so high, you might aswell poor milk down the tank, I'm paying the same for both it's crazy... I live in SW Florida we are at around 3.92 a gallon for regular.
Anyways last week I tried Mobil gas and my mileage icreased by a good 20 - 25 %,
the problem is now the car starts up with a really low idle, and when I turn her off, she shakes, kind of like when you put cheap gas in a 4 cylinder. I used to use gas from the SITE gas station, but I really was not getting good mileage.... Before I assume it;s something else I am guessing it's the gas but I do not understand.. Those this make sence to you guys, I assumed better mileage the gas must be better.
Just to be clear when I turn her on she barely idles for a second or two then gets back to normal, and when shutting off the engine rocks just a little, just started doing it once I started using the Mobil gas.
Any thoughts
Thanks
Peace
Cruz

Toyman01

Haven't paid any attention to it in my RX-7, but my work van (E-250) gets about 12mpg on Sonoco, and 15-18mpg on Amaco. When you buy $100-$200 in gas a week that makes a big difference. I don't buy no name gas anymore. Gas is like everything else, you get what you pay for.

Rogue_Wulff

Ethanol.

slate84

+1. 89octane 15% ethanol ftw

Joker1337

Ethanol and 89-octane? E85 specifically? What sort of results are you getting?

tallbozo

iTrader: (5)

Yeah with ethanol, I've been getting close to 28mpg....25 was my standard prior...

perfect_circle

are you running that in the boosted car, where the octane increase can be used? i wouldnt think that such a boost in octane would be good for a NA 12a. ive thought about converting to e85 as well.

ray green

iTrader: (14)

"Anyways last week I tried Mobil gas and my mileage icreased by a good 20 - 25 %, the problem is now the car starts up with a really low idle, and when I turn her off, she shakes, kind of like when you put cheap gas in a 4 cylinder. I used to use gas from the SITE gas station, but I really was not getting good mileage.... Before I assume it;s something else I am guessing it's the gas but I do not understand.. Those this make sence to you guys, I assumed better mileage the gas must be better"

You are right, this doesn't make sense. There is no way switching to Mobil gas can "increase (your gas mileage) a good 20 - 25 %". Government regulations require that all brand meet the same specifications, any differences between brands is simply advertising. For example, gas companies routinely buy each others gas and sell it under their own brands.

Also, as you point out, getting 20 - 20% better gas mileage cannot equate to poor engine performance (it would have to be the other way around).

So I would suggest the following:

1. Get better data before drawing conclusions about gas mileage. Typically this means running several tanks of gas (at least 3-4) along with careful recording of gallons used and miles driven ALL UNDER YOUR TYPICAL DRIVING CONDITIONS.

2. Tell us what that gas mileage is along with the details about your car and driving habits - these details are also important when drawing conclusions about gas mileage.

3. Get a tune up - I suspect the real explanation for your recent erratic performance is something entirely unrelated to gas brands.

4. Nice looking car, that stock SE should be getting around 23-24 mpg easy, not bad for a 23 year old car.

Good luck!
Ray

Rogue_Wulff

In my EFI Nissan truck, I get 15% lower MPG when running E10 vs 100% gas. It's an older (OBD I) system, and it was never programed for the ethanol. Ethanol is added as an oxygenate, and with a carbed system, it works well, but in an EFI system the oxygen sensor picks up the higher O2 level, and (incorrectly) assumes the system is running lean.
When the E10 was first starting to show up, my MPG was very erratic, because the E10 was slowly replacing real gas as it started becoming available. To add insult, this state doesn't require stations to label their pumps unless the blend is 15% or higher.
According to most tests, most all newer vehicles will see a 7-10% drop in MPG when using E10. This really sucks, as there are only a handful of stations that still sell 100% gas, none are located anywhere near my location.
As for E85, it requires either a "Flex Fuel" vehicle, or rejetting the carb on an older vehicle. It also provides ~25-35% lower MPG.

slate84

e85 = less BTU's FTL.

NoPis10

iTrader: (29)

As already stated above...
ALL gas is the same.... The only difference is the detergants that are added for their "Name" brand recognition. Have you ever seen the gas ports where the trucks load up??? The fill/storage tanks are used by ALL companies, there aren't different tanks for Mobile/Chevron/BP/Amoco etc etc etc..

Either way you may have gotten gas that was contaminated with moisture/ maybe fuel filter change is in order or else it may be time for a tune up...

L8R

zeroecco

think of it this way. If you want the same btu's from fuel that you can get today then get an racing fuel and do the math to use it as a additive. But KNOW your going to kill whatever cat you have on your ride. I personally am having a ridiculous time trying to get my 7 to pass emissions here in oregon. all of us carb guys have it easy, your ride WILL NOT run n the same ratio of fuel that it does now but you will be passing emissions. Now you will have less power in your car for sure but you could Technically throw just a cat on your ride and pass emissions most everywhere. meaning dumping the rats nest etc.

KansasCityREPU

iTrader: (9)

Running ethanol in a vehicle that was not designed to run it will lead to fuel delivery system failure. Ethanol does nasty things to metal and rubber products not designed for it.

Rogue_Wulff

You know that, I know that, as do many others. But, do the fuel retailers care? NO!

borinquen7

iTrader: (1)

You guys are abosutely right, Ray green and the rest, I should have gotten my facts and data better, before I made that assumption. I do honestly believe I get atleast a little better fuel mileage between the two gas stations. Also now that you guys mention it , yes it is time for her tune-up.. Because I am Definately not get the mileage you guys say, So I will do my research and report back. And thanks for the compliments on my Baby...
Peace
Cruz

ray green

iTrader: (14)

It looks like that SE is tornado gray with the red leather interior, doesn't get any better than that.

Siraniko

iTrader: (13)

Title is misleading...its about fuel, not the fart gas

shaunwil

lol, you guys should try living over here in the UK. Its currently $2.22 a liter and has been rising by about $0.04 a week for the past month or so.

Diesel is running at $2.52 a liter and rose $0.16 in the past week.

Most garages are expecting petrol to be almost $3 per litre and diesel even more.

Currently my 13b FB is running on LPG (propane mix) and loving it. The whole petrol system has been removed. I have a small tank of only about 30lt but it only costs me $0.90 per liter which is extremely cheap. I'm running an Impco Vapouriser and and Carb.

Shaun

theFBthatcould

can we get some pics of your setup pros and cons
and maybe some links to the parts

rxtasy3

iTrader: (2)

i saw a show once using a dyno to get power differences between regular gas and E85. the jets they put in the carb to change it over to run the E85 was like twice the size. E85 isn't that much cheaper when considering how much more fuel that's needed to achieve the same power output. i too have considered LP but would i still have the power from the engine i have with regular gas?

shaunwil

Petrol is cheaper now ! Only $1.70 / lt !

Probably the best discussion is http://www.mazdarotaryclub.com/forum...ad.php?t=30129

Ignore Oldone, he loves the smell of petrol and oil (who doesn't !)

Main setup is a Impco 300A vapouriser with vapouriser. The tank setup is just a standard LPG tank of 45lt. Running on a 65mm Throttle body on top of a 4 port Rx4 manifold with 6 port adapter on a S4 6 port 13b. Been Running like this for about 18 months without too much hassle !

Shaun