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-   -   Arrow Racing GTR .21 Engine Thread (https://www.rctech.net/forum/offroad-nitro-engine-forum/461596-arrow-racing-gtr-21-engine-thread.html)

Rsickles 04-22-2012 05:54 PM


Originally Posted by Jaz240 (Post 10638219)
halfway through it when my throttle servo died..I must have heated that to 300 degrees also

:lol::lol:


Originally Posted by Jaz240 (Post 10638219)
installing new servo now and will continue break in tuesday. Hoping to get about 10 tanks through it by Saturday and then race it Saturday night. I went with the Nova 9901 pipe to start with

I heat cycled about 12, or so, [150cc] tanks on an average break-in and it was good enough to put a fairly aggressive tune on for the first race. No fear! :deathstar

alvinsmith75 04-22-2012 07:02 PM

Great info here-subscribed :nod:

pcage 04-22-2012 11:56 PM


Hi,
Whats a good pipe to run with the Arrow?
OS 2060. Seems to have good runtimes.
But the low end seem a little weaker than most pipes.
It smoothens out the power from low to high. But some of my pals didn't like it.
I compensated with Ascendacy clutch which helps.
Uses 6.5 mm venturi and have about 11 mins in one tank full.

twitch_1 04-23-2012 03:27 AM


Originally Posted by Taffyjnr5 (Post 10636471)
Hi,
Whats a good pipe to run with the Arrow?

Hey Buddy a good pipe for this i've found are hong nor 2047 for bottom end ae 2035 for all round good bottom and top and hong nor 2080 for runtime and smooth power band which is the one i use on mine...

Jaz240 04-24-2012 07:26 PM

I got almost a quart of fuel through the engine today in very small increments. Break in of this engine is every bit the PITA that everyone said it was :rolleyes:

A few things I noticed that will hopefully help others..

It is redonkoulously tight..you have to preheat it good in order to fire it and also in order to keep it running...try to keep the heat away from the carb and the servo's :D..If you overheat it the fuel will vaporize in the carb and if you underheat it it will lock up on you repeatedly which is bad for the Con-rod. (220-240 is optimum)

This is one of the few engines that is actually very sensitive to your break in tune. I had a bitch of a time finding the sweet spot to keep it running and also to make sure it was getting proper lubrication. I must have flamed out about 100 times during the 6 tanks I put through it today...If your tune is too rich it loads up and dies, but the kicker is that its very small adjustments to the lean side or else it will instantly go lean because of the high pinch and heat.

The idle is all over the place during break in and I had to re-tune it pretty much every half a tank of fuel...the more pinch it lost the more it had to be adjusted to stay running, obviously the LSN needed tuning with the idle, but you all know that already.

Double check factory needle settings! Mine were out from flush about 1 mm on both of the main needles and was so fat it would not turn over. Set both needles right about flush and then adjust your idle from there. It ran great at times with the idle about .75 and I had to fluctuate the idle between 1mm open and .50 open depending on the tune required to keep it running.

The more fuel you put through it the more it needs to be tuned properly to stay running. Keep an eye on temps of both the engine and the carb..dont drop below 200 and dont exceed 250 if you can.

Remember that the key is just to get fuel through it, so dont get frustrated. It is a bit of a pain but should all be worth it in the long run...

Crash Test Dumy 04-24-2012 08:13 PM

Great Engine!!

My engine dropped it's nuts this weekend and really woke up! This is the smoothest engine I've owned.
I used a JP-4 for the break-in, cause it always seemed like a fuel hog. I've got a Werks 2013 I'm gonna try this weekend and see how it differs.
Love this engine!!
Hey James you've got a PM.
Thanks
Brian

pcage 04-24-2012 09:03 PM

anyone running this engine in the silver state ? how did it go ?

stallen50 04-25-2012 04:24 AM

2013 pipe on the arrow is pretty awesome but its very agressive on bottom like we all know. but run times are pretty good if your smooth on the trigger.

Mark Erce 04-25-2012 05:38 AM


Originally Posted by Jaz240 (Post 10648518)
I got almost a quart of fuel through the engine today in very small increments. Break in of this engine is every bit the PITA that everyone said it was :rolleyes:

A few things I noticed that will hopefully help others..

It is redonkoulously tight..you have to preheat it good in order to fire it and also in order to keep it running...try to keep the heat away from the carb and the servo's :D..If you overheat it the fuel will vaporize in the carb and if you underheat it it will lock up on you repeatedly which is bad for the Con-rod. (220-240 is optimum)

This is one of the few engines that is actually very sensitive to your break in tune. I had a bitch of a time finding the sweet spot to keep it running and also to make sure it was getting proper lubrication. I must have flamed out about 100 times during the 6 tanks I put through it today...If your tune is too rich it loads up and dies, but the kicker is that its very small adjustments to the lean side or else it will instantly go lean because of the high pinch and heat.

The idle is all over the place during break in and I had to re-tune it pretty much every half a tank of fuel...the more pinch it lost the more it had to be adjusted to stay running, obviously the LSN needed tuning with the idle, but you all know that already.

Double check factory needle settings! Mine were out from flush about 1 mm on both of the main needles and was so fat it would not turn over. Set both needles right about flush and then adjust your idle from there. It ran great at times with the idle about .75 and I had to fluctuate the idle between 1mm open and .50 open depending on the tune required to keep it running.

The more fuel you put through it the more it needs to be tuned properly to stay running. Keep an eye on temps of both the engine and the carb..dont drop below 200 and dont exceed 250 if you can.

Remember that the key is just to get fuel through it, so dont get frustrated. It is a bit of a pain but should all be worth it in the long run...

or do what I did and have Lance from RcRenew break it in for ya.....the $50 is more of a convenience fee the way I look at it :lol:

Crash Test Dumy 04-25-2012 05:39 AM


Originally Posted by stallen50 (Post 10649826)
2013 pipe on the arrow is pretty awesome but its very agressive on bottom like we all know. but run times are pretty good if your smooth on the trigger.

I wish I was more smooth on the trigger!:o I think this engine will make me better at that, I've had to dial in some expo to the throttle because the engine is so responsive. I think I'll try a smaller venturi, to experiment.
I'm running this in a MBX6-T and I was keeping up with the buggys. I'm looking forward to competing with this engine. So much so that I just ordered two more. I wish I could afford even more.
Looks like the consensus at the moment, for pipes, is a 2080. I have a Werks 2057 and might try that this weekend also just to compare. I can't spend the $$ for a new pipe just yet.:cry::cry:
Thanks
Brian

Jaz240 04-25-2012 08:19 AM


Originally Posted by Mark Erce (Post 10649997)
or do what I did and have Lance from RcRenew break it in for ya.....the $50 is more of a convenience fee the way I look at it :lol:

I will probably do that next time. I needed to Expierience everything about this engine for myself first hand. The reports are all great from other racers I wanted to get a good handle on things from start to finish to help me be better informed. Right now it's at the 1 quart mark and no where near ready for racing. I'm pretty sure after another quart it will be track worthy with a safe tune. I'm using VP powermaster golden break in blend and a nova 9901 pipe. I am not going to open or service this engine at all. I want to see how long it goes with all original parts. I will remove the break in shim when metal pinch is gone.

bigjayjay1 04-25-2012 08:56 PM

Thinkimg about picking up a few of these is it really that bad would you say worst motor you've broken in?

ForwardBite 04-25-2012 10:16 PM

This procedure would make the break in less painful and a lot quicker! Wouldn't have to worry about idle and tune as much either.

http://www.rctech.net/forum/onroad-n...rocedures.html

Jaz240 04-25-2012 10:21 PM


Originally Posted by bigjayjay1 (Post 10653675)
Thinkimg about picking up a few of these is it really that bad would you say worst motor you've broken in?

Not worst but definately most pinch ever. It really needs to be babied for the first 10 tanks or so and needs lots of attention at least that has been my Expierience, but it's not fair to give an overall opinion yet because it's still in the "bitch" stage. This may turn out to be the perfect buggy engine and the price is unbeatable. I'm getting reports from customers of 8+ gallons on all original parts also. I should have it on the track on 5/12 for a really good testing with almost a gallon of fuel through it at that point.

rfleck 04-26-2012 12:14 PM

The break in was pretty lengthy. I just put a comp heat on it and then had it idling blubbery flat trying to keep the temps in the 240-260 range for a quart.

Afterwards, I begun running mine on the track and keeping above 220. Run it that way unitl you reach 3/4 gallon, then start putting a race tune on it, and remove extra shim at 1 gallon.


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