Muffler extensions ?

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Steve & Chris Clark - 22 Nov 2004 00:10 GMT

There was a thread here last week about performance being compromised by
tuned muffler port extensions. I like the idea too but I don't do it just
for the fact that is does rob HP. Not that I haven't tried though. I
certainly don't like the messy fouling of the oil on the model and the dirt
it attracts causing longish clean-up after a full afternoon of racing and
bashing. I had an idea that I tried today (while my truck ran that is) it is
made from a simple piece of clear tubing that I have specially cut and added
some wire reinforcements to it that took less than a half hour to make and
install. I am posting a picture of the device on alt.binaries.radio-control
photo site newsgroup. The device was only on for two tanks but I would say
that it did a more than adequate job of directing the oils from the models
wheel, rear suspension arms and chassis structures by 90% while not
noticeably decreasing the HP. The device is not tubular but very much
open and soft. It directs exhaust straight down to the ground and away. I
doubt this had anything to do with my air in fuel line problem. Please have
a peak and let me know what you think!
--
Steve

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M78Ultra - 22 Nov 2004 01:41 GMT

We had no luck whatsoever with exhaust deflectors. It would seem also (to
me) not a good idea to have one pointed directly to the ground as it could
hit the ground and stall out the vehicle.
I'm thinking the best way is to get a way way oversized one at an angle.(if
its a tubular design)
(we have already tried .30 deflectors with the same decrease in
performance)
Oversized so it won't affect the back pressure as much, and angled so the
exhaust deflector won't "bottom out". Although as pointed out by someone
else here on the group,the stinger of the pipe is tuned to and for the pipe
itself, and any adjustments or tinkerings will probably be a negative or
decreasing effect on performance.
I'm thinking about trying some sort of "mudflap" type deflector/guard. It
may work to some extent, although I know it probably won't deflect all the
exhaust, and actually may make more of a mess. Never know till you try.
Anyone else want to experiment with this idea,let me know your results. And
if it works ,don't forget it was my idea come payday. =)

> There was a thread here last week about performance being compromised by
> tuned muffler port extensions. I like the idea too but I don't do it just
[quoted text clipped - 14 lines]
> --
> Steve

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Steve & Chris Clark - 22 Nov 2004 02:13 GMT

I'm not sure if you looked at the photos but the "mud flap" analogy is
exactly what I have made.
I did use the small stock rubber air breather frame from the HPI engine over
the muffler's exit pipe that came with my truck, it worked to some degree
too.
--
Steve

> We had no luck whatsoever with exhaust deflectors. It would seem also (to
> me) not a good idea to have one pointed directly to the ground as it could
[quoted text clipped - 13 lines]
> Anyone else want to experiment with this idea,let me know your results. And
> if it works ,don't forget it was my idea come payday. =)

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M78Ultra - 22 Nov 2004 18:34 GMT

Excellent,.. I had glanced at it looked like it was a round tube. I didn't
notice that the tube was split and open aired down the side.
Curious as to any noticable differences in performance with it attached and
with it off....

> I'm not sure if you looked at the photos but the "mud flap" analogy is
> exactly what I have made.
[quoted text clipped - 24 lines]
> And
> > if it works ,don't forget it was my idea come payday. =)

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Steve & Chris Clark - 23 Nov 2004 01:08 GMT

Thanks bud! I usually run dirt bonze on my truck but as I had some jumbo
wheels on with the slipper tightened almost to the stop it was hard to tell
for sure if performance was compromised. The truck still did lots of
wheelies and had lots of holeshot. As of yesterday the port extension was
just put on. I will try to remember to post a trial with the dirt bonze on.
I may have to shorten the length some however with the smaller outside
diameter of the dirt bonze. If anyone would like I could picture post a step
by step in the construction of this simple device, an easy to fabricate and
effective way to keep a cleaner truck. Could even post a smallish J-peg
movie while in use with the truck running if anyone would like too?
--
Steve

> Excellent,.. I had glanced at it looked like it was a round tube. I didn't
> notice that the tube was split and open aired down the side.
> Curious as to any noticable differences in performance with it attached and
> with it off....

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walker - 28 Nov 2004 00:01 GMT

> Thanks bud! I usually run dirt bonze on my truck but as I had some jumbo
> wheels on with the slipper tightened almost to the stop it was hard to tell
[quoted text clipped - 8 lines]
> --
> Steve

I would be interested in any more testing that you have a chance to do.
I would try it myself this weekend but I took my rig apart to do some
off-season intensive rework and it will be a few more weeks till I have it
back together.

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Model Forum / Radio Controlled / Land Models / November 2004

Muffler extensions ?