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Old 08-29-2016, 02:04 AM   #256
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Without reading all of the 17 pages, here is my opinion.

My first question is, is it that people dont drive 1/12 Mod, or just that people dont drive 1/12 in general? 1/12 is sadly very small now days.

1/12 Mod is by far the most difficult class to drive really fast in, the margins are very small and it is very easy to flip the car, thus the difference in pace between the Pros and us Amateurs, but every RC racers do not inspire to be world champion so it does not really matter.

However, I do not find 1/12 Mod very difficult to step into, in our club we had several racers who normally just do stock or F1 classes what I managed to talk into joining the 1/12 mod class, they go without any boost or turbo and they do just fine, they are behind but they take the car safely around the track driving in a good racing line. They enjoy it very much and are slowly increasing the boost and turbo when they feel confident. This is just the way I started Mod and I still do not utilize the full power (I still have battery left after 8 minutes, something the pros dont have..)

The biggest problem I find is the difficulty level of the track itself. On a track without any "dots" or "curbs" I am helplessly far behind the pros, more than 10% on the lap time but on a track with dots in the corners I can be quite close, around 2-3%.

The other issue if ofc tires, I have found that with the wrong combination of carpet and additive there are no way to go more than one run per set (Worlds race last week for example) but with the right combination 3 runs or more can easily be done.

I feel that the power and speed in a 1/12 Mod is very controllable compared to for example 1/10 Mod. The cars hold up fairly well if one drive within ones limits and the key to get a good result is not going crazy fast but to have a stable safe run. Every time I finish a run being practice or race I step of the drivers stand with a huge smile, it is just so much fun and adrenaline to run this class!

So how to get more drivers to join? I think many are just afraid of trying and need a push to actually go try and experience the fun! Maybe make sure the track layout is not too tight and that there are some margin for errors, like dots in the corners what makes the car go out of line but not flip etc. Also, the more 1/12 drivers in general, the more 1/12 mod drivers there will be..

For cost I think it is the tires what is the key, for electronics the quality demand of the parts is normally higher in stock where the motor power is the limit and every little extra power counts, in mod it doesn't unless you are going to be the world champion perhaps but that is not the discussion for today.

Amateurs will be far behind the pros, but the situation is the same when a pro take a stock car, they will still be way ahead even the cars are setup exactly the same.

I checked the race result of a random run and compared the No 1 with a middle driver in a few races.
1/8 on-road Europeans, 5% difference
1/12 worlds 10%
1/10 ISTC world 8%

Note that I really want 1/12 and specially 1/12 mod to grow, I love the class. The above is based on my view of the picture but it is limited since I mostly just do races in Asia.

In our club 1/12 stock died because everyone went into Modified despite the stock class having the MTS series with a free trip to Korea for the overall winner the class had to be discontinued from the series..

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Old 08-29-2016, 12:27 PM   #257
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reduce the lipo case dimensions....to have only 3000-4000mah
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Old 08-29-2016, 12:32 PM   #258
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reduce the lipo case dimensions....to have only 3000-4000mah
Lipos aren't like old battery tech. The WORST thing you can do to a lipo is charge it all the way up and then discharge it to the cut-off voltage, or as racers would probably do, drag it down even further where if you're lucky the battery won't turn into a bomb and torch your $1000 hand-tuned race car.

Reducing battery size to make people go slower is a terrible idea. Modern batteries failure mode is just too extreme.
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Old 08-29-2016, 01:04 PM   #259
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How about 2S LiFe?

Safer (I think?)

No need for boosters.

Higher voltage, but half (or less) of the capacity. Nobody is going to make time with a boosted 3.5. You will have to run less motor and reintroduce the possibility of dumping. Maybe you end up only running a 10.5 to make run time, but at a higher voltage so it's still pretty fast.
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Old 08-29-2016, 01:11 PM   #260
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I like that idea syndrome
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Old 08-29-2016, 01:23 PM   #261
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Also consider that teching battery voltage is already standard. You can lower the max allowable voltage to further correct things as needed.
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Old 08-29-2016, 01:42 PM   #262
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Life batteries were a fairly popular suggestion in last years monster "change onroad" thread.

Can the current speedo's operate with them?
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Old 08-29-2016, 02:01 PM   #263
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Originally Posted by syndr0me View Post
How about 2S LiFe?

Safer (I think?)

No need for boosters.

Higher voltage, but half (or less) of the capacity. Nobody is going to make time with a boosted 3.5. You will have to run less motor and reintroduce the possibility of dumping. Maybe you end up only running a 10.5 to make run time, but at a higher voltage so it's still pretty fast.
This is interesting, but I'll make a slight correction: the voltage has nothing to do with the speed attained if the motors are open. Speed will be determined by total energy contained in the battery (voltage*current*time), and the efficiency of the motor. EDIT: I just had a quick look at some LiFe cell specs, and the IR is high enough that the motor might be selected based on that restriction.

You are correct in that the motors used would be higher turn count than for 1S LiPo.

What is the maximum capacity available in a LiFe cell these days? Which ones would fit in a 1/12 scale car?
SON OF EDIT: A pair of 18650 cells would fit, but the highest rated current I found was 20A. This wouldn't be any good for an RC car.

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Can the current speedo's operate with them?
I don't see why not. I suspect most drivers would disable the voltage cutoff.

BRIDE OF EDIT: See SON OF EDIT, above.
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Old 08-29-2016, 02:24 PM   #264
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You could consider something similar with 2S LiPo and maybe lower end voltage restrictions, but encouraging people to dump LiPos seems irresponsible.
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Old 08-29-2016, 03:34 PM   #265
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Quote:
Originally Posted by syndr0me View Post
How about 2S LiFe?

Safer (I think?)

No need for boosters.

Higher voltage, but half (or less) of the capacity. Nobody is going to make time with a boosted 3.5. You will have to run less motor and reintroduce the possibility of dumping. Maybe you end up only running a 10.5 to make run time, but at a higher voltage so it's still pretty fast.
My reply to the LiFe possibility when it came up earlier in this thread:

I have two four cell sub-c sized life packs and have run them in an older sub-c chassis 12th car. The cells I have are 1100mah if memory serves me correctly, a four cell pack weighs close to a 5000mah lipo but gives you the rip like back in the 4-cell days. Now as you may have guessed at 1100 mah per cell run time is an issue. I was able to get 8mins in stock and be faster than 4-cell nimh cars due to the lighter weight; but no way a mod car could make time (and feel like a mod car) on these cells. I was playing with these ten years ago so perhaps there are better/higher mah life cells available today. Lots to like about life, tons of power, light weight, and no fire danger like lipo.

I have also bolted up a couple of 380 motors in the past,worked fine but the pods would need a redesign to work well with those small motors.

If a higher capacity LiFe cell is availible in the marketplace this could the answer to some of the current 12th issues.
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Old 08-29-2016, 04:27 PM   #266
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If a higher capacity LiFe cell is availible in the marketplace this could the answer to some of the current 12th issues.
A123 have a 3.3V 2,500 mAh cell. 26x65mm, 76g. 50A continuous discharge.

http://www.a123systems.com/lithium-i...rical-cell.htm
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Old 08-29-2016, 05:45 PM   #267
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A123 have a 3.3V 2,500 mAh cell. 26x65mm, 76g. 50A continuous discharge.

http://www.a123systems.com/lithium-i...rical-cell.htm
That's encouraging, but it will be a challenge fitting a 26mm diameter cell in a 1/12 scale car. It would at least require raising the center shock (which is maybe not a big deal) and a taller body (maybe a bigger deal).

The ROAR maximum Z dimension for a 1s LiPo/LiFe cell is 18.5mm.
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Old 08-29-2016, 06:23 PM   #268
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That's encouraging, but it will be a challenge fitting a 26mm diameter cell in a 1/12 scale car. It would at least require raising the center shock (which is maybe not a big deal) and a taller body (maybe a bigger deal).

The ROAR maximum Z dimension for a 1s LiPo/LiFe cell is 18.5mm.
http://www.batteryspace.com/lifepo4-...te-3-52wh.aspx

18mm diameter by 65mm length. 49.5 amp discharge, but only 1100mah.
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Old 08-30-2016, 03:38 AM   #269
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Originally Posted by avink007 View Post
http://www.batteryspace.com/lifepo4-...te-3-52wh.aspx

18mm diameter by 65mm length. 49.5 amp discharge, but only 1100mah.
We're getting much closer!

So now I'll make a right turn and ak a question that I don't think we have mentioned so far: If the battery energy capacity becomes a limiting factor for the speed of the car, would this only create a motor war where the battle is for maximum efficiency? And how would this be any better than restricting the motors to 6.5T (or some other appropriate number) that creates a motor war where the battle is for maximum power?
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Old 08-30-2016, 03:54 AM   #270
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We're getting much closer!

So now I'll make a right turn and ak a question that I don't think we have mentioned so far: If the battery energy capacity becomes a limiting factor for the speed of the car, would this only create a motor war where the battle is for maximum efficiency? And how would this be any better than restricting the motors to 6.5T (or some other appropriate number) that creates a motor war where the battle is for maximum power?
1/12 was always a battery war.. Remember the on grid bump boxes...
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