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Old 05-09-2008, 01:34 PM   #1
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Unhappy Help with a AXE mamba .21

Hi everybody on the forum this is my first post here and i'm in need of some help, i have a hyper8 pro with a AXE mamba .21 engine, i installed the turbo head. i just have finished the break in but after a 5 or 8 min of running the engine seems to stay accelerated at the point that when i do a jump and relase the throttle the engine keep accelerated all the jump, also when the car is running and i relase the throttle the car keeps going for about 2 seg and make take the turns a bit tricky. the iddle is ok. i checked the low speed needle but if i turn it rich a bit the acceleration feels slugish and i donīt know if l need to lean more, and for the high speed needle i think is ok, the temperature keeps around 260F its always blue smoke coming out the exhaust and if i turn it a 1/8 turn leaner the temp goes to 270 or 280F, so i donīt want to lean it more. The engine performace doesnīt feels right , it has a fine off line acceleration but after that feels a little slugish and sounds like is in the rich side, what should i look for?, i live in venezuela and we have here a very hot climate. any advise will help. thanks guys. iīm running with 20% nitro and a os p7 plug.
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Old 05-09-2008, 02:02 PM   #2
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Sounds like an air leak...could be Bearings,carb, or many other things.. also what shims are u running?
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Old 05-09-2008, 02:07 PM   #3
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First off, you have the wrong plug. You need a Axe Rossi, Novarossi or RB turbo #5 or #6 glowplug. Second, you may the idle open too much with a too rich LSN. Use the correct plug and try retuning.
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Old 05-09-2008, 02:15 PM   #4
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Quote:
Originally Posted by grivero View Post
Hi everybody on the forum this is my first post here and i'm in need of some help, i have a hyper8 pro with a AXE mamba .21 engine, i installed the turbo head. i just have finished the break in but after a 5 or 8 min of running the engine seems to stay accelerated at the point that when i do a jump and relase the throttle the engine keep accelerated all the jump, also when the car is running and i relase the throttle the car keeps going for about 2 seg and make take the turns a bit tricky. the iddle is ok. i checked the low speed needle but if i turn it rich a bit the acceleration feels slugish and i donīt know if l need to lean more, and for the high speed needle i think is ok, the temperature keeps around 260F its always blue smoke coming out the exhaust and if i turn it a 1/8 turn leaner the temp goes to 270 or 280F, so i donīt want to lean it more. The engine performace doesnīt feels right , it has a fine off line acceleration but after that feels a little slugish and sounds like is in the rich side, what should i look for?, i live in venezuela and we have here a very hot climate. any advise will help. thanks guys. iīm running with 20% nitro and a os p7 plug.
Still sounds like it needs more breakin. It usually takes about a full gallon to break this engine in. The temps will go down once it breaks in fully and the power will come up. This engine really loves the JP3 pipe too. Maybe try the P3 plug instead. The higher the humidity the hotter a plug you will need. On tuning the low speed pinch the fuel line at idle and see how long it take for the engine to change speed. If it is longer the 2 to 3 seconds it is too rich on the low speed.
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Old 05-09-2008, 02:16 PM   #5
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Yea the Axe or Nova Rossi plugs would be better.
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Old 05-09-2008, 02:25 PM   #6
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Quote:
Originally Posted by ezveedub View Post
First off, you have the wrong plug. You need a Axe Rossi, Novarossi or RB turbo #5 or #6 glowplug. Second, you may the idle open too much with a too rich LSN. Use the correct plug and try retuning.
What exactly happens to the engine when you open/close the idle needle?

I know the other needles let more/less gas flow, so is the idle with the air or something?
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Old 05-09-2008, 03:28 PM   #7
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Thanks for the replies, i have an AXE R6 plug so i will try to put this on and try lean the LSN. I put the original shim than came with the engine, i only take away the original head and put the turbo in. Is it really that hard this engine to break in?, so i would wait for the temp to drop down with every use i put on the engine?, thanks again.
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Old 05-09-2008, 04:00 PM   #8
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You need to leave the shims in.
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Old 05-09-2008, 05:28 PM   #9
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I check and it has two coopers shims between the crankcase and the turbo head
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Old 05-09-2008, 08:44 PM   #10
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YOu might want to try O'Donnel's 77 Plug. Try go back to factory settings.

Just a few Qs;

1. Does your car flameout during more than 1/3 throttle?
2. Does your car bog below 1/3 throttle?
3. What pipe are you using? (sorry if I missed out on this, I was too tempted to hit the reply button! My bad...)
4. How many times have you replaced your plugs? Your average plug life?

I'm speculating that you might be running too lean, and I don't think there's any air leak yet. Of course I could be wrong about this....

Last edited by razor_clawzz; 05-10-2008 at 08:57 AM.
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Old 05-09-2008, 08:47 PM   #11
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Originally Posted by new to rc cars View Post
What exactly happens to the engine when you open/close the idle needle?

I know the other needles let more/less gas flow, so is the idle with the air or something?
The idle gap coresponds to your LSN setting, and of course, basically lets your engine run at minimum RPM without dying out or engaging the clutch
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Old 05-10-2008, 04:34 PM   #12
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Quote:
Originally Posted by razor_clawzz View Post
YOu might want to try O'Donnel's 77 Plug. Try go back to factory settings.

Just a few Qs;

1. Does your car flameout during more than 1/3 throttle?
2. Does your car bog below 1/3 throttle?
3. What pipe are you using? (sorry if I missed out on this, I was too tempted to hit the reply button! My bad...)
4. How many times have you replaced your plugs? Your average plug life?

I'm speculating that you might be running too lean, and I don't think there's any air leak yet. Of course I could be wrong about this....
Hi, the car doesnīt flameout, i see blue smoke coming from the exhaust all the time, it sounds like itīs on the rich side but if i give 1/8 leaner the temp goes to +280F but there are still blue smoke comming from the exhaust so i donīt know if itīs safe to stay there, iīm not racing i just want the engine to perform better. the pipe iīm using came with the kit and says efra 2059. i donīt have changed any plug, the engine is brand new it has only about 6 or 7 tanks of use i put the os p7 during the breakin and iīm still using it. thanks for the interest. i feel that it bog below 1/3 throtttle to half throttle.
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Old 05-10-2008, 05:10 PM   #13
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Quote:
Originally Posted by razor_clawzz View Post
The idle gap coresponds to your LSN setting, and of course, basically lets your engine run at minimum RPM without dying out or engaging the clutch
dont mean to hijack the thread

so it controls gas flow?

my car kind of bogs out when I start it for the first time of the day and accelerate, am I running too rich or what? and I drove 5 or 6 tanks through it in a row with some friends yesterday, in a baseball diamond, so it was WOT like 80% of the time. end temp was only like 170F. im definately running too rich right? and I fooled around with my idle a lot, it wouldnt run, so I turned it like 1 turn, cant remember if it was CC or C, so im also thinking that thats offset.
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Old 05-10-2008, 05:13 PM   #14
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Quote:
Originally Posted by grivero View Post
Hi, the car doesnīt flameout, i see blue smoke coming from the exhaust all the time, it sounds like itīs on the rich side but if i give 1/8 leaner the temp goes to +280F but there are still blue smoke comming from the exhaust so i donīt know if itīs safe to stay there, iīm not racing i just want the engine to perform better. the pipe iīm using came with the kit and says efra 2059. i donīt have changed any plug, the engine is brand new it has only about 6 or 7 tanks of use i put the os p7 during the breakin and iīm still using it. thanks for the interest. i feel that it bog below 1/3 throtttle to half throttle.
damn thats hot, mine never goes above 220.

I find that my car bogs out too, It might be my clutch though.
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Old 05-10-2008, 08:50 PM   #15
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Quote:
Originally Posted by grivero View Post
Hi, the car doesnīt flameout, i see blue smoke coming from the exhaust all the time, it sounds like itīs on the rich side but if i give 1/8 leaner the temp goes to +280F but there are still blue smoke comming from the exhaust so i donīt know if itīs safe to stay there, iīm not racing i just want the engine to perform better. the pipe iīm using came with the kit and says efra 2059. i donīt have changed any plug, the engine is brand new it has only about 6 or 7 tanks of use i put the os p7 during the breakin and iīm still using it. thanks for the interest. i feel that it bog below 1/3 throtttle to half throttle.
Bro, I think let's ignore the amount of blue smoke rule. Right now if you wanna achieve a certain operating temp, go for that.

Remember, ignore the amount of smoke coming out at the time being.

Try HSN at Flush (3~3 1/2 turns out) and LSN at 4 1/2 out, Idle gap between 0.8~0.6mm. Tune from here, hoping to hear from you soon. Good luck! BTW I think it's best to always keep spare plugs

Hi new to rc cars

This is how I see my things: HSN influences the fuel flow, LSN influences the air flow. Oh yeah, simply put, idle is to allow enough air into the engine to keep it alive.

Please correct me if I'm wrong :S
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