Pages: 1
Posted by: Tree Farmer
The graphs, like the Bible, may "Say It All;" however, each requires some interpretation, in my opinion.
Dynojet could help by reporting horsepower vs. rpm, instead of horsepower vs. mph. Mph confuses the issue considerably with automatic transmissions; notice how different the curve profiles appear for essentially the same engine, but with manual as contrasted to automatic transmission.
My recommendation: let's stick with horsepower vs. rpm charts, comparing apples to apples. Even with a manual transmission quad, the horsepower vs. rpm presentation loses some specificity if the gears chosen during testing are unknown.
Dynojet, could you please provide horsepower vs. rpm data?
O.K., so, once again I've made a post that doesn't make any sense. Just compare the shape of a manual transmission horsepower vs. mph curve and an automatic transmission horsepower vs. mph curve, and see if they look like the graphs were generated by similar animals, nearly identical engines. They were.
I rest my case.
Tree Farmer
Posted by: Andy Bassham
What is the question here? What is trying to be determined exactly? Auto vs. Maunal? Suzuki vs. AC? let me in on it.
Posted by: Andy Bassham
Yours. What is the thing here, the minimum gain or what? I bet it helps to have the filter and pipe along with it. I wonder how long it will be before they make a needle jet for a manual 500? Highlifter says it shouldn't be too awful long.
Posted by: Andy Bassham
The Cat will do better than 43mph, but thats probably about where the torque or hp curve drops off all to hell. Notice that the sportsman and grizzly probably taper off at a slower speed than you would think would be the top end.
Posted by: TxDoc2
DynoJet's response to my letter on how and why?
1. SAE Corrected means that a correction factor has been applied to the
results to get a power number that is comparable to other dynos in differing
climates and conditions.
2. We do not have a 4wd ATV Dyno. We do have a 4wd car dyno and we measure
the output of the front and the rear wheel systems. This is done at the
wheels only. It will give you front, rear and combined wheel horsepower.
3. I have no idea what Honda does with their dyno. All of our dynos measure
the output of what ever is spinning the drum. In the case of a motorcycle,
that is one wheel, in the case of a quad it is both.
4. I am not familiar with their testing but a motor optimized for torque
will show, in some cases, less horsepower than one optimized for horsepower.
Posted by: BONER
[url=http://www.dynojet.com/quadmaster.htm] Auto[/url]
[url=http://www.dynojet.com/newrun6.htm]Manual[/url]
Posted by: BONER
Andy,
That depends. Who's post are your referring to?
Posted by: BONER
Thor
You'd be surprised what that 2.4% can do to the seat of the pants. I've seen a Sportsman 500 go from barely being able to get the front wheels 1 ft off the ground to being able to get them up about 3ft off the ground after that little 2.4%gain from a Dynojet kit.
Posted by: BONER
Well I was showing the difference in power between the Manual transmission and the Auto. For everyone that said the felt the Manual had more power I was helping to back them up with actuall findings.
Posted by: BONER
Well thats the way the rear wheel dyno was disigned to be used. In the top gear.
Posted by: BONER
Well I know the dyno( made by the same company) use on HOT Rod TV is like this, they put it in top gear and just nail the throttle to get the horsepower numbers. But since there is a wire that hooks up to a spark plug/coil wire it gives the mph and the rpms. According to Dynojet the ATV dyno is just a smaller Car dyno. So maybe they have the rpm #'s but just arn't posting them.
Posted by: BONER
I only used the Sportsman 500 cause I have no experience with Arctic Cat/Suzuki jet kits. I must say that I know a former Suzuki 500 Manual shift owner that took his jet kit off cause the only noticable thing about it was a slower top speed.
Posted by: Thor
An increase of 2.4% for how many dollars? Do they think we are morons? (Wait, The rest of this thread will explain that. )
Whatever it cost, I do not believe that it would be worth it for a 2.4% power increase.
Posted by: Thor
Boner?
Are we comparing AC to AC or Dynojet equipped AC's to Sportsman 500s? That's 6 variables. on the machines and 2 variables on the dyno charts. But.. back to your comparison.
The apples to oranges to pears comparison you are running here obviously qualifies you to be a contributing editor to Dirt Wheels or 4 Wheel Action!
I looked at the dyno chart for the manual trans AC 500 and looked at the difference in peak horsepower. 17.2 vs 16.8 HP the difference is .4 hoursepower a net gain of 2.4% is negligible.
If you had $97.60 in your pocket in coins and somebody handed you an extra $2.40 would you be able to tell the difference? I didn't think so.
Seat of the pants difference? With a totally different machine? Pleeeeeeeease. And a 2.4% difference at that. A 2.4% difference is not worth the time nor the investment in a dynojet kit.
P.S. They do not work on Honda 450 ES models either.
Posted by: Thor
Please re-read Tree Farmers post of 10/22.
I respectfully defer to our southern statesman on this issue.
Posted by: vtCatamount
Aahh, very interesting, thank you.
Posted by: Farmr123
Seems to me, both engines with a kit put out roughly 17 HP. The auto just puts it out at the start and the manual at a higher speed. Now for the $10 question. Did they leave the manual in one gear or shift it? If not, it would seem to me to be about the same. Look at the auto chart, the first half looks just like the manual chart, up until the auto shifts up, losing torque. It is very informative, and does explain why a gear drive seems to eventually pass an auto.
Posted by: girthyguy
this does show some interesting things, but it also disproves what you where trying prove, Boner. If you look at the graph of the man. its kept in the same gear the whole time, because if it was shifted you would be able to see spikes in the graph. The reason why the auto looks as if it comes on quicker in power because its always in the right gear. So if the auto is always in the right gear that meens you should be getting maximum performace from the enigine at all times. But then you look at the manual 500 graph its in the gear where it makes it maximum power at around 32-33mph and at the speed it puts out 3-4hp more the the auto at that speed. So either the autos clutch isnt tuned properly or the auto transmision soaks up to much power at the upper speeds. Just some food for thought
matty
Posted by: girthyguy
Boner the dyno is not designed to be tested in the high gear it doesnt matter what gear you are in. if you look the man. cat isnt in high gear I know the cat isnt the fastest by far but it will do more the 43mph in 5 gear.
matty
Posted by: girthyguy
thor
you can feel that little bit of power. for instance I have Gti golf with the vr6 when I put a chip in it It was only rated to gain 5-9hp If I was lucky, but because it smoothed out the power curve so much that it made a world of difference. And I do believe that a jet kit usually cleens up the peaks and valleys in a engines power curve to. So i think it would be a good improvemnt. But that agian dpends on the engine you instal it on some respond better then others.
matty
Posted by: girthyguy
well Boner i would like to correct myself. Maybe that cat was in 5 you cant tell because you dont know if they hit the rev limiter or they just let off the gas. but more then likely they hit the rev limiter wich would meen the cat wasnt in 5th
matty
