What e. motor kv would compare to a good .21 engine? Considering going 1/8 electric but don't want too much motor.

I would say most are using about a 2100kv motor. I varies a bit depending on the manufacturer.

I converted a Losi 1/8 buggy and used the Castle 2200kv. With a 6500MAH 4 cell I get 15 min no problem.

What e. motor kv would compare to a good .21 engine? Considering going 1/8 electric but don't want too much motor.

Unless you go with a conversion that uses a clutch set up, it's not gonna matter what motor you pick. That is, if it's feel you're looking for. Torque for days. I do know that just a 2200kv Neu motor is insane even on 4S. Castle should make a lower kv motor.

You need to choose a battery first then choose a motor. The most efficient setups have been using lower KV motors and Higher "cell count".
The higher the voltage from the battery the lower operating temps for motor and esc. This is because of reduced amp draw = less heat.
If you need MAX runtime then go for say a 1400 kv motor and 6s battery.... (3600maH gets 20+ min on most tracks)
Example: A buddy of mine runs a truggy L 2.0 w/1350/6S combo and gets avg 15 min runtime on a 3000 maH Lipo.
The higher the "S" the lower the KV you need. IF your planning on 4S and run on big tracks then 1900 ish is good. We routinly gear these motors to a "speed" dictated by the MAX heat allowed (170* is my safe limit) in the amount of time ran.
My current setup in a RC8B is 1900 kv /5S 3300 mah with 19/46 gearing ( 51 mph) and it comes off a 10 min main at 145* I also turn my EPA down to whats managable for the track and conditions (usually 110-120 on my M11)
This is plenty fast enuff to litterly Drag a nitro buggy faster than it could possibly go.

Hope this helps

You need to choose a battery first then choose a motor. The most efficient setups have been using lower KV motors and Higher "cell count".
The higher the voltage from the battery the lower operating temps for motor and esc. This is because of reduced amp draw = less heat.
If you need MAX runtime then go for say a 1400 kv motor and 6s battery.... (3600maH gets 20+ min on most tracks)
Example: A buddy of mine runs a truggy L 2.0 w/1350/6S combo and gets avg 15 min runtime on a 3000 maH Lipo.
The higher the "S" the lower the KV you need. IF your planning on 4S and run on big tracks then 1900 ish is good. We routinly gear these motors to a "speed" dictated by the MAX heat allowed (170* is my safe limit) in the amount of time ran.
My current setup in a RC8B is 1900 kv /5S 3300 mah with 19/46 gearing ( 51 mph) and it comes off a 10 min main at 145* I also turn my EPA down to whats managable for the track and conditions (usually 110-120 on my M11)
This is plenty fast enuff to litterly Drag a nitro buggy faster than it could possibly go.

Hope this helps

How many mah do you use in 10 mins?

How many mah do you use in 10 mins?

My setup usually runs 210-240 mah/min depends on track.

JCP's current layout avg44 sec laps = 220ish
Jtec Horizon Shootout track avg 32 sec laps = 240 ish
Reo Raceway Aug layout avg 34 sec lap = 215 ish

On a side note: my buddy Jube has been running a 1700kv and getting only slightly lower (10-15) mah usage on most tracks

hey curt i have a 1900 tekin in mine and its PLENTY fast