lets say its a 50dcoe/sp, its for a Turbo 12A, and could be for a large BP latter, track, weekend only fun car.

as we know the
The correct air-fuel ratio for gas is 14.1 to 15.1(stoich is ~14.7), but for alcohol it is 7.1 to 9.1(no idea about stoichness)

so does that (jet size for gas) * 1.50 = Alky jet size, since i need to double the flow?

also what else do i need to change, float bowls, lines, do i need a speacial fuel pump or will a normal carter/holley be fine?

The reasons I want to switch is:

1) I hear that unlike gas you will find alcohol fuel will continue to provide increased power for a mixture well above the ideal mixture strength and you can always tend, therefore, to jet up on the rich side, and so avoid any possible chance of running into troubles through weak mixture causing burnt valves and holed pistons.

2) cooling effect of alcohol is a cooler running motor, boy a rotary could use that

3) hardly detonation, so turbo-ing is a little safer with octane(~100) too

4)Timing is less critical, i hear you basically advance till no more power is felt(measureed)


Drawbacks:
1)its a lil expensive i think its a bout 2bux a gal here in cen-tex

2)its alcohol, it burns you eyes and other streetracers etc will knwo you have it

3)cold start problems(not a problem here) and takes a while to get engine to operating temps

4)very dangerous, burns clear(makes fires bad), poisonus, need protection for handeling

5) no one i know here has it at pumps except for some tracks.

 

The carb might have to be modified to flow enough fuel. Single sidedrafts already have enough problems flowing enough fuel for a gasoline powered engine, trying to run on alky would be even worse. And since you're going turbo, you're stressing the fuel passages even more.

 

alcohol fuel

Before I respond to this, are you talking about alcohol or methanol?!! IF we are talking the same as used in Liquor and beer, then we are refering to ethanol which is denatured alcohol.

The *****(I mean folks) at Mazda Racing are complete idiots when it comes to terminology and knowledge of these fuels. They were trying to convince me that ethanol is more corrosive then gasoline. And it is, IF you have pre-1960 rubber fuel hose. Anything made after that will be more effected by certain components in Gasoline believe it or not. If you are talking about Methanol, THAT last statement is not true obviously.

Ethanol is much cleaner burning the gasoline. Not poisonus as gasoline, and is just as dangerous to handle.

MN offers E85 or Ethanol 85% gas 15% blend. It is intended for FFV's. Flex Fuel Vehicles offered by most car manufacturers. Gas is $1.35. E85 is $1.19. If you were to compare BTU content per cost, then gas is SLIGHTLY cheaper. Gas is 115,000BTU's/gallon. E85 is 81,000BTU's/gallon. E85 link

It took my '85 50DCO weber powered 12a Bridgeport a extra 4-5seconds for it to start on a cool day with E85. Big woop? 15% gas is added to improve starting on cold minnesota days. It is actually blended down to E70 on days below 10F.
I don't have optimal jetting yet, but its nessessary to increase your accerator pump nozzles by 1/3 more flow....and simliarly for the main fuel jets. Air correctors can remain the same. Power increase is VERY noticable and well worth it.

Yet another myth, unless you're talken about Methanol to ethanol. Ethanol combusion smells much fresher and less dangrous to breath in then a gas powered rotary. Less CO is created and much less HC's since the burning is more complete with ethanol, and there is much less NOX created. And yes, the octane is above 110 with pure ethanol so you may advance timing. But compression isn't optimized so you'll see a 10-12%increase in power instead of 15-17% if you raise compression to take full advantage of the 110+octane.

 

Wacky knows better than I.

later
Van

 

Opps, forgot to mention, ethanol is better for keeping the fuel system clean and less carbon build up on plugs and rotor face, hence less fowling out. Plus ethanol that gets in the oil quickly evaperates off since its heat of evaperation is low. Plus, ethanol does have a good cooling effect and I always notice more condisation on the intake tubes.

It also keeps the exhuast track from getting much carbon build up too.

 

Wacky ... how much was it to convert over? (i drive an FD ... think it's be much different?)

would running ethanol be emissions legal?

Oh and by the way ... it doesn't burn your eyes unless you're in a closed area with the car burning ethanol ... after a while it builds up and starts to make your eyes water. The stuff my friends dragster burns has a cinamin flavour to it (i believe it's added) and that gets to your eyes faster.

 

Well, raw vapors could do that if its running too rich at idle or incomplete combustion...he he...common to a rotary Especially with overlap found on say..my bridgeport. As anyone knows, if you pour vodka and take a wiff, you will cause a little watering to the eyes, yes. But its not harmful unless you keep breathing it in over a long term. Gasoline will cause much more harm in raw form then ethanol ofcourse.

Well, jets to a weber are $6/jet. So experimenting with different combo's results at $70. Larger Accerator pump nozzles are like $7.50 if I remember.

IF you have a FD or any engine with a Haltech or other tunable computer, a couple large injector sizes to work with, ability to tune it, you would be well off with this conversion, but with stock computer, you will not be able to do this and would possibly cause a emission test failure. I DO not recommend this if you don't have cheap access to Ethanol blends or live in a area that tests emissions on cars. Anyway, with the haltech, you can automatically set the fuel map differently to bump up the overall fuel ratio by 1/3 as a starting point and go from there. This is why larger injectors may be nessessary. Pure ethanol is about ~8.5:1 E85(ethanol 85%) is ~9:1. Pure gas is~14.7:1.

 

You can definitely tell the difference between a petrol-burner and an alky-burned by the smell. Alky burning cars have a VERY distictive smell to their exhaust. Whether it's harmful or not (hell I find HC-rich exhaust to be invogorating on bike rides) is not of debate - if you're racing your competitors will know immediately

 

cripes!

Well most of what i put for drawbacks is jsut fluff, like the dangerous part, yea i know so is gas, the poisonous thing yea i think i was think of methanol. Same with price Methanol is 2.50 a gal here, My buddy races his Kart down here so thats how I know.

So...
wow, uhh other than the AP, jets what else do I need to prep the carb.

Hey Whacky, please hit me up on AIM ( Turbo5Valve )

or email me, I would like to discuss your BP a little more.

 

Exactly, that stuff is more toxic. Also can cause irratation and cancer later on. Ethanol will cause irratation in large concentrations and in prolong exposure will cause dermititis and other lung trouble. But has very good octane and not a denation prone fuel. Gasoline, will cause cancer ofcourse from the benzene component. One fuel that won't cause any bad things is methane which people and large animals such as cows produce.(he he) Also methane is 6X more potent as a greenhouse gas unburnt then CO2, But burns very clean.

Anyway, methanol has more oxygen in it then even ethanol which is why it give more bang. I can't remember but, I think it only has 61,000btu's/gallon which translates into much more fuel being needed. Probably around 7:1A/F or less. Worse milage which isn't a concern of a racing car...sort of... IT has a natural tendency for fast detonation under normal conditions(faster then a normal denation from gas) by properties of the fuel. Again, not a problem for a short term race engine. But very corosive to everything in the car and bad for the oil too.

As you go down the line and use some of the more potent fuels(with more and more oxygen in there chemical composition) such as nitromethane, you end up with fuel ratios lower and lower like 5:1 or less. (Top fuel dragesters) Due to the chemical makeup, its much more voliatile, even more detonation. BUT, more potential for huge power gains. VERY, VERY short engine life, which is why its perfect for top fuel dragesters that only run for <5seconds....

Keep on going the more volatile it gets, the next step would be nitroglicerine(spelling). This stuff doesn't even require outside source of oxygen to explode, and yes, it makes A LOT OF detonation!!! If you do add O2, it will burn more cleanly or completely....like it matters, your quite literally sitting on a bomb!!!! HUGE power gains...except the engine blows up when you start it(sarcasism) since no one would put this in your tank...

THis is why NOS NO3 is good for power in engines, since its got more O2 then O2.... Make sense???

 

I was reading something the other day stating that if you poured a puddle of nitromethane, and attempted to light it with a lighter/match etc, you would have a damn hard time starting it. But hit the puddle with a hammer and watch the head fly off in the distance, from the explosion

How true of ethanol is this? Do I need to run a cooler plug or hotter to help ignite fuel?

 

I would stick with stock plugs, I do with no problems. I don't run ethanol much except when I want to really beat on the car. Since I stated that its $1.19 a gallon of E85 and gas is $1.35 gallon here. THe net result is that gas is cheaper per BTU....once gas is like $1.60 or so, and E85 stays about $1.19, then your dead even for BTU per cost of each fuel. And my fuel range goes from 220miles to 170miles per tank E85 which is annoying.

By the way, I would'nt mess with nitromethane if I were you..it is volatile. The problem with lighting a puddle is that its not mixed with Oxygen really, you need to spray it to make it ignite. That explosion your mentioning is detonation. Fast moving flame front in a uncontrolled manner and not smooth combustion, buncing off the walls in the chamber back and forth(which is very bad in a rotary let alone a pistion engine) but great power potential...hence dragesters usage again....since their engines don't need to last longer then several runs or so.

Ethanol.... you should know how that lights, take some rubbing ackohal and pour it out on the table and bring a match to it! It burns like any puddle of flamable liquid does, but cooler flame then gasoline....haven't you ever taken high school chemistry? If it was spray'd out and a match is brought to it, it will make a big fast flame. If its spray'd and compressed like any fuel, it will displace the volume and cause it to expand rapidly when its ignited....

 

OK so this info on the ethenol sounds raly interesting. I run a pp12a and am still jetting it and tuning it, it runs smoothly but i am still experimenting with a lot of things on it. Any ways Wacky, do you think that it would be wise to convert over sometime in the near future for my application? I am running a 48 ida right now, From what i read above you actualy go to Larger fuel jets right? So i probably wouldent get my carb to flow enough would I? Any ways gas mileage meens nothing to me any ways, and cost per a gallon is not realy a concern as long as its under a few bucks. But i am very interested. Right now my plugs are fouling out bad and jetting is a big deal. Luckely i am not using the $35/plug irridium plugs.

CJG

 

What people keep forgetting with (converting over) is you can easily go back!!!! I go back and forth all the time. Just keep the jets for Ethanol and gas in your car. Just keep the others in the glovebox when using the other. Intially you need to get your jetting opimized for ethanol and then you'll be able to convert back and forth from gas as nessessary. This is rediciouslly supid easy to do with a sidedraft weber like mine. You shouldn't fowl as much with ethanol since there is less carbon in the fuel and wrong fuel ratios won't cause fowling as much as gas will.


Max flow of the carb has nothing to do with ethanol Rotortuner. If it flows enough for your engine, you just need to bump the fuel ratio by ~1/3 in everyway to make it work. This is extremely important for the accerator pump nozzles to be much larger or it will hestate badly if you slam the gas(ethanol actually) before taking off. Main jets need to be much larger by 1/3. Air correctors remain the same or slightly smaller if its slightly lean above 8000rpm.

 

Very interested in running this in my 13Bt.. I am running it with a haltech and oversized my injectors. So i should have no problems..

I don't think my Wideband will read this though.. it does an A/F of 10:1-20:1

I would normaly be aiming for a 11:1 A/F Ratio on my car with 93 octane Gas. So what would my target A/F be with Alcohol?


I guess i could tune with 93 Octane Gas, and then just do the math to create the map for the fuel ratios..


Then i could up the timming until it stops making power.


Any thoughts?


-Zach

 

Also what type of EGT do you look for? the same?


And with a turbo car would it still be safe to advance the timming until the power drops off?


-Zach

 

Also, I am running premix. Could i mix it in like a 50 gallon drum and just use that to fill up my car?


THanks,
-Zach

 

Zach, I run premix to with no problems whatsoever. Sure, you could do a 50gallon drum if you don't like to pre-mix at every fill up, but then can't go very far. That is like 50oz's of 2cycle oil though. Ofcourse when I say ethanol, I'm talking about E85(ethanol 85%). Which is why you'll run about 9:1 for stoicometric and 8.5:1 for best power. Pure ethanol isn't sold anywhere I know of. E85 is for Flex fuel vehicles but can be used by tuners like us also who can vary fuel ratio greatly.

I am uncertain about your wideband meter. You may have to do some guess work with math to figure where you should be. running rich is always safe and nessessary, and go richer and leaner as nessessary.

I wouldn't over advance the timing. Just a little more advance then you are now will yield the best power. Safety first for you engine. Over advancing will not result in major gains. But since you're running boost, you power increase will be well worth the switch. And with the haltech, you'll be able to have seperate maps to go between E85 and gas. However, you may need larger injectors to make it work with E85.

 

Well, i have 2x550 primaries and 2x1600 secondaries.. That should be plenty of injector

Yeah, i am looking at running E85..

So you think 8.5:1 is safe on a boosted car? Usually you run alot richer on a boosted car than you would with a non-boosted car..


As for timming i wanted to put it on the dyno & keep increasing the timming until there is no power gain then go back about 1-2 degrees.. Does that sound good?


Thanks,
-Zach

 

So basicaly i just need to take 1(1/3) and multiply my jet sizes that i am using now and thats a good starting pint right? See this is where the problem comes in. When i said "flow enough" what i meant was is that i am not srue if we can get jets large enough to make it work in my application. right now i am using like a 215 so if i multiply that by 1.3 then that means i would need like 280 main gas jet. But they only make fuel jets up to 260. So has any one been able to run ethenol through an IDA and been able to get jets big enough?

CJG

 

Rotortuner..

You could always just drill out a jet to the right size..


-Zach

 

I'd even start as low as 8:1 and go from there. You won't know were you're really at. You'll have to play with the fuel map a bunch to get it right.

 

Well my idea is to tune on 93 octane gas for 11:1.. then add about 1/3 to that. So that would actually be an A/F ratio of 7.7:1

Sound right?


-Zach