Ethanol is comeing. Ethanol will be everywhere by May 5th. Too bad we can't drink it.

I am annoyed. (more expensive gasoline, that contains less energy, and picks up virtualy every impurity in the system, makeing it more difficult to transport, YEA?)

In anycase, does anyone have experence how the 928 reacts to ethanol containing fuel?

The owner's mannual says no more than 10% right?

Also, does anyone have any proof that it actualy reduced carbon monoxide. Expecaly in the 928?

Thanks.

One more annoyed shark owner.

 

If you drive a racecar, stockpile some gas before this crap is everywhere. I was at an SCCA race at VIR a few years ago and you could tell who came from states with oxygenated fuel. They were the ones scratching their heads in the pits trying to figure out why their engines ran like crap.

 

I should say that I'm starting this with an axe to grind, and partly as a warning to other 928ers.

In 2 weeks I'm getting my Bs in Chemical Engineering. I know exactly what they're doing to the fuel. I know why they're doing it. I know how the L-jetronic EFI system works, and I know that the oxygenates can't do a damn thing.

Which is why I'm annoyed. VERY annoyed.

Please feel free to bait me. I will try to keep this on 928 topic.

 

How does the L-jet or LH-jet vary in how it deals with oxygenated fuel compared to say Motronic or Trionic? More importantly, how would it impact an open loop LH-jet?

(Good enough bait?)

 

I don't know motronic, or trionic. However, the net result is basicly the same on pretty much any car made with semi-modern emission controls.

Oxygenats were/are suppost to lower CO levels. The problem is they don't. Now it's being sold as a way to lower VOCs. I suspect they don't do that eighter.

L or LH would have the same effect, open loop, or closed.

1. The car will start up, but often run like crap, down on power, maybe it acts lean when it's cold.
2. Owner will take the car to the shop, where the mechenic will tune the car useing a CO meter. He'll enrich the fuel mixture to offset the effect of the addition of the extra oxygen in the fuel when it open loop.
3. When in closed loop, the O2 sensor (actualy a CO sensor) will tune the mixture to the proper CO level, regardless of what the oxygenates say it's suppost to be.
4. The cat will get rid of both the VOCs, and the CO as soon as it lights off, and we're back where we started.

And everything goes back to being the way it was before. Except instead of haveing alkanes, or aromatics, it's 10% ethanol for part of the fuel. Which reduces the amount of energy per pound. And picks up any salts, or water in the tank, depositing them inside you car's fuel system what the filer doesn't take out. Yea? Not to mention, the ethanol will try to raise the vapor pressure of the gasoline, resulting in more of it trying to evaporate, and create more VOC than come out the tail pipe, saturate the carbon cannastor quicker, possibly overloading it for even more VOCs. Yea?

So for 928ers, make sure you keep running plenty of detergent through the system, you may need to enrich the fuel mixture, and hold on to the wallet really tight, cause it's about to get lighter, quicker.

(the vapor pressure depends on how the fuel is blended. simply put, the ethanol doesn't help.)

 

If the car is forced to run richer, wouldn't that lower combustion and exhaust port temps thus reducing NOx emissions? If so, I can see why politicians would push this. NO2 is the most visible sign of air polution during the summer.

 

No.

The oxygenates actualy include oxygen in the gasoline. As mandated by federal law, it needs about 2% oxygen.

The next result is that the engine is actuly lean, because the fuel is also serveing as an additional source of O2. Guess what, a lean engine makes less VOC and CO. It just runs like crap.

And then it gets corrected for when the computer/mechenic corrects for the diffrence.

The NOX data I've seen, for what seems to be the origional studies back in the 1980s to the most current set I've seen was no change oxygenates, or not. I've never seen the raw data however. On a newer car that corrects for the mixture, everything would go back to like it was before the oxygenates were added. The cat. would destory the NOX, and everything would be like it was before. On most non cat equiped cars, the mixture would still be right at the peak of NOX production, so there would be basicly no change.

I belive the major source of NOX, car wise, is cars that are run w/o catylitic converters, or dead units. Industry wise, the main sources seem to be powerplants, but I can't confirm that.

On some non-cat equiped cars, the Chrysler Lean burn, or the Honda CVCC, weird things can happen, because they play outside of the normal mixture ranges. Honda hasn't officaly sold a CVCC engine in the US since 1979. I think Chrysler got rid of the lean burn in the late 80s, early 90s.

I'm something of a fan of enviromental protection. I don't mind too much the rolling frame testing of cars, or the federal testing of emissions. I'm just not a fan of mandates that don't work. Like mandating catylitic converters, ethanol, and CAFE. (IMHO, none of the above mandates work.)

 

Maybe rich was the wrong term from a stoichiometric ratio standpoint. There would be more liquid vapor to keep the exhaust temps down.

I read that the reason wideband O2 sensors were created was to enable accurate control of leanburn engines. I think it started as a Honda project. I also read that new Hondas run at ~15:1 instead of the usual 14.5-14.7:1.

 

I dought it. For the excess fuel to kill NOX emissions, you need to be alought rich, or alought lean.

Ethanol or MTBE is just enough to push the engine lean to were it won't run right. Not a whole lought. Almost certanly not enought to effect NOX quantities. The studies didn't seem to indicate a reduction in NOX, in any case.

The Honda lean burn engines are suppost to opperate at about 18:1, IIRC. That is about as lean as you can get before you start haveing miss fires. This improves the efficeny of the engine, but it makes the use of normal catylitic converters impossible. They've come up with new cats that can knock the NOX down, even with very lean mixtures, thus allowing a redevelopment of the lean burn engine. The wide band O2 sensor seems to be part of that effort.

 

Good to know. You're right about the 18, I don't know why I was thinking 15.

So in a car that already runs lean to the point of detonation like many 84-86 Euros without Lambda feedback, this could be potentially very bad...

 

This is not totaly new. Most of the midwestern states, major producers of ethanol, have been mandating it for a long time. I can't remember if Texas has as well. I thought no, but I can't remember now.

I've always been annoyed about the oxygenates, it's just the May 5th thing giveing me a extra reason to rant.

 

I have heard reports that it attacks some of the non-metal 928 components that have contact with the fuel. Then because of fuel system design this crud is circulated around & fills up the filters.
Do not know if this is fact or rumour but I could assume that 20 year old components were not designed to be ethanol proof.

Marton

 

Will normal fuel still be available?

 

Propylene Oxides works great. I used to sell it to pro drag racers,,, it a cheater fuel like liquid NOX. 3% mix = 3% increase in HP. we found this true all the way to a mix of 12% then we had EGT spikes. After the race when they would get the fuel tested they would open the tanks and it would evaporate before anybody was the wiser. I even tried using it as an injectable like nitrous with some mixed but positive result on a dyno.

THEN the EPA and OSHA made use of it nearly impossible because it was such a harsh carcinogen (sp?) it was flamable between 4:1 to 41:1 mixtures if my memory serves me right. IN Dallas I sold to all the hotrod shops and super fuels.
My biggest purchaser was Darrel Alderman with MOPAR until he got caught....

 

Maraton: ethanol was a big thing back in the 70s and 80s. (How big I don't know, it was before my time.) During the gas crunch, they were selling E85, E15, gasohol, and even just pure ethanol. Porsche should have known about the possibility of ethanol containing fuel. (It was discontinued because 1. ethanol is expensive, 2. ethanol is difficult to transport 3. MTBE was availible in sufficent quantities, and cheaper to make.)

I think my owner's mannual says "OK to 10% ethanol." Anything more than 10% could well start being the catylist to degrade the rubber in the fuel system.

whitefox: no, ethanol fuel will not be avalible anywhere in the US after May 5th, except in any location that gets a specific version of Bush's waiver. The waiver will be tempary at best. After that, it will not be avalible in the US as a road fuel. Raceing gasolines will still be possible with any composition that you like. TEL is still avalible in raceing gasolines, so anything is possible.

Loaded: what exactly is the propylene oxide? From the name your useing, my guess would be some sort of cyclic compound? But I guess it it could also be a diol, or a di propyle ether. Hints?