Which motor should I buy?

Welcome to RCTalk

Come join other RC enthusiasts! You'll be able to discuss, share and private message with other members of our community.

NitroWannabe

RCNT Member
Messages
37
Reaction score
0
RC Driving Style
I've got a question about engine sizes and the difference between them.

I'm shopping for a new motor and I'm a bit confused by the choices out there. I've been looking at the specs, mainly bhp...now for the really stupid question...bhp = horse power right?

Anyways, I'm seeing .12 motors which go all the way up to 1.2 bhp, while the bigger .15 only go up to about .8 that I've seen. So my big question is, if the smaller motors produce more power, whats the point of the bigger motor? (torque?)

I have a 4wd HPI nitro MT, if the .15s make more torque then wouldn't that be better for my purposes? or should I go with a more powerfull .12 motor?

And due to a lack of 4WD trucks at my local track, I'm considering buying a 2WD buggy so I can be in one of the bigger classes with more competition. A high hp .12 motor would be the way to go on a buggy, yes? or do they need a good .15?
 

Rob D

RCNT Addict
Messages
596
Reaction score
0
RC Driving Style
Bhp=base horsepower which is whats made at the crankshaft the main problem with that is it not what you will get at the rear wheels . I'm not sure how most engine makers check there hp as I'm new to nitro also but if its like most car 4 wheeler and on and on its not totally truthful ... if you can find a rear horsepower rating use that ,,


so what I'm saying is the 12 could be takeing its hp from the crank and the 15 from the rearwheels thats why you would get such a spread
as for the rest i really am not quailfied to answer but look forward to the answer of others...sorry for the mini novel

Rob
 

NitroWannabe

RCNT Member
Messages
37
Reaction score
0
RC Driving Style
I've gone with an OS-CV .15 motor. Its out back being broke in right now, the joys of breaking in a new motor :) It seems quite a bit peppier than my old stock engine, and I havn't really got on it yet.

Wo far I would have to agree that its easy to tune, followed the directions in the manual and its going great, starts on the 2nd or 3rd pull and runs till empty.

Rob: I talked to the guy at my local hobby shop, this is what he had to say about the subject...

Yes, the .15 produce more torque, the .12 produce more speed. Speed is for quick acceleration 2WD, torque is for 4WD and top end. I also asked about the BHP, he basically said it like you did, its the base horse power being delivered at the drive shaft. The usable horsepower depends on the gears, how much friction there is between motor and wheels, etc. The 1.2 hp from a .12 motor gets really cut down on a 4wd because of all the extra gearing and the friction associated with it. The extra torque from the .15 helps to cancel out the extra friction caused by the extra gear assemblies so you end up with more usable horsepower. The motor I have is rated at .68 hp, the guy at the shop said he'd seen 4WDs with a weaker motor than that out perform higher bhp .12s.

The .12's I was looking at were more expensive than the .15 I ended up going with. If he was just trying to make a sale I think he'd told me the more expensive motor was the way to go, but he didn't, so I have to think he's right.

Anyways, I guess time will tell. A few more tanks and I'll be ready to rock.
 

Rob D

RCNT Addict
Messages
596
Reaction score
0
RC Driving Style
good to hear ya found someone honest I'm looking at the 12 os for my rustler when i get back to work from being layed off so let us know how you like the 15 maybe ill get on instead or pop one in 4tec

Rob:banana:
 

El Pirata

RCNT VIP
Messages
7,237
Reaction score
2
Location
2nd Star to the Right
RC Driving Style
  1. Bashing
Hate to be my normal self here, but for clarity, a motor is electronic and an engine runs off fossil fuel.
 

NitroWannabe

RCNT Member
Messages
37
Reaction score
0
RC Driving Style
After the 10 tank break in, I finally got on it some....nice, a noticable improvement over the stock HPI engine. It seems to run a bit hotter than my old one. Although this is only my 2nd engine and I don't have anything to reference it by, I'm happy with the OS CV .15, no problems, easy to tune, better performance, reasonable price. Only one thing left, engine life....guess I'll have to wait to see how that turns out.
 

maxboost

RC Newbie
Messages
2
Reaction score
0
RC Driving Style
what about .10 engines? i have the kyosho gs11r .10 engine and it kicks butt
 

FLATTOP

llama boy
Messages
596
Reaction score
0
RC Driving Style
Originally posted by NitroWannabe
Only one thing left, engine life....guess I'll have to wait to see how that turns out.

That will depend on you, if it is tuned right and taken care of, it will repay you with many gallons of happy life.
 

NitroWannabe

RCNT Member
Messages
37
Reaction score
0
RC Driving Style
What exactaly is "tuned right"? I'm a noob so explain in small easy to understand words :)

What I do know so far...
Lean is right, fast and hot
Rich is left, slow and cool
A guy at the track said I should run about 240 with the OS CV. I went home and went over the manual, saw no reference to a recomended temp? Is this true for all engines or is this something that varies from engine to engine?

And how do I properly take care of an engine? keep the fuel and air clean, those are easy ones, but what else should I be doing?
 

FLATTOP

llama boy
Messages
596
Reaction score
0
RC Driving Style
Originally posted by NitroWannabe
What exactaly is "tuned right"? I'm a noob so explain in small easy to understand words :)

What I do know so far...
Lean is right, fast and hot
Rich is left, slow and cool
A guy at the track said I should run about 240 with the OS CV. I went home and went over the manual, saw no reference to a recomended temp? Is this true for all engines or is this something that varies from engine to engine?

And how do I properly take care of an engine? keep the fuel and air clean, those are easy ones, but what else should I be doing?

Yes you are correct, lean is fast and hot, rich is slow and cool, the trick is to find the happy medium. Having crisp performance and cool temps is called being dialed or tuned correctly. I would strongly urge you to buy a temp gun if you haven't already. the temp will vary from engine to engine, I would say on yours that 220 to 270 is good running temps. alway's start with the HSN first and get it dialed and then tune your LSN. before you make any tuning adjustments, bring your mill up to temp and make small adjustments, in 1\8 turn increments, think of it as the hour hand on a clock, doesn't take much to go from one hour to the next. after you make an adjustment run the truck for a few passes, this gives the mill time to react to the changes. Lean your needles until no further performance is noted and then back them off one click or hour or 1\8 turn however you want to look at it.

now as far as taking care of the engine, alway's use fresh fuel, don't leave your fuel on the floor, it will attract moisuture and don't leave it stored in direct sunlight. store it in a cool dry place. keep your mill tuned correctly and not run it lean, make sure you have a nice trail of blue smoke coming out of the pipe. Don't leave fuel in your gas tank, it will attract moisture, either run it dry or drain it out. Keep your air filter clean and oiled but not too much oil. Too much oil is just like having it clogged with dirt. After every run take your gloplug out and put a few drops of after run oil in and turn the motor over a few times to distribute the oil, be careful that the area around the gloplug is clean so that you won't get any dirt particles down in the mill.
hope this helps ya some, anymore questions please ask
 
Last edited:

NitroWannabe

RCNT Member
Messages
37
Reaction score
0
RC Driving Style
That does help a LOT. But I do have some questions still...

After breaking in my engine I was at the track, a guy there was helping me get the engine tuned a little better and explaining stuff to me. He seemed to know what he was talking about, so do you, but some of the things you two are saying are inconsistant.

1. Temp
He strongly emphasized no hotter than 240, you say 270. To me that sounds like a big difference, maybe its not. But he also strongly emphasized that I was still breaking in my engine. So I'm left thinking that either...
a. he wanted me running cooler since I was still breaking in the engine
b. 240-270 isn't much of a difference
c. exact temp is more of a personal/perfomance decision than it is a set number.

2. LSN
He said it doesn't need to be adjusted. The way he explained it was that its my low RPM mixture, which you want to keep pretty rich so you get plenty of lubrication to keep heat down when at an idle and also to help the cold engine idle better. But you say I should lean it out along with the HSN to increase performance until I get to the desired temp. I'm just taking a stab here, but I didn't think LSN and HSN were related, I thought they were two different settings. You say they are related (ie leaning out both). Am I misunderstanding something or are these settings related in a way I don't understand?

I appreciate you taking the time to answer my questions and explaining this stuff.
 

FLATTOP

llama boy
Messages
596
Reaction score
0
RC Driving Style
Originally posted by NitroWannabe
That does help a LOT. But I do have some questions still...

After breaking in my engine I was at the track, a guy there was helping me get the engine tuned a little better and explaining stuff to me. He seemed to know what he was talking about, so do you, but some of the things you two are saying are inconsistant.

1. Temp
He strongly emphasized no hotter than 240, you say 270. To me that sounds like a big difference, maybe its not. But he also strongly emphasized that I was still breaking in my engine. So I'm left thinking that either...
a. he wanted me running cooler since I was still breaking in the engine
b. 240-270 isn't much of a difference
c. exact temp is more of a personal/perfomance decision than it is a set number.

Yes 240 is fine, the 270 I gave you is still a safe operating range for a properly tuned mill. As I said before, the key is to achieve a strong running mill{ well tuned} and proper temps. You will not go wrong with either temp. Are you still breaking it in?

Originally posted by NitroWannabe

2. LSN
He said it doesn\'t need to be adjusted. The way he explained it was that its my low RPM mixture, which you want to keep pretty rich so you get plenty of lubrication to keep heat down when at an idle and also to help the cold engine idle better. But you say I should lean it out along with the HSN to increase performance until I get to the desired temp. I\'m just taking a stab here, but I didn\'t think LSN and HSN were related, I thought they were two different settings. You say they are related (ie leaning out both). Am I misunderstanding something or are these settings related in a way I don\'t understand?

I appreciate you taking the time to answer my questions and explaining this stuff.

Your track buddy is right about one thing, the LSN is the low end mixture screw, but that\'s where his knowledge stops. Have you seen his truck run? does it have good take off acceleration? I doubt it. Here\'s what you want from your low end----> after you warm up your mill bring it in, you want it to sit and have a good idle for atleast 30 seconds, more is fine, after that time you want to be able to hit the throttle and have a crisp take off without hesitation or as little as possible. If you leave your LSN at break in settings, I promise you will not get a crisp take off from idle, it will bog and hesitate because it will load up on fuel. A well tuned mill will get plenty of lubrication.

I never said the two needles were related, you are right, they serve two different functions. What I said was that you should adjust both to get the desired performance.

These little glow engines can be a pain, but with practice you will be able to get your mill dialed no problem. If you are ever in doubt, refer to your manual, that is your bible, do what it tells you to do and you won\'t go wrong. Oh and by the way, I bet the manual tells you to adjust your LSN right?

Feel free to ask any more questions you might have, that\'s what we are here for
 

NitroWannabe

RCNT Member
Messages
37
Reaction score
0
RC Driving Style
Originally posted by FLATTOP

Yes 240 is fine, the 270 I gave you is still a safe operating range for a properly tuned mill. As I said before, the key is to achieve a strong running mill{ well tuned} and proper temps. You will not go wrong with either temp. Are you still breaking it in?

I've got about 15-18 tanks through it. Manual says 10 tanks to break it in, guy at the track said its not really broke in for 15-20. So yes its been through the initial break in, but maybe not totally broken in yet.

While breaking in a new engine should I keep the temp a bit lower than normal running temp?

Your track buddy is right about one thing, the LSN is the low end mixture screw, but that\'s where his knowledge stops. Have you seen his truck run? does it have good take off acceleration? I doubt it. Here\'s what you want from your low end----> after you warm up your mill bring it in, you want it to sit and have a good idle for atleast 30 seconds, more is fine, after that time you want to be able to hit the throttle and have a crisp take off without hesitation or as little as possible. If you leave your LSN at break in settings, I promise you will not get a crisp take off from idle, it will bog and hesitate because it will load up on fuel. A well tuned mill will get plenty of lubrication.

His runs great, he won the only race I've seen him in. He may have been talking about not adjusting it durring the breakin, because we were making minor adjustments to the hsn between runs to get it at 240 degrees. I was so happy to have someone helping me I didn't think to ask him what I should do after it was broke in.

Right now, its still set at break in, but it accelerates pretty good I think. I'm the only one around with a 4wd truck so I don't really have anything to compare it to. All of the 2wd trucks I've seen out accelerate me. When I bought my car a friend got an RC10, the guy at the lhs said that he would out accelerate me and out run me in a straight line. So I don't know if it could be quicker or not, I'll try leaning it out some next time I run it. If I get it too lean it won't idle, correct? So I should lean it out while warmed up until I get the best performance, then let it cool off and see if it'll start, and richen it up a little if it doesn't idle well, correct?

I never said the two needles were related, you are right, they serve two different functions. What I said was that you should adjust both to get the desired performance.

gotcha, I think....the lsn is mainly for acceleration from idle and the hsn is top speed? Previously I thought it was just for idle.

These little glow engines can be a pain, but with practice you will be able to get your mill dialed no problem. If you are ever in doubt, refer to your manual, that is your bible, do what it tells you to do and you won\'t go wrong. Oh and by the way, I bet the manual tells you to adjust your LSN right?

It doesn't say enough about the needle adjustments, it basically just has the break in starting points. I've learned a lot more from this little chat than the 5 or so times I've read the manual.

And a continueing thanks, I'll be putting your words to work monday night with my new 1:8 buggy monday night :) Oh and speaking of which, any differences in between breaking in a .15 and a .21?
 

FLATTOP

llama boy
Messages
596
Reaction score
0
RC Driving Style
Originally posted by NitroWannabe
Originally posted by FLATTOP

Yes 240 is fine, the 270 I gave you is still a safe operating range for a properly tuned mill. As I said before, the key is to achieve a strong running mill{ well tuned} and proper temps. You will not go wrong with either temp. Are you still breaking it in?

I've got about 15-18 tanks through it. Manual says 10 tanks to break it in, guy at the track said its not really broke in for 15-20. So yes its been through the initial break in, but maybe not totally broken in yet.

While breaking in a new engine should I keep the temp a bit lower than normal running temp?


If you have 15-18 tanks through it, it is fully broken in.

Yes.during breakin you want the temps below normal running temps, you want to heat the mill up fast to about 200 degrees so that all parts can mate properly and try to keep the temps under 210 to 215 degree's. You are through with breakin and are ready to tune for perfromance.

Originally posted by NitroWannabe


I never said the two needles were related, you are right, they serve two different functions. What I said was that you should adjust both to get the desired performance.

gotcha, I think....the lsn is mainly for acceleration from idle and the hsn is top speed? Previously I thought it was just for idle.

It doesn\'t say enough about the needle adjustments, it basically just has the break in starting points. I\'ve learned a lot more from this little chat than the 5 or so times I\'ve read the manual.

And a continueing thanks, I\'ll be putting your words to work monday night with my new 1:8 buggy monday night :) Oh and speaking of which, any differences in between breaking in a .15 and a .21?

Yes you are correct, the LSN is for acceleration off idle and then the HSN takes over.

The LSN will have an effect on idle, when you adjust your low end you may notice a change in your idle speed, no worries that is that your idle adjustment screw is for. Just adjust your idle stop screw to bring the idle back to where it needs to be.

I honestly can\'t comment on breaking in a .21 as I have never owned one, maybe one of the other guy\'s on here can tell you more about that
 

NitroWannabe

RCNT Member
Messages
37
Reaction score
0
RC Driving Style
Let me see if I've got this now...

Durring breakin, keep it 210-215, run it real rich, lsn & hsn.

After 10 tanks start leaning it out, hsn first. Lean it out slowly, 1 click(1 hour on clock), run a few passes, check temp, keep leaning it out slowly until I feel I've reached max performance (or temp?). Then turn it back rich 1 click.

After hsn is set, then start the same procedure for the lsn, adjusting the idle as needed.

Now that you've taken the time to explain all of this to me it makes much more sense....not to mention sounds much easier...I think I was trying to make it too difficult.

A couple final questions....

1. How exactally to break it in? I've seen/heard/read the following:
a. set it on a stand and let it idle until out of fuel, let it cool off, repeat.
b. set it on a stand and let it run at a high idle until out of fuel, let it cool off, repeat.
c. run it from idle to half throttle, then back to idle, back to half, etc, until out of fuel, let it cool off, repeat.
d. run it at 2 minute intervals for a few tanks, letting it cool inbetween. Then upping to about 5 min after first 5 tanks.

Which is best or does it really matter as long as I'm not going full throttle on it? And what temp should I let it cool down to before starting it up again?

2. 240-270 is desired temp. While tuning it post-break in, I should stop leaning it out if it gets any hotter, correct? What can be done at that point? Leaning it out further will make it run faster and hotter, but thats not exactaly good for the engine, right? So what can I do, if anything, to run leaner/faster without getting temp above the desired range?

3. Where do you get these temps from? Experience? I've looked through the manual a number of times, I havn't seen any thing that specifies a certain temp. Are the temps pretty universal? or does it vary from engine to engine?

Thanks again :bow:
 
Last edited:

FLATTOP

llama boy
Messages
596
Reaction score
0
RC Driving Style
Originally posted by NitroWannabe
Let me see if I've got this now...

Durring breakin, keep it 210-215, run it real rich, lsn & hsn.

After 10 tanks start leaning it out, hsn first. Lean it out slowly, 1 click(1 hour on clock), run a few passes, check temp, keep leaning it out slowly until I feel I've reached max performance (or temp?). Then turn it back rich 1 click.

After hsn is set, then start the same procedure for the lsn, adjusting the idle as needed.

Now that you've taken the time to explain all of this to me it makes much more sense....not to mention sounds much easier...I think I was trying to make it too difficult.





Sounds like you have it, see your ar master tuner already lol.

One thing to remember, don't tune for temperature, this is a common mistake people make. A temp gun or guage is simply a guide, something to go by. You want to tune for perfromance while keeping an eye on temps. Are you totally confused yet? lol.
 

FLATTOP

llama boy
Messages
596
Reaction score
0
RC Driving Style
Originally posted by NitroWannabe

A couple final questions....

1. How exactally to break it in? I've seen/heard/read the following:
a. set it on a stand and let it idle until out of fuel, let it cool off, repeat.
b. set it on a stand and let it run at a high idle until out of fuel, let it cool off, repeat.
c. run it from idle to half throttle, then back to idle, back to half, etc, until out of fuel, let it cool off, repeat.
d. run it at 2 minute intervals for a few tanks, letting it cool inbetween. Then upping to about 5 min after first 5 tanks.

Which is best or does it really matter as long as I'm not going full throttle on it? And what temp should I let it cool down to before starting it up again?

2. 240-270 is desired temp. While tuning it post-break in, I should stop leaning it out if it gets any hotter, correct? What can be done at that point? Leaning it out further will make it run faster and hotter, but thats not exactaly good for the engine, right? So what can I do, if anything, to run leaner/faster without getting temp above the desired range?

3. Where do you get these temps from? Experience? I've looked through the manual a number of times, I havn't seen any thing that specifies a certain temp. Are the temps pretty universal? or does it vary from engine to engine?

Thanks again :bow:

Methods for breaking in a new mill varies from person to person, everyone has an opinion on that subject and everyone does it in a different way. Here is my thoughts on it----> I have done the idle method you mentioned without adverse effects but the more I have talked to other people and researched it myself, I have found out that's not the proper way to do it.

I would do what's called Heat Cycling the mill, basically what that means is, fire up the mill and run it, quarter to half throttle, vary your throttle input for 3 to 4 minutes and then shut it off and let it cool completely.. Now what that does is it brings the mill up to temp quickly so that the piston \sleeve can heat up properly and mate properly and then shutting it down after 3 minutes allows them to cool down properly.

You continue to do that, run for 3 to 4 minutes, vary your throttle input, shut down, allow to cool completely, keeping an eye on temps throughout the process.

After a few tanks you can extend the run time to 5 minutes and never go full throttle until the last couple of tanks and even then don't run wide open for over 2 seconds at a time.

As far as after break in temps, basically you don't want to go over 300 degrees, 280 to 285 is borderline hot and anything over is too hot. The 240 to 270 range I gave is a safe range, your mill should run great anywhere between those numbers.

You asked if anything could be done to get more power after those temps? you could get an aftermarked head with a larger cooling surface, this will allow you to lean a tad more and squeeze some more power out. Beware, there is a fine line between running lean and too lean. Keeping it a tad on the rich side will ensure a long engine life. Running lean or too lean will quickly take its toll on an engine, would you rather replace the piston\sleeve after 2 gallons or after 10 gallons?

Originally posted by matts6887


Actually; whether you want to believe it or not; If you tune for performance like that without a reference point from a temp gage or gun; then you could run into problems down the road.

Yes Matt, you are correct. I am not saying not to use your temp gun, absolutely use it and keep a good eye on temps, all I am saying is this, people will try to tune there mill for a certain temp. and that\'s not the correct way to tune an engine. You tune for maximum performance while keeping an eye on temps., if they get to hot, then you adjust accordingly. A temp gun is just a guide. People who tune for a certain temp are robbing there engines of perfromance.
 

sledgep

RC Newbie
Messages
8
Reaction score
0
RC Driving Style
I need to replace my GS11R any direct boltins? its for my kyosho Dodge RAM with QRC.

thanks
 

jon2

Nitro ASSpired!!!
Supporter
Messages
12,137
Reaction score
0
Location
Oxnard
RC Driving Style
  1. Bashing
sledgep.. no need to bump this thread since it is 5 years old and since you have created a thread already. Your responses will not be that great if you pose the question in different threas other than the one you have already.
 

rccars411

RCNT Talkaholic
Messages
397
Reaction score
0
RC Driving Style
how much you willin to spend on an engine? a cv-r from OS... rotary carb and standard shaft should work fine.
 

Similar threads

Top