JDK

iTrader: (8)

Steve,
Did you find you had to add alot more fuel to the cars you tuned in Toronto?
All the cars were using Sunoco Ultra 94 which is ethanol enhanced fuel, not sure on the percentage but I think it's 10%, any thought's....

cewrx7r1

iTrader: (2)

Howard wins, not really.

How about: Yuck Yuck Yuck Yuck!

enzo250

ethanol has been mixed into our pump fuel for years without us even knowing.
So i wouldn't worry about it too much. They have been secretly doing this for quite a while.

enzo250

Actually it burns slower!

Meth usually requires twice the amount of gas NOT ethanol.
Ethanol usually requires about 30~40 % more then gas.

thomas_m_cool50

How high fuel octane number should i put on my Rx7? Its imported from japan, and i dont think they use 95octane ore 98octane like we have in norway. Do i need to use an octane booster?

twokrx7

iTrader: (1)

I could be off here but I recall some gas stations in houston as much as 5 to 10+ years ago that had warning labels on their pumps saying the gas may have contained up to 10% ethanol. It was the cheap gas stations that displayed these warning signs, stations like Exxon and Chevron did not.

GoodfellaFD3S

iTrader: (213)

Is the car stock? 93 octane should be fine.

fastcarfreak

he is from norway. I dont believe they use (r+m)/2, for there octane rating. I think they only use RON.

I would just just use the highest octane available to you at the pump, it should be fine.

cardzrule

So r u saying that AFR aint based on weight?

I aint never heard of BTU denstiy. You got a website link that explains or is that something u just made up?

OK but teh thread is about AFR not power, or at least that what was written first. So did ur AFR change 3.5% or ur dyno readout 3.5%?

eastcoastbumps

iTrader: (1)

The thread is about ethanol, which has a direct relationship between AFR and heat, and is used to make power (since its in your gasoline). Lets review some basic principles of a motor. Its an air pump. An AFR richer than 14.7:1 is used to cool the combustion process. Adding more fuel without adding more air (running a richer AFR) will not substainially change power output. If you tune your motor to 11.0:1 and change to a gasoline with more ethanol (less energy) you will still be making the same amount of power if you remain richer than 14.7:1 and do not increase airflow. Since ethanol produces less energy, you need more of it if you want to balance out to your original tune of 11.0:1 and absorb all that extra heat.

I'm not sure what you have as far as datalogging cruising fuel trims, but if you were to look at the long term and short term fuel trims of just about any OBDII equipped car running 10% ethanol, you would see that they are adding fuel to compensate for the increase in ethanol.

svtcarboy

Ethanol is naturally over 100 octane, so that should not be an issue. However, I hate the crap, so I go to stations which sell off-road premium (non-ethanol). A biker site lists the non-ethanol stations in my area, and a network of them should be posting in your area.

BTU density is the amount of energy per quantity of fuel. Ethanol has about 15% less energy in it by volume.

I find my mileage is about 7-10% worse with E10.

Henessey

**** this **** man

fastcarfreak

lol, care to elaborate....

cardzrule

Mr Stevens my science teacher says that is called energy content. I aint never heard of nothing called BTU density. Is that metric stuff or something?

cewrx7r1

iTrader: (2)

The term is used in some articles about comparing alcohol to gasoline and other hydrocarbons, and sometime they refer to it as BTU per volume or BTU to gallon.

From one article:

We usually find the mass energy content of fuels tabulated on an energy/mass basis. Yet the energy/volume is often equally important for shipment, storage and use. This table includes the densities of various fuels and calculates the volumetric energy density.

peejay

That's your area.

NE Ohio has been 10% ethanol for at least the past 10 years. At least, I never remember seeing a pump that *didn't* say "10% Ethanol Added".

cewrx7r1

iTrader: (2)

According to the US GAS MAP dated May 2006, Ohio does not have any mandated gas requirements. Thus your gas is what ever anyone wants to sell. When I worked in Akron this last winter, no pumps there said anything about alcohol.
But then Akron is not NE Ohio.

SlingShotRX7

If your area isn't mandated by federal law to require Ethanol in your gas.
Its very likely it doesn;'t contain ethanol.

why??

Because Ethanol cost more and less effective..

So as a retailer if you had a choice to pay less why wouldn't you??
unlike you they like pissing money away..

Rx_treme

Everwhere i've ever lived has had 10% certain times of the year and other additives the rest of the year. It has signs on all the pumps stating what dates and what percentages and what its supposed to help with.

IRPerformance

iTrader: (41)

Keep tuners employed bah....Just add the fuel yourselves. If you have a wideband you can verify the change in a/f ratio. I do this in my cobra to compensate for weather changes/

cewrx7r1

iTrader: (2)

The map can be found on the Exxon site. I posted it's URl in another post on this forum. Most of Az has real gasoline, but from about the center of the state down to Mexico, there are two regions of AZ CBG and Oxygenated fuel.

Mr rx-7 tt

iTrader: (5)

You guys are a bit behind the curve.

https://www.rx7club.com/forum/showth...hlight=ethanol

peejay

Ethanol raises the octane content fairly expediently, and it absorbs water nicely. Good to prevent moisture in the fuel system from freezing in the winter. (It's why I laugh every time someone buys HEET, the damn fuel is 10% alcohol anyway!)

My co-worker used to work at a combo gas station/repair shop, and the word from him is that the 10% ethanol mix is actually cheaper, at least in our area, so everyone sells that. There used to be a few places that sold straight "gasoline" (however you choose to define it) but it generally cost a few cents more, and a few cents is a lot at a buck/gallon.


My question is, if oil prices are going way up, and prices at the pump have doubled to tripled depending on grade, how come race gas went from $7 to $5 in the past few years?

cewrx7r1

iTrader: (2)

Maybe so, but noticed the thread died, and no one even added or commented on it. That is the 3rd gen forum mentality and why many of us single turbo people do not go there too often.



Notice the response here, we care about our cars more!

cardzrule

So you saying E10 iz based on a mass ratio? Mr Stevens sez its by volume. I think ur numbers r wrong dood.

Also gas aint 14.7:1 stoich unless u mean leaded. Mr Stevns sez gas is like 14.5:1 and MTBE gas is as low as 14.1:1 for stoich. So goin from MTBE to E10 should be like equal for AFR neway. What teh AFR gauge sez is another story tho coz depens on how lambda is set.

I dont think ne1 understands it. I had to ask my science teacher to xplane. I aint seen ne1 yet who understands it without asking a science teacher.

Like teh Mr rx-7 tt article sez, if ur AFR gauge is set at 14.7 AFR for stoich then ur readings r totally wrong dood.