RCU Forums - exhaust rerouting.

Quote:

Originally Posted by rally dude (Post 12165552)

So I just got a body for my HPI super nitro rally and the tip for the pipe dose not reach the outside of the body which will require me to extend it.
But I got a cool but bad idea. Why not rout it to the back of the car? If I’m going to have to buy some tubing to extend the tip outside of the body why not buy some more, a Y fitting and a some pipe to make a cool looking dual exhaust system? Not only will it look cool but less oil and crap from the exhaust will get on the body.
Any modification you make to the exhaust will affect most aspects of how the engine runs. The longer the exhaust system (header, pipe, extension (if used)), the lower the power band is. The exhaust system of a 2-stroke engine is a tuned system in effect - any change in length affects that tuning. Some engines may benefit from extending the exhaust where others will not. Depends on how they're timed and setup internally. A short silicone exhaust diverter is okay, a tube extended to the back of the car will likely completely kill top end, possibly too much back pressure if too small a tube is used, and could just in general make the engine impossible to tune. In short - short exhaust extensions (2-3" MAX) would be fine - if the ID of the extension is same or larger than ID of muffler. Long extensions - bad for 2-stroke glow plug engines. No problem for 4-cycle and Diesel engines though.

Will putting a tube on the exhaust routed to the back of the car add too much back presser?
I don't mind losing top end performance as long as it's fine on the bottom end it better or the same.
anotherthought would be to make a complet DIY setup with daul rear exhaust, but that would be too much work.
I could also put a glow/spark plug on the pipe at the end and trigger it by the 3rd channel for a cool miss/back fire, but that would just be silly and dumb. On the red - This won't work very well if at all on a 2-stroke engine. You could disrupt the pressure waves inside (if any unburned fuel actually ignites) the pipe causing the engine to not run right. The whole idea of blowing flames from the exhaust like on full size classic cars does not translate well to scale RC glow plug engine cars.

Responses in blue.. Basically in a nutshell, exhaust extensions and dual exhaust mods are bad news. Looks cool, performs poorly.