stunthanger.com
Engine basics => Engine set up tips => Topic started by: Steve Hines on May 15, 2011, 03:48:16 PM
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Has anyone used this motor as a rear exhaust? I was going to call randy and see if he has a tuned pipe that would work.
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I must admit that it does look tempting doesn't it?
I am curious for answers too.
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Randy Smith said that he had a pipe that would work, now I need to find a header. Mac does not show one but I will call. called fox and they did not have one.
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Randy Smith said that he had a pipe that would work, now I need to find a header. Mac does not show one but I will call. called fox and they did not have one.
Yup, been through the header thing with that motor except I had the .19 version of the same engine. No commercial headers available for it and I would have to make my own. At that point I moved on. But that was years ago, maybe someone makes a header now? Let me know what you find.
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You might ask Scott Riese about a header. He goes by SQ8s and is in the members list. He makes custom mufflers, etc. A mill and lathe would make a header a pretty simple job for that engine.
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Just thinking about the header part of it, you would be more than halfway there simply by using the standard tilt down/up muffler and cutting the expansion chamber right off it, rounding the outer edges around the cut area and then slipping some silicon tubing over it.
Quick and dirty or what!
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Might pay to put " B.B. " in the title , to diferentiate it from the two earlier 25s .
Used the intake in a Magnum FSR 25 clone , but thats irelephant .good Ruck . ;D
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Well Mac does not make one. I will keep trying to find some thing and let you know.
Steve
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Use the motor as a rear exhaust?, heck, I don't know of anyone who has used it in stunt period (but I'm sure there are some out there). I'd just go with a high RPM, low pitch set-up and see if it is stunt worthy with a muffler. You may decided it's not worth the trouble to go any further. And for the record, I like and have used Fox engines but they do have their challanges. 8)
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Use the motor as a rear exhaust?, heck, I don't know of anyone who has used it in stunt period (but I'm sure there are some out there). I'd just go with a high RPM, low pitch set-up and see if it is stunt worthy with a muffler. You may decided it's not worth the trouble to go any further. And for the record, I like and have used Fox engines but they do have their challanges. 8)
So are you suggesting to rear exhaust it and use a standard Fox down tilt muffler on it?
The muffler would clear the tank with no issues and the outlet could be on any chosen side - probably the out side of the circle would be preferable. And the fuselage would hide most of the transverse body of the muffler.
But what I wouldn't do is to run the engine as a side exhaust and then switch it to rear because of the wear issue.
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No, actually I'm just suggesting that it be tried as a side exhaust with a muffler. I guess when the subject of tuned pipe for this engine was suggested I was thinking of either a curved header such as Randy Smith offers for the Magnum/Thunder Tiger .36 series of engines or a straight header on a side mount such as is used on profiles. It didn't occur to me to actually turn the exhaust 90 degrees. ???
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So Pete, do you think that rotating the upper barrel 90º to the rear and using a standard tilt down muffler that exits on the star board side would show promise?
I kinda like the idea, and as you said if that works (and why shouldn't it) then perhaps progress onto finding a header for it and a pipe - or try the suggestion I mentioned about using the stack of the standard muffler for a header. It seems to have an almost square outlet, unlike very rectangular ones on other motors, and should be able to be pushed into service.
I know that Brian Eather here in Oz would have a pipe that would work - pipe number 1 part number 2025.
Interesting stuff!
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That would be one way to go. 8)
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I flattened a piece of 1 in tube , bunged ends , cut Ex hole and fitted to K&B , & Irvine R.E. ,
but went up back of inverted engine , between bearers. 3/32 holes F&R to feed tube exhaust.
but was used as silencor .
You have to leave Cyl as youve run it , side or rear . You cant have both . ;D
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I've run both the .19 and the .25 BB on a profile plane. Both would belch/vomit in any outside maneuver when configured as a side exhaust, but ran consistent when set up as rear exhaust. This was without a pipe and on bladder pressure. They are extremely strong little motors. I think I was launching around 14,000 RPM. I never tried to run it in a stunt setup.
Arlan
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I've run both the .19 and the .25 BB on a profile plane. Both would belch/vomit in any outside maneuver when configured as a side exhaust, but ran consistent when set up as rear exhaust. This was without a pipe and on bladder pressure. They are extremely strong little motors. I think I was launching around 14,000 RPM. I never tried to run it in a stunt setup.
Arlan
Try blocking off the vestige of the port under the exhaust (if there is one) and completely blocking off the boost port - this should bring the rpm's back down to sane levels a bit and stop crankcase charge from 'belch/vomiting in any outside maneuvers' regardless of engine orientation.