risingsunroof82

iTrader: (3)

Well I'm about to drop my 12a bridgy into the 7 and was thinking, what octane will this want? I know my stock core engine likes it as low as possible but what about bridges?
And how about a few things not to do in a bridport... like is downshifting often good for them or do they not like those sorta things? Or maybe a couple things that I will need to do I didnt before...
Thanks guys!

Keith13b

iTrader: (6)

Unless you are under boost or have high compression, 87 should be fine...

Kentetsu

Yep, for any NA application go as low as possible.






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PercentSevenC

Not necessarily. The RX-8 ECU, for example, pulls timing when running on 87 octane. But with 9.4:1 rotors, 87 is just fine.

risingsunroof82

iTrader: (3)

Nice..... well I may be filling up every other day but at least its gonna be the cheapest stuff. lol And what about gas stations that have ethanol in their fuel? Should I go to a place that doesnt have ethanol? Cause sheetz has alot of ethanol in their gas but our local quick fill doesnt have any.

KansasCityREPU

iTrader: (9)

If you have a choice, go for the non-ethanol gas. I would thinmk that the ethanol would wash away more oil. My reasoning is not based on any facts though.

DivinDriver

iTrader: (15)

Driving my dad's old car from Iowa to California last month, I was shocked to see some gas along the way rated as low as 85 octane. Realized later it was due to altitude... was in the western parts of Wyoming.

OneRotor

iTrader: (3)

ethanol in your gas reduces the specific energy of your fuel.

Keith13b

iTrader: (6)

It also eats rubber and aluminum. I am surprised they are allowed to put it in everyday gas as many cars are old and use rubber o-rings and have aluminum in the fuel lines/rails. I have noticed a considerable drop in mpg when they switched to E85 fuel in my DD. Sad, but I guess its better for the environment and puts $$ in the pockets of the refineries by dilluting the gas but keeping the price sky high.

If you have the option, stay as far away from ethanol as you can. Just ask any boat owner who gets forced to use E85 in marine environments- the fuel tanks corrode and clog up filters, etc. Havoc on an engine thats not made for it!

Personally - it drives me nuts and cant stand it.

j9fd3s

iTrader: (3)

i think when CA switched to the 10% alcohol blend fuels in the 90's the only thing we really had fail/go wrong was the pulsation damper, and fuel injector orings.

but 15 years later, its fine, we don't see the dampers fail hardly at all anymore

wankelnewbie

iTrader: (2)

Umm, somebody correct me if I'm wrong, but I think E85 is 85% ethanol and only 15% gasoline, and you should only run it in vehicles with the flex-fuel tag. Maybe I'm wrong for assuming yours isn't flexfuel. Most of the regular gas you buy has up to 10% ethanol now, except a few smaller places that advertise they don't have any ethanol.

And yeah no kidding about the mileage, I rented a cargo van that was flex fuel so I filled it up with E85 (it was like 30% cheaper iirc, that was years ago), and it burnt thought the tank FAST. I filled it back up with regular, and when I was doing my expense reports the next week I added it up and the E85 was actually more expensive per mile than using 87 octane (even though the 87 was still "up to 10% ethanol").

I thought gasohol failed miserably during the Carter admin, now they stick a different name on it with more corporate welfare so the ethanol makers are getting rich while driving up food prices due to crops being diverted to fuel.

Screw it, I prefer my ethanol over ice with a drop of lime!

j9fd3s

iTrader: (3)

i guess it takes a couple gallons of gasoline to make 1 gallon of ethanol or something like that...

seems to be a great fuel for the turbo people though

PercentSevenC

E10 is mostly pointless. I want me some E85, but no one sells it around here. 105 octane pump fuel with more energy than gasoline at stoich? Sign me up. Screw range, I want more boost.

DivinDriver

iTrader: (15)

Nothing wrong with alcohol as a fuel (or majority mix like E85), so long as you don't care about:

Fuel efficiency: Alcohol delivers only 66% as much energy per unit volume (and we buy by volume measure, you know; gallons) compared to gasoline. Burning E85 yields 75% gasoline mileage, on the same engine geometry. An engine designed to run on alcohol can be made more intrinsically efficient than a gasoline engine & thus take some of the pain out of that, mainly by increasing compression. And you'll still go a lot less distance per dollar of fuel cost.

Greenhouse gasses: Burning 100% alcohol produces as exhaust only water vapor, and CO2. Used to be that was considered a LOT cleaner than producing CO, NOX, and HCs... until the global warming bunch started dithering about AGW; water vapor and CO2 are both powerful greenhouse gasses. (Not something I worry about, but many do...) Warmists who are also ecofiends tend to opt for highly-manipulative data (like calculated "life cycle carbon totals") to try to move the goal post, but the hard fact is the act of using a gallon of ethanol generates more volume of GHG than does burning a gallon of gas.

Cold Starts. Whole reason for E85 existing; alcohol's insufficiently volatile at low termperatures. Very difficult to cold-start a pure alcohol engine. Might lead to the revivification of system like the 1st-gen "cold start assist" that would inject measured gasoline or other volatile fuel below certain temps. Solvable problem for future designs, only really an issue for existing vehicles.

There's a bunch of other arguments having more to do with politics and economics rather than 'hard' science, but not worth opening that worm can here.

Pure alcohol's a dandy race fuel. Not quite as dandy for a direct-swap fuel.

Keith13b

iTrader: (6)

My bad - I meant E10

Brain fart - every damn pump now has it. Even premium....

Hyper4mance2k

iTrader: (40)

e85 has much less energy than gasoline...
stupid E10 used to be only Summer Gas.... Now as of 2002 I think it's all year nation wide.

Back on topic. Start out locked dizzy set at 20*BTDC with the lowest octane. Shoot for 12:1-12.8:1 AFR's. Once you're good and safe you can pull timing out and go up until the power starts to drop off. With a bridgy if it flows well you'll most likely make the most power at 20*BTDC if you need more timing than that it's most likely because of a flow limitation in the carb or exhaust. On my engine I make the most power at 27*BTDC but that's because of the long small runner intake manifold I'm running under my IDA.

PercentSevenC

It has lower energy density. However, stoichiometric for E85 is like 9.0:1 AFR, so the energy produced at a given lambda is a fair bit higher than gasoline.