Ya the headers don't do much LOL, they only about double the HP gain from a slip on only. This thread has a bit of misinformation in it I would suggest you use the search function and surf the net for more clarity. Search on pipes, airbox, jetting.

Problem with asking queations like this is you get the opinion of people who are trying to justify the mods they have made and make opinions with prejudice.

No comment on the front sprocket I haven't tried.

Bar none the cheapest mod... air box lid take it off and make a run. You need it to hold in the filter so you will have to cut it up if you like the gains from the test run. Also make a run if you can with no filter to see if the stock element is restrictive, this will answer the question for you.

Read the CTracing link.

 

I can't believe what I just read! Take off the filter to see if its restrictive??!!!! What kind of an idiot posts statements like that. And you accuse me of giving misinformation?! We know the stock element is restrictive. There wouldn't be much sense in replacing it if it weren't.

I challenge you Catalac, since you seem to know all about it, to find show me one single dyno that shows more than two horsepower difference between a full system and a slip on with all other mods being equal. Guess what, it doesn't exist for a raptor. All aftermarket headers are the same internal diameter as the stocker. The bends are the only change in the aftermarket designs.

Pull your head out of your b@tt and quit posting crap that does nothing more than take up space and confuse those who want a straight answer.

~HoundDog

 

I can't believe what I just read! Take off the filter to see if its restrictive??!!!! What kind of an idiot posts statements like that. And you accuse me of giving misinformation?! We know the stock element is restrictive. There wouldn't be much sense in replacing it if it weren't.


Point above is run stock then run with no lid then run with no filter i.e. 3 runs....

Stock versus no lid big difference when I tried it. Second comparison 'no lid' verses 'no lid AND no filter' there was no difference, point being the stock filter is not restrictive but the air box lid is.

Here ya go on slip on versus full of the company you recommended! Maybe I'm blind but it looks like double to me?

http://www.hmfengineering.com/yamraptor.html

 

Anyone that takes a chance running their engine with no filter deserves anything that happens to them. All it takes is one small rock, seed or anything else and you need a new top end. Telling someone to run with no air filter even for a short period is bad advise.

Secondly, buy a feeler guage and measure the inside diameter of the stock header, yoshimura header, hmf header... they are all exactly the same.

HMF claims that their header moves the hp curve upward. It provides less horsepower than the stock at low and mid RPM and more at high RPM but does not create much change on the overall gain through the powerband.

Here are the numbers from HMF: (hp gain)

Slip-ON Full System

4 hp @ 2500 rpm 4 hp @ 2500 rpm
7 hp @ 3500 rpm 7.5 hp @ 3500 rpm
5 hp @ 4500 rpm 6 hp @ 4500 rpm
4 hp @ 7500 rpm 8 hp @ 7000 rpm

If you do the math, this gives the slip on system an average of 5.0 hp gain and the full system an average of 6.375 hp gain meaning the full system showed an average difference of 1.375 hp. Hmmm, didn't I state that the header made no difference of more than 1 or 2 hp difference in my earlier post?


I don't know about your skunks but maybe you should make your your opponent is as unintelligent as you have proved yourself to be before starting another argument.

~HoundDog

 

Every time someone gets a new Raptor we go through this, so here is my 2 cents.

It sounds like the only racing you are going to be doing is with your buddies, maybe on a field or something. You can spend thousands of dollars on chromy-go-fasters and you still aren't going to be any faster if you left your quad stock. But, knowing that the need for speed is going to drive you to spend all your hard earned money on "stuff", my experience says you need to do this;

Buy a slip-on exhaust. You will find that there are as many opinions about slip-on's as there are slip-on's, so get one you can afford. I like White brothers R4. It looks good, sounds good withought being obnoxious and is fairly inexpensive. Forget the header replacement. Unless you are going to build your motor to be a dune blasting rocket, it's a waste of money. The stock header is good. By the way, you will notice the power increase expecially comming out of corners.

If you're going to be riding in a lot of dust like on trails, I wouldn't go with the K & N. Get the GYTR foam filter and adaptor for $100. The Pro Flow is pretty much the same and the same price. The K & N seems to be better suited for the sand.

With the new filter and adaptor (whichever one you get) you can really increase your power by taking off the air box lid but you will have to rejet your carberators or you can do damage to your motor by running too lean. Plus, it won't run worth a crap anyway.

Believe it or not, you can increase your speed by not doing any of the stuff I listed and improving your suspension instead, but that's another thread.

If you change your front sprocket and reduce the number of teeth by one, you will lose a little of your top speed, but you will feel tremendous difference on take offs and out of corners. It's hard to believe what difference one tooth can make.

This is my experience not my opinion and just 2 cents worth.

 

I agree not a great idea to run with no filter but I did say if you can, I have a clean area I could.

To challenge you, can you show any dyno information that shows a comparison of filters and airbox mods to back up your claim?

Misinformation from you yes... (unless DirtWheels are wrong) headpipes and mid pipes are different!

Copied from DirtWheels Feb 02
SIZE & WEIGHT
One area that can effect horsepower is the inside diameter of the headpipes. The stock Raptor headpipe measures 1.1 inches. This is the same diameter as the headpipes on the Alba, White Bros., CT, Trinity, FMF, Bill’s and the Pro Circuit units. The Graydon, Big Gun, Sparks and Yoshimura measured out to a 1.25-inch inside diameter.
The next measurement we checked out was the distance it took for the two header pipes to converge into the single mid-section pipe. The majority of the pipes made this connection within twelve inches from the engine exhaust ports. The FMF unit, however, traveled twenty inches before joining the midpipe and the Trinity headpipes traveled all the way to the muffler#.
Another measurement we compared was the outside diameter of the midpipe. Trinity, Bill’s, Pro Circuit and Yoshimura had the same 1.75 inch diameter as the stock Raptor mid pipe. Alba, CT, Sparks, Graydon, FMF and both White Bros. mid pipes were larger at two inches.
All of the pipes in this shootout weigh less than the stock Raptor unit, which tips the scales at 13 pounds. The lightest one of the bunch is the Pro Circuit at a feathery 7.6 pounds. The heaviest one is the CT unit at 11.25 pounds. The rest fall somewhere in between these two

Sorry on the "average hp" I didn't know that you only run your's at half throttle and never go over 4500rpm?? (that's how my wife drives though) At WOT 7000 rmp it's double!

 

The bigger name companys like Sparks and CT have pipes built for bigger hp gains when the motor is built with larger header and mid pipes with quicker bends coming out of the head for better over all performance through out the power curve. I tried 6 total pipe systems and header & mid pipe size and bend make a huge difference when wanting the power in a certain area.

 

This will be my last post on this thread. You have failed to produce any evidence save one article from dirtwheels (ask some members how much credibility dirt wheels has around here). You have no mathematical or published basis for your comparisons and you misquote actual publications from other sites. The question was never at what point the bike was being operated but what hp gains were provided by slip on and full systems. These bikes are being ridden at all ranges of the powerband so hp gains must be considered as a whole. You have wasted enough of my time.

~HoundDog

 

Catalac, I suggest you get more knowledge before you start chewing people's a$$! First of all, never ride or drive anything without a filter, have you ever RODE a 4 wheeler and seen how dirty the filter is? Get that in your carbs and cylinder and see how long it lasts. Next, You don't get much out of headers unless they are larger. But, if you can't have larger holes coming out of the head and into the slip on, then it is no help. I'm not saying that you won't get anything out of it, I'm saying that it's not worth 200 to 300 dollars more than just the slip on for 1 or 2 horses. My money can go into something more productive than that. That's why all headers are the same size, if they could go bigger, then they would. Then, this upgrade will never double hp from a slip on, you must be reading Dirtwheels. You'll get laughed at just for that!!!! You have a bad source of info. already. You'll learn a lot more by this forum then you would in that mag. Then, the airbox thing is the same deal, if you have no airbox, you have more air, which makes you jet to have more fuel, which gives you more hp. All you are trying to do is get the most air and gas and the right mixture, in and out of the motor as fast as you can. With the proflo comment, if you have a stock filter, and cut the holes in the top and cut the flaps, it will be about the same gain as the proflo, but if you have the same setup with the proflo, it will give you slightly more, not much, but more. On the sprocket issue, have you ever rode a mountain bike, cuz it seems as though you have never ridden a 4 wheeler? Change the gears and try to use the same power by your feet and see what happens.

Quote
Bar none the cheapest mod... air box lid take it off and make a run. You need it to hold in the filter so you will have to cut it up if you like the gains from the test run. Also make a run if you can with no filter to see if the stock element is restrictive, this will answer the question for you.

This quote is true to an extent, it will not cause any more flow, but ONLY because you didn't jet for each change. More air, more gas, more air, more gas. Write this on the board 50 times or until you learn it.

 

Hoouuund doggyyyy uu da mannn!!!!!!!!!!