neilh

Here is the 86, notice the CO is also 0.01!

Hilton

I have a few MOT test sheets for an 87 S4 of mine when it lived in the UK - they only test CO and HC however, no NOx, on cars with no cats. Done at idle.

10/2006:
CO measured: 1.13%
HC level: 410ppm



This is an 87 S4 running 98 RON gasaoline.

BC

That car has cats right?

neilh

Yes, cats - and i replaced the punched out cats on the 84 and it still did not pass, the NO came down, but still not enough.

jpitman2

In a WUR there is an O ring sealing the pressure regulating diaphragm, and if that swells or deteriorates, the control pressure will go out of spec pretty quickly IMHO.
jp 83 Euro S AT 53k

BC

Continued usage of E85 has shown no ill effects on any of the fuel system "hard parts" - and no effect noticed on the questionable piece - the plastic fuel tank.

I have a picture of a spark plug that I would like to post, but I cannot access the picture at work today. I'll try and post it up soon so we can have a look at the combustion process and glean some info, if any, on what the ethanol is doing.

I think I am still running quite lean in many situations. With the 02 sensor plugged in, the computer will obviously attempt to get as close to the lamba value it thinks is stoich - which should still work with the ethanol.

I believe that ethanol requires more fuel specifically at transition (accel enrichment) than originally anticipated, at least in this un-optimized engine. The LH was already having an issue doing this, so it may be exacerbating the problem.

My next experiment may entail (after I pass smog with cats this week) unplugging the 02 sensor and increasing the fuel pressure to see if I can hit the point at which the car does not SEEM to be lean.

I should probably try and get a wideband on the motor ASAP, but I'm not sure how quickly that will happen.

dr bob

BC--

The odd thing I see in your E85 results is the high NOx. No specific knowledge here, just thinking that with petrol timing dialed in, that should be cool combustion and a slow cold flame front. Your NOx numbers say different though.

---

Back to gas-turbine boiler tuning on clean-burning natural gas....

BC

This test was without a cat. Also, the timing is not advanced to take advantage of this fuel at all. Technically, I may find that its running somewhat lean, which would bring combustion temps back up. Though - the number is still below where it should be WITHOUT the cat.

Cooler combustion is indeed an offshoot of various mixtures of ethanol. Understand however, that as you add more fuel, you may actually get an increase in the speed at which the fuel will burn (still trying to look into this in various online journals) and thereby the flame front speed increases with thicker/fatter/richer AFRs.

Mongo

What gas mileage are you getting with E85?

BC

I don't think its as good as with petrol - but that is completely expected because the car is not tuned to use it, nor is the fueling system optimized for it.

Podguy

With 10% ethanol as sold in California our Hybrid gets 10-15% poorer gas mileage than on plain gas - when we could get it.

Stranger is the increase in mileage with premium over the cheap stuff. The difference is over 10% which justifies the extra cost. This on a car that is designed wit run the cheapest stuff going.

I seriously doubt the gas mileage on E85 will be very good. If you use more fuel by diluting the gas by 10% then where is the saving on the environment?

dprantl

On my last emissions test I thought I would try some acetone in the tank to see the effect on the numbers. I never had a problem with passing, just curious (my car has cats). I put in 4oz for 10 gallons of gas, even though 3oz was recommended. HC and NOx came out very good, but I almost failed on CO. My previous emissions tests all had CO way down. So it seems that ethanol shows higher CO readings, interesting.

Dan
'91 928GT S/C 475hp/460lb.ft

blown 944

I've been running ethanol for well over ten years. I have ran e85 for at minimum of 5 years on 944's. There has only been one ill effect that could be remotely associated and that was a fuel pump leaking. However, it was an old unit.

If you really want to get good fuel mileage out of the fuel you may want to think about a low load lean burn. I run around 40 degrees timing and between 16:1-18:1 afrs.

Strosek Ultra

I have been running E85 in a BMW car for about seven years. I have had no problems except the fuel pump stopped working a few years ago. The pump was old so I do not see it as E85 related. Bosch say it should be no problem pumping ethanol using their fuel pumps. The fuel pressure is increased from 2,5 bar to 4,5 bar. Same injectors. It is running a little lean, it is running better on E75 which we have during winter time. E75 will make the engine start easier at cold conditions. Cannot see any rubber parts being detoriated nor any corrosion from water in the fuel. In order to get the power up, the ignition had to be advanced quite a bit. I am now running 43 degrees advanced. This seem to be significant for a E85 conversion.

Ake

BC

An unoptimized engine will not see any increase in MPG with ethanol. For performance vehicles MPG is not the determinate factor, but octane and the Latent Heat of Evaporation is.

Please let us not go environmental with this thread. I am talking about using E85 in the 928 and the technical and mechanical parameters.