Has anyone raced an 800r?

[yammiman]

Not trying to be a smarta*s, but HP is the result of torque x rotational speed - the higher the two, the higher the horsepower - a dynometer is actually measuring the torque of the engine not the HP - it is the torque x the maximum RPM = the HP!! - no torque, no HP!!

A diesel has high torque but low rotational speed which results in lower HP!

 

[scottydog1]

Not trying to be a smarta*s, but HP is the result of torque x rotational speed - the higher the two, the higher the horsepower - a dynometer is actually measuring the torque of the engine not the HP - it is the torque x the maximum RPM = the HP!! - no torque, no HP!!

A diesel has high torque but low rotational speed which results in lower HP!

Thanks for clearing that up for me. I guess a (2) stroke under the same stress as a (4) stroke with approx the same HP will have the same torque #'s? My bad.

 

[unchained]

Not trying to be a smarta*s, but HP is the result of torque x rotational speed - the higher the two, the higher the horsepower - a dynometer is actually measuring the torque of the engine not the HP - it is the torque x the maximum RPM = the HP!! - no torque, no HP!!

A diesel has high torque but low rotational speed which results in lower HP!

Never thought about it, but that makes perfect sense

 

[yammiman]

....I guess a (2) stroke under the same stress as a (4) stroke with approx the same HP will have the same torque #'s?....

As long as you have the same rotational speed (RPM)

 

[Butta]

Very true.....and the ability for a motor to make it's max torque at it's max RPM is a huge benefit because it maximizes the advantage of gearing. High RPM with high torque, you can gear it more efficiently (and taller!). Take a turbine motor, for instance....not a whole lot of torque, but the max torque is made at a ridiculous RPM, which allows for incredible gearing ratios thus making turbine motors incredibly powerful (and fast!!!). On the other spectrum, is the diesel....HUGE torque, low RPM. Not as powerful, or as fast (typically), but will jump out of the hole like a bat out of hell.

If only we could make a 2 stage motor......a diesel for the holeshot, and a turbine for the high speed run out!!!! Wouldn't THAT be impressive?

 

[yammiman]

....If only we could make a 2 stage motor......a diesel for the holeshot, and a turbine for the high speed run out!!!!....

I guess the supercharger or turbocharger is the closet we're going to get!!

 

[morrisond]

Actually if you look at the Dyno Chart of the Nytro it does make more torque, about 96 lbs at 6700 rpm(trail speed cruising RPm) than it does at it's power peak of 8800rpm, where it's making about 85-88 if I recall correctly.

Perfect engine for an sled, nice 2,000 rpm power spread.

 

[SledFreak]

They all do it. DOO, CAT and YAMAHA all have race ECU's. Ulmer has 3 of them. They all advance and retard timing and ad and remove fuel to make it run perfect at where the motor makes peak HP. It's awesome....

I have yet to see anything really work on the 4-strokes like they do on 2-strokes. Advancing the timing on 2-strokes makes much more power then adding a fuel controller to our injected 4-strokes.
Race ECUs are proven miracles on the F-cats and Revs. Not on 4-strokes till someone can prove to me otherwise and figure out a way without changing engine components.

Dan

Ulmer says he pulls 8-10ho with a Fuel Controller and timing box for the Apex. I would say that it is a good gain and that is for trail riding. I believe it might even be better for 500-660 ft because they turn the timing up even farther and can change the max engine RPM up to 11,700. He has 3 race boxes from Yamaha.

 

[Dano]

Ulmer says he pulls 8-10ho with a Fuel Controller and timing box for the Apex. I would say that it is a good gain and that is for trail riding. I believe it might even be better for 500-660 ft because they turn the timing up even farther and can change the max engine RPM up to 11,700. He has 3 race boxes from Yamaha.

thanks for the info. I really don't understand how a 4-stroke can simply change the timing when dealing with a cam opening and closing valves. I understand adding fuel and playing with rev limiter can have its benefits, but I never heard or seen 8-10 hp gain with an ignition module. Not saying it can’t be done, I would be curios to see this on a Dyno. 10 hp gain for around $700 is a good bang for the dollar and should be much more popular!



Dan

 

[yammiman]

The most power is made at the threshold of detonation!!!!!

 

[SledFreak]

Dano, I forgot to add, that it is with an airbox mod and a CR10ek plugs as well. But, 8-10 is on the low side.

 

[timebomb]

Was at the Doo-Yam dealer last wed and hes had no 08 800 doos come in yet.

were you at sovies?

 

[DoktorC]

Ulmer says he pulls 8-10ho with a Fuel Controller and timing box for the Apex. I would say that it is a good gain and that is for trail riding. I believe it might even be better for 500-660 ft because they turn the timing up even farther and can change the max engine RPM up to 11,700. He has 3 race boxes from Yamaha.

thanks for the info. I really don't understand how a 4-stroke can simply change the timing when dealing with a cam opening and closing valves. I understand adding fuel and playing with rev limiter can have its benefits, but I never heard or seen 8-10 hp gain with an ignition module. Not saying it can’t be done, I would be curios to see this on a Dyno. 10 hp gain for around $700 is a good bang for the dollar and should be much more popular!



Dan

Dan, the ecu mods or a Power Commander and ingition control have shown good gains on the Apex. Ignition timing works the same 4s or 2s. The 2s just make more gains because of it. 10-15hp is quite conservative IMHO from the XPs, the 600's run right with an Apex on the grass but obviously that's not the case out on the trail. It's impossible to compare full blown race sleds to what you'll see on the trail regardless of the hp..they're tuned by the best and everything that can be changed (within the rules) is changed.

I'm sure the 800r will be a very fast sled...but for how long..who cares lol. I only ride with Yamaha's .

 

[redsnake3]

Not trying to be a smarta*s, but HP is the result of torque x rotational speed - the higher the two, the higher the horsepower - a dynometer is actually measuring the torque of the engine not the HP - it is the torque x the maximum RPM = the HP!! - no torque, no HP!!

A diesel has high torque but low rotational speed which results in lower HP!

its actually tq x rpm/5252 = H.P.

 

[yammiman]

The complete formula is:

p/hp=[r/(ft-lbf)] [w(r/min)] divided by 5252

but I was only trying to make a point!!!!