R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Nitro On-Road > Onroad Nitro Engine Zone

Reply
 
Thread Tools Search this Thread
Old 03-22-2014, 08:09 AM   #61
Tech Master
 
choisan's Avatar
 
Join Date: Jul 2004
Location: San Francisco Bay Area
Posts: 1,236
Default

how about the .21? need to shim .1 to run 25%? the other guy was running in the team machine in my city.
choisan is offline   Reply With Quote
Old 03-23-2014, 03:12 PM   #62
am
Tech Master
 
Join Date: Jul 2004
Location: Norway
Posts: 1,631
Default

Just a fyi.

I used to stop my offroad engies by plugging the exhaust. I used alot of glowplugs. I have now stopped doing it, stopping my engines on the flywheel insted. My glowplugs now last alot longer :-)
__________________
JConcepts
Kyosho MP9
KO PROPO
Top Elite distributor Norway
am is offline   Reply With Quote
Old 03-25-2014, 07:48 PM   #63
Tech Addict
 
Join Date: Jan 2010
Location: Hong Kong
Posts: 506
Default

Quote:
Originally Posted by dj apolaro View Post
With the testing we have done, you need to add a .1 shim to run 25%. It gives good power but can be sensitive to tune. Your temps will be lower than you are used to also. If you add .15, it will be safer and easier to tune and temps will be about the same as when you ran your 16%.

DJ Apolaro
How about the head clearance for .21 engine?
I've found out the 2 x 0.1mm and the under sleeve shim, the total head clearance around 0.58~0.62, there is lack of low end power.
__________________
GP: Capricorn C03 1/10 touring, Capricorn C803 1/8 onroad
Engine: Tesla .12 WC, Tesla .21 7 port on-road, Rody VS02, OS 2101
beebone is offline   Reply With Quote
Old 03-26-2014, 06:09 PM   #64
Tech Elite
 
dj apolaro's Avatar
 
Join Date: May 2005
Location: Miami, Fl.
Posts: 2,399
Default

Quote:
Originally Posted by beebone View Post
How about the head clearance for .21 engine?
I've found out the 2 x 0.1mm and the under sleeve shim, the total head clearance around 0.58~0.62, there is lack of low end power.

I have found that if you are running a good fuel, you can run .5 total clearance. Leave the shim under the sleeve and play with the shims under the button till you get the total clearance of .5

This will help with the low end torque.

DJ Apolaro
__________________
Capricorn RC, Capricorn Tires, Novarossi World, Spektrum, Horizon Hobby, PROTOform, RCTarget, IGT8.
dj apolaro is offline   Reply With Quote
Old 03-26-2014, 07:38 PM   #65
Tech Addict
 
Join Date: Jan 2010
Location: Hong Kong
Posts: 506
Default

Quote:
Originally Posted by dj apolaro View Post
I have found that if you are running a good fuel, you can run .5 total clearance. Leave the shim under the sleeve and play with the shims under the button till you get the total clearance of .5

This will help with the low end torque.

DJ Apolaro
Thanks! That's what I though about
__________________
GP: Capricorn C03 1/10 touring, Capricorn C803 1/8 onroad
Engine: Tesla .12 WC, Tesla .21 7 port on-road, Rody VS02, OS 2101
beebone is offline   Reply With Quote
Old 03-27-2014, 03:00 AM   #66
Tech Master
 
Join Date: Apr 2010
Posts: 1,098
Default

Quote:
Originally Posted by dj apolaro View Post
I have found that if you are running a good fuel, you can run .5 total clearance. Leave the shim under the sleeve and play with the shims under the button till you get the total clearance of .5

This will help with the low end torque.

DJ Apolaro
but will lost some top end
kyosho malaysia is offline   Reply With Quote
Old 03-27-2014, 06:19 AM   #67
Tech Elite
 
dj apolaro's Avatar
 
Join Date: May 2005
Location: Miami, Fl.
Posts: 2,399
Default

That is correct. But I can say with these motors, they have good top end and you will not notice much of a difference when you change the shim on the top. Unless you run on a very large track.

DJ Apolaro
__________________
Capricorn RC, Capricorn Tires, Novarossi World, Spektrum, Horizon Hobby, PROTOform, RCTarget, IGT8.
dj apolaro is offline   Reply With Quote
Old 03-27-2014, 10:32 AM   #68
Tech Master
 
Join Date: Apr 2010
Posts: 1,098
Default

Quote:
Originally Posted by dj apolaro View Post
That is correct. But I can say with these motors, they have good top end and you will not notice much of a difference when you change the shim on the top. Unless you run on a very large track.

DJ Apolaro
kyosho malaysia is offline   Reply With Quote
Old 04-09-2014, 08:57 AM   #69
Tech Addict
 
Join Date: Jan 2010
Location: Hong Kong
Posts: 506
Default

Quote:
Originally Posted by dj apolaro View Post
That is correct. But I can say with these motors, they have good top end and you will not notice much of a difference when you change the shim on the top. Unless you run on a very large track.

DJ Apolaro
Interesting thing was found. I did the soldiering test the head clearance is about 0.53, good figure . But the engine is lack of power, only the punchy feeling i can feel when exit.the corner, then no power at all. It was about 120C.

When I take away the shim under sleeve, and add 0.1 head shim to maintain the head clearance in 0.5. The overall power is back!!!! About 110C. But the punchy low end power is lower then with the under sleeve shim.

So, I know the under shim makes the port higher, but what does the higher port mean?
I wish to put the under.shim back to retrieve more low end power, but I don't know how to tune it to get back the mid and top end power. Any clue ?thx
__________________
GP: Capricorn C03 1/10 touring, Capricorn C803 1/8 onroad
Engine: Tesla .12 WC, Tesla .21 7 port on-road, Rody VS02, OS 2101
beebone is offline   Reply With Quote
Old 04-09-2014, 09:28 AM   #70
Tech Master
 
Join Date: Apr 2010
Posts: 1,098
Default

Quote:
Originally Posted by beebone View Post
Interesting thing was found. I did the soldiering test the head clearance is about 0.53, good figure . But the engine is lack of power, only the punchy feeling i can feel when exit.the corner, then no power at all. It was about 120C.

When I take away the shim under sleeve, and add 0.1 head shim to maintain the head clearance in 0.5. The overall power is back!!!! About 110C. But the punchy low end power is lower then with the under sleeve shim.

So, I know the under shim makes the port higher, but what does the higher port mean?
I wish to put the under.shim back to retrieve more low end power, but I don't know how to tune it to get back the mid and top end power. Any clue ?thx
the under shim is to raise the port to get faster discharge,at the same time intake also react the same,it will give you higher rpm but have to compromise with some fuel consumption and torque
kyosho malaysia is offline   Reply With Quote
Old 04-09-2014, 09:42 AM   #71
Tech Addict
 
Join Date: Jan 2010
Location: Hong Kong
Posts: 506
Default

Quote:
Originally Posted by kyosho malaysia View Post
the under shim is to raise the port to get faster discharge,at the same time intake also react the same,it will give you higher rpm but have to compromise with some fuel consumption and torque
Well, if the under shim acts as raising the charge and discharge actions, I understand the fuel consumption will be higher. So, if the charging action faster, does it mean the needles need a bit richer to feed enough fuel?
__________________
GP: Capricorn C03 1/10 touring, Capricorn C803 1/8 onroad
Engine: Tesla .12 WC, Tesla .21 7 port on-road, Rody VS02, OS 2101
beebone is offline   Reply With Quote
Old 04-09-2014, 04:15 PM   #72
afm
Tech Master
 
afm's Avatar
 
Join Date: Nov 2003
Location: lima-peru
Posts: 1,807
Default

Quote:
Originally Posted by beebone View Post
Interesting thing was found. I did the soldiering test the head clearance is about 0.53, good figure . But the engine is lack of power, only the punchy feeling i can feel when exit.the corner, then no power at all. It was about 120C.

When I take away the shim under sleeve, and add 0.1 head shim to maintain the head clearance in 0.5. The overall power is back!!!! About 110C. But the punchy low end power is lower then with the under sleeve shim.

So, I know the under shim makes the port higher, but what does the higher port mean?
I wish to put the under.shim back to retrieve more low end power, but I don't know how to tune it to get back the mid and top end power. Any clue ?thx
About Port Timing

Of course you know that when you place the undershim you will get a higher exhaust port, which will yield more rpmís, so more top end, and inversely lower exhaust will yield less rpmís, so more low end, but take into account that with the undershim you also move the transfer ports timing higher.

First of all we know that difference between transfer and exhaust duration needs to be at least 40 degrees so the tuned pipe works properly, then second thing you have to take to consideration is fuel consumption, higher transfer = more fuel will go, and some of it will not burn, then fuel consumption will go down.

In my opinion from what Iíve learned on RC cars motors is that .12 size transfer needs to be around 116-122 degrees. Everything over is going to hurt run time, everything lower will work against performance.

Just remember whatever you do, keep difference between transfer and exhaust 40 degrees at least.

Induction (crank opening) timing works like this: earlier opening = more low end . Later closing = more top end.
Also keep in mind that the greatest boost in power is gained by increasing total induction duration, and increasing inner diameter of passage in crankshaft.
With respect to head clearance:
Small chamber = Advanced ignition = Colder plug = More torque
Bigger chamber = Retarded ignition = Hotter plug = More top end
Plugs alone, with same chamber will give you: Hot plug = more top end. Cold Plug = more low end

So there is no special formula, itís just more up to trials. You see on our RC cars application specially on .12 motors we need some torque, some RPM, and fuel mileage.

Hope this helps
AFM
afm is offline   Reply With Quote
Old 04-10-2014, 05:17 AM   #73
Tech Master
 
Join Date: Apr 2010
Posts: 1,098
Default

Quote:
Originally Posted by afm View Post

Plugs alone, with same chamber will give you: Hot plug = more top end. Cold Plug = more low end
AFM

as i know for small track we use hotter plug to gain more torque,maybe i'm wrong
kyosho malaysia is offline   Reply With Quote
Old 04-10-2014, 05:23 AM   #74
Tech Master
 
Join Date: Apr 2010
Posts: 1,098
Default

Quote:
Originally Posted by beebone View Post
Well, if the under shim acts as raising the charge and discharge actions, I understand the fuel consumption will be higher. So, if the charging action faster, does it mean the needles need a bit richer to feed enough fuel?
usually i leaner LSN,richer the HSN compare to standard engine setting but i do mofidied the piston,crankshaft timing,crankcase,sleeve and button.
kyosho malaysia is offline   Reply With Quote
Old 04-10-2014, 05:47 AM   #75
Tech Addict
 
Join Date: Jan 2010
Location: Hong Kong
Posts: 506
Default

Quote:
Originally Posted by kyosho malaysia View Post
usually i leaner LSN,richer the HSN compare to standard engine setting but i do mofidied the piston,crankshaft timing,crankcase,sleeve and button.
I tried OS RP6, the power is back. Timing problem.
__________________
GP: Capricorn C03 1/10 touring, Capricorn C803 1/8 onroad
Engine: Tesla .12 WC, Tesla .21 7 port on-road, Rody VS02, OS 2101
beebone 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 08:24 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net