Nitro engine with a mind of its own. Need help?
08-26-2014, 12:31 PM
#26
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Where are you ;located ? the HPI fuel in Noth America is likely different then HPI in Europe.....I just considered this
So basically what I have found is that too much oil makes tuning difficult... So hence I say the more oil, the harder it is to tune
Higher the nitro the more reactive the fuel..which means the richer the fuel can be run and still burn clean
High oil does not protect that well if the engines are tuned in..as the higher oil requires a leaner mixture to burn clean...cancelling out the benefits of higher oil..as well increasing the rist of detonation.
A race fuel has a lower amount of higher grade oil as opposed to a bash fuel that has a higher quantity of lower grade oil....
Every brand is different, not all race fuels are good....however fuel is not something to overlook..the running and tuning differences between the products can be vast..with some fuel barely able to run, and others running so well the engines nearly tune themselves....... Fuel is huge and unfortunately the market is flooded with bad fuels that end up creating all sorts of crazy tuning headaches for nitro enthusiasts
So basically what I have found is that too much oil makes tuning difficult... So hence I say the more oil, the harder it is to tune
Higher the nitro the more reactive the fuel..which means the richer the fuel can be run and still burn clean
High oil does not protect that well if the engines are tuned in..as the higher oil requires a leaner mixture to burn clean...cancelling out the benefits of higher oil..as well increasing the rist of detonation.
A race fuel has a lower amount of higher grade oil as opposed to a bash fuel that has a higher quantity of lower grade oil....
Every brand is different, not all race fuels are good....however fuel is not something to overlook..the running and tuning differences between the products can be vast..with some fuel barely able to run, and others running so well the engines nearly tune themselves....... Fuel is huge and unfortunately the market is flooded with bad fuels that end up creating all sorts of crazy tuning headaches for nitro enthusiasts
Here most of the supplies come from eBay since we have only one local hobby shop and its specialised in aircrafts (as far as I am aware).
Most fuel that is available is either Optifuel Optimix RTR, Model Technics Zzip (and others), Tornado RTR and Byron Race Gen2.
Other brands are also flashing from time to time, but rarely.
This is how (my) HPI/Optifuel looks like
08-28-2014, 11:30 AM
#27
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I have been up to a lot for the last few days sorry for not posting much here for a some time.
Ive got all the parts I ordered, it wasnt an easy bolt on fit unfortunetly.
The upgrade flywheel was 2mm longer than the original stock tamiya flywheel, and that lead to a problem.
The clutch bell is not a clutch pinion design but a dogbone design, therefore there was 2mm of excess which if I forced it in would create huge amount of stress on the gears, central diff housing and binding. I had to grind the crank case mouting holes so I could shift the whole engine 1.5 mm backwards. Of course I tried other ways around but it was the only way possible (I was kinda crying when I was grinding away haha), but the engine will be replaced soon anyway. Other part was that I had to add a washer to space out the clutch bell from the clutch shoes, used a 1.0mm steel wire which was perfectly shaped for the diameter of the shaft, not a permanent solution but it will do the job. It was a very time consuming DIY job tho.
Now to the performance.
The new alu flywheel is 19g instead of steel 30g, the engines is sooo much better with the RPM acceleration, much better. The shoe springs are 1.0mm and they are decent to do the job.
Super clean acceleration when the engine is hot (250°F) but when at or lower 200°F it just starts to bog down to idle if you press throttle fully.
It works at 40-50% throttle alright-ish, but its weird. No matter the low needle settings, at "lower" temps it bogs down at full throttle when accelerating.
The slipper was tightened and worked just alright.
Noticed that if the tank is less than 50% filled with fuel, it starts to lean out the tuning. No leaks or nothing, the tuning is also tiny bit rich.
Little bit f*cked up that Tamiya (and other brands too) make cars so only original parts will fit. Change clutch or other garbage and you have a permanent pain in the arse, in my case its either getting aftermarket slideable engine mounts or grinding away the original engine mounts on the crank case.
Little bothered with boging down when engine is colder than 200°F and full throttle from stationary.
Ive got all the parts I ordered, it wasnt an easy bolt on fit unfortunetly.
The upgrade flywheel was 2mm longer than the original stock tamiya flywheel, and that lead to a problem.
The clutch bell is not a clutch pinion design but a dogbone design, therefore there was 2mm of excess which if I forced it in would create huge amount of stress on the gears, central diff housing and binding. I had to grind the crank case mouting holes so I could shift the whole engine 1.5 mm backwards. Of course I tried other ways around but it was the only way possible (I was kinda crying when I was grinding away haha), but the engine will be replaced soon anyway. Other part was that I had to add a washer to space out the clutch bell from the clutch shoes, used a 1.0mm steel wire which was perfectly shaped for the diameter of the shaft, not a permanent solution but it will do the job. It was a very time consuming DIY job tho.
Now to the performance.
The new alu flywheel is 19g instead of steel 30g, the engines is sooo much better with the RPM acceleration, much better. The shoe springs are 1.0mm and they are decent to do the job.
Super clean acceleration when the engine is hot (250°F) but when at or lower 200°F it just starts to bog down to idle if you press throttle fully.
It works at 40-50% throttle alright-ish, but its weird. No matter the low needle settings, at "lower" temps it bogs down at full throttle when accelerating.
The slipper was tightened and worked just alright.
Noticed that if the tank is less than 50% filled with fuel, it starts to lean out the tuning. No leaks or nothing, the tuning is also tiny bit rich.
Little bit f*cked up that Tamiya (and other brands too) make cars so only original parts will fit. Change clutch or other garbage and you have a permanent pain in the arse, in my case its either getting aftermarket slideable engine mounts or grinding away the original engine mounts on the crank case.
Little bothered with boging down when engine is colder than 200°F and full throttle from stationary.
08-28-2014, 01:39 PM
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I finished all 5 nights 20/20/20/20 and it was suuuuuuper hard.
Anyway, if you want I can post pics (of the kit and mods I did today)!
Last edited by Marciatelli; 08-28-2014 at 01:51 PM.
