Engine & Boat Tuning for Methanol

[Jeff Lutz]

Hopefully the nitro shortage will be short lived, and we can all still run high nitro. I hope nobody will dream of a "fuel rule". But for people that do want to cut back, my thoughts are you would want to run a little bit of nitro over straight methanol. When you consider how little oxygen you get in your cylinder per stroke, a little % of nitro will go a long way. Remember the facts,

1.7 kg of air is req. to burn 1 kg of nitromethane. Jeff Lutz

 

[AndyBrown]

If anyone is interested these are results of bench testing a .90 years ago on a fixed load when we were about to move from no nitro to being allowed to use nitro. Exhaust gas temperature is the interesting one. These tests were taken after optimising head and pipe length as much as possible.
RPM EGT (degrees C)

80/20 meth/castor 18200 430

80/20 meth/synthetic 18100 455

15% oil mix 20% nitro 19500 387

15% oil mix 5% nitro 18800 405

10% castor 20% nitro 19200 363

Dave

Dave,

I'm surprised that with your long experiance of testing engines that you provide test results for the purpose of making your claim of higher EGT for Methanol that uses different types and amounts of oil for several tests.

From your tests it is clear that the amount and type of oil has an effect on EGT.

Your chart makes it impossible to determine the exact quantitative effect of Methanol vs. nitro on EGT.

Now I do not disagree that Methanol increases EGT over Nitro, just as Gasoline increases EGT over Methanol. That is common knowledge that can be found in many sources.

There are however ways to reduce EGT with any given fuel. Some tests that Marty and his team did, have documentaton about one way to do this on RCBOAT.com.

Lower EGT with a given fuel source normally equates to more efficiency.

Did you optimize the head for each fuel source? What do you mean by Optimize? Head clearance? Head volume? Combustion shape? Squish angles? Plug heat range?

Did you test any or all of these combinations with each tested fuel source?

I know you no longer have detailed information of these Optimizations. I'm just asking in general if you tested any or all of these combinations.

Andy

 

[DaveMarles]

If anyone is interested these are results of bench testing a .90 years ago on a fixed load when we were about to move from no nitro to being allowed to use nitro. Exhaust gas temperature is the interesting one. These tests were taken after optimising head and pipe length as much as possible.
RPM EGT (degrees C)

80/20 meth/castor 18200 430

80/20 meth/synthetic 18100 455

15% oil mix 20% nitro 19500 387

15% oil mix 5% nitro 18800 405

10% castor 20% nitro 19200 363

Dave

Dave,

I'm surprised that with your long experiance of testing engines that you provide test results for the purpose of making your claim of higher EGT for Methanol that uses different types and amounts of oil for several tests.

From your tests it is clear that the amount and type of oil has an effect on EGT.

Your chart makes it impossible to determine the exact quantitative effect of Methanol vs. nitro on EGT.

Now I do not disagree that Methanol increases EGT over Nitro, just as Gasoline increases EGT over Methanol. That is common knowledge that can be found in many sources.

There are however ways to reduce EGT with any given fuel. Some tests that Marty and his team did, have documentaton about one way to do this on RCBOAT.com.

Lower EGT with a given fuel source normally equates to more efficiency.

Did you optimize the head for each fuel source? What do you mean by Optimize? Head clearance? Head volume? Combustion shape? Squish angles? Plug heat range?

Did you test any or all of these combinations with each tested fuel source?

I know you no longer have detailed information of these Optimizations. I'm just asking in general if you tested any or all of these combinations.

Andy

Andy, My chart was made for my own use when determining EGT for tuned pipe calculations and was not done for the purpose of proving anything to anyone else. I show it here as a matter of interest. Did I optimise every detail? of course not, did I optimise to my own satisfaction? yes. Does my chart show that no nitro has a big influence on EGT. Yes. If you think otherwise then we can't be looking at the same chart. You said there is no difference between running zero nitro and 5% but that is not the case. Small amounts of nitro make a big difference in overall running and reliability.

I certainly don't have all the answers but I have run many boats and engines on straight fuel unlike others who claim to have all the answers but clearly have not demonstrated that in practice. I also have no interest in who is right and who is wrong. I just proffer my experiences and my opinions on the options of running straght fuel or fuel with small amounts of nitro.

Dave

 

[AndyBrown]

If anyone is interested these are results of bench testing a .90 years ago on a fixed load when we were about to move from no nitro to being allowed to use nitro. Exhaust gas temperature is the interesting one. These tests were taken after optimising head and pipe length as much as possible.
RPM EGT (degrees C)

80/20 meth/castor 18200 430

80/20 meth/synthetic 18100 455

15% oil mix 20% nitro 19500 387

15% oil mix 5% nitro 18800 405

10% castor 20% nitro 19200 363

Dave

Dave,

I'm surprised that with your long experiance of testing engines that you provide test results for the purpose of making your claim of higher EGT for Methanol that uses different types and amounts of oil for several tests.

From your tests it is clear that the amount and type of oil has an effect on EGT.

Your chart makes it impossible to determine the exact quantitative effect of Methanol vs. nitro on EGT.

Now I do not disagree that Methanol increases EGT over Nitro, just as Gasoline increases EGT over Methanol. That is common knowledge that can be found in many sources.

There are however ways to reduce EGT with any given fuel. Some tests that Marty and his team did, have documentaton about one way to do this on RCBOAT.com.

Lower EGT with a given fuel source normally equates to more efficiency.

Did you optimize the head for each fuel source? What do you mean by Optimize? Head clearance? Head volume? Combustion shape? Squish angles? Plug heat range?

Did you test any or all of these combinations with each tested fuel source?

I know you no longer have detailed information of these Optimizations. I'm just asking in general if you tested any or all of these combinations.

Andy

Andy, My chart was made for my own use when determining EGT for tuned pipe calculations and was not done for the purpose of proving anything to anyone else. I show it here as a matter of interest. Did I optimise every detail? of course not, did I optimise to my own satisfaction? yes.

Does my chart show that no nitro has a big influence on EGT. Yes. If you think otherwise then we can't be looking at the same chart.

Dave, Your chart does show Nitro has a big effect on EGT. I agreed, you should read my post again. However, your chart also shows that oil has an equal effect. On your 80/20 tests there is a 25 deg. diff. between Castor and syn. oil.

On your 20% & 5% nitro test where your 'oil mix' is the same at 15% there is a 23 deg. diff between the tests.

Obviously one way to reduce EGT would be to run the type and amount of oil that favors low EGT.

So now we have two ways to lower EGT, Oil and the method Marty discovered.

You said there is no difference between running zero nitro and 5% but that is not the case. Small amounts of nitro make a big difference in overall running and reliability.

I have only run 5% in the boat, so I maybe wrong there, but I don't think so. I have run both 0% and different amounts of low nitro in the car and with the correct head I can find no difference in reliabily, ease of tuning or general performance, with the exception of generally less power. On the other hand if the head is not made to correctly match the straight methanol all the problems you and others speak of are present and are only improved upon by adding nitro.

I certainly don't have all the answers but I have run many boats and engines on straight fuel unlike others who claim to have all the answers but clearly have not demonstrated that in practice.

Dave, Does your many years of having difficulty running straight methanol out weigh mine or Bob Finn's short term success in running straight methanol in boats and cars? I have also attended a boat race in Italy that was 80/20 only. I saw lots of competitive racing. No one seemed to be struggling any more than at a nitro race.

I have no interest in who is right and who is wrong.

I also have no interest in who is right or wrong. But when you came on here telling everyone it won't work you are going to get a challenge from me. I'm got on this thread to show others how straight methanol could work.

 

Years ago there was a very good National Champion boat racer who had lots of good advice and helped many boaters become successful. When the IMPBA electronically timined record was was under 80 mph and I was talking about running 90 mph. he told me, "ain't never gonna be a model boat that goes 90 mph".

 

Dave, You can be a part of the solution or a part of the problem. If you choose to be a part of the problem then you can expect a challenge from me beause I only prefer to look for solutions.

I just proffer my experiences and my opinions on the options of running straght fuel or fuel with small amounts of nitro.

I likewise am here to offer my experiences, opinions, and ideas about running straight methanol. While I have not successfully proven my ideas by consistantly racing with Straight methanol I do have and have seen enough success that I believe it can be achieved by all boaters who wish to do so. Andy

Dave

 

[F.Orlic]

I have only run 5% in the boat, so I maybe wrong there, but I don't think so. I have run both 0% and different amounts of low nitro in the car and with the correct head I can find no difference in reliabily, ease of tuning or general performance, with the exception of generally less power. On the other hand if the head is not made to correctly match the straight methanol all the problems you and others speak of are present and are only improved upon by adding nitro.

My guess if you did not see any difference with your car engine than I would say your engine was not setup correct for nitro. I have only tested car engine but no comparison between 5% and 30%

Nobody said it is impossible to run low or no nitro but I'm sure it is impossible to get the same results we get with high nitro. I do not care if I run 5% or 85% as long as performance is there.

 

[AndyBrown]

I have only run 5% in the boat, so I maybe wrong there, but I don't think so. I have run both 0% and different amounts of low nitro in the car and with the correct head I can find no difference in reliabily, ease of tuning or general performance, with the exception of generally less power. On the other hand if the head is not made to correctly match the straight methanol all the problems you and others speak of are present and are only improved upon by adding nitro.




My guess if you did not see any difference with your car engine than I would say your engine was not setup correct for nitro. I have only tested car engine but no comparison between 5% and 30%

Nobody said it is impossible to run low or no nitro but I'm sure it is impossible to get the same results we get with high nitro. I do not care if I run 5% or 85% as long as performance is there.

Frank,

The 30% engine and the 0% engine were two complete different engine set-ups.

I had an engine set up for 30%. It TQ'd many races. It was a Nationlas A-main qualifier several times.

I had a different great set-up for 20%.

I had a different set-up for 0%. It was easy to start, easy to tune and only showed about 5% loss of acceleration and even less loss in top speed over the 30% engine.

Nobody has claimed the same power is possible from 0% and high nitro.

Frank, Below is Dave's first response to this thread. I think you will find the word "impossible", along with a few other words about why not to run 0%.

"We raced boats in the UK for many years on no nitro and sorry to give you bad news but believe me you don't want to be doing it. Motors and pipes run very hot and burn plugs like you wouldnt believe. Getting away from the shore is much more difficult, piston liners have to have a perfect fit and be replaced very often. Only the very best engine experts will have any kind of success with no nitro. Many people will find it impossible. "

 

[Tim_Duggan]

I have only run 5% in the boat, so I maybe wrong there, but I don't think so. I have run both 0% and different amounts of low nitro in the car and with the correct head I can find no difference in reliabily, ease of tuning or general performance, with the exception of generally less power. On the other hand if the head is not made to correctly match the straight methanol all the problems you and others speak of are present and are only improved upon by adding nitro.

All,

So would I be right in assuming that the compression ratio and squish %, and possibly angle needs addressing to avoid those issues had, which were "only improved upon by adding nitro".

I have a test day planned for this sunday coming and will be playing solely with a mod 20 tunnel with a Long Stroke engine. If I have time and don't break anything serious I will try some FAI 4:1 at the end of the day.

This boat currently runs on 50%Nitro, Has an air cooled head with 0.17cc bowl and 0 degree squish which is 50% of the bore. Clearance at 0.008". K&B 1L plugs. What suggestions would you make for a different button to suit the FAI 4:1 fuel?

Tim.

 

[AndyBrown]

I have only run 5% in the boat, so I maybe wrong there, but I don't think so. I have run both 0% and different amounts of low nitro in the car and with the correct head I can find no difference in reliabily, ease of tuning or general performance, with the exception of generally less power. On the other hand if the head is not made to correctly match the straight methanol all the problems you and others speak of are present and are only improved upon by adding nitro.

Hi Andy,

So would I be right in assuming that the compression ratio and squish % and or angle needs addressing to avoid those issues had, which were "only improved upon by adding nitro".

I have a test day planned for this sunday coming and will be playing solely with a mod 20 tunnel with a L/S engine. If I have time and don't break anything serious I will try some FAI 4:1 at the end of the day.

This boat currently runs on 50%Nitro, Has an air cooled head with 0.17cc bowl and 0 degree squish which is 50% of the bore. Clearance at 0.008". K&B 1L plugs. What suggestions would you make for a different button to suit the FAI 4:1 fuel?

Tim.

Yes Tim! Methanol needs much more compression than nitro. This is a documented fact in all circles of engine design.

Even the Italian engine makers know this. Rossi always offered Nitro heads and low nitro/methanol heads, refered to as "normal" heads.

The Nitro heads always had a larger volume.

The problem it that we nitro boaters in most cases found that even the Italian "normal" heads had too much volume for high nitro and their "nitro" heads were way too big for anything.

You do in fact want to have a trapped CR of 17:1 or more.

The other thing needed for Methanol is a more retarded ignition point.

I little nitro added to methanol will retard the ignition point, however if we want to run Straight Methanol me must find another way to retard the ignition point.

There are several ways to do this.

More later!

 

[Tim_Duggan]

Hmm,

the .17cc / 50% of bore bowl I'm running now is rather tiny (Not that much bigger than a glow plug thread!) I can drop the existing button down to about 0.004" clearance but thats not going to get me the extra compression points to get any where near 17:1. New button is the only way I'll get there. It would be easier on an engine of a larger capacity.

The only way I think I can drastically increase the CR on this long stroke motor with existing timing is to move the plug closer to the piston face at TDC, reduce the bowl diameter even more (and therefore increase squish band) or go away from a Hemi bowl entirely to something like a cone shaped chamber.

I'm very interested to hear your thoughts on retarding ignition timing. Ideally I'd like to do this without altering the sleeve if at all possible. I'm thinking a cooler plug might be only part of the eqaution and that it may have more to do with squish velocity.

Ahh - the intricacies of the 2 stroke glow engine. Anyone else having fun yet?

 

[Tim_Duggan]

0.005" clearance at 0.11cc = 17:1 CR with 184 deg exhaust on a Nova L/S bore stroke ratio.

 

[AndyBrown]

You're thinking in the right direction Tim. You can cut a stock head until you have a plug depth of .060"....maybe .05".

You want a bowl volume of close to .01 cc maybe a little less.

Then put about a .035" radius where the squish band meets the chamber. The radius will retard the ignition point.

Play with the head clearances until it works. I'd start at about .024" I know that seems high but for this 'make do' head that may be where it needs to be. This will depend on the radius you put on the edge of the squish.

 

[Jeff Lutz]

I'm shocked at the interest of wanting to make methanol work, although it could be done, the end result will be less power. A few people were trying to say just a little bit of nitro can make a big difference and not cost much at all, 15 % nitro would cut cost greatly and as many know would still perform good.

Of course I still stay focused:

Gasoline is for washing parts.

Alcohol is for drinking.

Nitro is for Racing!!!!!!!!!!!!!!

J Lutz

 

[Tim_Duggan]

I'm shocked at the interest of wanting to make methanol work, although it could be done, the end result will be less power.

I doubt you'd find anyone who wouldn't agree there is less power with less or no nitro. However, if the difference can be reduced to a smaller margin that what is seen currently through sharing the knowledge on how to do it - it may curb some of the losses to other power sources we are seeing NOW. Becoming less reliant on expensive nitro, glow plugs, pistons etc. might not be a factor for some of us, but it is for others and is a frequently used argument for switching to Gas (petrol) classes.

I love nitro, but I'd rather run a glow engine on 4:1 methanol /oil only fuel than run a gas boat. If nitro gets hard to find or beyond most people's affordability - an alternative to losing people to gas or electric could be a switch to Methanol.

 

[AndyBrown]

Methanol produces more power in an engine than Gasoline and it does not require a heavy, bulky ignition system.

Methanol can be obtained locally for many people, therefore saving the cost of shipping low nitro fuel.

 

[Tim_Duggan]

Methanol;

in a nitro engine will pull as many rpm as it will on nitro (propped accordingly)

is a performance race fuel. It's used in a lot of forms of motorsport.

is not oil based as it is an alcohol. Less reliant on imported mineral oil from certain parts of the globe than gasoline.

doesn't smell anywhere near as nasty as Gasoline / 2 stroke oil in the car if you don't use a trailer to / from the pond.

 

[Ken Retallick]

Nitromethane is chemical supercharging.

Supercharging, turbocharging are a way of getting more oxygen into the engine. Nitromethane and nitrous oxide

deliver this extra oxygen as part of the fuel. More oxygen means more fuel can be burnt, creating higher cylinder pressures which boils down to more Torque.

 

[AndyBrown]

For those who want to praise the virtues of nitro here, PLEASE read the title of this thread.

 

[Tim_Duggan]

Hi Ken,

Whilst I don't dissagree with your comment (even though this isn't really the place for it) - Is a tuned pipe not a form of supercharging in a two stroke engine?

Maybe taking the liquid supercharging out of the equation might make some people use "the other blower" on the boat to it's full potential, rather than being just a big, glorified muffler.

Congrats on your win in Finley BTW. FF21 + Novarossi = Good combination

 

[LH7018]

Correct me if I'm wrong as I'm no chemist, but I believe methanol has a pretty high heat absorption rate. So, if one could take advantage of that cooling effect and put it to use, particularly in the intake tract. For example, instead of using the rather common spraybar we use now in the carburetor, change to something similar to the Carl Brey annular discharge type to break the fuel into smaller droplets which are dispersed more evenly through the intake bore. This could possibly, just theorizing here, cool the entire intake tract more than available with conventional spraybars allowing a more dense charge into the motor. I would think then that the carburetor bore size would have to be altered (larger) to keep a somewhat stoichiometric ratio in range to take full advantage of this. A side benefit here might also be that a larger denser charge contains more oil for lubrication, as that was a concern mentioned in earlier posts due to the leaner needle required when just switching fuel types from nitro bearing to no nitro with minimal other changes. The next step then is how to efficiently burn this larger charge. Perhaps we really wouldn't need very much water going through the jacket, or a longer pipe. Just a couple of thoughts, not necessarily right or wrong.

 

[AndyBrown]

Correct me if I'm wrong as I'm no chemist, but I believe methanol has a pretty high heat absorption rate. So, if one could take advantage of that cooling effect and put it to use, particularly in the intake tract. For example, instead of using the rather common spraybar we use now in the carburetor, change to something similar to the Carl Brey annular discharge type to break the fuel into smaller droplets which are dispersed more evenly through the intake bore. This could possibly, just theorizing here, cool the entire intake tract more than available with conventional spraybars allowing a more dense charge into the motor. I would think then that the carburetor bore size would have to be altered (larger) to keep a somewhat stoichiometric ratio in range to take full advantage of this. A side benefit here might also be that a larger denser charge contains more oil for lubrication, as that was a concern mentioned in earlier posts due to the leaner needle required when just switching fuel types from nitro bearing to no nitro with minimal other changes. The next step then is how to efficiently burn this larger charge. Perhaps we really wouldn't need very much water going through the jacket, or a longer pipe. Just a couple of thoughts, not necessarily right or wrong.

Good points!

My work with the MAC buggy engines is what got me interested in the idea of Straight Methanol.

In our short 2 minute boating racing we could care less about fuel milege. Just burn more for more power and if we run out....just build a BIGGER tank!

However in car racing power and milege are important.

I'm pulling some numbers off the top of my head, but this will give you the idea.

A 4oz tank of 50% has about 1800 BTU's of energy. A 4 oz. tank of Methanol has 2300 BTU's of energy.

Let say we have an engine set up for 50% and it will use up the 4 oz tank in two minutes.

If we run the Methanol in this same engine set up for 50% nitro it would probably run for six minutes and not go as fast.

But look at the potential if we could build an engine that would burn up the full tank of Methanol in two minutes.

We could have 25% more power for a two minute race.

I just use this to illustrate a point. That is to attempt to burn up a lot of fuel as quickly as possible.

This means maximun compression and maximum mass flow through the engine.

Certainly this is the goal in every racing engine, but it's important to understand that the 4 oz tank of Methanol is going to need about twice as much air to burn it all up compared to the tank of 50%.