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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)

Danny Teh 06-02-2012 05:03 AM

it doesn't matter if the needle loose/hard. as long as the engine idle means there's nothing wrong with the carb.......

firecat 06-02-2012 07:31 AM

ran alpha 2081 pipe in 8t 2.0 8mm res 4 alum long wear shoes/gold springs great bottom and top ran against an os speed was just as fast at 1/3 the price 9 min run time easy gallon and1/2 thru it

Danny Teh 06-02-2012 08:01 AM

Yeap I agree.

The Arrow have insane top end. As the bore of the crankshaft is bigger than any OS crankshaft. That explained why it is fast in the long straight.
But softer in the low end. Nevertheless it is still enough. The Arrows have smooth power band transition all over from low to high.

Mark Erce 06-03-2012 05:01 PM


Originally Posted by Danny Teh (Post 10810070)
Yeap I agree.

The Arrow have insane top end. As the bore of the crankshaft is bigger than any OS crankshaft. That explained why it is fast in the long straight.
But softer in the low end. Nevertheless it is still enough. The Arrows have smooth power band transition all over from low to high.

i thought the vzb and the arrow have interchangeable parts? so if I put a arrow crank in the OS will it work? also will the Arrow P/S/R work in a OS VZB?

Danny Teh 06-04-2012 01:41 AM

Sorry to have confused you.

The crank OD is the same but the ID of the shaft is different.
Timing is different as it is bigger
Therefore you might find the low end not your cup of tea.
But top end will be awesome with endless power.

Arrow can fit into a vzb. vzb is obselette now.
But Arrow have its own feature and performance.

The Arrow's low end can be compensated with low end initiate pipe.
Most here prefer the OS 2060 though.
A little softer in the low end but easy to drive thus making less mistakes.

bigjayjay1 06-04-2012 08:20 AM

Still no feedback on the modded Arrow from the factory.

alvinsmith75 06-04-2012 08:34 AM

I'm right at the end of my second gallon thru my Arrow and have not seen any carb. issues. In the past when I had needles backing out I just used a little blue loctite. Motor has been awesome so far as is.

Hobby Pro USA 06-04-2012 09:37 AM

My first GTR-21 lasted 11 months with no carb issues. All I did was replace the o-rings with OS/Bullit o-rings.

My current engine flames some times so maybe the carb has a problem. Some people have no issues and others say the carb is junk so I guess there are some good ones and some bad ones.

I am not sure what the issue is, maybe some have a bad mid range or low speed needle or possibly an air leak some where.

Make sure you put a zip tie around the carb boot so there is no leak there. And check the boot for holes because they tare easily like the OS boots do.

stallen50 06-04-2012 03:52 PM

The mid range needles are off . they need too be at 2 o'clock. this is my findings. i messed around with the arrows alot and i found that the mid range needle is a lil off

Rsickles 06-04-2012 09:41 PM


Originally Posted by Danny Teh (Post 10816487)
The crank OD is the same but the ID of the shaft is different.
Timing is different as it is bigger

Sorry, I'm confused how timing would be different over the standard VZ? The crank cheek looks identical. Will have to breakout the caliper and see if the actual bore is larger, but I do not understand how that would change timing.

Hobby Pro USA 06-04-2012 10:24 PM


Originally Posted by stallen50 (Post 10819421)
The mid range needles are off . they need too be at 2 o'clock. this is my findings. i messed around with the arrows alot and i found that the mid range needle is a lil off

What do you mean by off? You mean out of the box? If so, then yes they don't pre set it. I always set mine to 2 o'clock before I start it. The mid range hole needs to be lined up with the high speed needle, same as on an os carb.

stallen50 06-05-2012 04:20 AM


Originally Posted by Hobby Pro USA (Post 10821079)
What do you mean by off? You mean out of the box? If so, then yes they don't pre set it. I always set mine to 2 o'clock before I start it. The mid range hole needs to be lined up with the high speed needle, same as on an os carb.

Yes out of the box.

Hobby Pro USA 06-05-2012 05:41 AM


Originally Posted by stallen50 (Post 10821627)
Yes out of the box.

Yep, at the factory they just put all 3 needles in until flush. They don't set them to where they should be.


High - 2.5 out
Low - flush 2 o'clock
Mid - flush 2 o'clock
Idle - 1mm gap

Do this before starting break in.

Danny Teh 06-05-2012 09:48 AM

Rsickles,

Get a caliper. The Vzb std and speed crank are different with Arrow's in terms of the crank ID and opening area.

Thats explain the Arrow's awesome top end.
If possible, try running both crank. You will feel the difference.
Arrow is much faster.

BrakeTurnAccelerate 06-05-2012 02:57 PM

DP.


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