1518 4s? - RC-Monster Forums

kneedeeppow · **1518 4s? -** 11.01.2010, 04:02 AM

hey guys
any ideas on spur/pinion ratios for a 1518 1800kv on 4s truggy. not looking for insane speeds,i get that out of my 2200kv. we are limited to 4s for racing which hamstrings things slightly i know

nitrostarter · 11.01.2010, 07:31 AM

What were you running before with the 2200kv?

I would just play with BrianG's calc to find the same end results. This motor will definitely handle it.

Nard Cox · 11.01.2010, 07:31 AM

I'm guessing 17T for about 40mph. Depends on your car and spur, but with 17T you will not be far off.

You can use BrianG's Calc to check what gearing you can try.

simplechamp · 11.01.2010, 09:46 AM

I just installed a 1518 in my F8T and have it geared 16/52 on 4S for about 40mph (I should note the F8T has 43/13 ratio in the front and rear, not very common in truggies).

The max RPM achieved with the 1518 on 4S is a bit low of the 30-35k sweet spot, but I think it is still OK. The extra torque provided by the 1518 over the 1515 should allow you to go up a few teeth on the pinion and gear for the same speed as with the 1515.

kneedeeppow · 11.02.2010, 12:34 AM

not sure if i am using briang's calculator right for my rc8t on 4s. i come up with 12t pinion on a 46t spur gearing to 40mph(which is probably more than really want). i was thinking more on the lines of 18t+ pinion but end up with speeds of 60+mph.have all the feilds filled in to the best of my knowledge. can anyone point me in the right direction?

kneedeeppow · 11.02.2010, 12:37 AM

Quote:

Originally Posted by nitrostarter

What were you running before with the 2200kv?

I would just play with BrianG's calc to find the same end results. This motor will definitely handle it.

i had 14t 46s with the 2200 in my mugen. i was expecting bigger pinion but after using the calc it recommends 12t.

nuz69 · 11.02.2010, 02:48 AM

Geared for the same speed at the same voltage the 1518 will run more efficient than the 1515, so there is no problem using it on 4S, whatever its sweet spot is.

Nard Cox · 11.02.2010, 03:34 AM

Quote:

Originally Posted by kneedeeppow

not sure if i am using briang's calculator right for my rc8t on 4s. i come up with 12t pinion on a 46t spur gearing to 40mph(which is probably more than really want). i was thinking more on the lines of 18t+ pinion but end up with speeds of 60+mph.have all the feilds filled in to the best of my knowledge. can anyone point me in the right direction?

Did you have the option ''put RC in trunk of 1:1'' switched on? I think you did something wrong, try again and post a screenshot of your data input and output.

thzero · 11.02.2010, 08:25 AM

Something sounds wrong. Using the http://scriptasylum.com/rc_speed/_top_speed.html calc, here is the RC8T with 46t on 4S with LPR tires. Thats ~26mph, without factoring in any ballooning. Looks like you'd need to go to 14t for ~30, 16t for ~35, and 18t for ~40mph.

Code:

Differential Ratio: 4.3
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 46
Pinion Tooth Count: 12
Total Voltage: 14.8
Motor KV: 1800
Tire Diameter (inches): 5.6
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor Coil Resistance: 0
Spur/Pinion Ratio: 3.83 : 1
Total Ratio: 16.48333 : 1
Tire Circumference (inches): 17.59 inches (446.86 mm)
Rollout: 1.07:1
Total Motor Speed: 26640 RPM
Vehicle Speed: 26.93 mph (43.25 km/h)
Effective KV Value: 1800
KT constant: 0.75 oz-in/A

Quote:

Originally Posted by kneedeeppow

not sure if i am using briang's calculator right for my rc8t on 4s. i come up with 12t pinion on a 46t spur gearing to 40mph(which is probably more than really want). i was thinking more on the lines of 18t+ pinion but end up with speeds of 60+mph.have all the feilds filled in to the best of my knowledge. can anyone point me in the right direction?

BrianG · 11.02.2010, 09:51 AM

Have you tried this version yet? After the initial calculation, it does a bit more.

RC-NUT · 11.15.2010, 04:56 PM

I don't have the same vehicle you do but I do run a 1518 in my Savage on 4s. It's no light weight at 12.3 pounds but on 4s it has more torque than I need. If I pull up to a curb the truck will do a standing backflip about 2-3 feet off of the ground and land back on it's wheels. I have conservative gearing at the moment so I get about 35 min of runtime on 3800 packs. The motor temp never breaks 90deg and the MMM fan has yet to turn on. It's a pretty efficient motor. I'm happy with it.

SV6000 · 11.15.2010, 10:54 PM

Your looking at Kmh not MPH. as per your screen shot with a 12t pinion you are doing 29Mph

kneedeeppow · 02.20.2011, 04:57 AM

been awile between innings for me and my trug. went out yesterday and ran two battery packs thru in quick succession on the 1518 1800kv motor. geared 16t/50 spur. finally got runtimes i have been looking for. 19.5 minutes for each pack. that was running on a moderate sized track running pretty much non stop. temp checks every 5 minutes and the motor and esc never saw any higher than 45 degrees C. very stoked