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Old 02-25-2013, 06:46 PM   #4561
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Originally Posted by ToysRUsKid View Post
Quick question - which Nova plug should be used in a .12 Keep-On and a .21 Keep-On? I'm new to .21 this year so I don't know but I have always used medium plugs for the .12s. I check the Nova plugs and they all seem to be hot or cold so I'm not sure which one to use for each motor.
For Keep on .12 C6TGF and

for Keep on .21 C8TGH

GHN
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Old 02-25-2013, 07:19 PM   #4562
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Originally Posted by ToysRUsKid View Post
Quick question - which Nova plug should be used in a .12 Keep-On and a .21 Keep-On? I'm new to .21 this year so I don't know but I have always used medium plugs for the .12s. I check the Nova plugs and they all seem to be hot or cold so I'm not sure which one to use for each motor.
Same as above

Keep On .12 C6TGF
Keep On .21 C8TGH
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Old 02-27-2013, 10:14 PM   #4563
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how do I get new heads for 12/353/rossi have 2 that have dropped fins and I am not certain about how hot they will get
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Old 02-28-2013, 02:45 AM   #4564
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Default Novarossi .12 Keep On

Dear all,

tomorrow will be breaking in the Keep On, since its bottom end is super and don't really need all that power would it be possible or recommended to make the sleeve higher by 0.1 in order to get more top speed?

Also my 12PT which still has good compression lost quite some amount of power and run time all of a sudden. What could be the issue?
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Old 03-18-2013, 06:57 PM   #4565
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Default Novarossi 353

Hello gang,

I am new to on road nitro but I have raced nitro off road. I was putting some after run oil in my Novarossi 353 Race.12 2009 3-Port .12 engine, when a fellow racer said that particular motor may not use after run oil. He mentioned something about adding some other additive. I have heard before how after run can be harmful to some nitro motors because they may have some sort of "coating" inside and that I may have to use something else.

Any hints as to what this additive is??
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Old 03-18-2013, 07:55 PM   #4566
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Hello gang,

I am new to on road nitro but I have raced nitro off road. I was putting some after run oil in my Novarossi 353 Race.12 2009 3-Port .12 engine, when a fellow racer said that particular motor may not use after run oil. He mentioned something about adding some other additive. I have heard before how after run can be harmful to some nitro motors because they may have some sort of "coating" inside and that I may have to use something else.

Any hints as to what this additive is??
You can put Novarossi after-run oil (1M1) in any Nova motor including the 353.
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Old 03-25-2013, 01:32 PM   #4567
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I'm trying to get my old TN12 running again. I bought 30% and it usually ran on 20%. I do have cold plugs. Will I need to shim it or will I be ok?
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Old 03-25-2013, 01:37 PM   #4568
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Also, I'd like to play with the porting. Can I do anything else to the engine to make it faster? Any tutorials?
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Old 03-25-2013, 03:14 PM   #4569
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I'm trying to get my old TN12 running again. I bought 30% and it usually ran on 20%. I do have cold plugs. Will I need to shim it or will I be ok?
Tuning For High Altitude
The general formula for power loss with increases in altitude is 3 percent for every 1,000 feet above sea level. If you race in Colorado at 5,000 feet instead of in California at sea level, you can expect to lose about 15 percent of the engineís potential power output, if the engine is tuned properly.

At high altitudes we face a problem: how do you maximize engine performance and speed in the thinner air? Internal-combustion engines require three things to produce power - fuel, oxygen and heat -- and they need them in specific ratios. Running at 70mph is nothing special at low elevations; the denser air at sea level contains more of the oxygen an engine needs to produce power. At higher altitudes, the thinner air means less available oxygen, so an engine will not be able to burn as much fuel as it does at lower altitudes. Less fuel means less power, and that means slower speeds.

What can you do to minimize the effects of altitude? Some equip their cars with a higher gear ratios to recover some of the rpm lost because of the reduction in power. Others improve airflow, by lengthening or shortening their tuned pipes until performance improves.

But can you do anything to the engine itself to compensate for thinner, high-altitude air? Compression creates power, and because the air at high altitude is less dense, there is less fuel/air mixture available to compress.
To recover some of the lost compression, you can:
ē Use a fuel containing a higher percentage of nitromethane.
ē Reduce engine-head clearance to increase the compression ratio.

To compensate for higher altitudes, you need to adjust your needle valve to a leaner setting to maintain the proper fuel/air ratio. The opposite is true for lower altitudes. The idea is to maintain the optimum ratio of fuel and oxygen by adjusting the fuel volume to compensate for ambient air pressure.

Elevation complicates the situation. A venturi such as a model engine carburetor's works on the vacuum principle: as air rushes through the venturi, it accelerates and creates a vacuum at the spraybar. This vacuum draws fuel from the spraybar and fills the crankcase with a mixture of air and atomized fuel; at very high altitudes, less air accelerates through the venturi and past the spraybar. This reduces the vacuum at the spraybar, so less fuel is drawn through it, and the mixture becomes too lean.
There is a way to compensate for this:
ē Switch to a venturi with a smaller area.

When you have a smaller venturi area, the airflow velocity through the venturi is increased. This also increases the vacuum at the spraybar, which, in turn, draws more fuel.

If you don't want or canít buy a separate carb just for high-altitude running, the easiest way to increase fuel flow is to open up the needle valve to richen the mixture setting. A richer needle-valve setting requires less of a vacuum to draw in a given amount of fuel. Ultimately, this won't be quite as effective as having a smaller venturi area.

Obviously, you have to experiment to learn which combination of these high-altitude tuning techniques best suits your model.

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Old 03-25-2013, 03:19 PM   #4570
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Also, I'd like to play with the porting. Can I do anything else to the engine to make it faster? Any tutorials?
General Notes on Engine Timings by A. Florez

High exhaust degrees duration = more power and rpm at top end
High transfer degrees duration = more power and torque at low end (watch out because if to high run time gets hurt)
High boost transfer duration =extension of the peak power curve
Advancing Induction opening = more low end (up to certain limits)
Retarding Induction closing = more high end
Bigger diameter on inner passage = more overall power = more fuel consumption past certain limits.

With regards to Induction timing, little changes in opening timing will not produce appreciable changes in performance. The factor that has a considerable effect on an engine performance is the closing timing. Closing 20% later will not affect high end, but will help low end because it limits "blow back" through the carb....past 20% youíll loose low end and increase high end.

Rotary Valve induction engines are relatively insensitive to opening timing. If there is a rule, itís that the opening timing is best established right at the point of transfer closing timing if you want a very wide power band engine.
If you want maximum power at the expense of loosing low end power, opening timing should come earlier from 130ļ to 145ļ BTDC, which means that the intake and transfer periods will have overlapping. The opening point has influence in power output, but as said earlier it is relatively insignificant as compared to closing timing.

The best closing timing for a wide variety of engines is 65ļ ATDC

With regards to exhaust and transfer timing and area. Widening an engineís exhaust port, increasing Itís time area value without actually increasing itís open duration, has much the same effect as raising itís height and thus increasing both time and area. That is to say, widening the exhaust port increases the engineís rpmís at which max power is realized, while reducing low speed power. Same pattern is to be observed in increases to transfer port time-area, though in the opposite direction.

With respect to Crankcase volume: The ideal crankcase volume has to do with the compression in it, giving that way the necessary force to the movement of mixture through the transfer passages and ports and into the combustion chamber. It also has impact on the aspiration of new mixture charge because it affects the suction and speed in the induction passage. Of course it is related to carburetor size.

Crankcase volume is a pretty complicated thing. Smaller crankcase volume will give you more internal pressure, but it is limited to the volume of mixture going through crankcase. For engines with very wide power band and highly restricted carb, crankcase volume needs to be smaller. For engines with narrower-short power band, and working on higher RPM, crankcase needs to be bigger. It is a general concept and in every engine Iíve studied it is different. I personally learned this the hard way.

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Old 03-25-2013, 04:12 PM   #4571
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Uh
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Old 03-27-2013, 02:09 AM   #4572
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What is the correct length of the tube from the exhaust into the tank?
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Old 03-27-2013, 02:29 AM   #4573
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hi guys whats the best glowplug for 0.12 flash PTA for 30 degrees outside temp and for 25 degrees outside temp?

i saw a nova plug that said in the container that its for offroad engines, is it the same?

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Old 03-27-2013, 06:54 AM   #4574
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Novarossi 353 .12 Plus 2 Tuned

I cannot complete a 5 minute race with this engine (see my thread Run Out Of Fuel).

Im aiming for a maximum temp of 130C.

Whats the maximum you can run these engines (long term) without damaging. (140C, 150C????)

How do I get more runtime.

Cheers
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Old 03-27-2013, 01:14 PM   #4575
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The piston has three little nicks at the top of it (burned glow plugs last race). I also marred the bottom edge of the sleeve. As long as the engine runs, this shouldn't effect performance bad should it? I'm not racing.
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