tcv_racing

Ill be buying my HPI firestorm really soon and this will be my very first nitro RC..

I decided to just follow the three tank break-in technique in the manual..

-While breaking-in the engine do you have to let the engine rest(how long) after each tank of gas?

-How long does it take to finish 1 full tank of gas during break-in?

Extra question:
-What parts can you install to the stock HPI G3.0 engine to get more power? Is changing the stock carburator an option?

Thanks in advance!

losi13

Glad to see you going to nitro. I love the sound and smell you get from nitro. When I have broken in my nitro engines, I didn't let the engine cool down between tanks. All I did is just fill it up again. Now some people will say (depending on the engine of course) that 3 tanks is not enough fuel and you should run 5 tanks. Now it's been my experiance that 3 tanks is plenty good as long as you run it plenty rich. Now as your fuel consumption goes, your tank should last about 12-15 minutes during break-in. Now when you break in your new motor, you shouldn't run it hard but a mixture of low to mid throttle.

tcv_racing

Thanks so much for your reply!!! I've been posting these questions in other forums and no one gives a reply..
I'll keep everything in mind and also follow the users manual carefully..

ttoks

traxxas break in

find a nice flat area.

step, run the engine at 1/4 throttle in passes, roll on throttle, hold at 1/4 trottle for 2 seconds then relise and let the car caost to a stop, turn around and repeat until the first tank is empty, let the engine cool for 15 minutes, repeat then move onto step two

step two, similar to step one, but instead of holing at 1/4 throttle, hold at 1/2 throttle for two seconds, after the second tank is finished allow to cool for 15 minutes before starting 3ed tank, repeat then move onto step three.

step three, like step two, hold at 1/2 throttle, but hold for 3 seconds this time instead of two, after this tank you do not need to let the engine cool, repeat, then move onto step 4.

for steps 4 and 5 you need to find a fairly open area.

step 4, hold engine at full throttle for 3 seconds, then allow to coast, turn around and repeat until tank is empty, move onto step 5

step 5, hold at full throttle for 5 seconds, allow to coast, turn around, then repeat until tank is empty.

after this stop, and go over the car and make sure everything is still tight, after this take it easy for a gallon to allow everything to bed in properly.

uh...3 tanks it break in an engine? what materials are the engines you use made of? super conductive flux core iron-aluminum alloy? sorry i just couldn't resist lol, seriously 3 tanks is not enough for break in and everyone in a sane state of mind will tell you that, on low performance engines the traxxas break in method is always a viable option, but doing steps one two and three twice (as i've written above, the traxxas recommended method involve sonly one tank of fuel for each ste), and letting the engine cool when specified, then take it easy for a gallon of fuel to let everything bed in before you go all out with the tuning and full throttle drag races.

once you get bored with the stock engine, or it wares out and you replace it with a high performance one, then the traxxas method isn't going to be good enough either, once you get into high performance engines you want to be using a variation of the heat cycle method (there are millions of variation of the heat cycle, do a search and pick one you like the sound of), the initial break in using heat cycle takes around 6 tanks of fuel, plus another 10 tanks of running rich but not "heat cycling" (letting the engine cool between after running for a specified amount of time, say run for 3 minutes then let sit until the engine is at ambient temperature) but just refueling and keep running, after 16 tanks you run slightly rich and taking it easy for another 1/2 gallons to a gallon before going all out.

hrdcoreglf

ABC break-in in the car

Set the main needle according to the manufacturer's specifications (e.g., 2 to 3 turns counterclockwise from closed). Open the idle needle several turns so the engine shuts off when abruptly throttled back.
-Start the engine
-Advance the throttle to 1/2. Listen for 4-cycling. Lean the mixture to a rich two cycle operation.
-Run the car in a 100 foot diameter circle or figure 8. Keep the throttle at 1/2 and listen for 4-cycling. Don't let this happen! If it does, immediately lean the main fuel needle a little at a time until the engine produces a clean, steady 2-cycling sound. Run your car in a cicle/ figure 8 for about 1 minute. When the minute is up immediatly check the head temp.
Keep a log of run time, head temp, estimated rpm and your perfomance comments.
The goal is to keep the head temp. at above 200 degrees F. and less than approximately 230 degrees F. If the head temp. is less than 200 degrees F. lean the high speed needle slightly, and try again after the engine has completely cooled. When the engine stops, using the fly wheel turn the piston to BDC.
-Perform the 1 minute run at least three times while you adjust the head temp. by "tweaking" the needle valve as needed.
-Now run the car around for 2 minutes at least twice. Remember: 1/2 throttle and no four cycling. Same game : check head temp., allow it to cool, record data.
-Don't be tempted to open the throttle wide! The mixture settings will probably be all wrong for wide open throttle(WOT)(. There is plenty of time for that later.
-The rest of the 1/2 throttle break-in runs will be 3 minutes long. When they tottle 35 minutes(minimum), you have successfully heat-cycled your engine and break-in is properly complete. If you like you can run it another 10 minutes or so it won't hurt.
-Tune the engine for WOT and idle operation.
To read " Super Engine Tining" by Steve Pond go to ( rcnitro.com/artcles/index.asp )

Heat cycling for stress relief
Stress relief is accomplished by repeatedly heating and cooling the engine-short engine runs followed by complete cooling repeated many times. ABC engine break-in involves such heat cycles, betit is not the same proceedure as is used for non ABC engines.

ABC break-in the inside story
Abc engines require a shorter break-in (heat cycling) than engines of the past- less than 45 min. for most. To attain and maintain maximum power levels, however, requires adherence to an entirely new set of break-in rules.
The primary objective of ABC break-in is to maintain the delicate top of the piston pinch zone while allowing the internal engine components to heat cycle with some minor smoothing and allignment (crankpin, wristpin, rod journals, etc.).

Here is how this is achieved:
FUEL- Use the same fuel for break-in as you will for normal operation. If you break-in your engine with low nitromethane fuel, e.g., 5% and then jump to 20% for actual running, the piston / cylinder fit will be too loose. Five % nitro doesn't generate as high a combustion temp., so the cylinder won't expand as much, and the pinch zone will wear more than if the cylinder had pulled away farther, as it would with the hotter burning, higher nitro fuel.

2- vs. 4-cycling operation
If you run a 2-stroke engine then you have heard of 4-cycling. When a two stroke engine is operated very fuel-rich or at somewhere below 1/2 throttle, it begins to fire on alternate crankshaft revolution. As the mixture is richened at wide open throttle, the ehaust sounds like this as it breaks from 2-cycling to 4-cycling: " RRREEEAAAHHHHHHH."
As the throttle is reduced to about 1/2, the exaust sounds like this, as it breaks from 2-cycling to 4-cycling: "RRRRREEEEETAT-TAT-TAT-TAT."
With both examples comes a simotanios loss of rpm with the change in exuast sound. This is 4-cycling. Learn to avoidit. Because the ABC-type engines were originally designed as WOT racing engines, their pistons and cylinders operated happily. Today, ABC engines are also expected to idle and throttle reliably. Unfortunatly this allows them to cool excessively, especially below 1/2 throttle, where poor cylinder scavenging (clearing) causes them to 4-cycle and wear away the critical pinch zone as the piston sleeve cools and tightens around the piston
Throttling is a necessary phase of running nitro engines in cars, so you can't simply eliminate it from your routine, but do not allow the engine to 4-cycle during break-in. Afterward, when engine components have been stess-relieved and bedded in through heat-cycling, the wearing effect of 4-cycling will be minimized.

Tight ABC piston/cylinder assemblies
Some new Abc-type engines are so tight at TDC that for the first few times the engine is cranked over and run, the possibility exist of damaging the connecting rod, crankpin, and piston. To avoid this, preheat the cylinder and the head with a heat gun or a hair dryer. This preheating expands the piston sleeve, and that minimizes the potential for stress on all the engine components during initial startup.