Super Jet Light Weight Couplers: How much difference?

[swapmeet]

I did a search but couldn't find the answer I was looking for.
After installing a set of light weight couplers, is the performance increase noticeable? It would seem like taking 3/4 of a pound out of the rotating assembly would be useful... but how much? Obviously this is a 'seat of the pants' measurement more than anything else.

Just debating if its a worth while investment. Considering the Epic Couplers.

 

[raytherace]

IMO if you bought an aftermarket coupler for performance increase its a big mistake. I use billet coupler in our BOB built only because its cheaper to buy aftermarket instead of OEM yami.

 

[Tyler Zane]

Its a small piece of the entire puzzle, and not one of the first things i would do.

 

[Joker]

Make it one of the last things you get.

 

[O2VW1.8T]

I like the smaller design, i have the cold fusion and you wont feel a difference but every tiny bit adds up plus they are stronger.

 

[Matt_E]

There are a couple of good reasons for those couplers:

- stronger
- smaller diameter will throw less water from the bilge back up into the bilge area

A gain in power is very unlikely once you consider just how much rotating mass there is to the entire driveline - flywheel, crank webs, driveshaft, impeller. Taking a little bit off the coupler likely will not be noticeable. (in a non-biased test)

 

[swapmeet]

Thanks everyone. Not what i expected everyone to say, so I appreciate the feedback!

 

[BruceSki]

I noticed more vibration with smaller couplers. Less leeway for slightly off alignment and most importantly, little to no power improvement.

I'll stick with stock. You can get a set of used stock couplers for 20-25 shipped.

I run the oem 5 finger ones now as thy are a bit stronger than the 3 finger.

 

[swapmeet]

Jez.... I bet the guys that make these arn't real happy with me. : /

 

[Matt_E]

There are real advantages and I like running them. Just not for power gain.

 

[motoman96]

^^^ x2!

 

[eeerieski]

A coupler won't gain you power, it will gain you faster acceleration due to a lower rotational inertia, the effects are magnified due to the fact that the coupler is a smaller diameter too since the moment of inertia is .5*MR^2. If I had some numbers I could tell you how much faster the drivetrain would reach unloaded peak rpm with a smaller and lighter coupler, you might be surprised.

 

[BruceSki]

Yeah all that math looks good on paper but I didn't see $100 worth of anything in a real world application. I tried them twice also. Two different brands of couplers. One with drilled holes and one without.

Do they do something? Yes of course.

I would recommend putting $100 bucks towards a port job before I suggest someone get smaller diameter lightweight couplers.

And when I said more power I meant that it just helps release power the motor is already making that is lost in spinning a heavier/larger diameter mass.

 

[Freakrider]

I agree it's fuzzy math...

 

[Matt_E]

A coupler won't gain you power, it will gain you faster acceleration due to a lower rotational inertia, the effects are magnified due to the fact that the coupler is a smaller diameter too since the moment of inertia is .5*MR^2. If I had some numbers I could tell you how much faster the drivetrain would reach unloaded peak rpm with a smaller and lighter coupler, you might be surprised.

unlikely once you consider just how much rotating mass there is to the entire driveline - flywheel, crank webs, driveshaft, impeller. Taking a little bit off the coupler likely will not be noticeable.

 

[zimmy]

I think the billet coupler is a must for surf riding, if you nose into the bottom once and the couplers come apart, stockers will tend to shatter when they come back together when you try to restart the ski leaving you stranded. The billet coupler can take way more of a beating than a stocker.

 

[Crab]

 

[swapmeet]

I think the billet coupler is a must for surf riding, if you nose into the bottom once and the couplers come apart, stockers will tend to shatter when they come back together when you try to restart the ski leaving you stranded. The billet coupler can take way more of a beating than a stocker.

That makes sense. I haven't taken the opportunity to ride surf yet. But i'm glad you mentioned it, I was scratching my head trying to understand how a coupler could break. I was thinking that maybe they break in a shearing situation because of the power of the motor... which just didn't seem likely, especially with my little 701.

 

[dragginblazer]

I got a set because they look cool!

 

['kotajoe]

I installed a set of CF couplers on mine, and a #zero flywheel, engine revs up very quick now. I believe it is nice to know you have a super strong coupler that while you barely notice it, it does help the engine rev quicker.