Any benefit of drilling holes through the mid section for the exhaust outlets?

[Spybot]

I have seen a few engines with the exhaust gases coming through holes drilled in the mid section.
Is there any benefit from this ??
I thought the engine needs back pressure from the exhaust to work properly.
​Any thoughts on this ???

[filthy phill]

Dont do it
it just makes engine loud, no gain in speed that you will notice.
when they do this they also cut through the can on the inside of the leg to let the exhaust out.
if you want to free up a bit of exhaust just drill two holes or one big one each side in the gearcase, you can then simply put a plate on and off when you want if you want.
but as for a gain , not realy. might get something like 1/4 second difference over a quarter mile if your realy lucky.
its ok to do it if yourgoing to be running over hub props and get a problem pulling away due to too much exhaust flowing over the prop on take off.
but I have 2 gearcases, one drilled and one normal, I wish now I had not bothered to drill the spare one as ive not come across any gains.
#its like the kids with mopeds taking off the exhaust baffle and thinking it goes faster, simpler way to think its faster is just paint it RED ha ha