running a 911 engine on pure alcohol

[svandamme]

hypothetical question:


converting a 911 to hydrogen , ain't all that practical considering the size of the hydrogen tanks... and loss of power...

but , alcohol, how effective would that work with a 911 engine?

what are the drawbacks, and other things to consider?
are there any seals or bearings or whatever in the 911 engine that would degrade by using alcohol ?

i'm pretty sure i'de have to trade in my MFI , and turn to something like EFI , but all in all, is it possible?

with the ever increasing oil prices, in a couple of years i might just start feeding my cars Smirnoff on the rocks, with a twist...


has anybody here ever experimented with this?

[beepbeep]

I actually posted a thread on this a while ago. I'm running my daily driver on E85 (85% ethanol, 15% gasoline) and it works like a charm. Pure 100% ethanol cannot be used in cars as it has very bad cold-start properties due to 4x higher specific vapor energy compared to gasoline.

There are meny people that convert their cars to E85 here in Sweden as it costs 70% of gasoline.

To keep it short...

Advantages:

- E85 has around 106 octane rating. It's VERY ping-proof. I'm going to use it in "race engine" that goes into 911 and I'm planning to boost around 1.6 bar on 9.2:1 C/R. (Stock boost is around 1.0)

- It has very clean emissions and CO will be reduced.

- It's produced locally and won't fill the pockets of either GWB or some middle-east emperor.

- It keeps combustion chambers clean

- It tolerates more ignition advance (due to higher octane)

Drawbacks:

- You need approx. 1.5 times more fuel to keep mixture on same stochiometric level, which evens out the cost.

- Cold start is a PITA, if air temp is under 0 deg Celsius. Very hard to start.

- Some rubber stuff doesn't like ethanol. Lot's of guys have been driving with it for long time but your mileage might vary.

Now I'm not sure which alohol you are talking about, methanol or ethanol. Methanol is very knock proof but totally unusable on day-to-day basis as it is agressive on fuel system components.

Ethanol is produced here in Sweden from wood and is ready available.

I've seen dyno papers for properly tuned turbo cars whose output rose from 280 to 330HP on E85. I like it a lot.

[svandamme]

cool , so if the sandmonkeys start raising the oil prices... i can run ethanol !

thanks for the reply , didn't know you guys in sweden did this

[1fastredsc]

I wonder how impossible it would be to find that here in the states?

[dwightp]

"I wonder how impossible it would be to find that here in the states?"

E85 is available. More so in the northern states (Corn).

http://www.e85fuel.com/

Look at "refueling locations" link at the left.

I'm working on a Motec MAP that will run E85. It's a bit of a hassle to get but no so much that I can't run it. The increased fuel delivery requirement is probably the biggest hurtle. Not so difficult with fully programmable EFI as long as fuel system can operate within required duty cycles. Next is probably ensuring that E85 doesn't have adverse reaction with exisiting fuel system. Many links at this site for info. Enjoy!

[beepbeep]

Actually, most of the times it's easiest to leave fuel maps as they are and just purchase 1.5 times bigger injectors. There is some additional power to be found in advancing the ignitionas well, as E85 will tolerate it easily due to higher octane.

Optimal E85 engine would have very high C/R and agressive timing.

Many people have runt E85 for a long time on their stock fuel systems and concensus is that problems are minor.

[dwightp]

Beep: I continue to enjoy hearing about your E85 experiences. Yes, you are probably correct that an appropriate increase of injectors is easiest. Perhaps more so for lambda closed loop systems.

I'm doing it the hard way. Alpha-N open loop. I'm finding that modifications to the open loop map are needed for simple fuel changes, like octane or even supplier. When I go to closed loop, the response for the closed loop to adjust quickly (to suit me) is just not there.

It's pretty easy with my current set-up as I can multiply the entire fuel map by 1.5. I am starting with injectors that were oversized anyway. I'm at the low limit at idle with normal pump gas. I'm getting pretty excited in setting this up. I've got a little over 12 to 1 compression so I'll be able to take advantage of much of what the E85 can offer.

[beepbeep]

Originally posted by dwightp
Beep: I continue to enjoy hearing about your E85 experiences. Yes, you are probably correct that an appropriate increase of injectors is easiest. Perhaps more so for lambda closed loop systems.

I'm doing it the hard way. Alpha-N open loop. I'm finding that modifications to the open loop map are needed for simple fuel changes, like octane or even supplier. When I go to closed loop, the response for the closed loop to adjust quickly (to suit me) is just not there.

It's pretty easy with my current set-up as I can multiply the entire fuel map by 1.5. I am starting with injectors that were oversized anyway. I'm at the low limit at idle with normal pump gas. I'm getting pretty excited in setting this up. I've got a little over 12 to 1 compression so I'll be able to take advantage of much of what the E85 can offer.

Very interesting!

I don't know if you already know this but it cannot hurt to type it once again:

Ethanol has roughly 4 times higher specific vapor energy coeficient, which means that it takes four times as much energy to vaporize it. It also means that engine is b$$$h to start when it's cold. Main reason for mixing 15% gasoline (E85 = 85% ethanol 15% gasoline) is just to help cold starts.

Unfortunately, this also means that cold-start maps cannot be extrapolated from gasoline maps by multiplying them with 1.5. you'll need substantially more than 1.5 times cold start fuel flow with cold engine, so i sugest bumping those numbers into 5-7 times range, compared to gasoline maps.

Luckily, you have programmable EFI so it's quite doable. This non-linearity during cold starts is main source of problems when using OEM ECU's with just bigger injectors. It's also E85's achilles heel...they are very filthy during startup.

Good thing with E85 is that is laughably ping-proof while adjusting the mixture. I was fiddling with carb adjustments on a converted car and it would rather die from too lean mixture than ping. You could clearly feel lean surge and all those effects that couldn't be safely explored when running on dinosaur bones.

[dwightp]

Oh yeah. Cold start map, gains and functions are a complete re-do.

I doubt that I'm going for the 1.5xmain fuel map. I'll probably do a rough multiplication, then trim individual points for desired lambda. Hope to start this conversion soon.