Go Back  R/C Tech Forums > General Forums > Monster Trucks
Tuning Redcat Earthquake 3.5 >

Tuning Redcat Earthquake 3.5

Tuning Redcat Earthquake 3.5

Old 09-19-2018, 07:53 PM
  #1  
Tech Rookie
Thread Starter
 
Join Date: Sep 2018
Posts: 3
Cool Tuning Redcat Earthquake 3.5

First off, forgive me if there is another post like this. Second, forgive me because I am new.
This is my second nitro vehicle the other one I have I was able to tune pretty easy and but this truck has been the death of me.

This is what I did today for tuning the truck. Note, I was on pavement when doing the tuning and all testing.
I reset the truck back to factory settings. Tightening both the LSN and HSN till it couldn't go any further down and then opened them up three rotations. Had the carb 1mm and slowly opened it up more till the car could start. I had some car run away but nothing to crazy. I warmed the car up by doing 10 minutes or so of figure 8's which the car did on its own without me accelerating too much. After that I tuned the HSN at first, I was leaning it out, but performance kept getting worse and the car kept dying. So, I placed it HSN back to factory settings and I had to richen it out a little more, so it would stop bogging down. I noticed when I was trying to tune the car sometimes, it would just quite when idling, yes, I did have breaks engage, yes, I know that is not good for the car, but it is the best that I could do for now. Anyways, I opened the carb slightly more yes it did move a little faster on its own, but it stopped dying on me. I stopped changing the HSN after it was how I wanted it.

1) My first question is, would this been an issue with LSN being too rich, from what i have read so far that a rich LSN can cause the car to die on idle but IDK if that is just when you start the car or if that counts all the time.

2) My Second question is, why does the carb need to be open to 1mm? Now, I know all engines are not the same, some might be needing the opening slightly more or less but how do I know I have the right amount of opening? I know if it is closed or just about close the car won’t start because of no air. I also know if it is too far open it will "run away" but how do I know if it is just right?

I played with the LSN and carb opening to try to fix the car running way and when I was accelerating the car from 0 to half parshall the car was bogged down. I ended up doing more damaged then good, so I reset that back to factory again and had to stop because it was getting dark and I was getting frustrated.

3) My third question is when I was adjusting both LSN and the carb opening, I had it to a point where the car would start but it would die a few seconds later even when I had the glow plug igniter on the glow plug. So, I opened the carb a little more and that fixed that issue. But was that really an LSN issue being extremely rich?

4) My last question is how do I know have the carb open enough that it doesn't run away and know the LSN is not to lean that it is getting the speed from there?

I thank you to anyone who reads this and can pass any knowledge my way.

mmurphy is offline  
Old 09-19-2018, 09:47 PM
  #2  
Tech Addict
iTrader: (1)
 
Join Date: Dec 2016
Posts: 589
Trader Rating: 1 (100%+)
Default

Make sure your endpoints are perfect. Carb should slam completely shut when you release the trigger and should not move when you squeeze the brakes. Make sure throttle slide doesn't open past the carb inlet when at wide open throttle. Then set idle gap to .5mm without the venturi. After that, lean the LSN until you can get it to at least idle then start doing high speed passes to set the HSN. Once you get the HSN to where there's no performance gain. Back off the high speed an hour or two. Do a pass and bring the car in and let it idle. If it maintains a high idle, back off the LSN an hour. If it doesn't maintain idle lean the LSN an hour and do another pass and repeat the same process until you can bring the car in after a high speed pass and it immediately drops to idle then completely lays down after about 6-8 seconds. It should have a steady lope to it with an audible miss. If you lean the LSN and it gets to the point where it starts to lean bog, back off until you're able to accelerate hard without it being too rich or too lean. Once you get it there and it still doesn't maintain idle, turn the idle screw an hour or less clockwise until you can get the idle low and consistent without it dying. .8mm is probably the max you would want your idle gap to be. The longer it sits the more it should load up with fuel to the point where it should stall out after a considerable amount of time. The longer you can get it to idle the better of course.

Last edited by Cardiak; 09-19-2018 at 11:41 PM.
Cardiak is offline  
Old 09-19-2018, 10:49 PM
  #3  
Tech Addict
iTrader: (1)
 
Join Date: Dec 2016
Posts: 589
Trader Rating: 1 (100%+)
Default

Also, is all of your equipment new? Make sure there's no leaks in the fuel line or tank.
Cardiak is offline  
Old 09-20-2018, 08:24 AM
  #4  
Tech Rookie
Thread Starter
 
Join Date: Sep 2018
Posts: 3
Default

Originally Posted by Cardiak View Post
Make sure your endpoints are perfect. Carb should slam completely shut when you release the trigger and should not move when you squeeze the brakes. Make sure throttle slide doesn't open past the carb inlet when at wide open throttle. Then set idle gap to .5mm without the venturi. After that, lean the LSN until you can get it to at least idle then start doing high speed passes to set the HSN. Once you get the HSN to where there's no performance gain. Back off the high speed an hour or two. Do a pass and bring the car in and let it idle. If it maintains a high idle, back off the LSN an hour. If it doesn't maintain idle lean the LSN an hour and do another pass and repeat the same process until you can bring the car in after a high speed pass and it immediately drops to idle then completely lays down after about 6-8 seconds. It should have a steady lope to it with an audible miss. If you lean the LSN and it gets to the point where it starts to lean bog, back off until you're able to accelerate hard without it being too rich or too lean. Once you get it there and it still doesn't maintain idle, turn the idle screw an hour or less clockwise until you can get the idle low and consistent without it dying. .8mm is probably the max you would want your idle gap to be. The longer it sits the more it should load up with fuel to the point where it should stall out after a considerable amount of time. The longer you can get it to idle the better of course.
The car does not move at all then i squeeze the breaks. What do you mean by "Make sure the throttle slide doesn't move past the carb inlet when wide open" I just looked at my car and i did notice when i have about 90% down on the trigger the carb is fully open and when I go to 100% down the carb still opens but past the part that I can see. Does that mean i have to adjust that? What is a venturi?
mmurphy is offline  
Old 09-20-2018, 08:24 AM
  #5  
Tech Rookie
Thread Starter
 
Join Date: Sep 2018
Posts: 3
Default

Originally Posted by Cardiak View Post
Also, is all of your equipment new? Make sure there's no leaks in the fuel line or tank.
Yes it is.
mmurphy is offline  
Old 09-20-2018, 12:40 PM
  #6  
Tech Addict
iTrader: (1)
 
Join Date: Dec 2016
Posts: 589
Trader Rating: 1 (100%+)
Default

Originally Posted by mmurphy View Post
The car does not move at all then i squeeze the breaks. What do you mean by "Make sure the throttle slide doesn't move past the carb inlet when wide open" I just looked at my car and i did notice when i have about 90% down on the trigger the carb is fully open and when I go to 100% down the carb still opens but past the part that I can see. Does that mean i have to adjust that? What is a venturi?
A venturi is the restrictor that sits inside the carb intake to limit air flow but your engine may not have one. And yes, your carb shouldn't open past what you can see. Go ahead and set your throttle end point so that the throttle slide isn't moving past the inlet. The wall of the slide should line up perfectly with the wall of the inlet when at 100% throttle input. Once you have that set, release the throttle and see if the throttle slide moves when you push on it. It should not move at all. Once you have that set, go ahead and recheck your idle gap to make sure it's at .5mm.

Last edited by Cardiak; 09-20-2018 at 12:51 PM.
Cardiak is offline  
Old 09-24-2018, 04:19 PM
  #7  
Tech Addict
iTrader: (1)
 
Join Date: Dec 2016
Posts: 589
Trader Rating: 1 (100%+)
Default

Did you ever get it tuned or did you give up lol?
Cardiak is offline  

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
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 On
Trackbacks are On
Pingbacks are On
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell or Share My Personal Information -

Copyright © 2023 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.