im not favoring anybody but i do beleive that a 400ex that had the same horsepower as a Raptor would win, because of the weight.it depends on rider weight as well.

 

The Raptor is so choked off that a pipe/filter/jetting will give it nearly 50 hp. I know ads sometimes seem off base by claiming high power gains, but those gains are there-though maybe not at the peak. White Bros. claims 4-7hp on the 400EX, but you see it in the midrange not at the peak so people think they are lying.

Torque is the real measurement here that matters. A broad torque curve is what makes you accelerate. HP is derived from the torque measurement. I think the formula is HP=Torque x RPM divided by 5250.

This is why the Raptor with only 34 HP can accelerate so quickly-it has loads of low end torque.

As for nitrous- you are not only gaining HP, your getting a ton of torque. A stock motor that makes 35hp at 4000 RPM would take 46 ft. lbs. of torque to get that. If you add a 15hp shot of nitrous to bump that to 50hp at 4000 RPM it would take 66 ft. lbs. of torque to get that. The HP only went up by 15, but the torque increase was 20 ft. lbs. That is what you feel.

A 50hp 400 would only have the same top speed as a 50hp Raptor (or anything else for that matter) if the transmission gearing/sprockets and tire size were the same on both machines, and the upper RPM hp figures were very close. If one machine has 25hp at 9000 RPM and another only has 15hp at 9000 RPM it will not go as fast.

I think what I said is pretty accurate but I'm sure there are a lot of guys who know more than me about this. Are there any engine builders with access to a dyno reading this? I would love to hear your comments on the subject.

 

Urbancowboy,
You are still considering that Horsepower is the be all end all. From what I understand, and I could be wrong, if you took a stock 400ex and increased the horsepower with a big bore kit it may be able to get to the same top speed as a raptor but would take it longer to get there. If you just increased the torque you would stay at the same top speed as a stock 400ex but would get there alot faster.

This is why I was disappointed after I had put in a big bore kit into my 250x motor and still got beat by piped only 300ex's. We had the same top speed but he got there a lot quicker because the 300ex's have more torque because of the larger crank. I had increased the horsepower but had basically the same torque and I was still being beat by over 50' with no chance of catching up.

So, to answer your question mudmunster, to beat a raptor you would need a big bore kit to get the top speed you want and a larger crank and gearing for the torque to get up to that top speed faster. Or like garyc660r said add some juice and that should get things movin in a hurry, of course not to mention a rebuild every couple of weeks that may slow you down.

If I am wrong or am missing something in this equation please set me straight with facts.

 

Just thought that I would let you know. Pick up a copy of the new ATV Action mag. They do a small article on a Raptor. They dyno'd stock and then after the addition of Jet Kit/Filter/CT Racing Full Pipe. On the low end starting about 3000rpm it picked up ~+5hp to the peak of +14.4hp which was just shy of the 50hp mark but barely! This looked to be independently done by the magazine, so we should see the same in the new Dirt Wheels. I know one thing, I'm happy with mine! Just raced my buddy on asphalt for the first time this past weekend. We've both got the same exact setup DMC Pipes/K&N's/Jet Kit. He's got the 400 and I've got the Raptor. He's still at stock gearing and I'm down one in the front and up two in the rear(geared for the tight trails). Flying down the road we all took off wide open, I was in the rear of the pack. I pulled on the 400 and passed him like he was standing still to what I would say was 65-70mph, basically topped out for the raptor with this gearing. Just thought you'd like to know, my buddy is on this forum if you think I'm blowing *hit.

 

hey man this is not another mine is better it is honest truth i have a 2002 400ex that has a 440 kit k&n power kit and a white bros pipe&silencer and i have race a raptor up hill and on a flat and beat them up a 100yd really steep hill now that may be the lack of guts on the rider but on the flat i spanked it through five gears and i did have but 400 yds and i beat it but that might not been enough roo i don't know how long it takes for a raptor tho get up to top speed but any one on the oklahoma dunes wants to prove me wrong that is cool w/ me but i do know one thing i am not going to back down from a challenger

thank you much for your time

 

We should be realistic here..Although I don't own my own dyno, i've never seen a four stroke four wheeler(any make, model, etc.) gain more than 4-5 hp when adding a pipe, jet kit, and filter. It's usually more like 1-2 HP!!!

 

We should be realistic here..Although I don't own my own dyno, i've never seen a four stroke four wheeler(any make, model, etc.) gain more than 4-5 hp when adding a pipe, jet kit, and filter. It's usually more like 1-2 HP!!!



If you don't own a dyno then where are you getting your info from?

 

mudmunster,
I just posted over on Yamaha forum about road tires for the Raptor. What are you getting? Are you getting a Raptor to ride on the road or a 400EX to ride on the road. I am getting confused on which one you are getting. I would say throw caution to the wind and get both the Le Raptor and the 400ex. Then and only then will you be satisfied until Honda comes out with there new sport ATV.
Chet

 

quadmxer....Go look at some dyno sheets sometime. If you run a pipe that is totally open, you might gain 4-5 hp for a very short time in the power curve, otherwise it's usually less than that. Reality is, with the low tech 4 strokes that are currently available in atv's(no, the Raptor motor is not high tech, cannondale? maybe. But not for the money) it takes a ton of money(cam,pipe,ported,etc.) to get any real hp out of it. After you've stuck all of your money into this motor to get what, a ten hp(if your lucky) gain, it is a time bomb, and it's too loud to ride anywhere but a racetrack or certain sand dunes. Sure, you can ride it anywhere you want, but that's part of the reason places to ride are getting few and far between. I get most of my info from experience.

 

Letitsnow
Well your certainly entitled to your opinion. If you have some dyno runs that you are referencing then by all means post a link to them. Try here- http://www.geocities.com/gtthunder.geo/ As for modified four strokes being time bombs-I'm sure there are thousands of owners and builders who would disagree with you. Do you think the Honda 600F4 street bike is a time bomb, because it definitely makes more than 50 hp? How about the DS650? That makes mid 40's stock and Rotax is one of the most reliable engines out there-even when modified. The 99 YZ400 made 42 hp stock. A new YZ250F makes 32hp stock. That's the same technology used on the Raptor, which is only making 34hp stock. Do you really think it would be that dificult to gain 10hp with it? A 400EX makes about 26-28hp stock. 440 kits will bump that to mid 40's. These are reliable motors as well. Thats around 20hp on a 400 class machine. You think a modded Raptor will only gain you 10hp (in your words-if your lucky). If so you have either had bad luck with a four stroke motor and your mad about that or your a diehard 2 stroke fan (which there is nothing wrong with by the way). I'm not trying to start anything with you letitsnow but I think your way off base with your post. A 4 stroke will never gain horsepower like a 2 stroke with the same mods but there are big gains to be found. If you don't believe that look to indy cars, nascar, and dragsters. All 4 strokes making huge power. I agree that quad motors are a little behind behind the times in technology but they can still make good power.