Power Now vs Rb mod divider plate

BucKat

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Mar 27, 2002
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Now before everyone bites my head off.......I know the RB mod is more than just a divider plate....and I do understand how both plates work differently from each other.......however....


Power Now has the divider plate on the air box side while the RB mod carb has it on the cylinder side.
Power Now claims to increase velocity by reducing turbulances while the RB Mod reduces effective volume and thus increases velocity.

Which is better if only the plate was installed?
Would there be a benifit to having both??


Please answer then shoot. :laugh:

Buc
 
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CaptainObvious

Formally known as RV6Junkie
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The PowerNow divider will rob you of both performance and your money!
 

BucKat

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Mar 27, 2002
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Originally posted by RV6junkie
The PowerNow divider will rob you of both performance and your money!


You know this...... or you know OF this?
 

CaptainObvious

Formally known as RV6Junkie
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It's basic physics (Bernoulli theory in practice). Adding the PowerNow device effectively reduces the area of the venturi in the throttle. By reducing the area of the throttle bore you will gain pressure at low speed velocities, but at the expense of total fluid flow at WOT. There is no free lunch when it comes to making power.

In short, it’s snake oil.
 

BucKat

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Mar 27, 2002
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Ah Bernoulli strikes again.....

I understand the principle and the trade-off..

I have an extra 35mm carb to strap onto my 220..Thought I'd experiment prior...
35mm with a divider is still better than 32mm without.

Perhaps I install both and see. ( homemade of course )

Buc
 

GreenPeace

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Dec 6, 2002
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Power now claims to work as follows:
http://www.worldpowerracing.com/howitworks.html
I think their theory is just back wards as air is not blown or forced into the mouth of the carb.
It is drawn through the slide from the engine side, so I think that their
little pictures are back wards. The turbulence isn't a factor on the air
cleaner side of the carb. The turbulence happen after it passes the slide on
the engine side.

The whole point of the RB mod carb plate is reducing the volume of the carb up to 1/2 throttle (making a smaller carb which is more throttle responsive at lower throttle settings).
This in turn make the low speed circuitry more sensitive and responsive at the lower throttle settings (better throttle control)

The RB mod plate installation is also cheaper than the power now, they bore your carb and install a plate for about the same price as the power now..

The power now also puts a reducer restriction in the intake bell of the carb.
 

BucKat

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Mar 27, 2002
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Hmmmm,,,yes,,,,,wonderful.All this info is great.
Now can someone out there answer question #2?
Is there anything to gain from installing both.... if the bore was increased to offset the obstruction.?

Thanks
Buc
 

jmics19067

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Jan 22, 2002
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I was toying around with an idea of using both with a power jet also. In My mind theoretically it would be similar to a progressive multi barrel carb like on a car. small intake and carb at less than 1/2 throttle, large carb/intake over half throttle.

2 things that bother me though are, that by adding a flat plate leading up to and coming out of the center of the venturi you are ruining the shape of the venturi. It shouldn't matter much under 1/2 throttle since your slide is ruining the venturi shape"I think" but I would have no clue on the losses at open throttle. Also if at slightly above 1/2 throttle would some type of wierd eddie form that would try and push down the jet instead of drawing up from it.

Just some random thoughts.
 

Johnnyboy

Member
Aug 25, 2001
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I would say that people have it, it makes power, and people love it. If it negates the venturi effect then so what? It still makes more power. I'm getting it this winter. Nuff said.
-John
 

kmccune

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Jul 3, 1999
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Thats because the 220 is the one that most people bore out( because of the 32mm carb) You can send in your 200 carb as well. They are great guys, drop them a line with you questions. I got a 35mm carab at that online auction site and and havining it bored and plated + cool air screw this winter.
 

kmccune

2-Strokes forever
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Jul 3, 1999
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OZKX250 said:
Don't they have a 33mm carb ??

Yup your right, sorry the 2 is right next to the 3 on the keyboard :ohmy:
 

nmilne

Member
May 30, 2005
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Well, its a little hard for me to 'RB it' since they are on the other side of the planet :) Hence why I am interested in whether the powernow works well. Should do, the theory is fine.

But the pics I've seen of the home made jiggers look pretty good, so maybe that's worth a try, just cut a couple of slots in the venturi, bit of flat alloy and away you go...

...then hose it up and start scowering e-bay for a replacement carb :laugh:
 

OZKX250

Member
Aug 26, 2005
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I'm in Sydney and have both the RB head and carb. Absolutely totally worth it IMHO. Power difference is amazing to say the least. Shipping isn't bad if you know who/how to send stuff. Email me at tinytrev<at>hotmail<dot>com for more info if needed. I also have a spare stock 35mm if you want a guinea pig.
 
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