Underdrive means to slow the speed of the accessories (alternator, a/c, power steering and water pump). It is done by reducing the diameter/size of the crank pulley or increasing the size of the accessory pulley/s. Only 10-15% of the power gains from our pulleys come from underdrive. Top
Weight reduction is how we are able to increase power! Each pound of weight removed from the crank is worth roughly 2.7HP and this increase jumps even higher with forced induction, nitrous and variable valve timing. Top
Crank pulleys are getting confused with a harmonic damper. Another term "Harmonic Balancer" is a loosely used term in the industry. Technically it does not exist. The "balancer" part comes from engines that are externally balanced and have a counterweight on the damper. None of the engines we make pulleys for use a balancer as they are all internally balanced.
The crank pulley on most import and small domestic engines has a rubber ring in the pulley making them look like a damper. The rubber ring quiets noise from the engine accessories (a/c, alternator, power steering, and water pump). The car manufacturers call it NVH control (Noise Vibration & Harshness) of noises that might be heard inside the car. It is important to know amount of weight mounted outside the rubber ring is too small in size to act as an effective damper. Many crank pulleys have no rubber at all. Examples are some Honda B & D Series engines, the Nissan Altima, the 1.8L Eclipse, 2.3L Fords, Chrysler 2.2L's, and 1.8L SOHC VW's. Most owners who have installed UR crank pulleys notice the engine feels smoother. This is because the stock crank pulley is not as well balanced as our crank pulley. NVH from the crank pulley is small but it can increase much more with the installation of aftermarket intake and/or exhausts. As an example stock intakes use baffles and resonators to quiet intake noise. Aftermarket intakes eliminate the resonators and create big increases in engine noise when you hit the throttle. To most car owners some type of NVH can make the driving experience more enjoyable because you can really hear the engine noises.
The traditional damper protects against crank failure from torsional movement and crankshaft frequencies. A damper is not necessary on most modern engines because of engine design. The reason why are things like shorter stroke length, smaller displacement, shorter piston dwell time, no piston pin off-sets. More importantly the actual tune (computer programming) is the biggest factor in the potential for engine damage. Poor tuning leads to detonation which is an engine killer that no damper can stop. Top
This is the biggest urban myth floating around. The fact is stock oil pumps fail with the stock crank pulley and were failing even before our pulleys were available on the market.
The gerotor oil pump is an excellent design but has weaknesses. There are a number of reasons why this design can have failures. These causes may act individually or in combination to cause the actual failure:
To help avoid these failures the following steps should be taken:
A competent, trusted machine or performance shop should be used to rebuild your motor. It only takes one simple mistake to turn a costly engine rebuild into a doorstop. Top
The second biggest urban myth with no basis in fact. UR pulleys have the opposite effect on engine bearings. The combination of tight tolerances, precise quality control, perfect balance, and dramatic weight loss reduces stress on your engine. Engine bearing problems are purely associated to poor engine maintenance, use of heavier than factory recommended oils, improper engine building practices (like poor balancing), excessively revving of engines when they are cold, and owners expecting their factory oil pumps to handle engine power outputs beyond 3, 4, even 5+ times higher than stock Top
Car manufacturers state if a specific component is not designed by them for use on your vehicle then the component voids your warrantee. This has been an area of controversy for years as many aftermarket products are better in design and function than stock components.
Most dealers are looking for any excuse to avoid working on vehicles modified with aftermarket performance parts.
The MAGNUSON-MOSS WARRANTY IMPROVEMENT ACT, requires a dealer or Manufacturer to prove the aftermarket part actually caused the problem. If your dealer gives you a hard time let him know you are aware of your rights and they should back down quickly. Top
In most cases if you can change your oil or do a tune-up, then you can install our pulleys. They come with model-specific instructions covering everything from jacking up the car to the factory torque specifications. It is important for you to be aware that although the product seems simple it is critical it be installed properly. Our instructions are not a replacement for a factory manual. So if you're not sure go to a professional. Our site lists approximate driveway and professional install times for each product. Top
Yes. Belts must be changed with all our pulleys. The installation instructions list the part number/s for the belt/s we have found to work most consistently. The belt/s you will need are available from our web-site. If you find a belt size other than the recommended size that works please let us know.
It is important belts are slightly over tightened when first installed as belts naturally stretch when new. Top
The black coating on some of our pulleys is for done for wear protection. It protects the aluminum from the back of the belt which can become like sand paper as the belt gets old. Without the hard black anodizing the belt would cut right through the aluminum. Top
The only maintenance required is to check and replace the accessory belts every two years. Otherwise you basically bolt on our pulleys and forget about them. Top
The pulleys have nothing to do with the transmission and the gear ratios. The pulleys only change the speed of the accessories. Top
Our underdrive pulleys are designed to allow for an additional aftermarket stereo of up to 600 watts RMS. If the stereo system in question is above that wattage our stock diameter crank pulley will maintain the voltage output just like the stock crank pulley. Top
A UR adjustable cam gears allow you to adjust the angle of camshaft. These changes dramatically improve the peak HP, where the HP is in the rev-band, and total HP throughout the rev-band. UR adjustable gears allow for cam degree changes of up to 10 degrees positive or negative. UR gears have timing marks held to within 1 minute of a degree (60 minutes being in a degree).
We engrave the marks in hard black anodized vastly improves readability when adjusting the gears. Our gears are 1/3 as heavy stock gears. We use only stainless steel washers and bolts so you can enjoy years of flawless performance and looks. The UR bolt pattern assures our gears will remained locked in place once they are set. Top
Adjusting the camshaft can increase HP in DOHC cars from 8-16 HP for normally aspirated engines and 12-24 HP for forced induction engines. SOHC owners can expect small increases in HP (2-4 HP).
Adjustments vary but we have found for stock and mildly modified DOHC engines, whether forced induction or normally aspirated, that 2-3 degrees negative on the exhaust and 1-2 degrees positive on the intake produce the highest overall gains. SOHC cam owners can adjust the cam 1-2 degrees advance for more bottom end or retard 1-2 degrees for more top end.
Owners who are beyond the basic bolt-on parts would find themselves best served by having their sprockets adjusted while measuring engine output on a dyno or at the track. Top
Actually the answer is fairly complex. Car Manufacturers state that if a specific component is not Car manufacturers state if a specific component is not designed by them for use on your vehicle then the component voids your warrantee. This has been an area of controversy for years as many aftermarket products are better in design and function than stock components.
Most dealers are looking for any excuse to avoid working on vehicles modified with aftermarket performance parts.
The MAGNUSON-MOSS WARRANTY IMPROVEMENT ACT, requires a dealer or Manufacturer to prove the aftermarket part actually caused the problem. If your dealer gives you a hard time let him know you are aware of your rights and they should back down quickly. Top
Installation of adjustable cam sprockets is one of the more difficult bolt-on installations. The key to the difficulty is the importance of sprocket alignment to the factory specified alignment marks. These alignment marks, installation marks, are only correct if the engine has been located at TDC (top dead center). Add to this equation that some engines use balance shafts and the alignment procedure can even more difficult. Each of our sprocket kits comes with model specific installation instructions, including torque specification on the factory mounting hardware. But we feel that this installation is better left to a professional installer unless the owner of the vehicle has a good deal of mechanical experience (i.e. having done engine disassembly, or camshaft installation before). Top
That decision should be based on a number of factors. First is the amount of mileage accumulated by the belt, factory recommendations vary so check your owner’s manual. If you have less than half of the recommended mileage the stock belt can be re-used as long as there are no visible deformities or abrasions. Anything beyond the half way point will require close inspection and if even the slightest wear is visible the belt/s should be changed for safeties sake, as the motor is most likely driven aggressively and the recommendations do not take into account the top ¼ of drivers (the performance enthusiast).
Safety is the key parameter in this decision as the additional parts and labor cost at installation is much cheaper than engine damage at a later date (many engines are non-clearance or interference and losing the timing belt would cause major valve/piston damage). We recommend the use of the factory OEM timing belts. Top
The hard black anodizing on our cam gears is for long-term protection of the aluminum from the abrasion of the timing belt. The hard black anodizing will not wear away on the belt sections where the belts ride on the sprockets unless foreign debris gets into the engine cover. Top
The only maintenance required is to check and replace the timing belts at the manufacturers specified intervals or sooner based on your driving habits. We always recommend periodic checking of the tension on the five bolts. The fasteners should be tightened in a star pattern and only need to be hand tight; over-tightening is unnecessary and will cause the threads to strip out over time. Top
UR has spent many hours designing and testing each clutch model, both on the street and on the track, to ensure that each clutch provides maximum performance without compromising drive-ability or durability. The design of each clutch assembly is tailored to maintain original equipment type drive-ability with maximum holding power. The engagement point of any new clutch must be learned by the owner and the shorter pedal travel sometimes experienced with certain clutches will be hardly noticeable after the break-in period (300-1000 miles). Top
UR clutches are installed the same way any stock clutch would be installed. However, there are a few important notes to be aware of when installing solid hub discs. Many mechanics, especially dealership mechanics that only use original equipment parts, are not used to solid hubs and have a tendency to follow the standard installation procedures for sprung hub clutches. Not following these important steps during installation may result in a bent clutch disc voiding warranty. A bent clutch disc is caused by the transmission being hung on the hub of the disc during remounting of the transmission. A bent solid hub disc will not engage or disengage properly causing gear grinding, chattering, or even not being able to put the transmission in gear. Top
Each clutch is balanced to standards that exceed original equipment specifications. We only use the highest quality components and combine them with the strongest discs, hubs, springs, and rivets that are available today. The consistency of the components and materials used in every Ultra G clutch are perfectly matched and balanced specifically for each application. These measures ensure the holding power and long-term durability of our clutches are unmatched in the industry, providing the quality owners come to expect from Unorthodox Racing. Top