[Terry Syd]

I read on one thread that there was little performance difference between ethanol and methanol when on a dyno. However, I wonder if the engine/s being tested had electronic injection systems that used a oxygen sensor in the exhaust. In which case, the extra caloric content of ethanol would likely result in a reduction of fuel flow through the electronic injection system, thus negating any perceived benefit of the higher caloric content of ethanol over methanol.

On a Turbo Diesel I understand that the methanol blend should be limited to no more than 50%. So for arguments sake I was running a 50% ethanol blend, would the extra energy content of the ethanol push the engine into detonation? In other words, are there different limits to the different alcohols in a turbo diesel?

This is an important consideration for me because I have a mechanical injection system on my TD that ceases adding fuel before full boost. If the detonation limits were the same, then I may be able to utilise the extra boost more efficiently by using ethanol wth the higher energy content.

[Terry Syd]

I have just tried to research the difference in energy content between ethanol and methanol and have been amazed (no confused is the proper word) at the various comparisons I have looked at. They varied from a low of 18% to a high of 145%! It seems the difference is probably around 23% (or a bit lower, or a bit higher, depending upon what expert you listen to).

The latent heat of evaporation is also varied. I got from 27 to 31% difference between the two alcohols.

So, does anybody know if in a turbo diesel the detonation limits on methanol may be around 50% blend and on ethanol at around 40% blend? That question is based upon the ethanol having a 23% higher energy content than the methanol.

[Rocket468]

We have done alot of testing, and have found that methanol will outperform e100. Its also cheaper which is another plus side.

[Terry Syd]

Rocket, thanks for the reply. My specific question is related to the maximum amount of ethanol that can be used in a turbo diesel. Is it different than with methanol?

If the BTU content of the blend is what limits the percentage of blending, then clearly methanol would be the preferred fuel as the blend with have a lower latent heat of evaporation (plus more oxygen). However, if both can be used at the same rate of blend, then for my application the ethanol would provide additional hydrocarbons for combustion.

My situation with the mechanical injection system is somewhat different than someone with an electronic injection system that monitors multiple inputs. With an electronic injection system the additional oxygen provided by using methanol over ethanol can be compensated with additional fuel from the injection system. Couple this with the higher latent heat of evaporation, and the methanol will always out perform the ethanol.

I also run the boost past the point of additional fueling and start 'leaning' the mixture entering the combustion chamber. Therefore, the more hydrocarbons I can inject with the WI the more material I will have available for the additonal air entering the combustion chamber.

It really comes down to the basic question; does the BTU content of the blend create the detonation limit for a turbo diesel? Or put another way; can both alcohols be used at a 50/50 blend?

[Terry Syd]

Not too much response over the Hoidays, so I've done some research. Yes, there are more BTUs with ethanol and yes the computer systems lean out the mixture to compensate for the increased hydrocarbons in the ethanol. Thus, the situation would be different on a mechanical injection system which would run richer.

Now about the detonation issue, even though ethanol has a higher octane (the figures on that are all over the place just like BTUs and latent heat of evaporation), a fellow that was running ethanol in his injection system on a Turbo Buick had the knock sensor come on earlier than with methanol (????) That was even after the computer system had leaned out the primary mixture. This was in a gasser, not a diesel by the way. Bugger if I can figure that one out, but if that is the case, then high blends of ethanol 'should' promote earlier detonation in a diesel water injection system than a methanol blend.

Further research, another fellow was taking E85 and mixing it with water. The water/ethanol would seperate and he would use the gasoline in his lawn mower and use the ethanol/water blend in his injection system. Sounds like a plan for cheap ethanol blends.

Here in Oz we can get E10 at about A$1.40 a litre, which would allow the ethanol to be recovered at A$1.40 a litre. Since menthylated spirits are selling at more than A$3.00 per litre, that process could be very viable.

The wife can have the petrol for her vehicle.

[Mike]

Hi Terry,
You don't know me but I sort of feel I know you as, after reading some of your posts on this forum, I followed some of your links and spent a lot of time (several evenings) reading as much as I could digest - boy, can you write some!! Although a lot of it went over my head, I persisted in reading as I have the same Bosch IP with LDA as you do and want to get the best from it as well as researching other injection methods such as WI and N20.

Keep up the good work, my man, we may not be replying to your enqiries but we're certainly interested in reading it!!

[Terry Syd]

Thanks Mike, I may have another mode for the IP. One of the members of the Oz Surf forum from Norway showed a picture of his metering rod and how he cut it to extend the fueling ramp. I had previously thought about it, but I was concerned that it might weaken the rod - yet, here he was running one successfully.

I'll have to give it a go and see how I can cut mine. I'll post a picture in the Oz Surf Boost Compensator thread if I do it. If in the future I have concerns about fuel economy, its not irreversable, I'll just put in a short spacer to limit the travel of the rod.

[Mike]

Sorry to hijack this thread, it wasn't my intention but I'm also interested in the use other fuels because my max fuel screw is behind armour!

I would imagine it may be wise to buy or make your own metering rods for experimentation, that way you can revert to stock at whim. Could you please link me to the relevant Oz thread(s) you refer to?

p.s. Have you tried or considered the governor mod? I think pump removal is necessary but apparently it begins reducing fuel flow from as early as 2200rpm.

[Terry Syd]

Here's a link to the Oz Surf forum on the boost compensator -

Toyota 4WD Surf Owners :: View topic - 2LT Boost compensator

I only know of one govenor in the IP from drawings I have looked at (I've never taken a pump apart). The govenor on my Denso Toyota 2LT allegedly runs up to about 1700 rpm and then stabilises at a base line flow for the pump.

I've never tweaked that adjustment as you have to take the pump off to adjust it. It seems to be oriented to getting a richer mixture down low for starting and taking off. I could see someone reworking that govenor to smooth in the transition to boost.

On my vehicle that transition is fine as I am getting some boost by 1300 rpm and I can get full boost by 2000 rpm.

If you know of any tricks to that govenor, or to something else you know of, please log on to the Surf site and include them in the Boost Compensator thread.