Freestyle Who wants actual dyno numbers?

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If you look at the snowmobile engines of equal displacement they're getting the 200 plus hp out of their engines but @ 8200 rpm to 9000 rpm, and thats using twin pipe setups. So how are watercraft getting that number at 1000 rpm lower and on a single pipe? I've done some dyno testing and you can definately fudge the numbers but it doesn't do any good if your trying to make improvement. For a good engine its all about torque and responce, and that responce comes from a good package ie: pump, ignition, engine rev charactoristics. If your screaming for hp numbers than most likely you don't really know enough about the subject to understand what makes a good setup. I'll take a good setup over supposed peak power any day. Oh yea, its gotta be tuned right to even make it worth the effort, and if you think "just give me the jetting specs" is what tunning is, you need to pay some one to do it.

did you read any of this thread? i would only hope the guys who designed these motors would have an idea of how they should be tuned.
 
What kind of dyno do OEM's use to proclaim their HP numbers?? I wonder how true those numbers are..

oems don't use dyno's. they figure hp by math. even with all the improvments in computer modeling they still aren't near perfect, but they do give you an idea. Also companies will straight up lie. for many years in japan 276hp was the limit for cheaper insurance or higher taxes or something along those lines. if you took the skyline or turbo supra for example. they were rated at 276 at the crank and would lay down 300-350 to the ground.
 
did you read any of this thread? i would only hope the guys who designed these motors would have an idea of how they should be tuned.
Yes, I read the posts. Now are you talking about a complete build or purchased parts for self assembly? Even a complete build goes out of tune.
 

Vumad

Super Hero, with a cape!
Location
St. Pete, FL
do me a favor. sober up and reread what you typed.

drag racing is gay. and i can't believe you just insinuated that a 650 motor with a perfect pump setup could compete with something else. seriously, the only way a stockish motor could compete with these motors is if you started in the water and someone else was on a beach cart a 100 yards away and the race was only 101 yards.

i think i see what you are saying, but, just like building a car. you pick a point in your setup and build for it. you don't buy a 14/20 prop and a 150 mag and go let me build my motor around that. you start with the motor and set your pump up accordingly. how much usable hp and tq is king. sorry.

I didn't mention a stockish motor or a 650. You made that part up.

But take that 650 example. The 650 with the milled head would create higher pressures on the same pump. Compare a ported 650 with a 650 with a milled head and the boat with the most thrust has the better complete setup. The same principle can be applied to a worked XS1000 vs a Dasa1000. The idea of comparing a XS1000 to a stock 650 is something you fabricated in your head, because I certainly didn't suggest it.

The point I am trying to make, the point that you are missing, is that the performance of the complete setup is the only thing that matters. Yes, it would be nice to test each component individually. Yes, it would be awesome to perfectly tune a motor on a dyno and then know that motor is at peak performance before attempting pump tuning. But, since I'm a practical kind of guy, I like to discuss things that might actually happen. Things like sticking a $30 flow meter in a jet stream, because I've been reading about Dyno's since I joined this forum 4 years ago and have yet to see a single number.
 

#ZERO

Beach Bum
Location
Florida - U.S.A.
Just a thought but your concern of the motor screaming to redline may very well be dealt with by using a weighted flywheel considerably heavier than the ones being used for freestyle. I've seen cranks and flywheels weighted to make the power of a 2 stroke mx bike more tractable and smooth allowing a rider to use the full potential of an engine on a slippery,muddy or loose based track. Just a suggestion but what do i know. I like brownies too!!!

Actually a tuned pipe is the rev limiter if the one in the CDI has been removed.

Who wants to add weigh to their flywheel; that would just slow the engines acceleration?

How much HP does my ski have?! I want to knowwwww!!!

T bottom
X top
B-pipe
185 head
carbon reeds
lightened flywheel
MSD Enhancccccccceeeerrr

GO! DYNO DYNO! GO DYNOOOOO!

My guess would be around 93.8 @ 6500 RPM if the chart is correct.

Dyno701SJ.jpg
 

Matt_E

steals hub caps from cars
Site Supporter
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at peace
:haha:

Well played, monsieur.

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theiba

Can't get a ski stuck...
Location
Southern NJ
The pump is the only thing that matters. HP on a shop stand is irrelevent.

I realize it's not a jetski, but we just bought a motor for a car we're restoring, and when we went out and starting looking for motors it's not the case that you bought a motor based on what you wanted it to be capable of and they build it, drop it in your car and dyno it.

They build it, dyno it, tell you what it's capable of, then you take it and attach whatever you want to it. No reason a jetski powertrain isn't any different. There's any combination of pumps or transmissions and rears or impellers out there. You take the power provided by the motor and do what you want with it.
 

Vumad

Super Hero, with a cape!
Location
St. Pete, FL
I realize it's not a jetski, but we just bought a motor for a car we're restoring, and when we went out and starting looking for motors it's not the case that you bought a motor based on what you wanted it to be capable of and they build it, drop it in your car and dyno it.

They build it, dyno it, tell you what it's capable of, then you take it and attach whatever you want to it. No reason a jetski powertrain isn't any different. There's any combination of pumps or transmissions and rears or impellers out there. You take the power provided by the motor and do what you want with it.

Don't think I don't agree. I simply don't see any of the motor builders doing this. I was trying to curve the discussion to talk about something that might be possible to be done with assembled skis, to compare set ups at a freeride, since that to me would be a plausable scenario that could happen.
 

wsuwrhr

Purveyor of the Biggest Brapp
So if I open the door and take a picture of DASA's own dyno(certainly not a rented one) with a motor coupled up to it would this thread go apesh it?

Who else could post their own similar picture?

I have said before, Dynos are good for nothing but tuning a combination of components in a closely monitored situation.
Noting changes and in what direction are those changes. Published Torque numbers aren't worth the pushed keys it would take to post them.

Brian
 
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Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
didn't you say peak wasn't what was important? but which one had the longer range of power? :kabong:

I think I did. But I wasn't commenting on peak on that curve. Take a look which torque curve is consistently higher, not just in one peak area. Further, even the HP curve is consistently higher for the B. The type 9 shines only 6500rpm and higher where the B has already signed off.
The type 9 certainly has a broader power and torque range. (at the expense of some bottom and mid)


But it's important to note that those curves use a 701 limited.
 
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