chassis dyno

[Striikar]

Z!! Come on now!!. I can see it now: Aye guys my new 32cc I buildt and ported makes 53hp!. I'm gonna put obr out of business!!.

I suggest renting buying or anything but building.
I've heard how super difficult it is to get it right and be consistent. That's why only a few people actually own one.
They invested serious trial and error time getting it correct.
I've seen many try to build one that worked correctly and consistent in minimizing variables. Talk to anyone of these engine builders that has one. I'm not saying don't but be aware of how difficult it will be in maintaining repeatable results.
Room temp,air pressure,humidity,altitude etc all play into consistent and Reliable numbers. Also remember there are different types of dynos. So fully investigate the information available.
Good luck if you should choose to accept this mission.?

 

[Z.hb71]

Z!! Come on now!!. I can see it now: Aye guys my new 32cc I buildt and ported makes 53hp!. I'm gonna put obr out of business!!.

I suggest renting buying or anything but building.
I've heard how super difficult it is to get it right and be consistent. That's why only a few people actually own one.
They invested serious trial and error time getting it correct.
I've seen many try to build one that worked correctly and consistent in minimizing variables. Talk to anyone of these engine builders that has one. I'm not saying don't but be aware of how difficult it will be in maintaining repeatable results.
Room temp,air pressure,humidity,altitude etc all play into consistent and Reliable numbers. Also remember there are different types of dynos. So fully investigate the information available.
Good luck if you should choose to accept this mission.?

Hell nah, 53hp from a 32? Nah, something better, something that won't last one pull ? but that's a long time in the future, if at all. No one rents out Dyno's over here. And if they do they are full scale real car stuff. I do definitely want to try an build one, since 2 stroke stuffing had good luck with his so why not? Cheap enough. I'll do plenty of research before hand.

 

[mark35]

Hell nah, 53hp from a 32? Nah, something better, something that won't last one pull ? but that's a long time in the future, if at all. No one rents out Dyno's over here. And if they do they are full scale real car stuff. I do definitely want to try an build one, since 2 stroke stuffing had good luck with his so why not? Cheap enough. I'll do plenty of research before hand.

Rovan pull start?

 

[DougStar]

Rovan pull start?

Yip???

 

[Seandonato73]

I agree it's not going to be as easy as these guys make it look to get good results. It will be fine for a rough estimate and for checking any power gains from a specific engine. But from experience I've seen a great deal of time and effort go into setting up wheel and engine dynos so they are accurate. With the wheel dyno you also have to factor in gear ratio. In real vehicles you run in 4th gear or what ever gear eliminates the trans and gives a 1 to 1 ratio so all you have to figure is your rear gearing. The same would be true for rc vehicles.

 

[1Coopgt]

So 4 pound rollers? Load is what I'm concerned about. And I want it rated all the way up to 50hp, for other...things

Z I think it's actually more than 4lbs. That's just that Roller. The motor is adding resistance also. I'm just guessing but I think he uses the motor as a kind of generator . The load resistors are being used to apply a kind of braking force against the motor which in turn is applied against the roller. His computer and controller boards are monitoring Voltage output from that motor and being converted to hp and torque. Smarter people than me could explain how that's happening.

 

[Seandonato73]

Yes he is using static and dynamic loads for the premade one. The dynamic is the variable load I was talking about. Each load will take a certain amount of torque for an engine to overcome. Thus you can figure out your hp ratings. Its about the same in the jet dyno we used at work. It used water through a variable oriface. At a certain rpm and pressure it took a known amount of power to make it work.

 

[Z.hb71]

Yes he is using static and dynamic loads for the premade one. The dynamic is the variable load I was talking about. Each load will take a certain amount of torque for an engine to overcome. Thus you can figure out your hp ratings. Its about the same in the jet dyno we used at work. It used water through a variable oriface. At a certain rpm and pressure it took a known amount of power to make it work.

yes but thats not the problem, my problem is calculating the correct amount of load required. also how am i supposed to assume a dyno is correct when ive never dyno'ed my motor? id think consistency is more important ?
ok wait i just red this "roll inertia should simulate about 30% to 100% of the actual vehicle’s mass" from https://www.dynomitedynamometer.com/dyno-tech-talk/dyno_hp_limits.htm what do y think about that?

 

[Seandonato73]

That's a good place to start I guess.

 

[1Coopgt]

Thing is no dyno is truly accurate. They are a tuning tool . Guys that run Dyno Jet ,Mustang dyno's can fudge the settings to get them to read almost what ever they want them to read. If you go to use a dyno to see what your HP is then you're going for the wrong reason . Sadly Z you could build one but you would never know if it was accurate for HP and Torque.

 

[Z.hb71]

Thing is no dyno is truly accurate. They are a tuning tool . Guys that run Dyno Jet ,Mustang dyno's can fudge the settings to get them to read almost what ever they want them to read. If you go to use a dyno to see what your HP is then you're going for the wrong reason . Sadly Z you could build one but you would never know if it was accurate for HP and Torque.

thats exactly what i thought. i do have sort of an idea what my hp should be at, around 13 with my carb, and i do want to use it for tuning aswell ?