boyesen powerwing

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At that price i would make one, if it even does anything
 
I've read some test on these powerwings, they are supposed to work, but the gain is a slight one, It is supposed to reduce turbulense and reduse lag in the gasflow by splitting the venturi, effectivly giving a bigbore carb the throttle response of a smallbore carb with the benefit of the gasflow of a big carb. but others say they are crap though, but I would try one.
 
hmm.....ya for a slight gain in power the are to expensive i think ill give it a miss
 
I've got a heap of these coming in next week, i'am guna try one when they are in.. Yes Price is very high i will let you know if it is worth any of it ;)
 
I put one in my yz450f and i could have spent the money on some thing else. Did not notice any power gain if there was one.
 
I remember seeing them in a Magazine Probably over a Year ago! and the reviews seemed pretty good! (used by the top races blah blah) and think there was a few tests , but i cant remember...
 
Dirtrider said:
I put one in my yz450f and i could have spent the money on some thing else. Did not notice any power gain if there was one.
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thanks bro that was the answer i was after.....

Hillz....are you using them in big bikes or pitties?
 
They split the air in two to turn the carb into something like a staged 2 barrel car carb .... The idea is to increase air velocity at part throttle opening to promote better bottom end torque and throttle response ....

But if you're the type who whops the throttle wide open on take off they'll do sweet FA ....

I'd make something similar up to test it (as others have stated) before forking out ....

Boyesen Engineering

Boyesen Power X-Wing - Hot Bike Magazine

There's some pics of 'em on this link :

Boyesen Engineering
 
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My be work on a 250f but i wasted my money on the 450 it has enough grunt down low as it does. And the 450 is not wide open all the time.
 
One thing's for sure .... They'll give Boyesons bank account a huge boost in spending power ... :p
 
Cactus Jack said:
One thing's for sure .... They'll give Boyesons bank account a huge boost in spending power ... :p
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oh yeah, if the racers use them, they must be good! the reason the racers claim they notice a difference is because boyeson pays them for saying just that, and thus the riders feel a difference in theire bank-accounts....

maybe as a last on-top-of-it-all mod this could give you an edge, after you've installed\performed every other possible mod to your bike.
 
ok well i only have a 250f and i do a lot of enduro racing and most of the time im in tight tracks so your not wide open alot of the time your more blipin the throttle on and off....so do ya reckon its gunna give me some more grunt down low cause i have a crf and its got heaps up top not so much down low and thats all im trying to improve....i wanna try and get a little bit of grunt like the rmz and kxf has down low
 
It's hard to get more low-end out of a 250F without throwing some money at it, a High-Compression piston would be your best and safest bet, a High-class exhaust could help also, but the gain would be to low to justify the price.
 
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The reason why increasing the intake velocity works to boost torque and throttle response is due to the fact that at low revs some of the intake charge gets pushed back out into the inlet port and it's called reversion or reverse flow .... reversion is worse at higher loads or under full throttle .... The pulse waves can reach the carb and cause the mixture to enrichen which causes bogging or simply ... loss of power ..... When intake velocity is kept high enough it exerts a ramming effect to help stop some of the charge from backing out .... As a result the cylinder holds more cc's so the engine makes more torque ....

In race motors with high overlap cams , reversion can get sooo bad that exhaust soot can form on the inlet port walls and in bad cases it can make it to the carb .... IF you have a black coating in your inlet port ... then you have reversion ....

If you over port a head or fit too big a carb and the engine makes a "whoooorlll' sound (usually heard thru the carb intake) when you give it full throttle and feels like it's holding back or it's not going like you feel it should ..... then you are experiencing the effects of reversion due to lowered intake velocity ...

intake reversion puzzle ? - Speed Talk
 
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One way to overcome this is to either make a carb spacer block or a longer manifold. The longer intake path makes for a higher gas speed and can neutralise the reversion but going to long can cause a lag effect similar to turbo lag
 
Custom said:
One way to overcome this is to either make a carb spacer block or a longer manifold. The longer intake path makes for a higher gas speed and can neutralise the reversion but going to long can cause a lag effect similar to turbo lag
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Spot on .... That's one of the main mods that were done to worked XR75's ... Anti reversion steps also help .... Going too long is similar to going too big in volume and causes hesitation or delayed reaction when you hit the throttle .... and also when you back off and throttle on again ....

I also meant to say something like fiddy@norway is saying .... an engine with a high overlap cam will suffer from reversion at low revs / high load like trail plonking .... a stepped header pipe or a pipe like the Power/Mega Bomb might help .... but the real problem is the lobe separation on the cam .... With YZF's (DOHC) you can move one of the cams over 1 tooth to give the same lobe separation as the WRF's for increased bottom end power but you lose some of the "hit" and peak power .... With a Unicam engine you could advance the cam to improve bottom end power but you'd have to check your piston to valve clearances....

Advancing Intake and Exhaust : This will provide the car with more bottom end power, and will decrease top end. Advancing both cam gears will move overlap earlier but will not increase it.

Retarding Intake and Exhaust : This will increase the top end, but will decrease low end. Retarding both cam gears will move the overlap later and but will not change the amount of overlap.

Advance Exhaust Only : This will help the top end, and it reduces overlap.

Retard Exhaust only : This will help the mid range power, very useful for cars with big turbos / big cams. By increasing overlap, It decreases lag significantly. Doing this will bring the boost on all at once. Very common DSM modification.

Advance Intake only : This will increase overlap and helps the bottom end and mid range power. This mod will bring the turbo on all at once, although isnt a very common mod for DSMS.
 
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