R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 07-30-2009, 12:46 AM   #1
Tech Initiate
 
lethalsassonic's Avatar
 
Join Date: Dec 2007
Location: Orange County, CA
Posts: 37
Trader Rating: 1 (100%+)
Default Question about why my tuning changes when I put the body on?

Hey guys, I'm running a Kyosho MP 777 with an OS .21 VG Motor. I like to tune my buggy with the body off so I can reach the needles easier, but when I put the body back on, the settings are slightly off. I have plenty of airflow, there are holes around the engine and where I refuel. I'm assuming the temperature rises though, and perhaps less air gets into the carb, so is the general solution for this just leaning out both needles by an hour before putting the body on? Is there a simple solution, or is this a case-by-case basis? Give me some opinions please. Thanks!
__________________
Cars: Tamiya TRF 417x, HPI Ken Block WR8, EREVO Brushless
Heli's: Blade 300x, Blade 130x, Blade mcpx BL
lethalsassonic is offline   Reply With Quote
Old 07-30-2009, 12:51 AM   #2
Tech Champion
 
losi_racer's Avatar
R/C Tech Elite Subscriber
 
Join Date: Nov 2008
Location: mesa,az
Posts: 6,470
Trader Rating: 25 (100%+)
Default

Quote:
Originally Posted by lethalsassonic View Post
Hey guys, I'm running a Kyosho MP 777 with an OS .21 VG Motor. I like to tune my buggy with the body off so I can reach the needles easier, but when I put the body back on, the settings are slightly off. I have plenty of airflow, there are holes around the engine and where I refuel. I'm assuming the temperature rises though, and perhaps less air gets into the carb, so is the general solution for this just leaning out both needles by an hour before putting the body on? Is there a simple solution, or is this a case-by-case basis? Give me some opinions please. Thanks!
whats going on? is it loading up? if so on top or down low
__________________

Byron Fuels/AKA Tires/Radiopost/TKO/Viper Rc/Dialed Inc/Empire Metal Product/Advantage Racing Products
losi_racer is offline   Reply With Quote
Old 07-30-2009, 01:28 AM   #3
Tech Regular
 
slumlord's Avatar
 
Join Date: Jun 2008
Location: Peoria, AZ
Posts: 455
Trader Rating: 10 (100%+)
Default

check to make sure your body isn't covering your exhaust pipe. I only say this because I have seen that before!
__________________
Jay Stuart #66
slumlord is offline   Reply With Quote
Old 07-30-2009, 01:38 AM   #4
Tech Initiate
 
lethalsassonic's Avatar
 
Join Date: Dec 2007
Location: Orange County, CA
Posts: 37
Trader Rating: 1 (100%+)
Default

The body is not doing anything to the muffler, and it's not pinching a fuel line, the tuning just changes when I put the body on. I feel the buggy struggles a bit at mid-throttle. Do u guys notice a difference running w/and w/out the body?
__________________
Cars: Tamiya TRF 417x, HPI Ken Block WR8, EREVO Brushless
Heli's: Blade 300x, Blade 130x, Blade mcpx BL
lethalsassonic is offline   Reply With Quote
Old 07-30-2009, 01:47 AM   #5
Tech Regular
 
cluffy1's Avatar
 
Join Date: Apr 2009
Location: blackwater, AUstralia
Posts: 482
Trader Rating: 6 (100%+)
Default

hay wat up

no i don't notice a differance

is the car just dieing as you are putting the body on or is it dieing as soon as you put the body on.

if it is dieing as you are putting the body on than it is probebly just ideling to long and has quite(keep the engine reved, every 10 secs just a quick tap)

if it is die as soon as you put the body on it could be cause the pipe is being blocked the air has been retricked or the air filter tube has been kinked. all will make the car stop.

if all else fails go back to stock settings and start again(with the body on) you may just have to change the tune while the car is off and then start it with the body on.

hope this helps
good luck
dane
__________________
go hard or go home
cluffy1 is offline   Reply With Quote
Old 07-30-2009, 07:55 AM   #6
Tech Elite
 
Join Date: Mar 2009
Location: Aurora, Colorado
Posts: 3,644
Default

Do you have a clean air filter, I have seen theis case before and the air filter was dirty and was not pulling enough air when the body is on

other than that how are you tuning - are you waiting for it to warm up first or just starting and tuning

and how is the tune changing. what is it doing
__________________
TLR - Spektrum - Horizon - TLR 8ight 4.0 - TLR 8ight-T 4.0 - TLR 22 4.0 - Orion
token is offline   Reply With Quote
Old 07-30-2009, 09:07 AM   #7
Tech Initiate
 
lethalsassonic's Avatar
 
Join Date: Dec 2007
Location: Orange County, CA
Posts: 37
Trader Rating: 1 (100%+)
Default

Quote:
Originally Posted by cluffy1 View Post

is the car just dieing as you are putting the body on or is it dieing as soon as you put the body on.

if it is dieing as you are putting the body on than it is probebly just ideling to long and has quite(keep the engine reved, every 10 secs just a quick tap)

if it is die as soon as you put the body on it could be cause the pipe is being blocked the air has been retricked or the air filter tube has been kinked. all will make the car stop.
It doesn't die as soon as I put the body on, it idles fine, that's not the problem at all, the problem is the tuning is just a bit off when I run it.


Quote:
Originally Posted by token View Post
Do you have a clean air filter, I have seen theis case before and the air filter was dirty and was not pulling enough air when the body is on

other than that how are you tuning - are you waiting for it to warm up first or just starting and tuning

and how is the tune changing. what is it doing
I always clean the airfilter and then oil it before using the buggy, and if the air filter is nasty I replace it. The exhaust is not blocked at all, it's not that, I warm up the car and measure the temperature before tuning, I know all the basics and follow the book, the buggy just loses a little at mid throttle and top end when I put the body on, does that indicate it's too rich? I'm going to the track Sunday so I want a little gameplan first so I'm not tuning all day long!
__________________
Cars: Tamiya TRF 417x, HPI Ken Block WR8, EREVO Brushless
Heli's: Blade 300x, Blade 130x, Blade mcpx BL
lethalsassonic is offline   Reply With Quote
Old 07-30-2009, 11:27 AM   #8
Tech Addict
 
Join Date: Nov 2008
Location: tallahassee, FL
Posts: 695
Trader Rating: 29 (100%+)
Default

what temps is the motor running at?
__________________
kyosho mp9:novarossi 21-4C, nova 2084, 7955TG, dx3R
slayyer is offline   Reply With Quote
Old 07-30-2009, 12:12 PM   #9
Tech Initiate
 
lethalsassonic's Avatar
 
Join Date: Dec 2007
Location: Orange County, CA
Posts: 37
Trader Rating: 1 (100%+)
Default

Quote:
Originally Posted by slayyer View Post
what temps is the motor running at?
It seems to run on the hot side, like 250-290 degrees.
__________________
Cars: Tamiya TRF 417x, HPI Ken Block WR8, EREVO Brushless
Heli's: Blade 300x, Blade 130x, Blade mcpx BL
lethalsassonic is offline   Reply With Quote
Old 07-30-2009, 12:45 PM   #10
Tech Elite
 
Join Date: Mar 2009
Location: Aurora, Colorado
Posts: 3,644
Default

Quote:
Originally Posted by lethalsassonic View Post
It seems to run on the hot side, like 250-290 degrees.
your to lean -

I know you go by the "book" but what i would do, is reset the needles to the factory settings and retune
__________________
TLR - Spektrum - Horizon - TLR 8ight 4.0 - TLR 8ight-T 4.0 - TLR 22 4.0 - Orion
token is offline   Reply With Quote
Old 07-30-2009, 01:27 PM   #11
Tech Master
 
pyromania's Avatar
 
Join Date: Feb 2009
Location: North Hills, CA
Posts: 1,283
Trader Rating: 18 (100%+)
Default

I know for a fact that the VG has a small cooling head, and sometimes the body covers the whole cooling head or leaves very little sticking out. That maybe part of your problem. You may also have the engine a bit lean.
__________________
Jesse Carrillo
Team Driver For:
TLR | Horizon Hobby | Nitrotane | Spektrum | HandleITHobbies | 818 Designs
pyromania is offline   Reply With Quote
Old 07-30-2009, 03:18 PM   #12
Tech Master
 
jrwoodchuck's Avatar
 
Join Date: Nov 2007
Location: Northampton, Massachusettes
Posts: 1,336
Default

you will have more airflow to the engine with the body off, so if you think about it, the body will slow the airflow around the engine and it will get hotter. i would try riching the engine up 1 hour from ware you tuned it without the body. for this reason i always tune with the body on, then dremel hole in the body so can get to the high speed screw.
__________________
Doug
TLR 22/M-11

Looks like I picked the wrong week to quit sniffing glue.
jrwoodchuck is offline   Reply With Quote
Old 07-30-2009, 04:24 PM   #13
Tech Addict
 
RETRO RC's Avatar
 
Join Date: Jan 2007
Location: AUCKLAND NEW ZEALAND
Posts: 715
Default

Quote:
Originally Posted by lethalsassonic View Post
I always clean the airfilter and then oil it before using the buggy, and if the air filter is nasty I replace it.
Dude NEVER EVER clean and reuse air filters all your doing is pushing the fine particles further into the filter. the price of a new filter is far cheaper than risking the price of a new engine.

also like it has been said before it sounds like the body is just reducing air flow
resulting in overheating.
__________________
Agama A8 EVO 11 spec/ Argus A52 .21
Agama A8T / Argus A52 .23

offroaders get more jumps and like it rougher!
RETRO RC is offline   Reply With Quote
Old 07-30-2009, 04:35 PM   #14
Tech Elite
 
Zerodefect's Avatar
 
Join Date: Apr 2008
Location: Underground, Ohio
Posts: 4,305
Default

I had that problem to. My needles were set too far apart. Something like I was way off, too rich on the high end and I compensated by accidentally running the low end too lean and vise versa.

If i screwed it up bad enough, the car would run ok, but was sensitive to everything especially the body being off or on.

I reset to factory and retuned, this time with a less heavy hand on the needles. With the right tune it went away give or take 20 degrees.
Zerodefect is offline   Reply With Quote
Old 07-30-2009, 08:44 PM   #15
Tech Initiate
 
lethalsassonic's Avatar
 
Join Date: Dec 2007
Location: Orange County, CA
Posts: 37
Trader Rating: 1 (100%+)
Default

Quote:
Originally Posted by RETRO RC View Post
Dude NEVER EVER clean and reuse air filters all your doing is pushing the fine particles further into the filter. the price of a new filter is far cheaper than risking the price of a new engine.

also like it has been said before it sounds like the body is just reducing air flow
resulting in overheating.
Wow, I didn't know that about air filters, I'm gonna toss em when they get dirty now!
__________________
Cars: Tamiya TRF 417x, HPI Ken Block WR8, EREVO Brushless
Heli's: Blade 300x, Blade 130x, Blade mcpx BL
lethalsassonic is offline   Reply With Quote
Reply



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 08:00 AM.


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