2 Different engines tuned the same...

[SSX]

Hi Guys,


I'm thinking of either building a twin engined car with either the Thunder Tiger eb4 s2 1/8 or a kyosho 1/10.

i have 2 x .12 engines but one is tamiya the other is kyosho.



can they be tuned to run side by side rpm & power wise?


would that theoretically equal .24?


would there be any power gain over the .21? i think the .12's rev higher?


or i'm thinking of getting an identical eb4 s2 .21 motor. the previous option would be ideal as i have both the engines already but getting another .21 would solve a lot of issues i expect.

 

[avelciario]

In my own opinion its very hard to tune 2 engine and adjust same performance and power even the RPM very hard to tell if they are running at thesame speed, most especially different manufacturers. But I saw so many rc cars running on twin engine but I don't know if it really works. Better to get a single big engine with a good power. If you want only power and speed put LRP ENGINES.

 

[2revo1maxx]

I would use the same engines.

 

[SSX]

thanks for your input guys.


i guess my theory is that 2 smaller engines will rev higher which in turn would maybe give a higher output overall than the equivalent sized single motor.....i could be wrong though.

 

[Extreme RC Mods]

Running two different engines is fine, they should be no harder to tune then a single engine, you just do them one at a time. The fact that they are both connected to the same gear means they will both run the same rpm regardless of if one is tuned better then the other. Unloaded both engines will spool well past the usable rpm that they would see in an rc so even if one is making less power, it will still push the spur gear to it's potential of what it's tune will deliver. Technically you could run a .12 and a .32 side by side and as long as the tune is close, they will both spin the exact rpm because they are both connected to the same drive gear. It's really simple if you think about it, you just have an extra engine to tune and that's as complicated as it has to be.

 

[SSX]

Thanks for that bit of info, i was under the impression that if one engine was bigger/more powerful it would muck up the system.

i have decided to get another .21 and run that along side my other .21, should be double the hp right? or am i getting that side of things confused?

 

[Extreme RC Mods]

You will have double the HP (torque) yes. You won't see twice the speed because it doesn't work like that in an application like this.

 

[Snook Man]

To 2nd what Robin has said, Tuning 2 engines is no more difficult than tuning 1. You just tune them 1 at a time.

I would however make sure if using 2 different engines that the carbs are as close to the same as possible or at least the distance the carb slide valves or rotary valves travel from idle gap to wot. They need to be as close as possible to make setting up the linkage as easy as possible.
If 1 carb is closed more than the other it will result in that engine performing less than its capabilities and the other engine will suffer the consequences.
A carb that the throttle valve travels only 1mm less than the other from idle to wot is very hard to sync with the linkage.