Don't forget that a whole lot depends on accessories. Exhaust, intake, reeds, carbs, ignition, compression, fuel type, and perhaps most importantly, pump setup. And what about the hull itself (intake tract). Al those things influence the power output. (If measured by water brake dyno). All of a sudden standard numbers are a bit more complicated.
Other PHP 937 or DASA 970?
- Thread starter SmittySX
- Start date
- Location
- Taupo NZ
True, which is why I'd support doing head to head comparisons on a dyno outside of the boat without a pump, since hull design is very ride subjective (and there is no real way to change that).
We see the same issue in cars (different intakes, exhausts, transmissions, gear ratios, fuel etc), which is why for crate motors, engine dyno numbers have become much more popular than chassis dynos, and people are still careful to look at atmospheric data when making comparisons.
I’d consider carbs/intake/exhaust/ignition part of the engine package, and ideally as a consumer I would like the builder to provide some guidance on which are best and to have a way of seeing what some set combinations would do before dropping some coin.
Knowing the engine's specs prior to building a pump would also make prop selection much easier (though then I'd want a pump curve too :grumble: ). That said the land and sea water breaks are mounted to the shaft through the pump after removing the nozzle, so minus the bearing losses, windage and rotating mass (probably the biggest variable), they should be fairly similar results even with different pumps and tracts. Did some more thinking, an AC motor/generator would make a great absorber for a permenant installation, but would be near impossible to do portably (both physical size and needed grid connection to backfeed).
Also did some googling and apparently Riva owns or owned a Huff Technologies engine dyno by the way.
We see the same issue in cars (different intakes, exhausts, transmissions, gear ratios, fuel etc), which is why for crate motors, engine dyno numbers have become much more popular than chassis dynos, and people are still careful to look at atmospheric data when making comparisons.
I’d consider carbs/intake/exhaust/ignition part of the engine package, and ideally as a consumer I would like the builder to provide some guidance on which are best and to have a way of seeing what some set combinations would do before dropping some coin.
Knowing the engine's specs prior to building a pump would also make prop selection much easier (though then I'd want a pump curve too :grumble: ). That said the land and sea water breaks are mounted to the shaft through the pump after removing the nozzle, so minus the bearing losses, windage and rotating mass (probably the biggest variable), they should be fairly similar results even with different pumps and tracts. Did some more thinking, an AC motor/generator would make a great absorber for a permenant installation, but would be near impossible to do portably (both physical size and needed grid connection to backfeed).
Also did some googling and apparently Riva owns or owned a Huff Technologies engine dyno by the way.
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masterblaster
X-H2
As we both mentioned it would need to be the same dyno used at a place like tona to really count..Riva and another un named builder already have dynos. You will find that most all them go out of their way to discourage this,then the cronies right behind them. No usable reliable data.Almost no one here has any clue about how a dyno works for skis,much less how motors would compare on it.these a/m motors are really sweet but We could do so much better as a performance motorsport..
It blows my mind guys spend 10k with no factual comparable data
It blows my mind guys spend 10k with no factual comparable data
There doesnt seem to be much interest in charts and numbers with this segment of motorsports. Participants spend whatever it takes for a backflip. Smaller budgets settle for barrel rolls. Higher costs bring more prestige among peers, that is all people are really after. If every ski and every rider could do it then nobody would spend more than what a 20yo Kawasaki is worth.
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masterblaster
X-H2
A bigger backflip doesnt matter in flatwater?
prestige among peers?....pathetic,and deff not who im talking about
I dunno about the whole theory there,I know alot of purpose built surf boats with high end motors that can barely get outa there own way,even though they could flip with a stock 701 in the surf.
masterblaster
X-H2
How many riders know what RPM their engines are loaded to? That is the most basic and important aspect of tuning anything running in a fluid. Without this info you are shooting in the dark yet nobody seems to care. Anything that is larger sells without question, this is why builders offer no details other than size. As far as peoples motivations, they do vary. A person who rides alone is probably different than one that rides in groups where hierarchy is important. Conspicuous consumption seem more prevalent than ever though.
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masterblaster
X-H2
kev, tach tuning is one thing,and deff helps in some situations,but a long way way from dyno tuning when your trying to pick up some extra low end torque..Picking up a few extra top end rpms doesnt tell ya much in these liter + motors. Id like to see someone attempt to tach tune a 1100 or 1200 in a stubby freestyle hull....lol
If our motorsport had been serious enough about these large motors to dyno tune them when they first were developed yrs back, it would have saved alot of people a buncha headache and time figuring out how to tune and water inject the large pipes for them to make max power. Using a dyno to tune port timing changes and pipe setup is critical in any other motorsport. In our sport they just keep adding compression and timing till it works,and becomes a shorter term grenade.
If our motorsport had been serious enough about these large motors to dyno tune them when they first were developed yrs back, it would have saved alot of people a buncha headache and time figuring out how to tune and water inject the large pipes for them to make max power. Using a dyno to tune port timing changes and pipe setup is critical in any other motorsport. In our sport they just keep adding compression and timing till it works,and becomes a shorter term grenade.
chadman154
#Itsonlymoney !!!!!
- Location
- Dirty south
so.... What motor did the OP decide on?
wsuwrhr
Purveyor of the Biggest Brapp
- Location
- Alta Loma, working in Upland
For just that purpose, I threw enough money at it to get someone to do it and finally gave up.
When I first developed the 16MM case and finished the first sets, Lenzi(who initially commissioned me to do the case) was nowhere to be found and noone wanted to buy the first one. Noone believed it would ever work(make more power than a 12mm) and the cost difference from a prepped factory case was prohibitive. I still rarely sell 10-12 cases.
One complete engine was given out for test data and I recieved no feedback.
Eventually, two got sent over the pond to go in carbon surf B1's and the rest is history.
4 years later, the only time I ever heard two-stroke noise in that room was an employee's spare 850 get strapped up for a few shakedown runs and then the room was torn apart. Again.
I left at least a year later and the room STILL wasn't completed. I have no doubts it is still nothing more than a high dollar storage room and a place for the guy to hide and talk on the phone.
Tuning tool, no doubt, nothing more. The way these engines are used, never even being legged out, a dyno chart/graph/curve isn't worth the ink cost it takes to show the purchaser.
Brian
When I first developed the 16MM case and finished the first sets, Lenzi(who initially commissioned me to do the case) was nowhere to be found and noone wanted to buy the first one. Noone believed it would ever work(make more power than a 12mm) and the cost difference from a prepped factory case was prohibitive. I still rarely sell 10-12 cases.
One complete engine was given out for test data and I recieved no feedback.
Eventually, two got sent over the pond to go in carbon surf B1's and the rest is history.
4 years later, the only time I ever heard two-stroke noise in that room was an employee's spare 850 get strapped up for a few shakedown runs and then the room was torn apart. Again.
I left at least a year later and the room STILL wasn't completed. I have no doubts it is still nothing more than a high dollar storage room and a place for the guy to hide and talk on the phone.
Tuning tool, no doubt, nothing more. The way these engines are used, never even being legged out, a dyno chart/graph/curve isn't worth the ink cost it takes to show the purchaser.
Brian
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KTM434
Jamie FN Hickey
- Location
- Palm Coast FL
I'm sure some of the bigger engine builders have used dynos for their own knowledge of port designs and building the most power from a certain engine size and setup but these specs are in house secrets that would never become publicized information just for the fact of another company building more power and taking more market shares. I understand other industries make this public knowledge as well but even those figures are not accurate when it comes to aftermarket bolt ons. A lot of bolt on "performance" parts on a stock engine (for a car) will lose power, but on a performance application with a built engine and every bolt on imaginable that same part will add power since the OEM part becomes restrictive. Now they dyno before and after adding their part and post those numbers without detail of their setup. They probably use ambient temperatures in their favor as well so the same exact setup would have shown increased power output on that colder day without changing anything. I'm basically referring to the simple mods like air filters, exhaust, headers, etc. Those parts (other than air filters) usually lose power unless the rest of the powerplant requires it. The big car companies have a lot more money for R&D than the small performance companies. They also need to find a good balance between power, fuel economy, noise output, etc. That's where the aftermarket performance companies come in. They sacrifice fuel economy and noise output in search of adding power.
I'm basically saying don't believe everything you read. Performance companies will twist their information to make their product look better.
Even if there was an engine dyno competition using the same setup certain engines would benefit from that exact setup while other engines would benefit from a different setup. I.E. One company uses stock 38mm carbs for air velocity, fuel economy, and off idle acceleration/torque. Their porting is also setup to run those smaller carbs and their engines make good power with that setup while other engines of the same size but different porting design would be restricted by that setup.
I would rather take advice from an average opinion of reputable people who's opinions I trust rather than the company that's selling the product. A non biased opinion from a good tuner is worth more to me than the company that's selling the product
I'm basically saying don't believe everything you read. Performance companies will twist their information to make their product look better.
Even if there was an engine dyno competition using the same setup certain engines would benefit from that exact setup while other engines would benefit from a different setup. I.E. One company uses stock 38mm carbs for air velocity, fuel economy, and off idle acceleration/torque. Their porting is also setup to run those smaller carbs and their engines make good power with that setup while other engines of the same size but different porting design would be restricted by that setup.
I would rather take advice from an average opinion of reputable people who's opinions I trust rather than the company that's selling the product. A non biased opinion from a good tuner is worth more to me than the company that's selling the product
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- Location
- Cleveland, Ohio
I havent decided yet.. Thinking about just buying a supra.....
masterblaster
X-H2
Brian..Back then it still should have been done,but there were not that many produced between all the manufactures combined neither was a market proven for its demand..Today is a diff time entirely with a global demand ..A single dyno curve chart would not be worth much without a true benchmark. Now a couple curves for a few diff motors,stoke vs bore dry pipe vs wet pipe injected in a particular spot...that would be worth alot to everybody involved. Even simple things like what a given setup would produce with a bpipe vs pfp,changes in low end torque from lower to higher compression. stock ign vs higher timing. More importantly torque for lower and higher port timing in these setups for a given purpose.
ktm..you would be surprised at what gets done and what doesnt in this sport really..Since racing died back in the 90s very little tech work or R&D takes place..We will prolly never see the likes of dyno work that was done at places like riva, dasa and others at that time.I know how much time was spent by tj and others doing this in that era..But we are not talking about racing,we dont need super tech changes to pickup 1mph or 100 extra rpms..just the basics and a good bench mark to improve on..A dyno shootout for diff manufactures is just one small aspect.So much could be done and learned inside one manufacturer in terms of what to choose...Although a shootout would be fairly easy,no one is tuning with anything other than 48 carbs,tl and pfp for such a purpose. Think of the shoot out as more of a means to a end...if it came down to shootout and facts,dont you think the competitors may take a little time on the dyno before hand to fig it out before hand.
ktm..you would be surprised at what gets done and what doesnt in this sport really..Since racing died back in the 90s very little tech work or R&D takes place..We will prolly never see the likes of dyno work that was done at places like riva, dasa and others at that time.I know how much time was spent by tj and others doing this in that era..But we are not talking about racing,we dont need super tech changes to pickup 1mph or 100 extra rpms..just the basics and a good bench mark to improve on..A dyno shootout for diff manufactures is just one small aspect.So much could be done and learned inside one manufacturer in terms of what to choose...Although a shootout would be fairly easy,no one is tuning with anything other than 48 carbs,tl and pfp for such a purpose. Think of the shoot out as more of a means to a end...if it came down to shootout and facts,dont you think the competitors may take a little time on the dyno before hand to fig it out before hand.
wsuwrhr
Purveyor of the Biggest Brapp
- Location
- Alta Loma, working in Upland
Hell, my request was simple enough.
Back to back test with a factory case 12mm stroker to a billet case 12mm, same cylinder even, just swap it, then switch to a 16mm setup. Couldn't get it done, even after I had arranged and paid to have the dyno controller repaired. Looking back, the broken controller was nothing more than an excuse not to bother with the dyno.
I still say for the little time these engines spend at upper rpms it is not going to prove much. On the gas to full throttle for a brief moment and back to part throttle. It isn't a drag race where the engine is legged out.
Dyno tuning would mostly be wasted, things like compression be too low, timing be too slow, and jetting specs would likely be too rich for the rpm range the engine will ever be used.
May work good on the dyno, but would just never work in the water because the motor will never see even close to the parameters it saw on the dyno.
Make any sense?
Brian
Back to back test with a factory case 12mm stroker to a billet case 12mm, same cylinder even, just swap it, then switch to a 16mm setup. Couldn't get it done, even after I had arranged and paid to have the dyno controller repaired. Looking back, the broken controller was nothing more than an excuse not to bother with the dyno.
I still say for the little time these engines spend at upper rpms it is not going to prove much. On the gas to full throttle for a brief moment and back to part throttle. It isn't a drag race where the engine is legged out.
Dyno tuning would mostly be wasted, things like compression be too low, timing be too slow, and jetting specs would likely be too rich for the rpm range the engine will ever be used.
May work good on the dyno, but would just never work in the water because the motor will never see even close to the parameters it saw on the dyno.
Make any sense?
Brian
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KTM434
Jamie FN Hickey
- Location
- Palm Coast FL
Makes perfect sense. It may seem like I'm against the dyno for jetskis from my posts... I'm not. I think any reputable company SHOULD be tuning on a dyno to perfect their own products and workmanship but not post this info publically since it'll be a biased opinion that's used as a selling tool. What I WOULD like to se is an outside source (whether it be a performance carb or pipe manufacturer, impeller company or just a well known tuner) compare all these engines with a given setup. Max HP/torque numbers aren't the only useful info a dyno will show. Most people here probably can't relate a dyno graph to a jetski and I doubt most freeriders know what RPM they normally ride at. A useful engine competition would be a time measurement with a loaded pump from 1500RPM to 6000RPM. Whichever engine revs the fastest with a loaded pump and same setup wins the shootout. That to me would be very useful info
wsuwrhr
Purveyor of the Biggest Brapp
- Location
- Alta Loma, working in Upland
KTM434
Jamie FN Hickey
- Location
- Palm Coast FL
All I'm trying to say is I don't believe everything I read about dyno results from companies that are selling that given product because there's too many ways to tamper the results like I stated previously. A public dyno competition at a freeride event would be fine with me or a private non biased comparison with untampered variables would be fine too. I could read a dyno graph to see the difference but not everyone is able to do that. A max HP and max torque output means nothing if it's achieved at an RPM that will never be seen for your given riding style. If a person can't read a dyno graph and doesn't care about max HP ratings then the rev time comparison would be something people could understand. That's not my only criteria, just an idea. Sorry if you can't understand how that could be beneficial to people. I've run dirtbike motors that were tuned on a dyno for max HP numbers and they were underpowered hunks of schit