Lynn E. Hanover

You didn't say what fuel you are using????



In the dyno room, the inlet air is seldom above 75 degrees. You don't want to be over in the high or low end of a correction factor sheet you want to stay near the center. Automated dynos correct for temperature, humidity and air pressure. All dyno outputs are corrected to sea level on a standard day. A 60 degree day. So if you dyno your engine in Sylmar California, and find that it goes flat at 9,000 RPM and will not pull above that. So you ship it to me, and I dyno it and see the same thing.



Or do I? If we have both done the correction factors correctly (pun) I will see the same thing that you did in Sylmar. So anything I do to help your engine will make sense.



The SAE correction tables are published widely and free. Please note that these tables all should result in straight lines when plotted, and there are a few typos in these manually created (people did these with pencil and paper) before computers. So when I first used these sheets on my old Stuska dyno, I kept getting results that seemed to be inverse to what I expected. I called George Montgomery in Dayton Ohio

Famous 33 Anglia altered coupe drag racer. He pointed out the errors in the SAE graphs, and said to plot them on big sheets of graph paper to take out all of those errors. I did that and never had another problem.



The correction factors take out the effect of hot air entering the carbs, humidity going up as the dyno leaks water onto the floor, and local air pressure going up and down with the weather.



So local air temperature at the track, and humidity, and barometric pressure have a massive effect, and must be accounted for, lest the engine run like **** one day and with no tuning changes at all run just fine the next morning. Been there, done that.



The sum of all of those factors is called the density altitude. The actual altitude is how far your car is parked above sea level. This is known fixed factor available all over the Earth. Central Ohio is about 950 feet above sea level. But how high the engine thinks it is based on available air pressure, humidity, and temperature is what make the engine perform

and one of the biggest factors is how much oxygen is in each cubic foot of air ingested.



Airplane people are concerned with barometric pressure, because their altimeters Gages that tell them how high they are rely on the local barometric pressure to establish that. The higher you go the lower the pressure. The lower the pressure, the fewer the number of oxygen molecules in each cubic foot of air.



So, if the car goes up pikes peak, say 9,000 feet in 15 minutes, what will happen to the engine if it has fixed fuel metering, like a carbureter. It gets richer as it climbs the mountain. Right? Yes that is correct.

At the top of the mountain there is about 30% less oxygen in each cubic foot of air, so you need to reduce the fuel being mixed by a similar amount.



The barometric change by itself is called the pressure altitude. You turn the **** on the altimeter in the airplane dash to agree with whatever the ground controller says is the local air pressure. Say you are Northbound from the Sun&Fun flyin in Lakeland Florida, and you have filed an IFR flight plan. You call Atlanta Center as you pass through 6,000 feet (high enough for the war surplus East German radar to pick up an echo) So, you say "Atlanta Center, Bonanza 373Z (you say Zulu not"Z") with you passing 6 for 10 thousand. If Atlanta Center can get their fingers out of their nose for a few seconds, they might come back with "373 Zulu altimeter is 3031". So the local barometric pressure is 30.31 (inches of mercury).



So, there is a clue right there. The local airport has a weather station, and a free phone number to get all of that weather stuff. So you could have that just like the airplane guys. If it was nice when you qualified yesterday morning, maybe it was 75 degrees with low humidity, and the car ran like a bandit, but this after noon for the race it will be 95 degrees, and the shower at noon has the place like a sauna, should I change the jetting at all. Only if being last is your hobby and not racing doesn't bother you.



So, you need a weather station (drag racers actually have weather stations with them) or, you need a cell phone and the flight service center number for the nearest big airport. The people may give you the actual density altitude or just the pieces, so you have to figure it out yourself. I know.........thinking makes you dizzy, but sit down and figure it out. After a few times you can show sombody else how to do it.



So does Racing Beat publish bullshit suggestions for jetting? No, they want you to use their stuff in your engine and go real fast. If what they say didn't work, you will tell everyone, and make bad Mojo for them.



Those people have toe nail clippings that know more about tuning than me and you ever will.



So what could be wrong then?



Context.



Under what conditions were the Racing Beat suggestions established.



Could Anehiem be close to sea level? Might the dyno room have been kept dry for the whole run? (you bet your *** it was).



So, here is what I think.



The jetting you have is fine for a cool dry day. The 90 degree day heats the track to maybe 100 or 110 degrees. It is the air off of the track that the engine breaths so that is the air temperature you tune to.

Take you tire pyrometer out to the track and measure it.



So if it is hot you have to lean the whole range of jetting (the main jets) and if it is also humid (water vapor in the air displaces available oxygen) you have to lean even more. If the barometer is lower today than for qualifying yesterday then you have to lean more (lower pressure means oxygen molecules are further apart and a lower number are in each cubic foot)



So now that 230 main jet is looking like a flame thrower out the tail pipe over rich. Maybe a 160 main jet would get you into the ball park, but you are not in it right now.



In the X formula Mazda car, the engines should turn under 8,000 RPM (I think Daryl Drummond still builds every one of them) and the 51MM carb can handle that whole range with no mods at all (good news).



The air correctors are used to tailor the very top RPM mixture. Smaller = less air supplied to the emulsion tube and a richer mixture, and bigger = more air supplied to the emulsion tube and a leaner mixture.



Smaller tube numbers are richer and bigger numbers are leaner. This is a general statement that works up to F-16 where they are special tubes and the scheme no longer applies. The F-2 is also one of those but it is for alcohol and seldom used. So f-7, f-8 and f-11 are in the center of the range and most folks end up with one or another and never change the tubes. You may find it usefull to run a leaner tube in the rear hole to account for an over rich condition when in lower gears from the surface of the fuel being at a 45 (one "G" or more) degree angle under acceleration.



The high EGTs are no good for the Apex seals, and are a result of fuel burning in the exhaust system instead of inside the engine. When you get close to the tune, the EGTs will agree with the F/A gage. This disagreement is one warning that you have missed the tune by a mile.



Once you have the emusion tubes and air correctors right, you can get lazy and just run the main jets up and down to account for density altitude. (the sum of all of the weather conditions).



Please note that high octane fuels are not required for rotary engines. High octane numbers mean the fuel can resist detonation at higher pressure and temperature than a fuel with a lower octane number.



Generally speaking NA rotaries do not detonate. High octane fuels have compounds in them that are a little difficult to light at high pressures. Makes sense right? High octane fuels usually have lower BTUs per pound than low octane fuels. So 93 octane is as exotic as you need. No alcohol ever. It makes thing burn slow, and has 1/3 the BTUs per pound of gasoline.



On very hot days (track temperature) very few oxygen molecules means slow flame front speed, and the timing will look late to the engine. You might want to try 25 or 27 degrees BTDC.



Lynn E. Hanover

Don1

--> I had hoped that you would give me some insight, Lynn. You have not dissappointed me. Thanks a lot.



"You didn't say what fuel you are using????"



--> AvGas 100 octane. SCCA tests fuel and unleaded fuel will not pass.



"So local air temperature at the track, and humidity, and barometric pressure have a massive effect, and must be accounted for, lest the engine run like **** one day and with no tuning changes at all run just fine the next morning. Been there, done that.

The sum of all of those factors is called the density altitude."



--> I am hoping that is what is read directly from my Longacre Air Density Gauge. Please correct me if I am wrong. So far it has not mattered because I have no baseline with this carb.



"The air correctors are used to tailor the very top RPM mixture."



--> I never heard that before. A very handy piece of information. When you say "very top RPM" I assume you mean above 7k rpm. I thought the air correctors would affect a/f and egt in the mid range as well.



"Smaller tube numbers are richer and bigger numbers are leaner. This is a general statement that works up to F-16 where they are special tubes and the scheme no longer applies. The F-2 is also one of those but it is for alcohol and seldom used. So f-7, f-8 and f-11 are in the center of the range and most folks end up with one or another and never change the tubes. You may find it usefull to run a leaner tube in the rear hole to account for an over rich condition when in lower gears from the surface of the fuel being at a 45 (one "G" or more) degree angle under acceleration."



--> Don't know how you know that, but, that's GREAT. I've never seen that in writing before.



"The high EGTs are no good for the Apex seals, and are a result of fuel burning in the exhaust system instead of inside the engine. When you get close to the tune, the EGTs will agree with the F/A gage. This disagreement is one warning that you have missed the tune by a mile."



--> Just what I suspected. I am sure now that I have missed the tuning "by a mile".



"Once you have the emusion tubes and air correctors right, you can get lazy and just run the main jets up and down to account for density altitude. (the sum of all of the weather conditions)."



"On very hot days (track temperature) very few oxygen molecules means slow flame front speed, and the timing will look late to the engine. You might want to try 25 or 27 degrees BTDC."



--> I didn't know I could safely run the timing beyond 24 degrees BTDC. I will certainly try that.



Thanks again.

Lynn E. Hanover

Unless they have changed the rule rather lately, in SCCA, rotaries are specifically allowed up to a 15 reagent black test to account for unleaded pump gas and the premix of 2 cycle oil. For a while there we bought race gas to be legal, But Daryl Drummond and other Rotary people convinced the comp board that requiring race gas for cars that usually run street gas was indeed stupid. For a while, it was illegal to run the pump gas that the show room stock people were required to run. Thus the insanity continues. The test is one discarded by the NHRA as incomplete, and many distillers can provide fuel that will pass the test and produce considerable extra power.



The short story is that the fuel (100 low lead aviation fuel) is more expensive and has fewer BTUs per pound than 93 octane pump gas (no alcohol). And my bet is pump gas with up to 1 ounce per galon of top oil will come in under 15 reagent. Check that out. I have been an SCCA member for 31 years.



Lynn E. Hanover

Don1

"Unless they have changed the rule rather lately, in SCCA, rotaries are specifically allowed up to a 15 reagent black test to account for unleaded pump gas and the premix of 2 cycle oil."



I was ignorant of the meaning and the intent of that entry on the chart on page GCR-79 that shows DC max = 15 and Reagent = N/A. I appreciate your clarification. Since I am running the standard oil injection, will adding, for instance, 1 oz. of Marvel Mystery Oil per gallon be benneficial?



"and many distillers can provide fuel that will pass the test and produce considerable extra power."



WHAT? Who are these folks that I need for my new best friends? Please enlighten me.



Thanks Lynn.

Lynn E. Hanover

Typically it is preferred that the crank case (sump) oil for the bearings be a straight weight synthetic oil such as Red Line 40 Wt.

racing oil. And the top oil for the apex seals be a synthetic 2 cycle oil such as Red Line racing 2 cycle oil. (for 2 cycle dirt bikes)



Synthetic oils have the highest film strength and reamain stable at very high temperatures. Since they resist breaking down into constituant compounds at high temps, they tend not to burn at all, and are a poor choice for crancase oil in Rotaries using the stock oil injection pump (OMP). So we don't use the OMP in racing. We premix 3/4 to 1 ounce of Red Line 2 cycle oil in the 93 Octane pump gas and run Redline synthetic in the sump. The 2 cycle oil in the fuel is designed to burn completely and clean.



If you must use the OMP and crank case oil, use a straight weight dino racing oil. Very few polymers to gum things up and it burns well, although it does carbon up the rotors a bit.



As far as the special fuels, Even though 06 was my last year of racing my own cars, I will not engage in anything like the activity that caused everyone in racing to have to have a test port, because a hand full of *** holes decided to cheat. I was not above pointing out who was not legal in that reguard, and felt nothing for having people thrown clear out of racing because of it. It was the supposed close drivers skill classes that caused the problem, the formula Vees, and then the formula Mazda people had a few clowns do it. The chemicals involved are deadly and take you breath away at 50 yards. Yet these idiots were pouring this **** right beside their own kids. The fumes would kill the grass in their paddock in one weekend. Loosing these *** holes didn't bother me one bit. Not one of those people was a competitive driver even with extra HP. They were all loosers.

These people did terrible damage to all racers. But I run on as usual.



Lynn E. Hanover

Don1

I have heard of, but not tried, running two kinds of oil. You've convinced me to try it. So, how do I disconnect the oil injection so as not to damage anything in preparation to premixing? I am hoping this doesn't involve pulling my motor.



As far as the special fuels are concerned, I hoped maybe you were referring to something that was legal. I hold the same view as you regarding the folks that illeallly doctor their fuel. To me, what is strange, is that I have no first hand knowledge of any of that. I was running a SRF in Nationals in the NE when the test ports were first required. It was a big inconvienence trying to figure how to, what to, and where to, install. I usually race 10 - 12 times a season and have never once been aware of anyone I was racing with participating in that type of activity even though I have run in FM, DSR, and CSR in addition to SRF. I remember guys not passing the test, but they weren't faster than the rest of us on the track and I never smelled anything out of the ordinary. Maybe I had my head in the sand, or, somewhere else even worse ;>)

Lynn E. Hanover

It got bad enough for corner workers to threaten to abandon the corners for some classes. So the club was late to testing and had to come up with something quick. Then there needed to be training, and there were errors where fuel needed to be sent out for testing when a guy was using the tracks pump gas in SSC as was the car beside him, and he would fail and the same fuel in another car would not. In the midwest, winter fuel has material to help prevent freezing, and as much as 10% alcohol and that puts you very close to failing. So there were some very big problems, and probably still are some. I think High Plains engineering did that test system and has a list of fuels and test results for each. I used to carry one of those sheets with me.



Anyway, if you have a regular 13B just replacing the gasket under the OMP with a new gasket minus the oil in port hole will do the job. You can remove the "C" clip on the shaft and remove the drive gear. No need to turn it. If you have the Renesis engine your OMP is electronic controlled and the gasket idea will work, but how to disable the electronic control without affecting the computer is a mystery to me. If it spins it needs to be lubricated, so I would try the gear removal idea as well, and perhaps leave the wires connected.



Lynn E. Hanover

Don1

Thanks for that info. I will do it.



"Even though 06 was my last year of racing my own cars, "



I hope that statement doesn't mean that you have left racing. You seem like the kind of guy that should be in the steward program. If you're not a steward already, you might find it to be a way to be involved that is very fulfilling. You certainly have a tremendous amount of experience and information and the willingness to share. I can't imagine you could just walk away.



Thanks Lynn.



Don MacCluskie

CSR #9 in the NE.

maccluskie@comcast.net

Lynn E. Hanover

Not out of racing. Just finished a IT 12A engine last night for some local guys. One of my first crew members from the 70s had a son who took to racing in a big way. His very big operation is just down the road, and I can stop in and bother him anytime. This saturday at 8PM on speed, look for the 6 and 60 cars of Michael Shank Racing in Daytona Prototypes.



Lynn E. Hanover

j9fd3s

basically if you're stuck with the stock ecu, you just leave it plugged in. it has no way to know if its actually pumping oil or not, and disconnecting it causees all kinds of limp homes with the ecu. so you just leave it plugged in and its happy