What are some inexpensive ways to pull a few extra hp out of my 2004 Pred.. I can't remove the airbox because I do a lot of trail riding and water and mud are common. Other then that I am all ears!!

 

Your engine is just a pump so you need to make it breath better to make more HP. About the best you can do is in this order:

#1 A good pipe.
#2 Advance key
#3 A good cam
#4 High compression piston

From here on out things can get crazy. Things like stroker kits or big bore kits, or you can even go nitrous oxide.
It just depends on what you want and how much you have to spend.

 

change the fliuds to full syn like royal purple frees up some hp. not sure how much on quads but it freed up some on an auto. i think it was horsepower tv awhile back did a before and after fliud change on an dyno

 

Not changing the intake makes it difficult. The preddy loses a lot of power because the air intake is very restrictive. In fact, I'm sure it is the most ridiculous, restrictive and backasswards intake out there! Removing the entire box improves performance tremendously. However, as you indicated, you ride in the mud and water. I can tell you from experience that I have to avoid any water as my intake has a prefilter for a lid on a completely different aluminum intake and even a very small amount of water will find its way up there. Doctorturbo is right on the money, as he should be, he has a long history of making hp's in cars and understands the concept. However, I don't think you will see much of a gain adding an exhaust without increasing the air intake. I'm not saying you won't add a couple of hp's, but I'm not sure if it will be worth your money or if you will notice the gain. Unfortunately, there are sacrifices to make whenever you want to make more power. In your situation, if you're really dissatisfied with the lack of power, I would consider buying an atv that will have the power you want in stock form, like a raptor 700 efi. But, that means selling your preddy and spending more money, which always seems to come up and get in the way of things!!! I think I would leave the preddy the way it is unless you don't mind parting with a few hundred dollars to make a small gain in power. Just my 2 cents!

 

<div class="FTQUOTE"><begin quote>Originally posted by: firehog

Not changing the intake makes it difficult. The preddy loses a lot of power because the air intake is very restrictive. In fact, I'm sure it is the most ridiculous, restrictive and backasswards intake out there! Removing the entire box improves performance tremendously. However, as you indicated, you ride in the mud and water. I can tell you from experience that I have to avoid any water as my intake has a prefilter for a lid on a completely different aluminum intake and even a very small amount of water will find its way up there. Doctorturbo is right on the money, as he should be, he has a long history of making hp's in cars and understands the concept. However, I don't think you will see much of a gain adding an exhaust without increasing the air intake. I'm not saying you won't add a couple of hp's, but I'm not sure if it will be worth your money or if you will notice the gain. Unfortunately, there are sacrifices to make whenever you want to make more power. In your situation, if you're really dissatisfied with the lack of power, I would consider buying an atv that will have the power you want in stock form, like a raptor 700 efi. But, that means selling your preddy and spending more money, which always seems to come up and get in the way of things!!! I think I would leave the preddy the way it is unless you don't mind parting with a few hundred dollars to make a small gain in power. Just my 2 cents!</end quote></div>


I am not dissatisfied with the power, just want to see if I can get a little more. What about upgrading the ignition? What kind of power gains are available there?

 

Actually, I forgot about the cdi. It does make quite a bit of improvement for your 04. It raises the rev limiter by like 1000 rpm's and gives a better power curve. I think there are only like two mfr's out there for the preddy. I haven't made that upgrade with mine as it is my understanding that polaris already increased the rev limiter on the 07's stock ignition and I'm not sure if an upgrade would make much if any difference. I have asked around and can't seem to find anyone who has made the upgrade or who has knowledge of it. Not going to blow $300 for nothing! LOL! But, I know for you it will make a noticeable difference. Doesn't increase horsepower, but improves timing.....glad you mentioned it!

 

Off Road Junkie, I speak in generalities about engines and not of specific makes unless I own one, or have owned one.

This being the case, it's always really nice to have someone on here that knows specifically about your engine; like firehog. He can talk about things that I don't know about like crappy intakes and other specifics like that. That is why information from people like firehog is invaluable.

Now I'm goiing to talk generalities again. Dollar for HP, an upgraded ign system is probably the worst investment you can make. Although, if you can raise your RPM some, you can pick up some power. Modern CDI systems work very well and the curve from the factory are usually very good. Again, I don't know about your Preddy.

The whole idea is to get your engine, (just an air pump) to flow more air. If firehog says the intake is crappy, then by all means, get an intake. This will improve flow, and this is what you want for a few more HP.

If you do get an intake and put it on, come on here again and let us all know how it works out so we can all learn.

 

<div class="FTQUOTE"><begin quote>Originally posted by: Doctorturbo

Off Road Junkie, I speak in generalities about engines and not of specific makes unless I own one, or have owned one.



This being the case, it's always really nice to have someone on here that knows specifically about your engine; like firehog. He can talk about things that I don't know about like crappy intakes and other specifics like that. That is why information from people like firehog is invaluable.



Now I'm goiing to talk generalities again. Dollar for HP, an upgraded ign system is probably the worst investment you can make. Although, if you can raise your RPM some, you can pick up some power. Modern CDI systems work very well and the curve from the factory are usually very good. Again, I don't know about your Preddy.



The whole idea is to get your engine, (just an air pump) to flow more air. If firehog says the intake is crappy, then by all means, get an intake. This will improve flow, and this is what you want for a few more HP.



If you do get an intake and put it on, come on here again and let us all know how it works out so we can all learn.</end quote></div>

Doctorturbo, in your opinion, would he notice any gain by adding an exhaust without modifying the intake? The key word being notice, as it does allow more air out which should give you some gain, I would just hate to recommend he do all the things I did without modifying the intake, thus seeing him throw good money away. Unfortunately, when I make my mods it is not in stages. I wish I had the patience and then documented them so everyone here could see what mod did what. Maybe someone else has done that and will share it with us?

 

Wow, firehog, there you go putting me on the spot. Ha ha ha ha.......

As a gereral rule the exhaust is the most compromised piece on any factory engine. The factories have to keep it at a low DB and also have to have some backpressure to keep decent low end torque.

If it's anything like my KFX it needs to be replaced with an aftermarket exhaust system. I cut my can up to see what's in there. I was horrified at the design of the can. The exhaust had to go half way down the can and bounce off a wall and go back up the can and then bounch off another wall , go through a pipe into a stratified pipe and then find it's way out of the tip!!! It was crazy restrictive!!!

Is the Preddy the same way? I just don't know? I have added headers to engines and always picked up power without any other mods. I would think the Preddy would be the same. BUT, most quads have a good intake so all bets are off.

<div class="FTQUOTE"><begin quote>Unfortunately, when I make my mods it is not in stages. </end quote></div>
As you already know, this is the best way too make mods. IMHO mods are best to do in packages.

If you say that the intakes are junk, then the best thing for ORJ to do is to is to by one and buy an exhaust, jet it and go have fun.

 

Thanks for the input doc. Unfortunately, like ORJ said, he isn't willing to modify his intake due to his riding style. I do know he will see a noticeable increase with a new cdi box as the preddy's see their rev limit way to fast stock. And, if he wants to throw a few bucks at an exhaust and jet it, he will see some more improvement without jeopardizing his intake and riding style. It would be good to hear back from him after his mods and find out what gains he made and if he is happy with them....so, go for it ORJ! Now you're on the spot!!!!