wthdidusay82

iTrader: (15)

I've been doing my homework and read up on ethanol blend fuels having potential to cause us rx7 owners problems while using premix, I'm sure it can still cause problems even if you arent as well.

What kind of problems has this caused anyone? There's so many places using ethanol blend fuel that its become a task to find pure gas to avoid potential problems.

There's no doubt in my mind that not all rx7 owners or car owners are aware of this problem and still run this stuff even though there's no good reason to.

Anyone still running this stuff, anyone have problems? I'm **** when it comes to my car and knowing this I don't ever want to run any of that in my Turbo2.

The only thing I was aware of is that it makes your gas mileage worse.

peejay

I've been premixing with E10 in RX-7s since 1998, since 1998 was when I got my first RX-7 and I never had one with a working MOP so I've been premixing for oh, about maybe 200,000 miles of rotary driving. And E10 is all they sold in Ohio since at least the mid-80s.

It is not an issue, period. There is nothing wrong with E10 as as motor fuel. Essentially everything made for sale in the US since the early 70s is fine with E10, back when they called it "gasohol".

wthdidusay82

iTrader: (15)

Is your car turbo or NA?

peejay

N/A, but it doesn't matter. Any air/fuel ratio difference is in the same range as sensor drift (5% or less), and the factory turbo calibrations have the engines running extraordinarily rich, nearly to the limit of stable combustion. So you go from 10:1 to maybe 10.1-10.2:1.

The world will utterly fail to end.

BTW - I used to get 27mpg regularly, a high of 33mpg, on E10. Oh, the horrible things it does to fuel economy I get 24mpg with my bridge ported 13B with 4.78 gears and fat tires.

wthdidusay82

iTrader: (15)

My car is an 87 t2, I'm just a paranoid over analyzing person.

urquiola

Hi!: the SAE paper 800974 by Syvaro on their 440 cc per chamber engine, oil cooled rotor, air cooled housing, and also by Total: SAE paper 19740201, 19730201 on Fuel and Lubricating Oil requirements of RCE, same subject as SAE paper 2014-01-2611, point a lower thermal load, lower emissions and better SFC with 10% alcohol on gasoline than with gasoline only. Does anyone have experimental figures in a 13B for the Gasohols vs Unleaded? Thanks, + salut

DeaconBlue

iTrader: (31)

Old thread, but....

Late this summer I switched all my 2- & 4-stroke power equipment over from 89 octane pump gas to 89 octane Ethanol free gasoline and was amazed at the difference it made. The small engines run smoother, started quicker and worked harder.

I couple years ago when I started pre-mixing, I started using 89 octane pump gas in my S5 n/a vs. the 87 octane pump gas. She seems to like the higher octane fuel, but after experiencing the change with the power equipment, I decided to eliminate Ethanol from the RX7's diet as well. I run her tank down and then add 5 gals of non Ethanol gas, run it down again and repeated until most if not all the Ethanol had been run out of the system. The engine seems to be running much smoother now and pulling noticeably harder and quicker from 3000 RPM and up. She will now pull smoothly in gear from lower RPM's as well as requiring less down shifts and I can keep her in gear while coasting down all the way to 1100-1200 RPM without any stumbling issues, before I need to push in the clutch.

I know that 89 octane Ethanol free gas is not cheap at $3.79 per gal. It also may be hard for most folks to find. This is the same gasoline that they sell at marinas for $5-6 gal. I used this guide to track down a local station with a drive up pump that make it convenient to fill up the tank and/or 5 gal Jerry cans;
Ethanol-free gas stations in the U.S. and Canada

I only drive the RX7 about 2K miles a year so the cost impact is less than $200. Just to have her running better and knowing the inside of the fuel system is not being corroded by pump gas with 10-15% Ethanol along with the water it attracts, is worth the cost. Plus I am sure the 2-stoke oil is working better without the Ethanol in the gas as well. It may also help to boost the MPG a bit as well since the energy per unit mass is greater with non Ethanol gasoline compared to 10-15% Ethanol content oxygenated pump gas. Maybe I am being a worrisome **** retentive engineering type, but Ethanol is very astringent, and its presence cannot be helping the life of the apex or side seals, whether the fuel is pre-mixed or not.

One other benefit is that non Ethanol gasoline actual smells the way gasoline used to smell, which brings back fond childhood memories

As always, YMMV.

peejay

Be cautious when trying to make a direct comparison - if that fuel is not normally intended for road use, it may have a different specific gravity and/or RVP, which can affect combustibility.

I can think of some "pure gasoline" fuels that are absolutely horrible for drivability.

DeaconBlue

iTrader: (31)

This 89 octane Ethanol free gasoline is motor vehicle fuel they start out with at the fuel depots before they blend in the 10-15% Ethanol content, then load it into tanker trucks and deliver it to the gas stations. You can't transport Ethanol blended fuels in most pipe lines due to their carbon steel construction, so it has to be blended at the fuel depots and carried in stainless steel tankers.

Keep in mind that if you take 0.9 gals of 89 Ethanol free octane gasoline and add 0.1 gals of 113 octane Ethanol, you end up with 1.0 gal of 91 octane "oxygenated" pump gas.

You can also buy the supplies and remove the Ethanol from pump gas yourself at home.

http://www.mcnews.com/mcn/technical/2012decethanol.pdf

You just need a way to flash off the Ethanol water mixture.

j9fd3s

iTrader: (3)

in California we've also had E10 for 20 years? a really long time.

there are no problems to report with it, its fine.

since we are right next to Oregon, and they don't switch, Dad has A/B'd the two, and the cars all run the same, but E10 does drop milage by maybe 1mpg.

DeaconBlue

iTrader: (31)

Yes California has had E10 for many years and it had MTBE laced gasoline before that. Yes your MPG will be lower when using E10 fuel simply because the BTU per unit mass of the E10 fuel is lower than that of non Ethanol gas.

The problem with the EFI controls on the FB & FC models is that they lack modern sophistication - we only have the 1-wire O2 sensor and these are pre OBD-I systems. Back in the day running oxygenated fuels required a different base calibration in the fuel and spark maps, hence the old "California only" and "49 state Federal" calibrations / certifications for vehicles. As time went on the "California only" fuels spread, first to six other western states and then nationwide. The only difference today is that premium fuel in those western seven states is limited to 91 octane, while most of the rest of the country you can still find 93 octane - but that is another issue.

Basically running what amounts to the old "California only" fuel (E10) in a 25-30 year old vehicle that has the old Federal calibrations is that the engine has a tendency to run lean. That is the whole idea and propose of using oxygenated fuels - run the engine lean to reduce HC and CO emissions. Combine that with E10 propensity to attract water and the astringent nature of Ethanol itself, all adds up to negatives for the older rotary engines. By running non Ethanol 89 octane fuel in my S5 n/a, I have eliminated those issues. What I found is that by using basically the fuel that was available back when my car was new, results in my engine running noticeable better than using today's E10 fuel. Logically, that should not be a surprise.

As always of course YMMV.

peejay

"California" and "49 state" has nothing to do with the fuel, but everything to do with the emissions standards. As a rule of thumb, California has roughly 75% of the allowable emissions of Federal. The rules for degradation over time also vary, under one system the lifetime degradation is based on the as-new standard and under the other system the degradation is based off of what the car produced new. (So a car that produced .1ppm when new on a .5ppm limit and produces .4ppm when at 100k, is unacceptable, even though it's still lower than the limit it was designed to)

Two completely different systems, one country. CARB gets grandfathered in to being allowed to have their own separate set of emissions standards because the CARB existed before EPA automotive regulations.

DeaconBlue

iTrader: (31)

Unfortunately there are completely different fuel formulations for California and the other six western states vs. the rest of the country. They also change the makeup of the formulations of the "west coast fuel" at least six times a year, compared to the fuel in the rest of the country that is reformulated twice a year.

The point I was trying to make is that running a modern oxygenated fuel (which started out as a California only fuel back in the day) in a 25-30 year old car that was designed for a non-oxygenated fuel may not be optimal. My S5 n/a runs much better on the 89 octane non-Ethanol gas. I just wish I had started using it before the last few weeks of the driving season.

As always of course, YMMV.