R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Nitro Off-Road

Reply
 
Thread Tools Search this Thread
Old 03-20-2010, 05:41 PM   #1
Tech Elite
 
Join Date: Mar 2009
Posts: 3,657
Trader Rating: 5 (100%+)
Default can a to rich high speed needle

load up the case on the bottom end?

Just curious. If this happens then you theoretically could have a to lean lsn to compensate for a too rich high end and loading up the case making you assume the lsn is too rich?


I know it usually goes the other way, but wanted to know if this was possible as well.
__________________
"You are not understanding the fundamental principles of my fragmented personality"

Mugen
dreaux is offline   Reply With Quote
Old 03-20-2010, 05:48 PM   #2
Tech Elite
 
Quad Racer 34's Avatar
 
Join Date: Mar 2009
Location: OHIO
Posts: 2,973
Trader Rating: 4 (83%+)
Default

thats weird u asked that because this exact thing was happening to me today. i reset the needles to factory settings and going to retune it on another nice and warm day.
__________________
Dylan Gerard

Serpent - Desoto Racing - Picco - AKA - Hitec - RC Addictions Products - Tekin - VRP - Avid RC - SMC - MIP - SkipGear - The Ohio RC Factory
Quad Racer 34 is offline   Reply With Quote
Old 03-20-2010, 05:52 PM   #3
Tech Regular
 
Join Date: May 2009
Posts: 431
Trader Rating: 1 (100%+)
Default

im my experience, yes it can...just tune your top end first,dont even touch the bottom end. so do high speed passes till you feel its at race tune...then work on your bottom end so it idles good and the responsivness if right, still doing high speed passes to clear out the motor.
absolutemayhem is offline   Reply With Quote
Old 03-20-2010, 06:37 PM   #4
Tech Elite
 
Join Date: Mar 2009
Posts: 3,657
Trader Rating: 5 (100%+)
Default

thank you. I thought so. No one really talks about this. It seems like a major pitfall.

But then again, a too lean low end is better then a too lean top end.
__________________
"You are not understanding the fundamental principles of my fragmented personality"

Mugen
dreaux is offline   Reply With Quote
Old 03-20-2010, 07:37 PM   #5
Tech Master
 
chris c's Avatar
 
Join Date: Nov 2006
Location: So Cal Westminster
Posts: 1,155
Trader Rating: 60 (100%+)
Default

what you need to remember is that the high speed needle has control over all the fuel that goes into the motor....Think of it as a water valve the more open more water etc...
__________________
--------------------------------

If you can make it I can break it
chris c is offline   Reply With Quote
Old 03-20-2010, 08:00 PM   #6
Tech Elite
 
Join Date: Mar 2009
Posts: 3,657
Trader Rating: 5 (100%+)
Default

Quote:
Originally Posted by chris c View Post
what you need to remember is that the high speed needle has control over all the fuel that goes into the motor....Think of it as a water valve the more open more water etc...
it has the most control over the medium to high speeds. But if it is to rich on the high end, some will remain that won't get burned off and load the case.
thinking you have a rich low end. So you lean the low end until the low end is running off the residual fuel left over and if it sits long enough it will lean bog at take off. So i guess technically it is never really lean, just a really bad tune. And i guess if your low end
__________________
"You are not understanding the fundamental principles of my fragmented personality"

Mugen
dreaux is offline   Reply With Quote
Old 03-20-2010, 08:02 PM   #7
Tech Apprentice
 
mudslinger's Avatar
 
Join Date: Mar 2010
Posts: 96
Trader Rating: 2 (100%+)
Default

Absolutely it can happen. I think it's one of the more common tuning problems people run into. The water hose analogy is a pretty good one too. I use that one all the time.
mudslinger is offline   Reply With Quote
Old 03-20-2010, 08:02 PM   #8
Tech Elite
 
Join Date: Mar 2009
Posts: 3,657
Trader Rating: 5 (100%+)
Default

are you also saying the hsn gives the lsn the fuel it needs to work with?

so a lean hsn automatically makes a lean lsn??? a rich hsn gives the lsn more fuel to work with?
__________________
"You are not understanding the fundamental principles of my fragmented personality"

Mugen
dreaux is offline   Reply With Quote
Old 03-20-2010, 08:14 PM   #9
Tech Elite
 
Join Date: Mar 2009
Posts: 3,657
Trader Rating: 5 (100%+)
Default

Quote:
Originally Posted by mudslinger View Post
Absolutely it can happen. I think it's one of the more common tuning problems people run into. The water hose analogy is a pretty good one too. I use that one all the time.
to bad it's not in the "tuning bible".

This has been my tuning pitfall. I rarely if ever tune a lean high end and a too rich low end.

because i set my idle screw. I never tune my idle to the fuel mixture on my lsn.

But, if your hsn is to rich you can set your idle gap pretty small and lean the crap out your lsn and get a false idle.

This is what happens to me. Not the other way around.

Now I finally understand just about all the dynamics of tuning. I can be absolutley aware of the carburator balance.

the trick it seems is to tune the hsn first but you would have to do high speed passes and keeping your lsn out of the equasion and to get a acurate read on your hsn by not letting the case load at all.
__________________
"You are not understanding the fundamental principles of my fragmented personality"

Mugen
dreaux is offline   Reply With Quote
Old 03-20-2010, 08:18 PM   #10
Tech Elite
 
smokinu's Avatar
 
Join Date: Apr 2008
Location: MODESTO CA
Posts: 4,863
Trader Rating: 60 (98%+)
Default

Quote:
Originally Posted by dreaux View Post
are you also saying the hsn gives the lsn the fuel it needs to work with?

so a lean hsn automatically makes a lean lsn??? a rich hsn gives the lsn more fuel to work with?
the LSN and HSN are ALWAYS talking to each other and you need to tune them together... just one at a time.
__________________
Marcus P.
\\Speedzone USA//Savox USA\\Caster Racing Parts//
www.speedzoneusa.com. www.casterracingparts.com
smokinu is offline   Reply With Quote
Old 03-20-2010, 08:25 PM   #11
Tech Elite
 
Join Date: Mar 2009
Posts: 3,657
Trader Rating: 5 (100%+)
Default

Quote:
Originally Posted by smokinu View Post
the LSN and HSN are ALWAYS talking to each other and you need to tune them together... just one at a time.
i hear you. That is what i try to do and usually end up with a bad tune on top or bottom. I am not that good yet.

I did however whip my motor into a really good tune by going high to low. The only thing is, my high is to rich and my low is to lean. I can tell because if i blip it several times and it idles long enough it will race to a high idle.
__________________
"You are not understanding the fundamental principles of my fragmented personality"

Mugen

Last edited by dreaux; 03-20-2010 at 08:59 PM.
dreaux is offline   Reply With Quote
Old 03-20-2010, 08:44 PM   #12
Tech Apprentice
 
mudslinger's Avatar
 
Join Date: Mar 2010
Posts: 96
Trader Rating: 2 (100%+)
Default

I like to richen them way up until both needles are just pig rich. Then start from there. Lean the hsn until you get good smoke trails, and good top end performance. Then lean the lsn 1/16th at a time. It won't take much at all on the lsn. On the lsn you can use the pinch test to get it in the ball bark, then do a punch test to dial it in. Of course you have to start off with the idle gap set properly or as stated earlier the lsn will have to be off to compensate.
mudslinger is offline   Reply With Quote
Old 03-20-2010, 09:00 PM   #13
Tech Elite
 
Join Date: Mar 2009
Posts: 3,657
Trader Rating: 5 (100%+)
Default

yeah, but to even get started you have to have the lsn in the ballpark. Maybe outfield but still in the park somewhere.
__________________
"You are not understanding the fundamental principles of my fragmented personality"

Mugen
dreaux is offline   Reply With Quote
Old 03-20-2010, 09:36 PM   #14
Tech Regular
 
Join Date: May 2009
Posts: 431
Trader Rating: 1 (100%+)
Default

also set your idle gap....witch i belive is .5mm and LEAVE IT THERE....i your car wont idle check your lsn, it may be to rich .
absolutemayhem is offline   Reply With Quote
Old 03-21-2010, 01:30 AM   #15
Tech Elite
 
merdith6's Avatar
 
Join Date: Oct 2009
Location: Brazoria, TX
Posts: 2,350
Trader Rating: 3 (100%+)
Default What I see most...

At the track is others making the high speed needle too lean then making the bottom too fat. This causes way too many issues. I always fatten the top then lean the bottom then check to see if the idle drops after being warmed up and sitting at idle. If it drops then lean it more on the bottom. when it gets steady then adjust the idle a bit, only a bit. Then go drive it on the track and if it's slow then lean the top in small steps until it hauls butt. If you go past that then you will shorten the life of the engine.... Finally recheck the bottom end to make sure it has enough fuel at idle after driving it at race speed. If it idles fast it may need more fuel on the bottom. If it races then drops then your idle is off and you need to lower idle and lean the bottom to get it steady....The top is usually fine....Maybe a little lean but this is only one hour adjustment at this time. Hope this helps.
__________________
Mad Dog drives a Mugen MBX-7, Novarossi engines, Clockwork Racing, Futaba radio, AKA/Proline Tires
merdith6 is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
How To Break In ?????? MaTt 93 Nitro Off-Road 11 10-09-2007 01:44 PM
High speed needle setting on MR-12 ttektek Nitro On-Road 6 05-14-2003 12:49 PM
I am planning to Break in my MT12, Give me some tips Team_Akina_1 Nitro On-Road 24 03-06-2003 07:44 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 01:57 PM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net