RunRyder RC
WATCH
 1 page 320 views TOPIC CLOSED
HomeRC & PowerAircraftHelicopterEngines Plugs Mufflers Fuel › OS 70 SZ-H back pressure
09-22-2017 11:43 AM  14 months agoPost 1
MartyH

rrProfessor

USA

My Posts: All  Forum  Topic

I run an OS 70 SZ-H in a Raptor 60 but use an MP-2,5 or 6 looking muffler from Curtis Youngblood designed for the OS 91 engines. My engine tunes ok but I got to thinking that maybe I'm not providing enough back pressure to really properly tune the engine for power. I'm very rich and the engine makes enough reliable power for just sport flying around but it seems it's possible to have the engine real rich AND pretty hot at the same time. It's not a worn out engine and it fires right up with no issue. Should I be using a fairly restrictive muffler with the 70? Maybe a muffler designed for a 61 it would have typically been replacing?

I have read some old threads that suggest the 91 muffler(s) are more appropriate than a 61 for the 70 so I'll close this thread.

PM  EMAIL  GALLERY  Attn:RR
WATCH
 1 page 320 views TOPIC CLOSED
HomeRC & PowerAircraftHelicopterEngines Plugs Mufflers Fuel › OS 70 SZ-H back pressure
 Print TOPIC  Make Suggestion 

 1  Topic Subscribe

Saturday, November 17 - 7:16 am - Copyright © 2000-2018 RunRyder   EMAILEnable Cookies

The RC discussion world needs to consolidate. RR is now one choice for that. Its software is cutting edge. It hosts on-topic advertising. Help RR increase traffic buy making suggestions, posting in RR's new areas (sites) and by spreading the word.

The RunRyder Difference

• Category system to allow Rep/Vendor postings.
• Classifieds with sold (hidden) category.
• Classifieds with separate view new.
• Answer PMs offsite via email reply.
• Member gallery photos with advanced scripting.
• Gallery photo viewer integrated into postings.
• Highly refined search with advanced back end.
• Hosts its own high end fast response servers.
• Hosts thousands of HD event coverage videos.
• Rewrote entire code base with latest technology.
• No off-topic (annoying) click bait advertising.
Login Here
 New Subscriptions 
 Buddies Online