The Gasohol A Go-go

[higgy88]

It sure is nice to read some of these posts in the Chiangmai forum from people who know what they are talking about. There are just way too many “experts” in the motor forum. Mr McG obviously knows his <deleted> about engines when he talks about using additives that control the flame front, especially the flame speed. As this speed approaches the speed of sound it is called detonation, and this can cause a whole lot of engine damage. The octane number doesn’t affect this at all, it only affects what is called pre-ignition which is when the fuel starts to burn before the spark plug fires. It causes a different type of engine damage, but both can easily trash your engine. You have also added some good information Mr Bliss, and I do agree with most of what you said, but I do have a very big problem with telling someone with a vehicle that needs 95 that he can use 91. It may be just fine when he is sitting in the middle of CNX traffic going nowhere quickly, but as soon as he gets some open road (is there still such a thing here?) and decides to hit it, nail it, floor it, or step on it, then he is opening himself up to some very big problems. What you called "calorific value" I have always known as "heat energy", and this heat energy is released during combustion. The internal combustion engine that you use in your car is called a heat engine because it converts this heat energy in the fuel into mechanical energy, which is then delivered to the drive wheels. Ethanol does in fact contain less heat energy per the same volume as pure gasoline. That is why you do get slightly less performance from your engine when using gasohol. But your engine will actually last longer with gasohol. How can I say that? Because the lower heat energy in gasohol produces lower combustion temperatures and pressures, the two biggest things that causes engine wear and component failures. The only problem with gasohol is it’s corrosive effect on some of the rubber seals and gaskets (and maybe some other parts I’m not sure of exactly which ones) of the fuel system. For a vehicle manufacturer to say in the owner’s manual that you can use gasohol means that they have eliminated all of these problems and it is safe to use it. And as I said before, Chrysler started doing this back in 1986. I have a hard time with people who are blaming gasohol for everything from flat tires to worn wiper blades. I am sure any problems with the gasohol here is caused by water contamination. I would suggest not buying fuel from areas that are prone to flooding, and if you can to use stations that are relatively new. So much for your engineering lesson for today. Now I could use some information. Peace Blonde is concerned with getting 91 gasohol so I am too. I have not been paying much attention since I have just been filling up with 91 and I assumed that they have not introduced gasohol 91 yet, only 95. I have never even looked at the 95 pump. Questions for those who know; how can you tell if the 95 is gasohol or not, and has 91 gasohol been introduced already?

[BlissfullyIgnorant]

91 RON Gasohol is definately already for sale - I've seen it at numerous outlets around CNX already, but can't recall if it was signed in Thai or English unfortunately (I read both fluently so it often doesn't register). In any case, if you're concerned about inadvertanly running 91 Gasohol in your car and can't read Thai, here's the "evil" word you'll need to commit to memory:

แก๊สอฮอล์ - actually if you can just remember the word "gas": แก๊ส that'll get you by.

Given the level of damage water in fuel can most definately cause, and the exceedingly high risk of it occurring in gasohol in this country of flood plains and lax controls, all I know is that putting any form of gasohol in your car is a fairly big gamble. IMHO, a much bigger gamble than whether you car manufacturer allowed for tolerances down to 92.5-93.5 RON for your 95 RON car, or how far 91 RON benzene and 95 RON E10 actually sway from their base ratings anyway.

It's probably not worth debating the use of 91 RON in a 95 RON sea-level rated car any further, it's really up to your own discretion. There's plenty of good info that's been posted for you to base your own decision around.

[BlissfullyIgnorant]

Sorry, I should also mention that I haven't seen 95 RON ethanol-free benzene for sale for quite some time now at the places where I normally fill up (PTT, Caltex and JET).

Edited July 9, 2007 by BlissfullyIgnorant

[higgy88]

Thank you very much for the information Mr Bliss. I will now be on the lookout for 91 gasohol when I put fuel in my vehicles.

Since we have some differing opinions on this subject, I think a friendly one on one debate with you over a few beers would be very stimulating, and I think we could both walk away with some good additional knowledge. However, a debate over which fuel would be most likely to cause engine failure in a particular engine would be a moot one since the Thai gov’t has shown that they are determined in taking away our choice of using ethanol free fuels whether we like it or not. Personally I think mixing alcohol in the fuel is like putting a very small band aide on a very big problem, but then that’s just my opinion. My question to you, Mr Bliss, would be, if you had a vehicle like lotus eater’s Mazda Thailand and your only two choices were 91 gasohol or 95 gasohol, which one would you choose? I know which one I would use, and I would be searching high and low for a gasoline station that I could trust. I had thought that since I used 91 I could get away with waiting a while longer, but it looks like I’m going to have to start my search right now. As I said in my first post. The writing is on the wall my friends. Prepare yourselves.

[BlissfullyIgnorant]

The 2.0L MZR engine in the Thai Domestic Market Mazda3 is quite obviously an economy tuned variant - as evidenced by its low specific output (54KW/L - about the same as the economy tuned Toyota 1NZ-FE 1.5L in the Vios/Yaris), and with low compression (10:1). With this in mind, and seeing as it of course will feature a very adaptive EM system, I'd feel 100% safe runing 91 RON in it around the northern region of Thailand. The worst case is you'll lose a kilowatt or two, which you'd lose anyway by driving it in this heat.

Of course if it was the MazdaSpeed 2.3L turbo version (or any other engine that has been tuned for performance) that would be another story - in that case I'd be buying drums of Toluene (easier to get than benzene or leaded avgas) and mixing it with regular 91 RON unleaded to boost the octane to 95+ RON as required.

But alas such dilemmas aren't mine anymore - unlike "back home" I just can't afford a high performance car here. But I console myself with the thought that I couldn't use it anyway

Edited July 10, 2007 by BlissfullyIgnorant

[BlissfullyIgnorant]

Just found something interesting - the Redbook states that the Mazda3 2.0L only requires 91 RON:

http://www.redbookasiapacific.com/th/vehic...D07CK&new=1

But then again it does specify the fuel type as being "Petrol - leaded" oops! ;-)

The Mazda Australia website also states that the Mazda3 2.0L (which comes from the same factory in the Philippines) only requires 91 RON:

http://www.mazda.com.au/mazda3/specifications.aspx?ID=73

This all fits with my assessment of the MZR 2.0L engine this model is using.

[BlissfullyIgnorant]

Sorry higgy - I just re-read your post and noticed you were asking whether I'd run 91 gasohol or 95 gasohol - I thought you were asking if I'd run 91 regular or 95 gasohol. OK, that's a good question then, but I'd need to uderstand the Ethanol mix in 91 first - if it's lower (E5 for e.g.), then it's less risky of course.

Fortunately the choice won't be taken away from us just yet - the interim govt cancelled the plans to outlaw ethanol-free fuel back in January 2007, so it's going to be up to the next govt to decide whether it will actually be taken off the market or not.

If ethanol-free fuel is taken from us, then the only real solution is to turn over your cars more reguarly There's no way I'd want to own a 3yo+ car that's been running on Thai gasohol its whole life and is now out of warranty ;-)

Edited July 10, 2007 by BlissfullyIgnorant

[higgy88]

Mr Bliss. I am getting rather tired of this thread but I do feel I need to respond. While I do agree with your basic theories, I very highly disagree with your practical application of it. You are making some very dangerous assumptions on the design of this particular engine, and it appears engines in general. Neither of us know how this engine was designed. The person who owns this vehicle, Mr Lotus Eater, has three choices to make. He can use 95 like I suggest. He can use 91 like you suggest. Or he can use what Mazda tells him to use. The worst case senerio if he uses 95 is that he spends a little more money on fuel. Nothing else. The worst case senerio if he uses 91 is that his engine pre-ignites from the lower octane fuel, it burns holes in the tops of his pistons, the engine is completely destroyed, AND Mazda refuses to honour his warrenty because he did not use the fuel that they told him to. I can assure you Mr Bliss, I've been there and I have refused warrenty claims for people who did not use the recommended fuels and oils because, for whatever flawed reason, they thought that they didn't have to. For all you vehicle owner's out there who are still bothering to read this thread, don't bother listening to either of us anymore. Read your owner's manual, find out for yourselves, and do what the people who designed your vehicle tell you to do. For those who love cars and motorcyles and do your own modifications or have a shop do it, you're on your own.

[BlissfullyIgnorant]

The worst case senerio if he uses 95 is that he spends a little more money on fuel. Nothing else.

Seeing as you can't buy non-ethanol blended 95 RON anymore, the worst case is he gets fuel contaminated by water and destroys his engine. Mazda are sure to pass the ball on that one, just as Ferrari and Toyota have already done here in Thailand.

Anyways, I called off the debate a long time ago, so it's your fault for pulling me back into it

[lotus eater]

higgy88 and blissfullyignorant, you've somewhat blinded me with your science - though with the best of intentions. It's all very well for you to get fed up and call of the debate, but I now have to come to a conclusion on what to put in my mazda3 2L 5dr sports (which I can't afford to risk damaging).

The only consensus I'm seeing is

1) choose 95 petrol if possible (it'll cost more but will have no damaging effect - higgy says 95 gasohol may be kinder on the engine)

2) but failing that, higgy says definitely use 95 gasohol (also manufacturer's advice); blissfullyignorant says equally definitely use 91 petrol (apparently australian manufacturer's book advises that way); especially as northern thailand is above sea level (but is australia?)

I hope I got that right.

There seems to be contradictory info on whther or not 95 petrol has, or will soon be, banned by the government - I can only hope it won't come to that.

I don't understand why the water, if it gets into the gasohol storage in a given station isn't just as likely also to get into the petrol storage. And if it does then why isn't watered down petrol as bad as watered down gasohol - but I've no doubt missed something in the debate.

I'll just try to stick 1) ie to 95 petrol as long as possible.

[higgy88]

I’m sorry Mr LE, I just figured that this thread had become so boring to everyone that no one was bothering to read it anymore. As you have noticed, Mr Bliss and I have our very strong differences of opinion on this subject, and unfortunately you and others with vehicles that need (or at least the owner’s manual says you need) to use 95 octane fuel are caught between a rock and a hard place. Let me try and summarize all this for you, from my own perspective of course. I just used your car as an example to make my point since you had previously asked me what you should use. The page I linked to at Mazda Thailand was just what I got from googling your car. It is very clear from that site that it says you need to use either premium 95 or gasohol 95. I assumed that your owner’s manual says the same, so that is what I recommended for you to do. And I also recommended that you do your best to try to find a gas station that does not have a water contamination problem, as I certainly believe that they do exist here in Thailand, and just as a side note I really hope that the ones that have the problem either fix it or are forced to go out of business. Mr Bliss appears to have looked at the same specs, found some other sites and came to the conclusion that you can safely use 91. I very highly disagree with that. He is right on a number of things, but I believe his conclusion is faulty. We engineers are by nature a very cautious group. One thing he is right about is that we have a tendency to over-engineer things, add safety factors, over-compensate for variabilities such as the fuel as well as many other things, and in general engineers would much rather err on the safe side than the other way around. The engineers at Mazda Thailand tell you to use 95, and I have to think they have some good reasons for doing so even if I do not know what they are. Try to think of using 91 in your car the same as adding another floor to a 10 story building. Maybe you can add another floor and it would still be safe. But maybe it won’t. Only the building engineer can make that determination, and he does so by carefully looking at everything in the building plans and exactly how the building was designed. I cannot and will not say that your engine would be completely safe using 91 octane fuel. Mr Bliss can and he does. Maybe Mr Bliss knows more than I do, or maybe he is more willing to take a risk where I am not. Now, as far as water contamination in the fuel, the difference between pure petrol and gasohol is this. Water and pure petrol do not mix very easily. Water is heaver and usually will sink to the bottom of the fuel storage tank. You can run into problems with pure petrol when the storage tank starts getting low and it's time for the station to call the tanker truck for another fuel delivery. Another good thing to note is, if you see the tanker truck is there filling up the station’s storage tanks, go away for an hour or so. As they fill up the storage tanks, all of the <deleted> in the bottom of the tanks gets mixed around and it takes a while for the contaminates to settle back down to the bottom again. One of the properties of ethanol is that it attracts water, so some of the water in the storage tank will mix with the 10% ethanol in the gasohol and cause water contamination of the fuel. Your engine does not like even a small amount of water in the fuel. My belief is that you will know if the fuel is contaminated almost immediately because your car will run extremely badly and you will want to take immediate steps to identify and fix the problem. The fix is usually just a matter of draining out the contaminated fuel and flushing out the fuel system. Not that big a deal, and definitely easier than replacing a damaged engine due to using too low of an octane fuel. I hope I have made this simple enough for you. If Mr Bliss would like to continue this discussion and add his views, or if any of the other motorheads here would like to add their 2 cents, please join in. Otherwise, Mr Bliss and I can either continue our discussion via pm or just agree to disagree and go on to other things. I need to shut my computer down now and will come back online tomorrow morning and see what else has been written. See ya’all later.

[lotus eater]

Higgy88, many thanks for the clear and practical synopsis of your advice. Also for the explanaionabout the higher risk of ethanol contamination than petrol.

Finally the tip about avoiding taking fuel while or just after the tanker lorry was worth my noting.

By the way Mazda only had a Thai manual with the car - though they did get me a cd in English (from the Philippines) which I've misplaced, but it'll turn up one of these days somewhere, I hope.

[JimGant]

Gow-sip-et, mai ow gasohon krup

Peaceblondie, I would suggest "ow gow-sip-et benzene" instead, and not using the word 'gasohon,' which may be the only operative word they understand. (This suggestion from my wife, who knows how crummy my Thai is.)

Also, PTT has color coded their pumps, with 91 red being benzene, 91 green being gasohol. (Someone please correct me if I'm wrong.) Have any of the other stations color coded?

[PeaceBlondie]

Gow-sip-et, mai ow gasohon krup

Peaceblondie, I would suggest "ow gow-sip-et benzene" instead, and not using the word 'gasohon,' which may be the only operative word they understand. (This suggestion from my wife, who knows how crummy my Thai is.)

Also, PTT has color coded their pumps, with 91 red being benzene, 91 green being gasohol. (Someone please correct me if I'm wrong.) Have any of the other stations color coded?

Yes, I can see it's much easier to ask for 95 benzene than to ask for 95 without gasohol. We had a confusing attempt at conversation around midnight at the Shell station on Huay Kaew. The Shell 95 benzene pump seems to be colored yellow. There are at least four, in some cases maybe five pumps of different type in some of the bigger stations. The smaller stations have poor labelling if any (in English or numbers).

Now I'm so afraid to buy 91 octane fuel, for fear that it contains gasohol, that I'm wasting maybe 1 baht per liter on 95 benzene. This topic helps me guess how to maybe switch back to 91 benzene.

My engine has 11:1 compression ratio, and has 45,000 km on a 150cc engine. Could carbon deposits have built up to the point my c.r. is closer to 11.4:1?