wsuwrhr
Purveyor of the Biggest Brapp
- Location
- Alta Loma, working in Upland
You made my exact point I have said on this board for 4 years
Other PHP 937 or DASA 970?
- Thread starter SmittySX
- Start date
You made my exact point I have said on this board for 4 years
masterblaster
X-H2
ktm,a ski motor revs out to 6000k so fast it wouldnt be a justifiable conclusion. Its all about getting the motor "on the pipe" so to speak quickly and how much torque the motor can make lower in the rpm range.
Brian...I dont think anyone has enough experience dyno tuning larger motors to know that is the case. We can dyno tune other types of motors for low end response and power curves can be manipulated in many ways to achieve the desired low end power and responce. Setting the load on the dyno as close to a natural load the motor would see in the water would be,no diff than what was done in the past,the only variable would be not just tuning for max power at max rpm
Brian...I dont think anyone has enough experience dyno tuning larger motors to know that is the case. We can dyno tune other types of motors for low end response and power curves can be manipulated in many ways to achieve the desired low end power and responce. Setting the load on the dyno as close to a natural load the motor would see in the water would be,no diff than what was done in the past,the only variable would be not just tuning for max power at max rpm
KTM434
Jamie FN Hickey
- Location
- Palm Coast FL
Masterblaster, The RPM numbers I gave were just examples. Don't get hung up on the numbers, you basically explained the point I'm trying to make. An engine that was tuned and build for max HP numbers will take forever to get "on the pipe" and that's my reason for the idea of the time taken to rev through a given RPM range. This will ensure the engine was built for a linear torque curve and won't lag or bog too long before it gets into it's torque range. This comparison example would also be done by an outside vendor (not the engine builder) to ensure the engine builder took the time to build useful power.
masterblaster
X-H2
lol thats actually pretty funny...
ktm. I get your point on revs,but it just happens so fast that would be hard to get conclusive results.if someone tuned a motox bike for max hp and not for low end torque as well they were not a very good tuner..just like a builder has to be worth a shizz so does a tuner.. I can promise you all the race skis that were dyno tuned back in the day for max hp and rpm,where also very nasty outa the hole and through the midrange..its all relevant to a good tuner..most the time its partial water tuning and partial dyno tuning to get the desired result..Everyone seems to act so incapable about it here...sure it takes time but its worth it.Most people would be surprised what could get done in a day on a dyno with a few cylinders and a couple diff shaped domes for each to establish the best mid range linear curve. Id have a test pipe looking like swiss cheese with injection testing.
there are huge strides made in motorsports with this kinda tuning,there is major interest in it at shootouts,and MANY motor packages and bolt ons are sold directly because of this..I really believe that as tuners and consumers learn more about these motors,advances in tech come much quicker and sales increase as a direct result..ill post a few links for reference..
http://forums.haltech.com/viewtopic.php?f=3&t=7826 ......1100 hp and well tuned
http://mkiv.supras.org.nz/members/kevin_linkecutune.htm ...trying new things on the dyno to raise power
http://www.superstreetonline.com/featuredvehicles/sstp_1011_1995_toyota_supra/viewall.html...great shootout dyno and street
http://www.youtube.com/watch?NR=1&v=cZDCSqhQYQA&feature=fvwp 1400 hp on dyno
http://www.youtube.com/watch?v=JECyJKvZFRg
http://www.youtube.com/watch?NR=1&v=US2Y8c327YA&feature=fvwp ....how 1400 hp looks on the track 7 secs
all this kinda stuff creates excitement and further interest in the sport...in turn increasing sales...that is after all what its all about now,selling motors,no ones trying to win a racing title by couple mph with these kinda motors...secrets dont pay the bills anymore
what curve would you prefer? lol
Uploaded with ImageShack.us
Last edited:
KTM434
Jamie FN Hickey
- Location
- Palm Coast FL
It was Honda in 2002 when they switched the CR250 to the case reed setup with electronic powervalves. That engine felt as if the power valves were stuck open at lower RPMs. There was a 250cc shootout in a magazine that year and they even mentioned that the new frame was great for handling but the engine was tuned on a dyno for max HP #s instead of usable power. That's a perfect example of what I'm getting at. If that was Hondas advertisement they would say "most powerful engine in it's class" (which is why dyno results listed from the engine manufacturer are useless) but from a mixture of knowledgable riders in a magazine shootout for dirtbikes they could tell that although it had higher peak #s than their previous engine the power output wasnt usable power. That was the opinion of motocross racers that are on the pipe all the time (similar to racing jetskis) now imagine that same engine racing in the woods and riding a gear higher than usual to utilize the torque for better traction and smoother faster riding... Didn't work very well
Last edited:
Remember that pump load squares with rpm, there is very little load at low rpm. Trapped volume is the most reliable indicator of low rpm torque on any two stroke. Look at dyno charts for outboards, torque below 4000 is inversely proportional to port height and directly proportional at 8000. This is where exhaust valves can make a big difference provided they act quickly and accurately enough for freestyle use. Knowing where the engine/pipe goes rich is a big help when tuning the pump. A dyno can tell you it goes rich at 7000 but if its turning 7200 on the water then you know its underloaded without having to change the pump five times looking for the power bubble.
Last edited:
- Location
- Cleveland, Ohio
Well ive been talking to Art at jetworks and Im almost positive im going with his 888cc 5mill at this point. At seems more logical for my wallet than the 1100, right now anyways.. I figured i cant go wrong with a motor and a set of 46s tuned by him. Anyone running this motor?
61x cyl?
chadman154
#Itsonlymoney !!!!!
- Location
- Dirty south
I used to run a 760 BB from art with 44's. Then i had a chance to try a PHP 771 and thats when i switched to PHP.
KTM434
Jamie FN Hickey
- Location
- Palm Coast FL
Unless they were both 61x cylinders that's not a fair comparison. Not to mention it needs to be compared in the same hull with same compression, pipe, electronics, pump and impeller, carbs etc. And ported for the same riding purpose. I don't favor either builder, just had to point that out to be fair
Last edited:
chadman154
#Itsonlymoney !!!!!
- Location
- Dirty south
my boat was an AM hull with more goodies and mag pump
and the other boat that hit better with the php in stock sj with stock pump on FP dry pipe
I not trying to start a war, its only my opinion and it means nothing.....
KTM434
Jamie FN Hickey
- Location
- Palm Coast FL
Everyone is entitled to their opinion and I'm not saying you're wrong or trying to argue. I'm just pointing out that all those variables play a big role in the engines power output. If I had to guess from reading other threads I'd say the SJ you rode was Zack's wifes SJ? The fact that he's an engine builder means he can tune a ski and engine to it's full potential better than most as well. Maybe it wasn't that ski and I'm just rambling... Like I said you may be right, I'm not arguing that. I'm just pointing out the influence all those variables make on an engines final power output
Last edited:
chadman154
#Itsonlymoney !!!!!
- Location
- Dirty south
actually zacks wifes sj, my q8 sky was set up decent and should have walked all over that ski, but i didnt.
This is why zack tunes my skis now....
KTM434
Jamie FN Hickey
- Location
- Palm Coast FL
I knew I wrote the name wrong, I meant Zack haha
- Location
- Cleveland, Ohio
Arts 888 is a 61x top and 62t bottom. From the research I've done he seems to know what he's doing. I'm pretty pumped. I'll be running his blackjack 46s on an 888 with a b pipe, msd enhancer, stock pump( for now) with a 9/15 hooker. I have a jetnetics flywheel and I haven't heard good things... Gould I run a stock lightened flywheel or something else..?
Save yourself the trouble. Save for TL and a mag pump. You'll be happy you did.
I was very happy with the 760BB Art did for me. Kicked billet SS ass all day.
- Location
- Cruising Around
^^^^ Yami stroker with T/L all the way
- Location
- Edmonton, AB
I'm running the 888, it's an awesome little motor! Walks all over my buddy's dasa 950
- Location
- painesville,ohio
Little motors beating big motors? I think everyone realizes by now that it's all the parts working together more than anything else. I think you'll have a winner if you go with a good builder such as Art and follow ALL his advice. Pull the trigger Smitty and come on summer!
BTW Matt, the 760 BB still hits pretty well.
BTW Matt, the 760 BB still hits pretty well.