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Author Topic: Everything you ever wanted to know about racing fuel  (Read 8756 times)

Offline rsss396

Everything you ever wanted to know about racing fuel
« on: December 09, 2013, 01:23:58 PM »

Everything you ever wanted to know about
Racing Fuel

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By Peter Billllinton , Rex Heatley and JohnStorm

SOME BASIC FACTS


WELCOME to the world of racing fuels. Within the pages of this book we will bediscussing such exotic and volatile fuels and fuel additives as Methanol,Nitromethane, Dinitropropane, Acetone, Propylene Oxide, Nitrobenzene andothers.

However, in order to evaluate the advantages and disadvantages of these specialfuels for use in high performance engines it is necessary to have a clearunderstanding of the laws of thermodynamics as applied to the internalcombustion engine.

HOT AIR ENGINE

For our purpose it is sufficient to state that such an engine is in simpleterms a hot air engine depending on the expansion of a quantity of air, heatedby the combustion of fuel, in a confined space, thus providing the drivingforce on the piston the reciprocating motion of which is converted by thecrankshaft into a rotary motion, so driving the flywheel and thus the source ofpower.

It follows, therefore, the more air, by weight, we can ignite in a givencombustion space and the greater we can increase the temperature, the greaterwill be the expansion and the force applied to the piston.

COMPRESSION

This at once highlights a term used by many without quite understanding itsimplications, the term being Compression Ratio.

This is the ratio between the piston at the top of its stroke leaving a spacein the combustion head and this volume added to that swept by the piston, thatis the bore and stroke volume. If, for example, this works out at ten to one itmeans the mixture is compressed to one tenth of its normal volume and thenignited.

If we assume the engine is not supercharged and at normal atmospheric pressure14.7 Ibs. per sq. in. approximately, and 100 per cent volumetrically efficient,the force on the piston would be 147 Ibs. per sq. in.

This, however, will not be the case in practice as the engine will not take ina charge of mixture equal to the space left by the piston at bottom deadcenter, in some cases the exhaust gases are not completely evacuated and theheat of the cylinder walls, head and valves, all have their effect on heatingup the incoming charge, reaching, with petrol, some 700°F.

Thus it is obvious, owing to the heat conditions existing in the engine, thatthere are definite limitations to the power output which can be maintained, andthese conditions, so far as petrol is concerned, are reached much
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

Everything you ever wanted to know about racing fuel
« Reply #1 on: December 09, 2013, 01:24:52 PM »
earlier than with alcohol.

LESS POWER

There is a common mistake in thinking that so called racing fuels contain in themselves, quantity for quantity, more energy than petrol. This is not so, and in fact alcohol's have considerably less internal energy than petrol, their respective calorific values being 19,000 British Thermal Units per-pound weigh tfor petrol and some 8100BTU's for alcohols.

This means that, gallon for gallon, less power can be obtained from the alcohol's, but the limiting conditions mentioned above eliminate this particular drawback.

The amount of air required by petrol to burn correctly is several times more than that required by alcohol, so that in effect the advantage of alcohol is that the amount of heat liberated per pound weight of air used is greater.

Since the engine is an air engine where air is the working medium, heated by the ignition of the mixture, causing expansion, the fact that we can get a cooler and therefore heavier charge into the engine means a higher power output to be attained, fuel for fuel and weight for weight.

In other words the advantage of alcohol is its high latent heat evaporation figure as compared with petrol, allowing it to act as a refrigerant.

You may have at some time or other noticed inlet pipes tending to show frost when using alcohol.

The difference, for those interested in the heat values, is some 135 BTU for petrol and 472 BTU for alcohol, and just to clear all that up, it might be worth while saying that one British Thermal Unit is defined as the amount of heat required to raise the temperature of one pound of pure water one degree F.

OPTIMUM ON PETROL

Over the years the motor engine has been developed and adjusted by design features to operate at its optimum on petrol, this being available in bulk at a reasonable cost.

This fuel is a natural product of the earth, but, as we know, it has undergone a number of changes and has had certain additives incorporated to produce the required results when used with the modern combustion engine. Here then is our reference level or datum line.

If you have an engine, in good condition and tune, running, shall we assume, on top grade petrol and providing a known power output, it is possible by change of fuel to obtain a higher output, and to do this you can go to an alcohol based fuel.

To get maximum benefit from the new fuel you will have to adapt the engine to run under the new conditions being applied, and you will at once find there are advantages and disadvantages.

As we now have some understanding of the nature of the work the fuel is expected to carry out, they can be considered, and the new fuel used to its maximum.

ALCOHOL FUELS


RIGHT at this point it might be as well to point out to readers that the handling of alcohol fuel, even in small quantities, is dangerous since poisonous Methyl Alcohol is the basis of most of these fuels.


« Last Edit: December 13, 2019, 01:34:33 PM by Tbone07 »
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

Everything you ever wanted to know about racing fuel
« Reply #2 on: December 09, 2013, 01:25:22 PM »
In some cases toprevent it being used for drinking an additive is used, called Pyridine, aboutone half per cent being the amount.

This gives it a nasty smell and a vile taste, but pure fuel is, of course,without this deterrent.

The problem still remains, however, since it can get into the system byabsorption through the skin or cuts, and can be inhaled from exhaust gases.

The effects are cumulative and if enough build up is allowed it oxidizesforming Formaldehyde causing blindness and insanity.

The use of rubber gloves, avoiding splashing and handling in confined space andin general treating with commonsense, however, reduces the risks to acceptableproportions.

Should, however, any get in the eyes immediate medical attention is necessary.

For those who have not handled alcohol fuel it might be as well to say it is aclear, colorless liquid, cool in touch, with an odor different from petrol, andhas an attraction to moisture in the atmosphere.

ADVANTAGES AND DISADVANTAGES

Let us now investigate the advantages and disadvantages of going over to thisfuel, and at all times taking petrol as our reference level, having in mind thebasic requirements of fuel in the heat engine.

The first question must be is it easy to obtain and the answer is there are anumber of garages retailing the fuel, in certain cases with other fuels addedin specified quantities.

Having obtained the fuel, as already explained, it must be handled with careand commonsense.

There is no real problem in keeping in store any quantity left over from onemeeting to another, provided it is kept in a can, or tank for that matter, withthe cap kept on during the store period, which can extend into years, contraryto popular belief.

COST

Cost of the alcohol depends on what other fuels have been incorporated, but asguide pure alcohol is, in small quantities, about just over half as much againas the cost of top grade petrol. You must bear in mind at this point, however,you will require double the amount of alcohol as compared to petrol for reasonswhich will be explained later.

Another point to consider is that alcohol is a solvent and so far as certainpaints are concerned it acts as a perfect paint stripper. Alcohol also has avery thorough scouring effect on tanks, pipe lines and so on, not forgetting itcan on certain

types of fiberglass tanks cause them to disintegrate into a rather nasty stickymess.

CONSUMPTION

Consumption of alcohol will be, in rough figures, double that of petrol, due tothe calorific value being about half that of petrol.

The correct air-fuel ratio for petrol is 14.1 to 15.1, but for alcohol it is7.1 to 9.1 so that means we must pass at least twice the weight of fuel, in thecase of alcohol, to heat the same amount of air to the same temperature as weneed for petrol.

Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

Everything you ever wanted to know about racing fuel
« Reply #3 on: December 09, 2013, 01:25:54 PM »
Since the specificgravity of the two fuels is near enough the same it means in effect we have topass through the jets double the quantity of the fuel.

Apart from doubling up the flow capacity of the jets, and we would add herethat this does not mean doubling up the diameter of
the jet hole as many people think, but, in fact, increasing the diameter by 1.4times or if you like by 40 per cent since a little thought will remind you ofthe fact you are dealing with the area of the hole in the jet and not thediameter.

It is of little use increasing the capacity of the jet to pass double theamount of fuel unless steps have been taken to establish that the fuel lines,taps, float chambers and so on are also capable of passing double the fuel andthe actual flow should be measured.

RICH SIDE

Now unlike petrol you will find alcohol fuel will continue to provide increasedpower for a mixture well above the ideal mixture strength and you can alwaystend, therefore, to jet up on the rich side, and so avoid any possible chanceof running into troubles through weak mixture causing burnt valves and holedpistons.

This larger amount of fuel compared to petrol and especially as it is a fuelwith much higher latent heat value tends to do two things. The density of thecharge entering the engine is higher than petrol and a greater weight ofmixture is therefore being exploded.

This is a fuel with a large cooling effect provided by part of it evaporatingafter it has reached the combustion chamber and so tending to cool the valves,piston and so on.

Some may well get into the combustion chamber as liquid, due to the reductionin temperature of the induction system, pipes, carburetor, etc., and soextending the cooling effect, in the process counteracting the effect of thehigh internal temperature.

In view of this amount of fuel entering the chamber, with possibly some of itin liquid form, the ignition system must be beyond reproach since if the sparkis weak the mass of fuel will just soak the plug and then at once ignitiontroubles arise affecting starting in particular.

Owing to the use of alcohol a higher compression ratio can be used with thisfuel as compared with petrol, another consideration is the type of plug usedwhich will be a hotter type than used before with petrol.

NINETEEN TO ONE

We have just mentioned the higher possible compression ratio used with alcoholand the limit that can be used with any particular fuel depends on the tendencyof the fuel to detonate.

As a rough guide the ratio for petrol is limited to about ten to one, or withcertain additives to as much as 12 to one. With alcohol, however, you can go upto 19 to one or higher in certain cases. (For all practical purposes however,14 to one should be considered the maximum usable ratio in modern short strokeautomotive engines.)

The possible use of a much higher ratio, of course, means we get a higher poweroutput from the engine, and this, in fact, is almost the main advantage ofalcohol fuel.

DETONATION

Detonation with alcohol fuel is really not a problem, but pre-ignition is, orcould be unless the mixture is kept
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

Everything you ever wanted to know about racing fuel
« Reply #4 on: December 09, 2013, 01:26:21 PM »
well on the richside.

The reason for this is that if the mixture is on the weak side it burns slowlyand can still be so doing when the exhaust valve has opened which then becomesoverheated. This in turn ignites the next charge before the correct time, thewhole process becoming a chain reaction causing even more rise in temperatureand so it goes on until the piston holes and other damage then follows.

The first signs of this process taking place are a loss of power, a generalrise quite quickly of overall temperature, the head in particular.

To avoid this, run on the rich side always and use plugs with a good heatcapacity.

It might be worth mentioning at this point that an engine set up correctly forrunning on alcohol, even though on a rich mixture, will be found to be(compared to petrol), a much cleaner running engine inside the cylinder head,and provided the ignition side is up to its job there will be less fouling ofplugs than on petrol.

IGNITION SETTING

Due to the different rate of burning of alcohol compared to petrol the ignitionsetting will have to be changed.

It will have to be advanced and the amount necessary will depend on the shapeof the cylinder head and general design.

For example, on a well designed hemi-head an extra five to six degrees mightwell be enough, whereas on a poor designed head it might be something like 15degrees.

Optimum ignition setting is tied up with the air-fuel ratio and it will befound that with alcohol it is not so critical as with petrol, that is to saythe drop off of power is not so progressive as will be seen later.

STARTING

Provided the engine is set up for running on alcohol correctly there should belittle trouble in starting except perhaps on a very cold day and it should bepossible to start up on the fuel mix used for the actual racing.

The main problem, due to the cooling effect of the fuel, is to get the engineto operating temperature in the short time available from fire-up to staging.

For this reason so far as motor cycle type engines are concerned, you willnote,

in many cases, the finning on the cylinder barrels and heads is almosteliminated. This, by the way, also helps to increase the power to weight ratio,or if you like tends to counteract the weight of the extra amount of fuelcarried as compared to petrol.

LIMIT

From reading this far, you should have come to the conclusion that if yourengine is now on its limit running on petrol, while large increases of powerare obtainable by the use of higher compression ratios it is possible to get areasonable increase in power output, ten per cent or so, with the existingratio, provided you make quite certain you get enough fuel through to theengine and, in fact, that you tend to run on the rich side.

Once you have gone over to alcohol and obtained satisfactory running, you havecommenced an extension of your power output by anything up to 25 per cent asyou adapt the engine to run with the new fuel.

The rather attractive feature that you tend, even with the increase of power tostand less chance of doing
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

Everything you ever wanted to know about racing fuel
« Reply #5 on: December 09, 2013, 01:26:45 PM »
damage to the engine than when on petrolshould also be considered.

FINAL POINT

One final point to consider. If you change over to

alcohol from petrol where you were using a mineral oil, it is not necessary tochange over to a castor based oil. For modern engines, the present typeadditive mineral oils offer a higher performance level than the additive castorbased oils, and under controlled conditions the light viscosity oils have anadvantage where the warm up time is limited.


FUEL FLOW AND CAPACITY

Now that the decision to change to fuel other than petrol has been made, thefirst thing to look at is the fuel tank. If of fiberglass, bear in mind the newfuels act as solvents and most petrol resisting paints, shellac, varnish, ethylcellulose, cellulose nitrate and soft Bakelite suffer in contact, notforgetting sealing compounds such as Bostic, Hermatite, Osotite and similarleak stoppers.

If the tank resists on test, do bear in mind that if, at a later date, youpropose using Nitro Methane you will have to test still further as this acts asa solvent on many resins, polyvinyl acetate, acetylchloride, chlorinated rubberand low boiling hydrocarbons.

The obvious way to test is to deposit a little of the fuel on the tank surfaceand see if it reacts, bearing in mind it may attack the paintwork and not theactual material of the tank itself, so do not get misleading results.

If the tank is of metal construction, particularly of aluminum, it should beanodised, thus stopping chemical reaction causing a white deposit to formtending to clog fuel lines and carburetor parts that come in contact.

If of steel and tin plated, the fuel will tend to take off the tinplate andform a deposit on other metal parts in the fuel system.

Washing out the entire system is sometimes carried out with petrol to stop thisdeposit building up too much.

Bear in mind alcohol will descale material unaffected by petrol and it isadvisable to wash out and clean the whole tank first with a small amount offuel, to make sure you start clean, and to frequently inspect it to keep insuch condition.

In passing it might also be worth consideration that at least one well knowncarburetor uses a plastic float that gets more than a little upset with fueland another uses plastic cut-off valves in the float chamber which also object.

FUEL CAPACITY

At this stage it is necessary to work out how much fuel you need to carry andat what flow rate it will have to leave the tank.

There is no point in carrying more fuel than required, since, apart from theweight, you are just increasing the fire risk.

The rate of flow will establish the diameter of the outlet pipe or pipes, and apoint often missed, the diameter of the breather hole, usually incorporated inthe cap. This last point does not apply if the tank is pressurised.

Having decided on the amount and the rate of flow, you have to consider thecut-off valve and the fuel lines
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

Everything you ever wanted to know about racing fuel
« Reply #6 on: December 09, 2013, 01:27:10 PM »
themselves.

in the case of a small engine the minimum bore diameter anywhere in the systemshould be 6mm., and for the rest 13mm. and the fuel lines should have, atworst, that diameter, preferably up to twice the diameter to reduce friction,and be made of Polythene, Neoprene or other alcohol resisting material.

Do not fall into the trap of using fuel lines of these diameters and use, attheir termination's, unions which restrict the actual effective diameters tomuch less. The ideal set-up is where the internal diameter right throughout thewhole system to the carburetors is of the same diameter, providing thatdiameter is large enough to reduce friction to a sensible minimum.

FUEL FLOW

Now check the actual flow right down to the fuel line that supplies thecarburetor or fuel block.

If gravity feed is used this is simple to do, but remember to check with thetank at the same height as used, and time the flow and quantity.

If the tank is pressurized, for your own interest, check with the cap open,then under pressure and the difference will surprise you, also how quickly theair pressure drops, more so if the air space over the fuel be smaller.

If the tank supplies some form of fuel pump, remember the pump diaphragm willhave to be of Neoprene or it will dissolve.

Electrically driven pumps are easy to check, but those driven by the engineitself present a problem.

If the makers' figures are available all is well, but if not you will have toestablish the actual quantity of fuel pumped per stroke, then from the rate atwhich the pump is operated, calculate the actual flow rate.

In all cases the rate should be at least twice the estimated maximum demand ofthe engine at peak requirement.

The major obstruction will usually be found in the cutoff valve of thecarburetor float chamber and although some manufacturers can supply valvesmodified to increase the flow at this point, they usually do not allow enoughand you will have to fabricate your own.

Remember here by increasing the diameter of the orifice by 40 per cent you willdouble the flow of fuel.

Do check however the flow rate through the valve and make certain it is enough. . . so many fall into this simple trap.

The figure of twice the required maximum demand rate may sound excessive, butbear in mind apart from the sudden demand, you have to force the fuel againstthe actual acceleration of the car or bike.

One final comment before leaving the fuel lines and means of getting the fuelto the engine itself.

Do check that the fuel cut-off valve, when in the open position, is in factfully open, and having done that check, if the tank has a breather, that fuelcannot spill out and possibly be blown back onto or into the engine, or forthat matter the driver.

TWICE AS MUCH

The actual amount of fuel required by the engine will be double the amount itconsumed when on petrol, but if you are starting from scratch so to speak, thea mount is determined by the amount of air consumed by the engine, which ineffect is directly related to its capacity at full throttle.

Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

Everything you ever wanted to know about racing fuel
« Reply #7 on: December 09, 2013, 01:27:35 PM »
With regard to a supercharged engine the amount requiredwill be dependent on the boost pressure, so that for every 15 lb. approximatelyof boost, that is the amount over atmospheric pressure, as would be indicatedon the gauge, you will have to consider the actual effective capacity increasedby the same amount as the basic engine capacity.

For example a 1000 cc. engine running at a boost pressure of 15 lb. would beregarded as of 2000 cc. and the same engine running at some 30 lb. pressurewould work out at 3000 cc. and proportionally for other boost pressures.

FUEL-AIR RATIOS


SINCE fuel-air ratios are quoted by weight of both parts it will be necessaryto establish the actual weight of each component before we can determine thecorrect ratio we require.

To put this into practice you must take the cubic capacity of one cylinder ininches, since we are considering weight in pounds, multiplied by the number ofcylinders that are fired per revolution, times the total revolutions per minutefor a normally aspirated engine, but for a supercharged engine this figure willbe increased as indicated previously.

This total figure will be the volume of air consumed per minute, which must nowbe converted to weight of air in order to find the amount of fuel necessary tomix with it at the nominated ratio.

In order to carry out this calculation it is necessary to know that you convertcubic centimeters to cubic inches by dividing the total figure by 16.4, whichmust be converted yet again to cubic feet by dividing by 1728.

Since one cubic foot of air weighs 0.081 pounds at a temperature of 32 degreesF, or alternatively one pound of air equals 12.4 cu. ft., it is now possible todetermine the weight of air in pounds involved per minute.

The next step is that of ascertaining, from the previous calculation, theactual amount of fuel involved by considering the fuel-air ratio.

SIX PARTS TO ONE


In the case of pure methanol a ratio of approximately six to one, that is tosay six parts of air to one part of fuel by weight.

This means a total of seven parts, one will be that of the fuel itself, that isto say a seventh, but since the actual weight of the fuel is eight pounds pergallon of methanol, we will have to divide that figure by eight to convert togallons.

The final figure so obtained is the fuel required at full throttle in gallonsper minute.

Since this is assuming 100 per cent efficiency it means in effect this will bea mixture on the rich side, but as methanol is insensitive to small ratiochanges this is unimportant and in fact a built-in safety factor, avoiding leanmixture troubles such as burnt pistons.

From this calculation it will be possible to determine the total amount of fuelrequired to carry in the tank, plus the rate of flow to the carburetors orinjectors, single or multiple as the case might be.

Providing the actual fuel flow can be allowed to take place as it would undernormal operating conditions, it will be possible to check the jet sizes relatedto the actual amount of fuel they will pass per minute.

Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

Everything you ever wanted to know about racing fuel
« Reply #8 on: December 09, 2013, 01:28:24 PM »
If this is not possible, for example in the case of anengine driven pump system, either the maker's figures will have to be used, orthe displacement per revolution or stroke established, times the number ofthese per minute, giving the estimated flow.

These figures are empirical but will at least provide a basis on which to startand experiment, and will prove whether the pump has sufficient capacity or not,and for the particular application in mind, this figure should be at leasttwice the estimated flow rate.

READY TO START

At this stage we are ready to start up and from the actual running of theengine, commence to see if the mixture is about right by the normal methods,but -it must be appreciated our estimated requirements have been taken at fullthrottle or maximum fuel demand.

Tuning, insofar as intermediate settings of the throttle, follows normalpractice, but for starting conditions, it may be slightly different, as in mostcases of fuel other than petrol, it is unnecessary to provide an excessivelyrich mixture for starting as this will only cause plug wetting, making itdifficult or even impossible to start.

As previously stated when the engine is set up, which is often not the case,and in tune, it will be possible to start up and run right away. However forthose that may find starting a problem, especially in cold weather conditions,it may be advisable to add some volatile component to the fuel, or even startup by the simple means of introducing another fuel, such as lighter fuel, bythe simple means of squirting a small amount into the air intake of the engine.

FIRE DANGER

A warning at this stage would not be out of place in the use of Ether orcompounds containing a high proportion of Ether, such as Easistart, . orsimilar aerosol packs, except those specifically formulated for spark ignitedengines, as opposed to diesel, due to the danger of flash fires, and alsodamage to the engine caused by possible detonation.

The preferred method of obtaining easy starting is that of blending certainother fuels with the methanol in controlled proportions, for example the use ofAcetone up to a maximum of 5 per cent by volume, petrol also up to the samemaximum amount, or Ether, but at a maximum of 3 per cent.

With regard to Ether, the blending of this with the fuel should, for reasons ofsafety, be left to the fuel supplier due to the extremely low flash point ofthis material, in fact, a figure of minus 40 degreesF.

Since as stated before, these fuels, if by any mischance, get into the eyesimmediate medical attention is necessary.

If this is impossible due to circumstances, to obtain, the following actionwill do until professional attention ca n be secured.

The eyes should be continually washed out with clean water for a period of atleast 15 minutes, needless to add, with care.

Clothing contaminated with fuel should be removed to stop the fuel penetratingto the skin, and if it has, the area effected washed thoroughly with soap andwater.

It may seem some stress is made of the dangers of fuel, but it is better toknow the dangers and take the necessary precautions, which after all onlyamount to common sense, rather than go along in total ignorance.

Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

Everything you ever wanted to know about racing fuel
« Reply #9 on: December 09, 2013, 01:28:51 PM »
COMPRESSION RATIOS


WHEN we were first considering changing over to Methanol it was stated a smallpower gain would be obtained right away with just the change of fuel, but toobtain the full benefit the engine would have to be modified to do so.

Going back to our simple heat engine again as a basis, we can say by the use ofMethanol we are getting twice the weight of fuel to ignite, at the same time wecan increase the compression ratio to a much higher figure thus producing muchgreater power or force on the piston, and so in fact obtaining a more efficientengine.

This extra power will, however, do two things, one being to produce more heatso the engine will run hotter, the other being that it will create much highermechanical stresses.

The extra heat generated we can cope with, for example by using a richermixture so gaining the cooling action of the Methanol itself, but themechanical stresses are another matter.

When the fuel is ignited the resultant force is applied to the piston top, alsoto the cylinder head, but since the head is fixed and the piston movable, thelatter starts on its downward stroke, the closed valves making sure the wholeforce is so applied without possible escape elsewhere.

Now if the studs or bolts, holding the head down, cannot cope with the nowincreased power we are going to be in trouble.

On the other hand if the head is well and truly held down, the force will beapplied to the bolts holding the cylinder barrel to the crankcase.

Provided all these hold, the extra force is applied to the little and big ends,plus the crankshaft itself.

This is why, as a good example, the dirt track JAP engine has the bolts thathold the head on extended right down past the barrel, or in some cases throughthe finning, right into the crankcase itself, making a really solid mechanicalassembly.

HIGHER COMPRESS!ON

There comes to mind as another example a well known twin cylinder machine withthe engine made as an alternative in light alloy, the barrels and heads beinginterchangeable, the makers advising the use of the iron barrels for Methanoldue to the alloy barrels tending to fracture at the base.

We must also, at this point, consider if it is proposed at this stager or at alater point in time, to use Nitro-methane, the question of the actualcompression ratio to be used will be determined by the amount of Nitro-methanein the Methanol and as a guide Chart 1 gives approximate values on theconservative side.

Methods of obtaining higher compression ratios depend on many factors, which ina simple case, may be had by the fitting of high compression pistons, ifavailable.

In some cases a thinner head gasket may be the answer, or total elimination ofthe gasket and face grinding the mating surfaces.

Again it may be possible to have the ratio increased by removal of metal fromthe head, or the block for that matter, but in such cases you must check thatthe valves have enough clearance to miss the piston.
Another method is that of building up the inside of the cylinder head with newmetal and then machining to the required shape.

Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

Everything you ever wanted to know about racing fuel
« Reply #10 on: December 09, 2013, 01:29:27 PM »
Remember in the case of a V-8 engine if you have the headsskimmed to get higher compression, you will be in trouble with the inlet portsnow being out of line with the manifold, due to the heads sinking lower inrelation to the manifold itself, so give the matter some careful thought beforegoing ahead.
CHART 1
Approximatecompression ratios recommended for use with Nitro-methane / Methanol fuelmixes.
[TABLE=class: MsoNormalTable, width: 144]
[TR]
 [TD=width: 80, bgcolor: transparent]  
Compression  Ratio
 [/TD]
 [TD=width: 102, bgcolor: transparent]  
% Nitro in  Methanol per volume
 [/TD]
[/TR]
[TR]
 [TD=width: 80, bgcolor: transparent]  
16 to 1
 
15 to 1
 
14 to 1
 
13 to 1
 
12 to 1
 
11 to 1
 
10 to 1
 
9 to 1
 
8 to 1
 
7 to 1
 
6.5 to 1
 [/TD]
 [TD=width: 102, bgcolor: transparent]  
10%
 
18%
 
28%
 
38%
 
46%
 
56%
 
66%
 
75%
 
85%
 
94%
 
100%
 [/TD]
[/TR]
[/TABLE]

It must be remembered that for all practical purposes 14 to 1 should beconsidered the maximum usable compression ratio in modern short strokeautomotive type engines.
NITROMETHANE
NOW that we are considering the use ofNitromethane it may be as well to get one well held idea out of the way beforewe go any further . . . that is that more power and therefore more performancecan be obtained by simply adding more Nitromethane to the fuel tank. Nothingcould be further from the truth, friends!

In actual fact this is perhaps one of the quickest ways of running into seriousmechanical trouble.

The actual name Nitro in itself to most people sounds explosive and at once theidea of using this fuel leads the imagination to think of it getting into thecylinder head end then being exploded by the spark, thus producing a violentexplosion in the engine, the extra power then doing more work and so giving theextra performance.

The introduction of more Nitro-methaneto the fuel is not just that of the addition until enough power is obtained,but rather that of well controlled amounts used in relation to the otherfactors.
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

Everything you ever wanted to know about racing fuel
« Reply #11 on: December 09, 2013, 01:30:02 PM »
CHART 2
Recommended jet diameter increases(guide only) for Nitro - methane / Methanol fuel mixes over those used forstraight Methanol fuel.
[TABLE=class: MsoNormalTable, width: 146]
[TR]
 [TD=width: 94, bgcolor: transparent]  
%  Nitro in Methanol
  per volume
 [/TD]
 [TD=bgcolor: transparent]  
Jet  diameter
  increase
  over Methanol
 [/TD]
[/TR]
[TR]
 [TD=width: 94, bgcolor: transparent]  
0%
 
10%
 
20%
 
30%
 
40%
 
50%
 
60%
 
70%
 
80%
 
90%
 
100%
 [/TD]
 [TD=bgcolor: transparent]  
1.0
 
1.12
 
1.22
 
1.32
 
1.41
 
1.5
 
1.58
 
1.66
 
1.73
 
1.8
 
1.87
 [/TD]
[/TR]
[/TABLE]
Chart 2 indicates the increase in jet size toallow the increased amount of fuel to flow as the ratio of Nitromethane to fuelis increased.

These figures in all cases provide a mixture on the rich side since aspreviously pointed out, these fuels are relatively insensitive to mixture ratiocompared to petrol, and the consequences of running weak mixtures with thesefuels is likely to be more serious than with petrol since the power level willbe so much higher, also the thermal stresses.

Note how with 40 per cent nitromethane mixture the jet size has increased by1.41, or put another way by 40 per cent on the diameter, which as mentionedbefore means an actual fuel flow of twice the original amount, so by comparisonwith petrol we now have four times as much fuel required by the engine.

At 80 per cent mixture the fuel flow rate has be-come three times the rate andtherefore six times greater than petrol, hence the need to check the fuel pumpand fuel lines to make quite certain they can cope with this requirement.

DANGERS

Now, as before, it is necessary to know the dangers involved with the use ofnitromethane mixtures so

that the necessary precautions can be taken and understood, reducing them to adegree that makes the use of
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

Everything you ever wanted to know about racing fuel
« Reply #12 on: December 09, 2013, 01:30:32 PM »
such fuels acceptableunder the circumstances in which we normally operate.

Provided you know the dangers you can work with these fuels and come to noharm, but if you do not, then it is possible through lack of simple precautionsto suffer, so bear them in mind at all times.

After combustion, mixtures containing nitromethane exhaust relatively largeamounts of nitric acid in vapor form, making the use of a proper gas maskessential by the driver, and for those close to the car in the start area.

The reason for this is that nitric acid, when inhaled, causes a muscularreaction making it impossible to breathe.

Little imagination is required to see the dangers involved with this possibleevent taking place, and in fact there have been cases of drivers becomingalmost unconscious due to the bad fitting of face masks.

FIRESUITS

The mandatory use of fire suits adds to the generally held view that withnitro-methane mixtures the fire risk is increased, but this is not so.

If you care to test this you can do so as follows. Take a small amount ofpetrol, about one teaspoonful say, and place in a small tin lid and thenignite. It will catch fire almost with a bang.

Now take the same amount of methanol and after the tin has cooled down, repeatthe exercise observing the almost lazy manner in which it ignites, burning witha blue colour, the edges of the flame lined in places in yellow and orange.

Now take the same amount of nitro-methane, 98 per cent if you like, and repeatthe experiment and see how difficult it is to ignite, burning with a greentinted flame in a reluctant manner.

This is due of course to the respective flash points of the three fuels, petrolbeing the lowest at between zero and 40 degrees F. approximately, methanol at67 Degrees F., and nitromethane at 110 degrees F.

In other words with petrol you have a major fire risk and far less so withnitromethane mixtures.

The real problem with nitromethane is its ability to release high power,especially when ignited in a confined space.

Associated with this is its liability to be affected by shock.

Dropping a can of nitromethane will not cause an explosion, as the can, due toits construction of light weight material, will not have sufficient rigidity,but an amount in a very solid thick-walled container may.

EXPLOSION

There are three main possible causes of nitromethane becoming shock sensitiveand they are as follows:

The use of hydrazine as an additive, which, be it noted, is barred byregulations in the USA for that very reason.

The use of caustic soda or any other alkaline, used for cleaning out a tank orfuel lines.

Alloy tanks, which before anodizing, have been cleaned with such a substanceand have retained a small deposit.

To avoid any such possible troubles the tank must be filled with water and 10per cent vinegar, plus a little ordinary household washing-up liquid, and leftto soak for several days.

Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

Everything you ever wanted to know about racing fuel
« Reply #13 on: December 09, 2013, 01:31:01 PM »
One final note of warning concerning burning nitromethaneand methanol is that they can burn almost unseen in daylight, and you may wellhave a carburetor or injector ignited by a backfire without appreciating thedanger.
RUN IT RICH!


We are now in a position to consider the use of Nitromethane blends inpractice.

Like methanol, nitromethane has a strong tendency to pre-ignition, but unlikemethanol it has a much lower knock rating, that is to say it will detonate.

Both these conditions will be fully explained at a later stage, but in themeantime by making sure the mixture ratios are well on the rich side, these twoconditions should be reduced to manageable proportions.

In addition to rich mixtures it is highly desirable to have a very cleancombustion chamber, giving both freedom from Carbon deposits and a smoothflowing surface with no sharp edges that can get too hot.

While polished combustion chambers are the subject of much debate inconventional high performance engines, they have a real use when usingnitromethane fuels.

Since, as has been stated, the figures quoted tend to provide a rich mixture soas to be on the safe side, it will be as well to know the signs of an over richmixture.

Difficulty in starting coupled with mix-firing during the early part of therun, cleaning out at a later stage, or large quantities of liquid fuel comingout of the exhaust system are the two major signs.

PLUG READINGS

Plug readings are another method and can be taken without the usual method ofcutting the engine at full power.

An examination when the engine has completed a run will prove quitesatisfactory, provided new plugs are used.

Signs to look for are as follows whenever the amount of nitromethane is 25 percent or over, starting with a weak mixture, as this is the most dangerouscondition and to be avoided at all cost.

WEAK. The center insulator rather white looking in color and may wellhave the surface rough or blistered, even in some cases with the insulationchipped, a fairly sure sign of pre-ignition.

One or both electrodes on careful examination may show very small beads ofmetal attached to them evident to the naked eye, and almost always considerableblueing of one or both electrodes.

CORRECT. The porcelain center electrode insulator light grey brown incolor, often with the earthed electrode just showing signs of heat.

RICH. Sometimes difficult to distinguish from a weak mixture as in bothcases the center insulator will be rather white looking, but in this case thesurface will be smooth and both electrodes will be almost as the originalmetal.

Another check as a rough indication is that with the engine being turned overwith the ignition off, signs of vapor should be seen at the exhaust, and ifnot, a weak mixture could well be suspected.


Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

Offline rsss396

Everything you ever wanted to know about racing fuel
« Reply #14 on: December 09, 2013, 01:31:25 PM »
Fuel pump pressure is of importance since with Nitromethane(as already mentioned) we are dealing with a fuel that is liable to becomeunstable when confined and subjected to shock.

If you now consider a high pressure pump forcing the fuel under pressure alongthe line, it is quite possible for an air bubble to form, which can then beregarded as a slug of air, which by the pressure behind it, will be forced alongthe line in a series of pulses hitting the fuel in front of it, now compressedin a narrow space, thus providing the ideal conditions for an explosion, hencethe limit of 100 Ibs. per square inch mentioned.

In view of this you must consider placing the fuel cut-off valve after thepressure pump, provided the re-lief valve is set well below the 100 lb. persquare inch point, the advantages of so doing being evident on a littlethought.

PUMP PRESSURE

While on pump pressures there is also the question to be considered when usingcarburetors fed from float chambers, of the actual fuel cutoff valve liftingunder pressure.

In some cases some four pounds pressure will do just that and cause flooding,so a check will have to be made to establish just what line pressure can beutilized without this taking place.

OIL CONTAMINATION

It is most important to check the oil at frequent intervals and if the amounthas increased, as a result of the fuel getting down the bores past the rings,essential to change when the increase is 25 per cent or more for two reasons.

In the first place such a mixture of fuel and oil is no longer a goodlubricant, and in the second place there will now exist a danger of sump firesand even explosions, since the oil mist plus the oxygen-rich atmosphere is veryliable to catch fire or explode.

The only way to overcome such a fire is by the use of C02 type or"OnBoard" Freon type fire fighting equipment, the nozzles directedinto the sump itself.

The first signs of such a fire are lazy, yellowish flames, seen possibly at oneor more of the sump breathers or rocker cover outlets.

It is important when using over 20 per cent nitromethane mixtures to check theengine over after shut off for at least two minutes by visual examination forsuch possible fires.

BLENDING NlTROMETHANE


BLENDING various proportions of fuels to provide our "experimental"batches of Nitro laced fuels means that at some time or other we will be leftwith quantities of unused fuel of a known percentage mixture strength. Becauseof its high cost, leftover fuel is remixed with more fuel to provide a newbatch of greater or lesser Nitro strength as required. To accomplish this, aspecial mixing chart below indicates how this can easily be done.

NITRO PERCENTAGE

Provided you know the exact mixture you have in use and the amount, it ispossible to get your supplier to provide additional fuel to bring the totalquantity up to the new required percentage mixture.

On the other hand you can do this yourself by using a hydrometer which isavailable specially calibrated for just
Anyone looking for a great builder I highly recommend the following.
For CP products dealers I would recommend:
Arlan at LED(site sponsor), Pete Schemberger at Hybrid Engineering, Mat Shearer at Shearer Custom Pipes, Dennis Packard at Packard Racing, and Nate McCoy of McCoys Peformance.

Other great builders I also would recommend: Neil Prichard, Jerry Hall, Bubba Ramsey and James Dodge.

 

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