How to compare gasengine size to outrunner ?
 

I'm going to put a outrunner in my hpi baja ss. but i don't know how big a outrunner are that are equal to a 26cc gas engine ?

What is the rated HP on the Baja engine? For a ballpark figure take that a multiply it by 750. Since 1 HP = 750 W, that will give you the sustained wattage (~5 seconds) you would want from an electric setup to achieve the same performance. So if it's 3 HP, then 3 * 750 = 2250- meaning the system should be capable of sustained bursts to 2250 W.

This is just a guide. Personally, I'd want a system capable of 4000 W in a vehicle as heavy as the Baja. But see what the stock engine is rated for and that will give you an idea. What voltage do you plan on running? 10s LiPo sounds like a good starting point. I'm sure someone here has experience with converting the Baja so they can chime in as well.

but you need a motor with enough bottomend grunt to make an effechent set-up not just topend watt's :) i i meen you can pull lot's of watt's from a neu 1515 motor but i don't think the can power a heavy car like the baja ! Then they woud pull amp's like a big cigarette lighter :)

Well, if the motor can handle the power, then the rest is gearing. If you have limited gearing choices you need to find a motor in a certain kV range. Outrunners have plenty of torque, and happen to be in the same speed range as gas engines.

Would a kb45 xl motor with 800kv be enough ? I i drop the gearing from stock 17/57 down to 60/14t ? and run it on 8-10 lipos ?

or how about this motor ? if i put the piniongear on the gearbox shaft and the spur on the motorshaft to compensate for the low rpm and torque ? it's supose to be equal to a 30cc + nitro engine ! and it's lite ! i think my baja will weigh aboud 4 pound less than with yhe gas engine :)but it will go sooo mutch faster :)

If you don't have money for a Neu 1515 or 1521 go with a Medusa 70-80mm motor they are 100x better than Feigao and only about 150

very funny man ! They woud burn ! this is a 1/5 scale buggy not an 1/8 !!!

Which motor?

Neu 1512 and Medusa 60mm are for 1/8 buggy even some truggies, 1515 is for MT's and some truggy setups and will be just fine on a 1/5 2wd buggy with the right motor and voltage, though the 1521 would be better. The 70mm medusa is too small sorry, but the 80mm should be fine.

Neu
1515 - 1500/2700watts 30sec
1521 - 1700/3000watts 30sec

Medusa
70mm - 1100/?30sec
80mm - 1300/?30sec

My vote is for the 1521 1y w/ 6s lipo, that would be more than enough, if he was to use a 1515 or medusa 80mm he would need low kv and HIGH voltage 10s-12s range and a very expensive ESC to meet the demands.

I can safely say that a 1521 will not be too happy trying to move a 20+ lb vehicle at 40+ mph.

That only depend on the gearing and general terrain. Gear it for 25 mph instead of 40 and it would survive just fine. Remember that some kid jeep can bear said child with 2 550 brushed can...

For such a big vehicule if you are dead set on an outrunner then maybe A60-L?

http://www.aero-model.com/motordetai...es=A60&style=L

ops sorry ! http://http://www.hobbycity.com/hobb...nner_(Eq:5240)


The model namefor this motor is :HXT63-74

hmm that 1521 will generate at least as much HP as that gas motor can. Is he doing something different with the transmission? After looking at the gearing and what not you would really need at least 8s to run 40+ properly w/o heat issues iMO (6s maybe 32-35). That is with a 19t pinion on the 1y or change up accordingly if using a different motor. there is always a 1527 or the 21xx's if you are really crazy :)

Hmm id bet a dual 1515 1y config on 5s x2 (dual mmm's) would do the trick too.. seems like there is plenty of room :)

you can't compare motors based on bhp ! i meen a .21 nitro engine can put out about 3bhp but they don't have the tq of an scooter 3bhp engine !