Go Back  RCU Forums > Glow Engines, Gas Engines, Fuel & Mfg Support Forums > Engine Conversions
Reload this Page >

How sensitive is intake mani length on a little 4 stroke?

Notices
Engine Conversions Discuss all aspects of engine conversions in this forum

How sensitive is intake mani length on a little 4 stroke?

Old 04-29-2011, 05:37 PM
  #26  
tkg
My Feedback: (1)
 
Join Date: Jan 2002
Location: Riverton, WY
Posts: 3,114
Likes: 0
Received 0 Likes on 0 Posts
Default RE: How sensitive is intake mani length on a little 4 stroke?

The $5 words for tuning an intake are Helmholtz resonance.
Using the basic formulas you can tune the intake ( make the intake tract resonate) to certain frequency. If the tuned freq matches the engine rpm you get a positive, supercharger effect and gain power. Operating out out of the freq range you get a 0 increase or an actual decrease in power.
Old 04-30-2011, 02:36 PM
  #27  
NorfolknGood
Member
 
Join Date: Jun 2007
Location: Norwich, UNITED KINGDOM
Posts: 36
Likes: 0
Received 0 Likes on 0 Posts
Default RE: How sensitive is intake mani length on a little 4 stroke?

I made an intake manifold for my GX31 from a piece of steel from a kids bicycle it worked a treat.

Attached Thumbnails Click image for larger version

Name:	Zx70542.jpg
Views:	11
Size:	91.9 KB
ID:	1601542  
Old 05-01-2011, 10:04 AM
  #28  
av8tor1977
My Feedback: (6)
 
av8tor1977's Avatar
 
Join Date: May 2003
Location: Tucson, AZ
Posts: 7,217
Likes: 0
Received 2 Likes on 2 Posts
Default RE: How sensitive is intake mani length on a little 4 stroke?

Looks good and I'm sure it works fine.

The only difference is when I used a plywood spacer, I gave mine two coats of epoxy thinned with a little alcohol to seal it. Probably not necessary...

AV8TOR
Old 05-01-2011, 11:25 AM
  #29  
NorfolknGood
Member
 
Join Date: Jun 2007
Location: Norwich, UNITED KINGDOM
Posts: 36
Likes: 0
Received 0 Likes on 0 Posts
Default RE: How sensitive is intake mani length on a little 4 stroke?

Yes I should have explained I ran thin cyno all over the ply.
Old 05-01-2011, 11:49 AM
  #30  
gkamysz
Senior Member
My Feedback: (19)
 
gkamysz's Avatar
 
Join Date: Jun 2003
Location: Crystal Lake, IL
Posts: 3,397
Likes: 0
Received 1 Like on 1 Post
Default RE: How sensitive is intake mani length on a little 4 stroke?

There are two tuning phenomena. Helmholtz and dynamic flow.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.