RCS 140 and Bisson custom muffler...too restrictive?
05-30-2003, 12:31 AM
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RCS 140 and Bisson custom muffler...too restrictive?
I had a muffler custom built by Bisson for my rcs 140 to go in my TF P40. I have been running in the engine and the highest rpm with the muffler is about 7700, briefly. At first I thought it just needed more breakin in before it would turn more. Then I realized that on the spec sheet they send with the engine from rcs, that they had run it at 9100. I decided to try it without the muffler and I get around 8500, open exhaust. Thats a difference of 800 rpm. Is my muffler too restrictive? How much rpm do mufflers rob from an engine, but yet still quiet it down? Any ideas?
05-30-2003, 09:24 PM
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RCS 140 and Bisson custom muffler...too restrictive?
GIVE BOLD MUFFLER A CALL, (772)344-8785 THEY WILL BE ABLE TO HELP YOU WITH YOUR PROBLEM. THEY MIGHT BE ABLE TO DO SOMETHING WITH YOUR HOME MADE MUFFLER.
05-30-2003, 10:23 PM
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RCS 140 and Bisson custom muffler...too restrictive?
800 sure does seem like a lot i can get 8300 on a 18 x 6 mejzlik sometimes 8500 but consistance 8300-8400. one tube pitts muffler.
05-30-2003, 10:36 PM
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RCS 140 and Bisson custom muffler...too restrictive?
How quiet is the muffler?? Ive made some very quiet setups and only lost 500 rpm. Ive gotten my 46cc poulan down into the mid 80db range and only lost 300 rpm from an open header. These are all large volume cannisters with some baffling.
Adam
Adam
05-31-2003, 01:07 AM
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RCS 140 and Bisson custom muffler...too restrictive?
The muffler isn't really "homemade." It's "custom" made by Bisson, to fit inside the cowl of my topflite p40 without any pipes coming out. Jim did a really nice job, in fact. It has two pipes coming out of the canister that are the same diameter as the pipes on my slimline pitts muffler on my g23. It is fairly quiet. It doesn't have the "throaty" sound like the g23 muffler, it's more weadeater sounding, and it has a pinging instead of a burble. I'm guessing its restricting the engine a little too much.
This is a rear exhaust 140, but that shouldn't matter. Any of you guys using another style muffler on a rear exhaust rcs 140, or a side exhaust for that matter, and can you give me some rpm numbers.
Oh yeah, the 7700 I'm getting is with a MA 16X8.
Thanks,
Jai
This is a rear exhaust 140, but that shouldn't matter. Any of you guys using another style muffler on a rear exhaust rcs 140, or a side exhaust for that matter, and can you give me some rpm numbers.
Oh yeah, the 7700 I'm getting is with a MA 16X8.
Thanks,
Jai
05-31-2003, 09:38 AM
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RCS 140 and Bisson custom muffler...too restrictive?
just as a guess i would suggest that you try blocking some or all of one of the exhaust ports on the muffler and see how it runs. the bisson pitts mufflers i use on my st90 engines have twp ports and on my engines you can get some rpm back if you block part of a port. but the sound goes up. i don't bother to block mine because i am ok with losing the rpm to get the quieter engine. but i have done this- blocked a port some- and the rpm and noise went up.. however with a different engine i am not sure if yours will act the same.
you might e-mail bisson and ask them what to try..
ed
you might e-mail bisson and ask them what to try..
ed
