21 beta

[Jeff Barnes]

I see hobby supplies is offering a new 21 beta does anyone know if it's worth the extra money thanks for any input Jeff Barnes

 

[RaceMechaniX]

You mean the Beta with the GPX tuning kit. I arguable how much of a gain there is, but an experienced tuner can likely squeeze out a little more.

 

[Jeff Barnes]

Yah that one I'm no motor guy thank you Tyler for your input Jeff Barnes

 

[RaceMechaniX]

The standard Beta is an excellent motor as is. Just clean up the ports and chrome flashing, set the deck height for the fuel you run and it will run well right out of the box. If the GPX sleeve comes with a small volume head button for high nitro this is a worthwhile swap. Of course you can find an engine builder to make you a custom head button for the motor with the right volume and your choice of standard or turbo plug.

 

[Buckshot]

From my in boat testing, the stock GPX revs better than the stock Beta Evo.

 

[Bradley Maglinger]

The standard Beta is an excellent motor as is. Just clean up the ports and chrome flashing, set the deck height for the fuel you run and it will run well right out of the box. If the GPX sleeve comes with a small volume head button for high nitro this is a worthwhile swap. Of course you can find an engine builder to make you a custom head button for the motor with the right volume and your choice of standard or turbo plug.

Who do you suggest to make head buttons?

 

[mark ham]

From my in boat testing, the stock GPX revs better than the stock Beta Evo.

how does the CMB compare to Al's 21?

 

[Jeff Barnes]

I'm no motor guy is there anybody out there that sets up new 21 betas for heat racing and 50 percent nitro

 

[Buckshot]

how does the CMB compare to Al's 21?

K21 has more TQ and still revs. (I will be replacing all my CMB .21’s w/K-21’s when they are available).

I'm no motor guy is there anybody out there that sets up new 21 betas for heat racing and 50 percent nitro

No need for a motor guy, set the head clearance (.008”-.010”) and go race.

 

[mark ham]

K21 has more TQ and still revs. (I will be replacing all my CMB .21’s w/K-21’s when they are available).

No need for a motor guy, set the head clearance (.008”-.010”) and go race.

thank you, i plan on doing the same with my 21 and 45.

 

[Jeff Barnes]

Me to when there available

 

[Bill Gibson]

**** war........just sucks for everyone. Id like to purchase a motor also.

 

[Bill Gibson]

**** war........just sucks for everyone. Id like to purchase a motor also.

 

[Jeff Barnes]

I here yah Bill

 

[David Ashcroft]

I'm no motor guy is there anybody out there that sets up new 21 betas for heat racing and 50 percent nitro

Like buckshot said 008" and a bowl volume 17-19cc

 

[Zimmerman]

You might want to re-consider a bowl volume of 17-19 cc. Last I checked the total displacement of a 21 is 3.5cc.

 

[David Ashcroft]

You might want to re-consider a bowl volume of 17-19 cc. Last I checked the total displacement of a 21 is 3.5cc.

Those bowl cc measurements will work fine

 

[Zimmerman]

OK

 

[David Ashcroft]

I have a custom made head button for my Nova.28 .
Bowl volume .23cc runs very well on 65% 0.008"

 

[Mark Anderson]

David, I believe you meant .17 to .19cc. Not the 17-19cc as you typed and Zimmerman was pointing out.