R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 12-05-2008, 03:53 PM   #16
Tech Fanatic
 
Join Date: Aug 2008
Posts: 850
Trader Rating: 42 (100%+)
Default

Quote:
Originally Posted by losi_racer View Post
i never have understood this and i wont follow it because its backwards. If its hotter outside they say you should lean it out. When its hot you need more oil to cool the engine down and vise versa for cold weather


Interesting.... I disagree. Actually, this is really backwards. An engine needs more fuel on a cold day. Since the air is denser, the engine needs more fuel to find the optimal fuel/air ratio. The air is denser and so it will need more fuel to operate well.
I really think you are just pulling a forum prank here. Otherwise, let us know how this works out for you.
__________________
On-point/ EA horsey power/XFactory / Hudy / Tekin / Trinity / KO Propo / Reino's Ragu
mracer is offline   Reply With Quote
Old 12-05-2008, 03:54 PM   #17
Tech Adept
 
kanai kid's Avatar
 
Join Date: Feb 2005
Location: USA
Posts: 204
Send a message via AIM to kanai kid
Default

Being that I am from the midwest, we see a wide variety of temperatures and race in all of them. In the summer, it can reach upwards of 100 degrees and in the winter months can get below zero. I think the main thing is to keep the engine tuned to the temp that you are running in. I also believe that pre-heating the engine is a great thing to do.
kanai kid is offline   Reply With Quote
Old 12-05-2008, 04:14 PM   #18
Tech Addict
 
Steve Walters's Avatar
 
Join Date: Oct 2006
Posts: 662
Trader Rating: 1 (100%+)
Default

losi_racer,

You can believe, and tune how you think its best for your motor to achieve maximum performance/lifespan. But your philosophy on how motors should be tuned for atmospheric change is wrong, but there your motor's. Best of luck....
__________________
"CVR" Central Valley Raceway (Madera, CA)
Team "WTF" Racing member
TEAM BCE (Product/Field Tester)

X-Ray 808 (Active Diff)
BCE 8X8 Pro Chassis
OS Speed (XCustoms Head Mod)
Hitec 5995TG (S&T)
M11 & Spectrum.
Steve Walters is offline   Reply With Quote
Old 12-05-2008, 05:35 PM   #19
Tech Elite
 
easyryder's Avatar
 
Join Date: Apr 2006
Location: Tucson,AZ
Posts: 2,543
Trader Rating: 1 (100%+)
Default

Engines are simple little beast, Humans are complicated little beasts!!
Tune for performance not temps!!
The more you goof with the needles the more your engine goofs with you
Try to keep it simple!!

Thats my best advise
__________________
XRAY XB9. Rubber tires with foam inside and super glue to keep them on. Cheap, but fast radio, high dollar servos, savox, mostly.
Cheap .21 engine. Modern starter box, finally!
easyryder is offline   Reply With Quote
Old 12-05-2008, 06:05 PM   #20
Tech Lord
 
Join Date: Jul 2008
Location: Houston, TX
Posts: 11,530
Trader Rating: 21 (100%+)
Default

Quote:
Originally Posted by hobdog View Post
Let's put this to rest. I keep on hearing it is tough on a engine to run in cold outside temps (30*-50*f). I am having a hard time buying this unless you are unable to get the engine to reach its good running temp. I heat my engines up before starting them, and my running temps seem to always get up to 220*. I run snowmobiles all winter and those are two strokes, why would it not be hard on them and hard on nitro engines? I am just curious to some ideas, I got a great os speed that I am running and I am getting a bit worried about hurting it.
Somehow this seems to have turned into tuning for hot and cold temps. Def need to know what to do for ambient temp changes, but what's bad about running a nitro engine in the cold is if the engine can't get to some minimum operating temp so piston/sleeve expand enough, the rod is getting hammered, slamming into a tight pinch all the time since P/S haven't expanded proper amount.

I ususlly see 200F quoted as minimum temp for running. At some ambient temps thats hard to maintain - this is where you use something like tin foil to block cooling air so the engine can keep the heat and stay above this minimum temp. Even if you're tuned perfectly, running at 155F is going to load the rod excessively and cause premature wear to the pinch zone. Even if you're preheating to start, if you can't maintain that min temp while running, you're wearing parts prematurely, pinch will disappear quickly.

Two stroke engines (motorcycles, snowmobiles) have less taper in the piston/cylinder fit and use rings, not pinch, to provide seal. This is why they don't have probs running at low temps given that they're tuned correctly.
Duster_360 is offline   Reply With Quote
Old 12-05-2008, 06:16 PM   #21
Tech Elite
 
easyryder's Avatar
 
Join Date: Apr 2006
Location: Tucson,AZ
Posts: 2,543
Trader Rating: 1 (100%+)
Default

SSSSSSSSSSSHHHHHHHHHHHHHHHHHH
__________________
XRAY XB9. Rubber tires with foam inside and super glue to keep them on. Cheap, but fast radio, high dollar servos, savox, mostly.
Cheap .21 engine. Modern starter box, finally!
easyryder is offline   Reply With Quote
Old 12-05-2008, 06:35 PM   #22
Tech Champion
 
JAMMINKRAZY's Avatar
 
Join Date: Jun 2007
Location: Pittsburgh PA
Posts: 6,575
Trader Rating: 17 (100%+)
Default

sssssssssuuuuuuuuuuxxxxxxxxxx JK lol
__________________
-Koby Kubrin-
Thanks to my Sponsors:
Serpent America | Team Novarossi | Desoto Racing | Race AKA | Ridgeway Bodies
JAMMINKRAZY is offline   Reply With Quote
Old 12-05-2008, 07:03 PM   #23
Tech Elite
 
easyryder's Avatar
 
Join Date: Apr 2006
Location: Tucson,AZ
Posts: 2,543
Trader Rating: 1 (100%+)
Default

I own nitro off road!!!!!!!! Toninte!
__________________
XRAY XB9. Rubber tires with foam inside and super glue to keep them on. Cheap, but fast radio, high dollar servos, savox, mostly.
Cheap .21 engine. Modern starter box, finally!
easyryder is offline   Reply With Quote
Old 12-05-2008, 07:07 PM   #24
Tech Elite
 
easyryder's Avatar
 
Join Date: Apr 2006
Location: Tucson,AZ
Posts: 2,543
Trader Rating: 1 (100%+)
Default

TEAM WTF!!!!!
__________________
XRAY XB9. Rubber tires with foam inside and super glue to keep them on. Cheap, but fast radio, high dollar servos, savox, mostly.
Cheap .21 engine. Modern starter box, finally!
easyryder is offline   Reply With Quote
Old 12-05-2008, 07:19 PM   #25
Tech Rookie
 
Join Date: Apr 2008
Location: Cooper City, FL
Posts: 5
Trader Rating: 2 (100%+)
Default

Quote:
Originally Posted by losi_racer View Post
ok well i live in az, when it gets colder i have to lean my buggy out. When it gets hotter i have to richen it. So i guess i live in a universe where things make sense
This post made me look for the IGNORE feature.
Bernowt is offline   Reply With Quote
Old 12-05-2008, 09:30 PM   #26
Tech Regular
 
Join Date: Sep 2008
Location: Cullman, AL
Posts: 271
Trader Rating: 7 (100%+)
Default

Quote:
Originally Posted by Duster_360 View Post
Somehow this seems to have turned into tuning for hot and cold temps. Def need to know what to do for ambient temp changes, but what's bad about running a nitro engine in the cold is if the engine can't get to some minimum operating temp so piston/sleeve expand enough, the rod is getting hammered, slamming into a tight pinch all the time since P/S haven't expanded proper amount.

I ususlly see 200F quoted as minimum temp for running. At some ambient temps thats hard to maintain - this is where you use something like tin foil to block cooling air so the engine can keep the heat and stay above this minimum temp. Even if you're tuned perfectly, running at 155F is going to load the rod excessively and cause premature wear to the pinch zone. Even if you're preheating to start, if you can't maintain that min temp while running, you're wearing parts prematurely, pinch will disappear quickly.

Two stroke engines (motorcycles, snowmobiles) have less taper in the piston/cylinder fit and use rings, not pinch, to provide seal. This is why they don't have probs running at low temps given that they're tuned correctly.
Great post!
__________________
Jarad Henderson
Caster Racing parts plus crpplus.com
Team Finish Line Racing
x195svt is offline   Reply With Quote
Old 12-05-2008, 10:25 PM   #27
Tech Master
 
rpm1968's Avatar
 
Join Date: Oct 2008
Location: Bend, OR
Posts: 1,449
Trader Rating: 18 (100%+)
Default

you really stirred up some sh*t Hoby!

Let's just drive tomorrow and mull it over a few beers?
rpm1968 is offline   Reply With Quote
Old 12-06-2008, 07:37 AM   #28
Tech Addict
 
EBMods's Avatar
 
Join Date: Aug 2003
Location: PA
Posts: 504
Default

Quote:
Originally Posted by Steve Walters View Post
Itís a simple fact: for optimum performance, you must retune your nitro engine every time you run it. Anyone who assumes that the needles can be left alone once they have been set is sadly mistaken. An overnight change in weather conditions may prevent an engine from running or may put it at risk of some damage if adjustments arenít made to the fuel-mixture settings. Ignoring an engineís tuning needs compromises its ability to make horsepower. In response to certain changes in weather, equipment and other variables, nitro engines must be regularly retuned.

Temperature. Hot weather requires a leaner mixture setting; cold weather requires a richer setting. Most people assume the opposite because they treat the mixture needle like a thermostat. It is wrong to assume that colder weather requires a leaner setting to keep heat in the engine and vice versa. Cold air is denser than hot air. The denser, colder air packs more oxygen into the engine, so going from hot weather to cold needs a commensurate increase of fuel to balance ratio of fuel-burning oxygen and the fuel itself. The opposite is true in hotter weather. Going from cold to hot weather requires a leaner mixture setting.

Humidity. Humidity is the amount of moisture (water vapor) in the air. Moisture in the air takes up volume that would otherwise be occupied by fuel-burning oxygen. Less oxygen means less fuel is required to maintain a proper ratio of air and fuel. High humidity requires a leaner mixture setting than dry conditions.

Barometric pressure. A barometer measures the atmospheric pressure (generally listed in the local newspaper or on the local weather forecast on TV). Higher barometric pressure readings mean more air is getting into the engine, requiring a richer mixture setting to balance the air/fuel ratio.

Altitude. Altitude is an important factor that most of us ignore, yet it affects the engineís performance possibly more than any other element. The general formula for power loss with increases in altitude is 3 percent for every 1,000 feet above sea level. If you race in Colorado at 5,000 feet instead of in California at sea level, you can expect to lose about 15 percent of the engineís potential power output, if the engine is tuned properly.
Air is thinner at higher altitudes, which means thereís less fuel-burning oxygen than at sea level. You might sense a common theme here: less air (oxygen) means less fuel to maintain the proper air/fuel ratio. So, running at higher altitudes requires a leaner mixture setting than running at sea level.

TUNING
This chart indicates the direction in which you should adjust the fuel mixture when faced with changing weather and other conditions. It assumes the engine is currently well tuned. You could face any combination of conditions listed in the chart; knowing which way to go with the mixture adjustments is half the battle.

Higher air temperature Lean
Lower air temperature Rich
Higher humidity Lean
Lower humidity Rich
Higher barometric pressure Rich
Lower barometric pressure Lean
Higher altitude Lean
Lower altitude Rich
Higher nitro content Rich
Lower nitro content Lean
Higher oil content Lean
Lower oil content Rich
Hotter glow plug Rich
Colder glow plug Lean
Quote:
Originally Posted by Duster_360 View Post
Somehow this seems to have turned into tuning for hot and cold temps. Def need to know what to do for ambient temp changes, but what's bad about running a nitro engine in the cold is if the engine can't get to some minimum operating temp so piston/sleeve expand enough, the rod is getting hammered, slamming into a tight pinch all the time since P/S haven't expanded proper amount.

I ususlly see 200F quoted as minimum temp for running. At some ambient temps thats hard to maintain - this is where you use something like tin foil to block cooling air so the engine can keep the heat and stay above this minimum temp. Even if you're tuned perfectly, running at 155F is going to load the rod excessively and cause premature wear to the pinch zone. Even if you're preheating to start, if you can't maintain that min temp while running, you're wearing parts prematurely, pinch will disappear quickly.

Two stroke engines (motorcycles, snowmobiles) have less taper in the piston/cylinder fit and use rings, not pinch, to provide seal. This is why they don't have probs running at low temps given that they're tuned correctly.

These two post are dead on.........
EBMods is offline   Reply With Quote
Old 12-06-2008, 07:46 AM   #29
Tech Adept
 
sp2thielen's Avatar
 
Join Date: Dec 2006
Location: Council Tuckey, IA
Posts: 192
Trader Rating: 2 (100%+)
Send a message via MSN to sp2thielen
Default

how can you argue with that!!!!!! im pretty sure Ed knows a thing or two about engines. lol
__________________
IMPULSE RC when only the very best will do!!!!
Hobbytown Hobbyplex
Kyosho SP2/ Medial Pro
Kyosho ST-RR/ Medial Pro
sp2thielen is offline   Reply With Quote
Old 12-06-2008, 09:38 AM   #30
Tech Master
 
DavidR's Avatar
R/C Tech Elite Subscriber
 
Join Date: Jun 2008
Location: Lake of the Ozarks, Mo
Posts: 1,669
Trader Rating: 97 (100%+)
Send a message via Yahoo to DavidR
Default

OMG! Thanks Ed!

If that isn't proof enough that one if the industries premier engine modders is agreeing with the concensus then nothing is!!
DavidR is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Go-Tech Engines Thread MassiveMods Offroad Nitro Engine Forum 15106 06-26-2017 04:07 AM
Ninja Engine by GRP ogreasurada Offroad Nitro Engine Forum 1526 09-16-2013 07:13 PM
Palmaris engine thread EdwardN Onroad Nitro Engine Zone 2533 08-12-2013 10:48 AM
Serpent 710 Ron C. Nitro On-Road 23347 03-16-2010 01:47 PM
GOOD FUEL scarlet Nitro On-Road 147 03-10-2007 08:41 AM
Ninja MR21B01 Carb settings? xlgraphicspro Electric Off-Road 13 07-30-2006 06:00 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 10:38 AM.


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