Originally Posted by 1QwkSport2.5r
We are not dealing with a $175 LRP or HPI or $140 Traxxas engine here. You can get mediocre performance with whatever pipe you have, but certain engines are tuned for a more specific purpose (powerband) and some pipes specifically address these areas. As I understand it, this engine was specifically tuned/modified by Ron Paris to his own specs which means a pipe you'd use on the regular version of the engine may work fine but on the modified version may be a total waste. I hear all of these numbers thrown around (053, 086, etc) but know so little (since I'm not a racer) about them that if I'm going to drop $75-125 on a pipe on an engine that costed 3 times that, I want it to be the right one right off the bat. I do not believe a pipe designed for a .21 will work as effectively on a .28, especially a "fast" engine like a Nova.
For or those that know, what do the 3 digit pipe numbers stand for, and does a high rpm pipe wake up a mid rpm engine or would a mid rpm engine get a mid rpm pipe just because? The short stroke Nova I have is designed and ported for insane power coming out of turns. It's said to be a crazy fast revver and is considered a low-mid rpm engine. I think the listed top rpm from Paris Racing is 34,600rpm with the 7 port version eeking up to around 36,000rpm. I would have gotten the 7 port version but I didn't have the extra $50 they wanted for it.
What I have not been able to find out about this engine is what specifically is done differently in the Ron Paris version of the BX21 SBK versus the standard BX21 SBK. Also, does anyone know if the boost chamber (which is said to have no performance advantages) can be removed from the backplate?
Without someone having experience with that particular engine (with mods) and having the knowledge of trying different pipes on it, then I think it will be very difficult to get the perfect pipe for it and how you use it with one shot.
The numbers (generally) refer to the size and shape of the pipe...so in effect the numbers give a gauge to how it will perform.
I am a bit reluctant to say X is the pipe you need because it would be a guess...but I will say that the Dynamite 053 and 086 are $50 a piece (looking at US Ebay), both pipes will "work" and with testing you will decide which is best suited. Sure if you had a hundred different pipes to hand then you may find one that suits the engine and you better but those two will cover a wide spectrum of needs at a reasonable price.
As for the boost bottle- Looking at pictures of the BX21SBK online....it could be either screwed into the back plate or maybe a press fit. Personally I would leave it on there, if you do not want it connected then remove the nipple (below carb.) and block the hole with a screw and a fibre washer or dab of sealer....
Some of the Hyper engines have a similar set up but the bottle is screwed to the backplate using the backplate screws...I have tried a back to back test with the bottle connected/disconnected and if there is a difference then it is far to small to tell...but the principal is sound and I know it works on larger engines.
On the subject of which buggy...my choice would be the Hyper7...tough as old boots, cheap, full spares available (and will be for along time yet).