dazzi220 Posted September 19, 2005 Author Share Posted September 19, 2005 tuning is not the issue, the 21 was'nt designed to take 2 26 engines, I'm not up for the costly repairs wen the cash could be goin into the 4.6. Anyway I fitted 2 servos today and a cheap reciever, shes up and running, nice to have a savvy again after all this time lol it'll do for now... Quote Link to comment Share on other sites More sharing options...
Mel Posted September 19, 2005 Share Posted September 19, 2005 exactly and when you get your 4.6 you can use the .21 for doing stupid jumps with Quote Link to comment Share on other sites More sharing options...
Fusion Racing Posted September 20, 2005 Share Posted September 20, 2005 hop your .21 up like hell!! get a picco .26 engine for it and some other bits, maybe the 3-speed. but its just an idea, you could also use it for spares Quote Link to comment Share on other sites More sharing options...
dazzi220 Posted September 20, 2005 Author Share Posted September 20, 2005 hop your .21 up like hell!! get a picco .26 engine for it and some other bits, maybe the 3-speed. but its just an idea, pointless I'm gettin a 4.6 and hoppin that up Quote Link to comment Share on other sites More sharing options...
Thunderwolf Posted September 20, 2005 Share Posted September 20, 2005 pointless I'm gettin a 4.6 and hoppin that up not much you can hop-up on the 4.6 is there? Quote Link to comment Share on other sites More sharing options...
dazzi220 Posted September 20, 2005 Author Share Posted September 20, 2005 not much you can hop-up on the 4.6 is there? alloy, 3 speed, Quote Link to comment Share on other sites More sharing options...
madmanluke Posted September 21, 2005 Share Posted September 21, 2005 theres not a singlee part on the savage that you cant hop up i dont think. it can be replaced with carbo fiber, alloy, n other buetifull bits n bobs. Quote Link to comment Share on other sites More sharing options...
Thunderwolf Posted September 21, 2005 Share Posted September 21, 2005 alloy, 3 speed, i thought it came with a 3 speed Quote Link to comment Share on other sites More sharing options...
madmanluke Posted September 21, 2005 Share Posted September 21, 2005 nope. Quote Link to comment Share on other sites More sharing options...
Thunderwolf Posted September 21, 2005 Share Posted September 21, 2005 nope. oh back to the title of this thread, what is the point of putting two engines in a savvy anyway? just sounds like a big waste of time to me. Quote Link to comment Share on other sites More sharing options...
madmanluke Posted September 21, 2005 Share Posted September 21, 2005 there is no point. tis just for showing off. as said its pointless as if one engine is as little as 1 rpm higher than the other, that one engine is taking the load of the whole truck. techniquly make it a singgle engine car Quote Link to comment Share on other sites More sharing options...
Thunderwolf Posted September 21, 2005 Share Posted September 21, 2005 thaks for answering, that will save my time and money Quote Link to comment Share on other sites More sharing options...
dazzi220 Posted September 21, 2005 Author Share Posted September 21, 2005 there is no point. tis just for showing off. as said its pointless as if one engine is as little as 1 rpm higher than the other, that one engine is taking the load of the whole truck. techniquly make it a singgle engine car well I'm not so sure its showing off, in my case I was offered a sav 21 cheaply but already decided to get a 4.6, I saw the twin conversion in my lhs window and thought maybe I'd do it, if it was worth it, got advice on ere and decided against it. I'd like to see hpi do a twin engined savvy in the future though Quote Link to comment Share on other sites More sharing options...
madmanluke Posted September 21, 2005 Share Posted September 21, 2005 the thing is, youl never have the engines running the same...ever... thats the point im making. its techniquly a single engined truck if u do it, as even 1 rpm faster than the other engine, that one engine is taking all the load of the truck. Quote Link to comment Share on other sites More sharing options...
Thunderwolf Posted September 22, 2005 Share Posted September 22, 2005 the thing is, youl never have the engines running the same...ever... thats the point im making. its techniquly a single engined truck if u do it, as even 1 rpm faster than the other engine, that one engine is taking all the load of the truck. so you mean your better of putting a bigger engine in it, if you want a faster truck. Quote Link to comment Share on other sites More sharing options...
Samari Posted September 22, 2005 Share Posted September 22, 2005 the thing is, youl never have the engines running the same...ever... thats the point im making. its techniquly a single engined truck if u do it, as even 1 rpm faster than the other engine, that one engine is taking all the load of the truck. I can't be bothered at the moment to explain it but trust me twin engines work well. I know a lot of people at SC use them and have great results. Quote Link to comment Share on other sites More sharing options...
dazzi220 Posted September 22, 2005 Author Share Posted September 22, 2005 but it must be practically impossible to tune them both exactly? Quote Link to comment Share on other sites More sharing options...
madmanluke Posted September 22, 2005 Share Posted September 22, 2005 it is imposible. take some timee to think about it. youl soon work it out forr your self. only reason the torque on them is so great is beecuase there is too much load on one enginee as it eccelerates, n it slows down untill it reaches tthe same rpm on the other one. only then wwill they bee running the same briefly. Quote Link to comment Share on other sites More sharing options...
Big T Posted September 22, 2005 Share Posted September 22, 2005 To stop the bickering. You will never get 2 engines to run exactly the same......ever, as no 2 engines are the same. If one engine revs slightly higher than the other it will take the full strain of the truck, the slower engine will have zero resistance on it so it will spin up to catch the other one. This will happen back and forth til you have maxed them out and it will take no time at all. It would be different if the powered seperate ends, but as they are both putting the power through the same spur gear there will be no problem.......until all that power transfers to your diffs and they go bang If you wanted to be silly you can fit the .70 conversion for the savvy, it's about £240 and includes the extended chassis. But again this would mean no diffs Hope the bit about 2 engines helps clear things up. Tony Quote Link to comment Share on other sites More sharing options...
madmanluke Posted September 22, 2005 Share Posted September 22, 2005 exactly the point im trying to get at. hpi need to come up witth a 6 bevel gear diff convertion, then you can start putting silly power in your trucks with out worrying too much about your diffs. Quote Link to comment Share on other sites More sharing options...
Samari Posted September 22, 2005 Share Posted September 22, 2005 Sorry Tony but what you put is not right at all. Engines perform one function and one function only, they overcome load. In this case, the weight of the truck and its resistance to movement. Remember that. You will never get 2 engines to run exactly the same......ever, as no 2 engines are the same. If one engine revs slightly higher than the other it will take the full strain of the truck, the slower engine will have zero resistance on it so it will spin up to catch the other one. The slower/weaker engine does not have "zero" resistance. The engine that makes less power does not somehow disengage itself from the driveline. It does not try to "catch up" with the stronger engine. The quicker (not stronger) engine sees the load first but a loaded engine will NOT accelerate as quickly as an unloaded engine. The unloaded engine will then catch up with the loaded one and SHARE THE LOAD. The "lag time" between the two engines would be measured in increments far smaller than milliseconds. Even engines that run at steady, consistent rpms share loads. The whole fundamental reasoning behind this goes even farther, a piston engine, especially a two stroke, only applies power to the crankshaft during a narrow arc of crank travel (about sixty degrees) so if you've got two engines (or two cylinders, because there really is no difference), the moment of peak power production between the two will seldom -- in the case of twin engines -- or never -- in the case of twin cylinders on a common engine -- occur instantaneously. Two engines are tied to a spur gear in a fashion that is fundamentally no different than the way two connection rods are tied to a crankshaft and you wouldn't say that the stronger cylinder in a two cylinder engine is just dragging the other one behind it! This will happen back and forth til you have maxed them out and it will take no time at all. Nope not in the real world. Take for example sea going ships that have not two but THREE drive engines powering ONE propeller. From what I can gather the internal drive for the marine gear, though complex, is fundamentally the same as what we are discussing here. Quote Link to comment Share on other sites More sharing options...
MR_TiGGer Posted September 25, 2005 Share Posted September 25, 2005 Take for example sea going ships that have not two but THREE drive engines powering ONE propeller. From what I can gather the internal drive for the marine gear, though complex, is fundamentally the same as what we are discussing here. Very clearly explained, well said Samari, HOWEVER ... If there's an R/C version of the boat you described I NEED THAT RIGHT NOW I mean 3 big engines powering one big prop?? Whooooooop!! Give my Revo to the orphange for that Grrrr:-) Quote Link to comment Share on other sites More sharing options...
Samari Posted September 25, 2005 Share Posted September 25, 2005 Yeah that would be amazing. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.