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Today’s modern big-bore utility quads produce plenty of stump-pulling power. They also have plenty of power-robbing obstacles to both overcome and contend with-the machines are inherently bulky, they have big heavy tires, and we can’t forget about all that waist-deep mud we always find ourselves getting stuck in! Yes, even though utility quads have plenty of power on tap, it seems that we always want a bit more. With that in mind, we put together plenty of tips and tricks, ranging from mild to wild, to get the most power from your 4×4.
4 Stages of Power
Today’s utility ATVs are powerful, agile, and tough, but that doesn’t mean that they can’t get any better. We have outlined four different stages that will take your stocker from a standard issue 4×4 to a “built to the hilt” utility machine that breathes fire (not really, but darn close).
Stage 1: Pipe, air filter, jet kit, and spark plug
In your search to coax more horsepower from your 4×4, the place to start is the exhaust system. Since aftermarket systems flow spent exhaust more freely than stock, they are the quickest way to get more horsepower from your quad (as well as adding a throaty engine note that tells of the power buried within your machine’s engine cases).
A good exhaust can be either a full system or a slip-on, and many of the newest quads only require a slip-on for optimum performance. Older machines and machines with smaller engines (400cc and smaller) generally benefit more from a full system, because the stock head pipe is closer to a pea shooter than a fire hose. When buying any pipe, be sure to ask for the dyno charts so you can see if the cost of buying a full exhaust system is worth the power gained, as well as what jets the company feels will work best for your type of riding. Usually richer jets accompany a high-flow exhaust modification.
A high-flow air filter is also necessary to get that mild performance gain you’re looking for. There are two types of filters-the foam type and the gauze type-both of which offer great performance gains. In our experience, neither is better than the other; it’s just up to personal preference. A good filter should seal well on the airbox manifold and come with a pre-filter cover for added longevity.
A clean air filter, properly jetted carburetor, and pipe, when working correctly, can produce as much as a six horsepower gain over a stock machine (depending on engine size, etc.). To round out the package, add a new iridium spark plug (we like NGKs) and you will see these four parts produce a gain that makes a big difference on the trail.
Stage 2: Power Commander, Cams, and Clutch Kit
The next logical step after Stage 1 is to add a Power Commander, cams, and a clutch kit. Power Commanders come in many different shapes, sizes, and even names, but essentially they all do the same job-for a carbureted unit they boost the ignition curve to produce extra power, while in a fuel-injected model they serve to remap the fuel injection and timing to produce more power than a stock unit. In the simplest sense, a Power Commander is an electronic ignition box that replaces an existing module or plugs into your quad’s wiring harness separately. These can add as much as four to five horsepower gain on top of an already powerful Stage 1 engine setup.
The other two horsepower parts of a Stage Two utility machine require special tools and generally the masterful hands of a technician. But with the right amount of time and some decent tools, both cams and a clutch kit can be added to your utility machine. Camshafts can be added to non-pushrod motors very easily and do not require any disassembly of the motor besides removing the valve covers. Horsepower gains from camshafts are not usually significant (usually one to two HP), but the throttle response and boost to the bottom, mid, and top-end of the power band are the most important power gains. Most camshaft manufacturers offer differing styles ofamshafts that are ground to produce power in specific areas in an attempt to increase low-end grunt or add over-rev power.
The purpose of adding the clutch kit to this package, even though it does not add horsepower to your unit, is simply that it will help to handle the extra horsepower your engine now puts out. Aftermarket clutch kits come in different shapes and sizes, so it is important to do some research on the specifics of each product before purchasing one for your unit. The clutch kit will reduce belt wear and slippage because of its beefier design.
Stage 3: The Mighty Big Bore
If bolt-on accessories just aren’t enough to pimp out your 4×4, then a big-bore kit is the way to go. Big-bore kits coupled with high-compression pistons are a potent way to max out the power of your utility machine. The size of the big-bore kit and the aggressiveness of the piston’s compression drastically affect the amount of horsepower yielded by a big-bore kit, so not all big-bore kits are created equal.
As with any ATV modification, big-bore kits are different for every machine. In fact, some machines can have multiple sizes of big-bore kits depending on the amount of material available to be removed from the cylinder. The general thought is that the more ccs gained by the kit, the more radically different the power output will be. However, size is not the only thing that matters for the power of a big-bore kit-the cams play an important role in allowing a larger fuel/air mixture to flow into and out of the engine.
A big-bore kit is one of the most costly and time-consuming engine modifications that can be made to a utility machine, but it can also make the largest gains in horsepower. The results of a big-bore kit being added to your 4×4 are strong bottom, mid-range, and top-end power, plus a substantial increase in torque. So if you’ve got the money, why stop at stage two when you can have the whole enchilada?
Stage 4: The Button Of Insanity
If you are a rider who needs the wildest, most powerful utility machine around, then look no farther than a nitrous oxide system. Installing a nitrous oxide system can mean an extra 20 horsepower at that push of a button! If that instant power increase doesn’t get your attention, then the hefty $800+ price tag will. Depending on your choice of system, it could mean a price tag as high as $1,200! Why would anyone turn to expensive nitrous? The answer is simple-raw power. Some of our ATV compatriots are looking for a no-holds-barred game of horsepower, and nitrous is the ultimate weapon.
There are two types of nitrous-oxide systems available for purchase: the wet system and the dry system. Briefly explained, a wet system injects the nitrous directly into the combustion chamber via the intake manifold, while a dry system is external and is mounted inside the air box (outside of the air filter). There are really no advantages (horsepower wise) to one type of system. The dry system is the easiest to install and requires minimal teardown of the machine, while a wet system requires a bit more work to install, but doesn’t affect the machine’s air/fuel mixture like a dry system (which requires rejetting the carburetor). Ultimately, nitrous is pricy and a bit exotic, but it can sure turn heads with the simple push of a button.
Sidebar 2:
How Does Tire Size Affect Utility Horsepower?
Most ATVers put larger tires on their machines before they even take it out of the dealership. Bolted on to stock machines, bigger tires put more weight and rolling resistance against the drivetrain, which decreases top speed and acceleration. New meats also affect the shift points of the CVT mechanism and overwork the clutch, causing belt slippage. But don’t despair-these symptoms can all be significantly decreased or eliminated by regearing the transmission of your quad.
Most riders put pipes, air cleaners, jet kits, and power modules on their machines in an attempt to regain the horsepower that is lost from larger tires. However, the performance gains from those bolt-on items can be seen again when the transmission is regeared. When the final drive of the transmission is reduced (to compensate for the larger tires) it adjusts the gear ratio to mimic the machine’s power and acceleration characteristics in stock form. This performance upgrade works to help enhance the individual gains of the previously installed pipe, air cleaner, jet kit, and power module.
The general rule of thumb for regearing is that any machine turning a tire 28 inches or taller should be regeared. The actual regearing process and installation is an internal affair and requires the skills of an experienced technician, but isn’t a monumental undertaking for a seasoned mechanic. However, we would suggest that only a trusted mechanic crack open your quad’s cases, because an ATV transmission can be complex and frustrating to work on in a home shop or garage.
Sidebar 3:
Clutch Kits For Torque
A good strong clutch is the only way to get as much of the horsepower that your machine has to the ground (which is why a clutch kit is included in stage two of the horsepower upgrade section). Even though a clutch kit does not add or take away horsepower, it has the power to make or break the power characteristics of any machine. Clutch kits have a number of different variables within them that make them complicated and difficult to install, but luckily, many of the top manufacturers have done nearly all of the testing already and produce ready-to-install units.
Most aftermarket clutch kits raise the engagement rpm of the machine in order to produce a powerful initial acceleration. For example, a stock clutch may engage at 600rpm, while the aftermarket clutch could engage at 800-1,000rpm. The higher rpm engagement of an aftermarket clutch is a double-edged sword, because it may limit the top speed of your quad. This is due to the idea that the engine can only rev to a certain rpm amount and the clutch mechanism takes away necessary rpm to produce speed. This can limit a machine’s top speed by as much as 10mph, or not at all, depending on the ATV and clutch mechanism.
The potential limiting of top speed takes a back seat to the good things that a clutch kit does. First, and most importantly, it keeps the drive belts of the CVT system tighter, which puts more power to the ground and reduces the amount of belt fatigue caused by a weak clutch. The clutch kit also allows the CVT system to upshift and backshift more effortlessly due to its consistent belt tension. As a final note on clutch kits, be sure to check with the manufacturer to determine if any special tools are required for installation (chances are there are) or if it voids any warranty your quad may have.
Sidebar 4:
Three Steps To Help Keep It Cool
Once you have pumped up the horsepower of your quad, it is going to produce more heat faster than it does in stock form (not to mention the fact that you are probably going to work it harder). There are a couple of things that you can do to make your ATV run cooler.
1. To start with, drain the old coolant and replace it with something like Liquid Performance Racing Coolant, High Lifter Liquid Cool, or Redline Water Wetter. Any of these coolants will significantly decrease the temperature of your machine (some as much as 40 degrees F), which increases engine life while having better lubrication properties for the water pump. One important note about these coolants is that they are not antifreeze, meaning they do not prevent your motor from freezing. Drain these coolants before winter if you live in a cold area.
2. Add an oil-cooling agent like High Lifter’s Motor Cool. Motor Cool is designed to reduce friction between moving parts, which can decrease operating temperatures (High Lifter has recorded up to 57 degrees F decrease in temp). High engine temperatures can lead to excessive parts wearthe horsepower that is lost from larger tires. However, the performance gains from those bolt-on items can be seen again when the transmission is regeared. When the final drive of the transmission is reduced (to compensate for the larger tires) it adjusts the gear ratio to mimic the machine’s power and acceleration characteristics in stock form. This performance upgrade works to help enhance the individual gains of the previously installed pipe, air cleaner, jet kit, and power module.
The general rule of thumb for regearing is that any machine turning a tire 28 inches or taller should be regeared. The actual regearing process and installation is an internal affair and requires the skills of an experienced technician, but isn’t a monumental undertaking for a seasoned mechanic. However, we would suggest that only a trusted mechanic crack open your quad’s cases, because an ATV transmission can be complex and frustrating to work on in a home shop or garage.
Sidebar 3:
Clutch Kits For Torque
A good strong clutch is the only way to get as much of the horsepower that your machine has to the ground (which is why a clutch kit is included in stage two of the horsepower upgrade section). Even though a clutch kit does not add or take away horsepower, it has the power to make or break the power characteristics of any machine. Clutch kits have a number of different variables within them that make them complicated and difficult to install, but luckily, many of the top manufacturers have done nearly all of the testing already and produce ready-to-install units.
Most aftermarket clutch kits raise the engagement rpm of the machine in order to produce a powerful initial acceleration. For example, a stock clutch may engage at 600rpm, while the aftermarket clutch could engage at 800-1,000rpm. The higher rpm engagement of an aftermarket clutch is a double-edged sword, because it may limit the top speed of your quad. This is due to the idea that the engine can only rev to a certain rpm amount and the clutch mechanism takes away necessary rpm to produce speed. This can limit a machine’s top speed by as much as 10mph, or not at all, depending on the ATV and clutch mechanism.
The potential limiting of top speed takes a back seat to the good things that a clutch kit does. First, and most importantly, it keeps the drive belts of the CVT system tighter, which puts more power to the ground and reduces the amount of belt fatigue caused by a weak clutch. The clutch kit also allows the CVT system to upshift and backshift more effortlessly due to its consistent belt tension. As a final note on clutch kits, be sure to check with the manufacturer to determine if any special tools are required for installation (chances are there are) or if it voids any warranty your quad may have.
Sidebar 4:
Three Steps To Help Keep It Cool
Once you have pumped up the horsepower of your quad, it is going to produce more heat faster than it does in stock form (not to mention the fact that you are probably going to work it harder). There are a couple of things that you can do to make your ATV run cooler.
1. To start with, drain the old coolant and replace it with something like Liquid Performance Racing Coolant, High Lifter Liquid Cool, or Redline Water Wetter. Any of these coolants will significantly decrease the temperature of your machine (some as much as 40 degrees F), which increases engine life while having better lubrication properties for the water pump. One important note about these coolants is that they are not antifreeze, meaning they do not prevent your motor from freezing. Drain these coolants before winter if you live in a cold area.
2. Add an oil-cooling agent like High Lifter’s Motor Cool. Motor Cool is designed to reduce friction between moving parts, which can decrease operating temperatures (High Lifter has recorded up to 57 degrees F decrease in temp). High engine temperatures can lead to excessive parts wear and heat buildup that will eventually lead to an engine failure. And we all know that we want to eliminate that as much as possible!
3. Finish off the cooling treatment of your utility monster by installing some heat wrap for the exhaust system and bodywork. Wrapping the exhaust with heat wrap will keep heat from reaching the rider and melting any plastic pieces that may come in contact with the exhaust system. It has also been said that keeping heat wrap on exhaust components improves engine performance by increasing the velocity of the exhaust.
Ultimately keeping your quad running cooler using these techniques will make its engine last longer and maintain peak horsepower for more rides-two things that will keep you in the saddle instead of in the shop.
Sidebar 6:
The Power Players
These are a few companies that make horsepower upgrades for utility machines. Check with them to see exactly what products they make and what machines they specialize in.
Moose Utilities Division-see your local Parts Unlimited Dealer or go to www.mooseutilities.com
High Lifter-800-699-0947 or go to www.highlifter.com
Penland Brothers Racing-706-746-2812
EPI-218-829-6036 or go to www.erlandsonperformance.com
Big Gun-909-948-7029 or go to www.biggunexhaust.com
Pro Circuit-951-738-8050 or go to www.procircuit.com
FMF-310-631-4FMF or go to www.fmfracing.com
DYNO Jet-800-992-4994 or go to www.dynojet.com
HMF-866-HMF-PIPE or go to www.hmfengineering.com
Dalton Industries-902-897-3333 or go to www.daltonindustries.com
wear and heat buildup that will eventually lead to an engine failure. And we all know that we want to eliminate that as much as possible!
3. Finish off the cooling treatment of your utility monster by installing some heat wrap for the exhaust system and bodywork. Wrapping the exhaust with heat wrap will keep heat from reaching the rider and melting any plastic pieces that may come in contact with the exhaust system. It has also been said that keeping heat wrap on exhaust components improves engine performance by increasing the velocity of the exhaust.
Ultimately keeping your quad running cooler using these techniques will make its engine last longer and maintain peak horsepower for more rides-two things that will keep you in the saddle instead of in the shop.
Sidebar 6:
The Power Players
These are a few companies that make horsepower upgrades for utility machines. Check with them to see exactly what products they make and what machines they specialize in.
Moose Utilities Division-see your local Parts Unlimited Dealer or go to www.mooseutilities.com
High Lifter-800-699-0947 or go to www.highlifter.com
Penland Brothers Racing-706-746-2812
EPI-218-829-6036 or go to www.erlandsonperformance.com
Big Gun-909-948-7029 or go to www.biggunexhaust.com
Pro Circuit-951-738-8050 or go to www.procircuit.com
FMF-310-631-4FMF or go to www.fmfracing.com
DYNO Jet-800-992-4994 or go to www.dynojet.com
HMF-866-HMF-PIPE or go to www.hmfengineering.com
Dalton Industries-902-897-3333 or go to www.daltonindustries.com