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Do the hp and torque numbers drop off the same for both bikes at altitude? Does the throttle body bore matter as much with thinner air?
ktm 500 vs 450
- Thread starter cisco
- Start date
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A motor is an air pump...the more efficient you make it...the better it runs. Altitude affects air volume going into the pump (there is less air as you get higher in altitude.) The bigger throttle body has less restriction to air intake at all elevations. All motors loose approximately 2+% of their horsepower per 1000 ft of altitude increase. More horsepower and torque are good things.
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Does anyone have video of their sled hitting that rev limiter.
I'm pretty sure I've never hit it on the dirt with my yz450, and just have a hard time connecting that thumper sound to its RPMs.
I'm used to hearing two strokes at high revs, or crotch rocket type 4 strokes.
The snow bikes on YouTube just seem like they're chugging along.
I'm pretty sure I've never hit it on the dirt with my yz450, and just have a hard time connecting that thumper sound to its RPMs.
I'm used to hearing two strokes at high revs, or crotch rocket type 4 strokes.
The snow bikes on YouTube just seem like they're chugging along.
in bikes.
Usually the ecu cuts fuel and pulls timing at the limiter.
crazy fast popping sound.
in mx you hear it when a guy panic revs trying not to land nose down off a jump.
Sleds often just bog on the rev limiter. (Not sure how it’s relevant to the discussion but you asked about sleds)
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Yea, i meant bike.
Ill try to listen for it..
Thanks.
Been learning a lot from you guys...
Appreciate it.
Found a video
Bunch of brilliant individuals.
S
You will make similar numbers with both after mods, yes the 500 will have slightly more torque but you give up a a wider power band with more available power and even peak power. In the right conditions and a steady climb the 500 could/should put more overall power down and will climb. add a few lumps into the mix and vary the rpms a bit and the 450 will put more power down because as the track speed changes it will stay in the power band longer assuming you were riding in the correct gear to begin with.
The 500 will be more forgiving but need more mods to keep up stock. mod for mod they make very similar overall hp numbers. The 450 will have more power stock and will need to be ridden at a higher rpm and more aggressively, If you ride them half throttle mid range the 500 will be better overall.
If you ride it like you stole it 450, if you cruise around more often 500. but also 450 because imo nothing beats the hymn of a motor at 9-11k rpm all day. that's my $.02
The 500 will be more forgiving but need more mods to keep up stock. mod for mod they make very similar overall hp numbers. The 450 will have more power stock and will need to be ridden at a higher rpm and more aggressively, If you ride them half throttle mid range the 500 will be better overall.
If you ride it like you stole it 450, if you cruise around more often 500. but also 450 because imo nothing beats the hymn of a motor at 9-11k rpm all day. that's my $.02
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ok
Agreed. I've got couple hundred hours on a 500. Riding buddy on the 450. I am the half throttle mid range and he is the on the rev limiter guy. If he stays in the rpm (correct gear) I will struggle to match his climbs but, if he starts out a little low in rpm I sometimes pass or out climb him. Probably because the 500 is more forgiving and I am a less talented rider I prefer the 500. Bit more mods on 500, both have vortex.
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So you guys are saying on my 18 500. If I get some head work done, throttle body bored and a higher compression piston I'll be pushing closer to 70 HP. With proper ecu running of course
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The 2020 and up 500's use the 450sx head and are therefore generally able to produce more power than the previous generations.
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SO....anyone got a 450 MX head laying around ? lol
Yah that what riding a 500 on the snow is like , It kills the track speed, The 450 never taps the limiter and pulls another 2500 rpm over the 500.
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I found some videos of bikes hitting the limiter spinning in mud and stuff.
I don't think ive heard any snowbikes hitting it yet. I swear they always sound like they're way under revved.
The sound of dirt bike 4 stroke just sounds like fewer revs, maybe its the deep tone.
Crotch rocket 4 strokes sound like they are getting spun the full 10k
I just don't have an ear for thumpers.
All the 500,s we built hit rev limiter 100,s times a day. Its Most fatal and destroys track speed and is why the 450 just smokes the 500 on the snow. If your not even hitting rev limit on any 500 then ewe have performance issues, intake, stock exc exhaust or stock ecu, gearing ect. The 500 is an easy bike to ride since its never wound out tight for newer riders. HP does not really reflect the total performance, RPM equates to high track speed on a gear box machine.
I think a big factor in this how you use the bike in the summer. If it's a singletrack bike, the 500's are quite nice and the 450's are hard to manage for an average rider. Vice versa if you like to ride MX in the summer, then the 450 is a no-brainer.
If you already own a 500 and like it.....it will make a fantastic snowbike I don't care what anyone says. You can argue the sticking points forever, but it is a good solid choice, we have built a ton of them for snow, and they work GREAT. That said....if you own 0 bikes, and are buying a bike specifically for a snowbike, a 450 is lighter, cheaper, makes more power and revs more as stated.
If you already own a 500 and like it.....it will make a fantastic snowbike I don't care what anyone says. You can argue the sticking points forever, but it is a good solid choice, we have built a ton of them for snow, and they work GREAT. That said....if you own 0 bikes, and are buying a bike specifically for a snowbike, a 450 is lighter, cheaper, makes more power and revs more as stated.
Ewe are spot on ,If ewe juant juan bike for snow and dirt[trail riding} the 500 is the best choice, For snow only the 450 is on a different level. Even if ewe pump up a 500 it still wont pull the higher RPM like the 450 race motor. the long stroke has RPM limitations.
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Just going to leave this here:
2020 Ktm 450sx - Stock
2020 Ktm 500 Xcf-w with 450sx stock throttle body, intake, and muffler - Vortex Ignition.
When you add a FMF muffler, and a Vortex to the 450sx it picks up 3 hp and approx 3 ft lbs of torque.
Still no match for the 500.
On later tunes for the 500...we moved the rev limiter up to 11.2k like the 450 sx...and it would rev out just as far as the 450.
Chris
2020 Ktm 450sx - Stock
2020 Ktm 500 Xcf-w with 450sx stock throttle body, intake, and muffler - Vortex Ignition.
When you add a FMF muffler, and a Vortex to the 450sx it picks up 3 hp and approx 3 ft lbs of torque.
Still no match for the 500.
On later tunes for the 500...we moved the rev limiter up to 11.2k like the 450 sx...and it would rev out just as far as the 450.
Chris
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Same day...same stingy dyno.
P.S. Unless you guys start posting up dyno graphs supporting your thoughts....it is just your unsupported opinion.
P.S. Unless you guys start posting up dyno graphs supporting your thoughts....it is just your unsupported opinion.
