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Old 05-30-2004, 11:06 PM   #1
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Default RC10gt too much bottom end

Hi there, problem with RC10gt. When excellerating out of corners the .12 CVR O.S. max tends to spin the tires. I am trying to mellow out the bottom end so I can better control the power.
What I have done so far.
Adjust both top and low end needles.
Modifed clutch to engage at lower rpm.
Installed a carb restrictor to smooth out the power band.
Installed a second head gasket .
Adjusted my radio linearty graph so the servo reacts slower.
This helps but still have to be very very smooth on the trigger to prevent the tires from breaking traction.
Have tried many types of tires,including bow ties.
Have loosen slipper clutch, but cant get enough quick speed for the doubles if too loose.

All these changes i have made and really improved this motors power very little. I am racing so the control factor is very important. The associated motor that came with this car was much more controlable. the O.S.max .12 has had about 10 tanks of gas throught it and is broke in. Just produces too much power right off the very bottom end thats all.


Does anyone know of a heavier flywheel available for the RC10gt.
I think this would help.
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Old 05-30-2004, 11:16 PM   #2
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MIP makes one.

http://www2.towerhobbies.com/cgi-bin...?&I=LXAX63&P=7
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Old 05-30-2004, 11:32 PM   #3
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Try putting a bigger clutch bell on it. That will give you more top end less bottom end.
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Old 05-31-2004, 01:09 AM   #4
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I would put your radio settings back at zero (specifically, the linear graph you were referring to). By having that adjusted, it will fix problems in one area, but make them worse in another.

In gas truck racing, you will have to be very light on the throttle..that's all there is to it. The TR makes a lot of power, more than what is usable in most areas of any track. It's not that your equipment is bad, it's just how gas truck racing is.

Try moving your pipe a little closer to the header..they should be about 1/4" apart, and that will soften some of the initial bottom end hit. Running an MIP 4-shoe clutch will also help your traction woes.

Bow-Ties are usually not the best when it comes to trying to find the most traction. What do the fast guys use? If they use Bow-Ties, try Losi Studs.
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Old 05-31-2004, 02:05 AM   #5
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If you are using the stock AE pipe, that is also contributing to the excessive bottom end. That pipe makes lots of bottom. If you can find a pipe with moreof a gradual taper (like the O'Donnell) that may help as well.
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Old 05-31-2004, 09:54 PM   #6
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Have you played with the suspension? Try some softer rear springs, lowering the rear ride height, moving the rear hubs forward and if your not already try CVD's. Does everyone have this problem? If not there is something wrong with your truck, setup wise that is, if so try to make it better but dont expect the wheelspin to dissapear.
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Old 05-31-2004, 11:15 PM   #7
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Default some great ideas

Thanks guys. I am ordering the heavier flywheel right away. I should mention that the tires I have on right now are the losi studs, they are the best traction ones so far. Also I am running the mip 4 in 1 clutch on the #2 setting. Would anyone recommend 1 or 2 heads gaskets to d tune the motor to make less power. The reason why I am after more control is to race but I base my comparison on the associated motor that was in there before. It was a .15 but the control on this motor was much better than on this .12 cvr. My lap times have become much slower than before. Same track and conditions. Noticed a difference in the motor right off the get go. By the way the carb restrictor I used is the associated in the O.S carb. Does O.S make a carb restrictor for there own carb. I think its a 10e, rotary. Mant thanks. Great board , great people.
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Old 06-01-2004, 01:07 AM   #8
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O.S. doesn't make a restrictor that I know of.

Try richening your bottom end needle a little more, and leaning out the top end to compensate. I run my low end needles a lot richer than most people, and it helps to soften the powerband.

I wouldn't mess with a heavier flywheel yet. It will change how your truck handles because of the extra rotating weight, particularly over jumps.
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Old 06-01-2004, 03:14 AM   #9
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Using lower nitro content....somethiing like 10%...will also soften the pick up from the engine...
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Old 06-01-2004, 07:38 AM   #10
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Nitro content won't have much effect on power at all. Going from 20% to 10% will make the engine run hotter, which will trick you into tuning the engine richer than you already have it, killing gas mileage.

Nitro burns cooler than alcohol, the third ingredient in fuel. When you lower the nitro content, you must add alcohol to take up the extra volume (because you wouldn't add more oil!).
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Old 06-01-2004, 08:43 AM   #11
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Interesting comment. I have observed the hotter temps by using lower nitro (30% to 25%), but I've also noticed a drop in power when going from 30% to 16%, so I'm not entirely convinced of the same power from lower nitro theory. Somewhat confused??? can you elaborate pls?

edit- Actually a drop in "power" is probably not exactly what I noticed. It was more of a drop in engine pick up from lower revs and over the course of the track equating to slower lap times.......

Last edited by dtm; 06-01-2004 at 08:49 AM.
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Old 06-01-2004, 03:10 PM   #12
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To tune an engine correctly for racing, you can't go by temperature alone. Serious racers and engine experts know to tune their engines until they make the power needed to go fast, and then check the temperature of the engine for future reference. At an important race, I will run my engine as hot or as cold as I need to to be competitive (go to a nitro touring car race, they will run their engines up 300 degrees).

When properly tuned, you should be able to get the same amount of power regardless of what percentage of nitro is in your fuel. The difference will be the temperature of the engine and carb settings.
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Old 06-01-2004, 04:53 PM   #13
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Quote:
Originally posted by Aaron Waldron
To tune an engine correctly for racing, you can't go by temperature alone. Serious racers and engine experts know to tune their engines until they make the power needed to go fast, and then check the temperature of the engine for future reference. At an important race, I will run my engine as hot or as cold as I need to to be competitive (go to a nitro touring car race, they will run their engines up 300 degrees).

When properly tuned, you should be able to get the same amount of power regardless of what percentage of nitro is in your fuel. The difference will be the temperature of the engine and carb settings.
The engine should have improved torque though with a higher nitro content fuel - shouldn't it?
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Old 06-01-2004, 08:51 PM   #14
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There may be a slight change, but theoretically, there should be no difference once the motors are tuned correctly.
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Old 06-02-2004, 04:49 AM   #15
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But I did not mention anything about tuning my engine to temps...just mentioned that I observed hotter temps! So does that make me a serious racer!!??!!hmmm...... (I certainly don't want to be categorised into that group!!)

Anyway, you didn't really go into the power/torque thing. Even if you refer to my very original post, my comments where using lower nitro softens the engine pick up... this is what
I have noticed by trying (no reference to power here).......
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