bzwigart

iTrader: (9)

I've been researching and planned to purchase an A/I system this spring. However, upon reading the E85 threads, I'm starting to question my decision. Is it money better spent to go Alky Injection or put the funds toward running E85? Or ultimately both? Suggestions would be greatly appreciated.

Brian

Howard Coleman

iTrader: (6)

you just posed THE question re turbo'd higher performance rotaries.

the only sure answer is that if you are not running either E85 or AI you are rolling the dice w your setup.

alcohol is profoundly different than gasoline and there are now two ways to deliver it to your rotary.

how often have we read the following...

"i went to the dyno, filled up w racegas, and made 6XX rwhp at 30+ PSI, here's the chart."

"then i filled up w pump, turned down the boost to one bar and drove home w 4XX hp."

alcohol changes that. you can run all the time what you ran on the dyno.

so whether it is E85 or AI alcohol is the ticket.

i look at the AI option being similar to running a turbo. turbos are neat as you only use them when you wish.

perhaps the point is better made looking at a piston engine. to get lots of hp out of a NA piston engine you need a big cam among other items and the car becomes a PIA around town.

or

you can just bolt on a turbo and you don't need to live w a lumpy cam. for example, 546/524 NA on E85 and w a GT42 at 13 psi made 850/833. that's a 10.3 to one static compression motor. add a turbo and sidestep having to live w a big cam. power only when you need it.

so, no changes but the addition of a turbo and the motor made another 304 hp.

(Hot Rod Magazine. "Ethanol, what's the deal?" Jan 08)

i think the AI setup is alot like running a turbo since it performs only when needed.

AI systems are changing rapidly.

99% of the AI systems currently in service utilize a nozzle and depend on a controller sensing boost levels to direct delivery amounts via pumpspeed.

this system works amazingly well for drag racing where you are pretty much pedal to the metal but not too well for on off throttle as the pump can't keep up w the changing boost dynamic.

new school AI:

the pump merely provides pressure. just like your OEM fuel system.

a fuel injector is directed by a computer using boost and rpm to accurately deliver.... in Ms. just like your OEM fuel system.

tuned off an X Y grid w 100s of cells. just like your OEM fuel system.

i run a 4 gallon JAZ fuel cell for my methanol. i inject enough alcohol to eliminate about 25% of my 93 octane pump.

no knock no where.

three vendors offer the new school AI currently. Aquamist, Coolingmist and FJO. i run FJO. there's lots of info in the AI section.

the other option is E85.

you'll be adding around 20-25% fuel volume to make similar hp so obviously you'll need to add pump and injector capacity along with, probably, larger fuel lines.

since you will be running alot more alcohol through your motor you will be reaping more of the benefits of alcohol...

the 200 degree F higher autoignition temperature is at the top of my list given the rotaries sensitivity to knock. gasoline atuoignites at 660 F. alcohol is 858F.

the degree of charge air cooling w alcohol is nuts. my friend runs an NHRA RX3 w a 2 rotor running enough boost to make very very close to 4 digit rear wheel on methanol alone.

he has run 7.58 at 186 and doesn't run an intercooler. at the end of a run you would not want to put your hand on his intake manifold. you might not be able to remove it.

alcohol is magic w re to cooling and what does the rotary need?

delivered.

so i have no conclusion for you re E85 or AI. it will depend on lots of factors and we all won't end up picking the same option.

the only thing i do know is you'll want to check one of the two boxes.

good luck,

howard coleman

Gorilla RE

iTrader: (1)

When you say AI vs. XXX race fuel you're comparing apples to oranges. E85 is no different than most other "high octane" fuels in the sense that they act as a band aid of sorts. I'M NOT SAYING THEY DON'T WORK. I'm saying that E85 is NOT fixing the main cause of detonation, instead it simply helps aid in an "after the fact" knock suppressant (and yes it does work). The main cause of detonation IS heat mainly heat in the intake tract. By using AI you are fixing this BEFORE it becomes an "issue". Instead of putting on a kevlar vest and running in front of a gun....lets just remove the "gun".
-J

Howard Coleman

iTrader: (6)

J

that is an excellent point. if you run E85 thru your regular situated fuel injectors you will not be cooling the charge air.

my drag race friend cautioned me not to place the AI injectors too close to the combustion chamber as he said alcohol needs some space to "flash" so it can do it's cooling deal. i listen to him and his advice has always been sound.

whether, when injected almost directly into the combustion chamber, you get the cooling is beyond me. i am not trying to do rocket science, i just want my car to run properly and i will leave further more esoteric questions to others.

here's my thinking on the new AI architecture... my FJO injectors.







hc

Gorilla RE

iTrader: (1)

Howard,
Your setup looks very nice! And to answer your question: I believe the AI injector should be early in the intake but after the IC....this will give you the most cooling and distribution of the AI fluid and its affects. Though I'm not against 2-3 different locations for them either!! ie pre-turbo, after IC and before throttle bodies maybe! But your racer friend was right in his thinking.
-J

bzwigart

iTrader: (9)

Thanks for the posts guys. Howard, I've read all your posts concerning A/I and have been the biggest inspiration for me to go that route. Both of you make valid points. I like the fact of using it "only when needed" (foot to the floor) and instead of simply providing a Band-Aid, eliminate the issue (heat) from the start. Think I'll go the A/I route. There's always time in the future to try out E85.

Gorilla RE

iTrader: (1)

Don't get me wrong....they both serve a purpose and can both be used with great results in a ton of applications.
-J

bzwigart

iTrader: (9)

E85 does have its merits. I've been thinking about it through the day. It would be nice to not worry about an auxillary system. Just fill up the tank and your ready to roll. How bout on a cost basis? Which way would be the more economical route? Cost of A/I system with a re-tune compared the cost to upgrade the fuel system to E85 and a re-tune?

Brian