If not, you won't make the boost that the blower is capable of. In this instance, if the blower pulleys were selected to make decent boost at low engine speed, you would end up with excessive boost at higher engine speeds. Superchargers are currently available on several Ford models, as well as Buick and Pontiac cars. Recommended primary tube diameters and collector sizes are: Small Blocks: 1-7/8" to 2" with 3-1/2" collectors Big Blocks: 2-1/8" to 2-1/4", with 4" collectors, Maximum effective compression ratio on gas not to exceed 24:1. Trending Stories. So our power output estimates above are somewhat typical of any of Weiand's blowers, with the following exceptions: At very low engine speeds, the smaller blowers will typically produce more torque than the bigger blowers. The main thing that needs to be addressed with a blower is to make sure that detonation is controlled. Table 2 shows the amount of air per blower revolution the Weiand blowers pump. 2. You will need carburetors that have a "boost referenced" power valve circuit. The amount of boost that can safely be run is primarily determined by the compression ratio of your engine and the gas that you are using. Again, the 6-71 through 14-71 will outperform the smaller blowers in the high rpm ranges. Formulas have been developed that convert your static compression and supercharger boost to the effective compression ratio. Centrifugal superchargers and screw type superchargers are called "internal compression" blowers because the air compression takes place inside the supercharger. There are currently three basic types of superchargers being sold in the performance market today: the Roots type, centrifugal, and "screw" type. 34� is a very safe figure and should provide close to optimum performance. This allows for a more compact package for easier underhood installation in many applications. Supercharging is an extremely effective way to reliably increase horsepower and torque, particularly in the low to mid rpm ranges where most street machines are operated. The Pro-Street 256 is a good all around compromise. Supercharger boost is largely misunderstood, even by some experienced performance enthusiasts. In addition to providing fuel for the motor, the carburetor also is the restriction through which air must pass to get into the blower and the motor. The helix style rotor was developed by General Motors for larger GMC superchargers. This phenomenon can improve gas mileage under certain circumstances, although typically on an overall basis fuel economy will decrease about 3%. With a Roots blower, the carburetor functions basically the same as it would on an unblown engine, except it now sits on top of the supercharger. The Rolls-Royce Merlin is a British liquid-cooled V-12 piston aero engine of 27-litres (1,650 cu in) capacity. How you plan to drive your vehicle is important because you can set up your blower to be more efficient at high engine speeds or more efficient at low engine speeds, or you can arrange for the best compromise for the full engine rpm range. Cranks & Balancing; assy, mallory/ lead, micro-polish. Rods; recondition, re-bush, float, pin fit. The 2020 Camaro is here to deliver the kind of bold design, precision thrills and advanced performance technology that can only be experienced behind the wheel of this iconic sports car. You can build what appear to be two identical engines and one will detonate and the other one won't, so the numbers given in this chart are not absolute hard and fast figures. It is usually a good idea to run spark plugs that are one to two ranges colder than normal with a blower. If your carburetor is too lean, it will cause detonation, which can destroy your motor. Then read the new 34� mark like you would read TDC at idle speed. However, when you step on the gas and the engine goes into boost, this timing setting may cause detonation. 2 If you install a Weiand blower and your observed boost comes up on the low end of our estimated range, it means you have a really good breathing engine. A Roots blower does not compress the air inside the supercharger. If your engine is not as free-breathing as it could be (because it has a stock or low performance cam, small valves, restricted ports, etc.) One important thing to keep in mind with respect to Weiand roots superchargers is that throughout the rpm range, the air ratio of the supercharger is consistent with the engine displacement. Installing a blower is one of the easiest ways to substantially improve a vehicle's overall performance. However, if you never drive your vehicle in the higher speed ranges, you may be giving up impressive improvements in the lower speed ranges. We'll use the terms supercharger and blower interchangeably. In actuality, the blower normally only goes into boost when the throttle is opened substantially or when the vehicle is under load, such as going up a steep hill or pulling a trailer. The choice of camshaft can make or break a blower motor. Plus, the 110� center line provides even sharper throttle response and helps lower initial cylinder pressure (you won't miss the cylinder pressure with these blowers, since they make plenty of boost). The 8-71 is for all-out competition style engines that will see high rpm usage. The Rolls-Royce Griffon engine was designed in answer to Royal Naval specifications for an engine capable of generating good power at low altitudes. Best results are achieved by driving the vehicle under boost and adjusting the unit until any detonation is eliminated. Keeping the cylinder pressure up also gives you excellent throttle response. Four exhilarating powertrains. 5 miles, Intercooled Turbo Regular Unleaded I-3 1.0 L/61, MPG City: 27 MPG Hwy: 29***, 4DR, Shadow Black Exterior, Cloth Seats Medium Light Stone Interior, 6-Speed Automatic w/OD Both are rebuilt with 2X4s hooked to a T 10, 4 speed. Bolting one of Weiand's Pro-Street Superchargers on an otherwise stock small block Chevy will result in an increase of approximately 100 to 120 hp. Including machine shop work, engine builder/ building, or engine rebuild. Machine Shop. Experience has shown that if you attempt to run more than about a 12:1 effective compression ratio on a street engine with 92 octane pump gas, you will have detonation problems. One of the big advantages of a supercharger is that it can overcome many induction deficiencies in an engine, especially in the low to mid-range rpm area. Obviously, the amount of boost your supercharger produces is going to be a factor in choosing a camshaft. Minimum of a 3" diameter dual exhaust with free flowing street/race mufflers and large tube headers. The more boost, the colder the plug required. For example, if your vehicle typically will be driven at speeds under 4,500 rpm and will never, or infrequently, see high engine speeds, you may want to select one of Weiand's smaller blowers. The centrifugal supercharger is very similar to a turbocharger, except the centrifugal supercharger is driven by a belt off the engine, while the turbocharger is driven by the force of the exhaust gases. The increase in performance is not justified by the increase in cost for street applications. Minimum of a 2-1/2" diameter dual exhaust with headers. An internal combustion gasoline engine draws in air which is mixed with gasoline. The key to any supercharger installation is that detonation must be controlled. The amount of boost that is being produced by the blower is the critical factor. In order to make boost, the blower must get air, and during most driving you will only have the throttle open a slight amount. It is actually an air pump. These rotors were designed to hold their tolerances 360� for maximum boost pressure efficiency. Weiand also offers cams for these type of applications. When the piston goes back up, this fuel/air charge is compressed to a fraction of its original volume. Under boost, the engine could need up to 40 to 50% more fuel and air, so it's key to pick a carburetor that is up to the task. Recommended primary tube diameters and collector sizes are: Small Blocks: 1-5/8" to 1-3/4" with 3" collectors, Big Blocks: 1-7/8" to 2' with 3-1/2" collectors, Four bolt main caps with quality bolts or studs, Severe duty stainless steel valves or iconel, Solid or roller cam designed for high boost, High output ignition management system or magneto, Blueprinted carburetors or fuel injection. Roots type superchargers first appeared in automotive applications as far back as the 1930s. With a supercharger, the amount of air and fuel that can be packed into the cylinders greatly exceeds the 100% volumetric efficiency of a highly refined unblown engine. Coincidentally, prices start at US $21,807. Conversely, if you choose a larger blower for this same application, in order to achieve the same boost level, the larger blower will have to be turned at a relatively slow speed. Now that supercharging is becoming quite common on stock factory vehicles, more people are realizing that a supercharger is a safe, practical source of performance increases. The basic design of a Roots supercharger has been developed over many years and has resulted in a highly refined product offered by Holley under the Weiand brand. A larger blower, such as Weiand's 6-71, on a similar engine to the one described above could push the top power output well over 500 hp. In all supercharger applications, Weiand recommends running roller rockers and chromoly push rods. This is because at lower blower speeds, the clearances between the supercharger case and the rotors allows for air "leakage" with some loss of boost efficiency. On a given size blower and a given size engine, boost can be increased by running the blower faster in relation to the engine's speed (overdriving) or it can be decreased by running it slower (underdriving). The smaller superchargers use new (not remanufactured) CAD/CAM designed two lobe rotors. This combination will not produce the low end power that the faster turning small blower will, but will significantly outperform the small blower at high engine speeds. Weiand offers three different levels of superchargers, and each requires a different type of cam. You'll have several obvious indications, like glowing red headers, audible "lean pop," or engine surging. For more information on Lunati's line of blower cams, consult the Lunati section of this website, or call Lunati and speak with one of their cam experts at 901-365-0950. This cam design provides good overall power on pump gas and also aids in engine cooling. Gonna "Get up & Go! Engine Assembly. All of these figures are based on a blower that is producing about 6 or 7 pounds of boost. Interestingly enough, even when not making boost, the spinning rotors improve the volumetric efficiency of the engine to the point where you can maintain high cruising speeds at lesser throttle openings, and in normal driving around town, you will notice that the vehicle is much livelier even when not making boost. Please note that all engines differ in their tolerance to detonation. A legend in the industry, Lunati offers several camshafts specifically designed to work with Weiand blower kits. If your car was getting 20 mpg before the blower that means you will be getting 19.4 mpg after the blower installation but with a 40 to 50% increase in horsepower. Build your own custom newsletter with the content you love from Chevy Hardcore, directly to your inbox, absolutely FREE! Your distributor should have a centrifugal advance mechanism that has been set up so that the entire advance is in by 2,500 rpm. Remember that at full throttle your engine is going to need about 50% more air than it did before the blower was installed. Five distinct trims. When Roots blowers are turned at very high speeds, they actually can heat up the inlet air to such an extent that the air expands substantially. Rolls-Royce designed the engine and first ran it in 1933 as a private venture. Call now and schedule your engine test -n- tune for the new racing season. On a street vehicle, this typically occurs for short periods of time. The reason that larger displacement engines make more power and torque than smaller ones is that more fuel and air are available for combustion. Conversely, it is not practical to run a small blower on a big engine, because you would have to turn the blower so fast to make a reasonable amount of boost that the blower would become very inefficient, particularly at higher engine speeds. The compression ratio that is built into your engine is called "static compression." The addition of a set of good heads can boost this into the 440 to 470 hp range. You want to see a medium to dark tan color. Conversely, as engine size goes down, boost goes up. The Pro-Street 177 is a good all-around compromise that will perform well across the board, but it still won't deliver as much power as the 6-71 or 8-71 at extreme engine speeds. Porting; bowl porting, port match, full porting, flow bench & supercharger porting. If you run one or more Holley carburetors, be aware that they contain power valves. Concepts for adapting the Spitfire to take the new engine had begun as far back as October 1939; Joseph Smith felt that "The good big 'un will eventually beat the good little 'un." The 10-71 through 14-71 supercharger kits come with drive ratios that will produce 5 to 8 pounds of boost. machine shop engine builder engine rebuild, 1572 Fullenwider Road, Gainesville, GA 30507, US. Engine Builder- Machine Shop & Custom Automotive Center. Helix rotors also resist flex under extremely high boost situations. Since the air is now being forced into the engine, you can put a substantially denser fuel/air charge into the cylinders. Although this is somewhat of a simplification, you can think of a roots supercharger installation as removing the carb and intake manifold from the engine and reinstalling the blower and blower manifold in its place and then bolting the carb on top of the blower. If it were even possible to gear the blower so that it would spin fast at low engine speeds, it would then make too much boost at higher engine speeds. Brand New Super Flow Engine Dynomometer will OPEN 1ST WEEK of APRIL 2019! This would provide 34� of total timing or if you wanted 32� of total timing, you could line up the mark on the damper with the 2� ATDC mark on the timing tab instead of "0.". Table 1 shows that you obviously can't try to run 10 pounds of boost on a 9.0:1 compression ratio engine. If the cylinder filled completely with air, the engine would have a volumetric efficiency of 100%. When the spark plug ignites this compressed fuel/air charge, the resulting combustion causes an expansion of the charge which forces the piston down. Unfortunately, due to the wide use of superchargers in drag racing, many people think a supercharger is an exotic race component and is not truly suitable for the street. Weiand uses two types of supercharger rotors. Retarding the timing under boost increases the combustion temperatures. Even if you don't experience these conditions, you should still read your spark plugs for proper color. For optimum performance at higher engine rpm's, select an aftermarket performance ignition system. These devices usually operate on a "degrees of retard per pound of boost" and are typically adjustable from 1� to 3� of retard per pound of boost. To be more specific, the Pro-Street/ Marine 142 makes an excellent low to midrange blower for a 350 Chevy. Holley "Supercharger Carburetors" are specifically designed with this feature. We state that your boost will fall within a particular range, such as from 5 to 8 pounds, because a lot of factors can cause boost to vary. If doing your project right the first time around is a top priority for you, don't waste your time- Bring it to the oldest Speed Shop in the Southeast where we restore Street Cars & Hot Rods from the ground up. These blowers were developed for Alcohol Dragster and Funny Car racing and are extremely expensive, making them impractical for anything but professional racing. By removing these restrictions, or at least reducing them by improving the cylinder heads and cam timing and using a larger carburetor, the volumetric efficiency of an unblown engine can be improved. Just because your car is old doesnât mean itâs outdated. If your compression ratio is higher than this, you will have to run less boost. Assuming a constant speed ratio between the engine and the blower, a larger blower will make more boost than a smaller one on the same size engine. Power valves provide additional fuel when there is no vacuum at the base of the carburetor. This overheated expanded air loses so much density that even though your boost gauge says the blower is making boost, in reality you aren't putting any more air into the engine than an unblown engine would get. It Still Runs is your ultimate auto resource, whether you rotate your tires or change your oil. Usually with a mild blower cam and a larger carburetor you can expect a typical small block to produce anywhere from 360 to 400 streetable horsepower. While this is true with all Weiand blowers, it is particularly attributable to the smaller ones. Running too small a carburetor therefore means that you can't flow enough air to produce maximum boost. In addition, the following are a few basic guidelines for selecting the proper cam for your motor. These rotors require an extremely high degree of tolerance and, as a result, the screw type supercharger is more expensive than a Roots. With one of Weiand's superchargers, here are some of the improvements you can expect: 1. Unfortunately, as in many aspects of dealing with modified engines, trial and error is about the only way to achieve your ideal combination. Engine Builder or Engine Rebuild. With the "boost retard control," the driver can dial in ignition retard with a dash-mounted knob. This isn't much of a factor. In most instances, this will provide you with enough information to provide a workable and safe combination that will provide substantial performance improvements. On most street type blown applications running 6 to 7 pounds of boost, approximately 40 to 50% more fuel and air can be packed into the cylinders than in a comparable unblown engine. 3. This is because the blower immediately is pushing the inlet charge right into the cylinder, rather than waiting for the engine vacuum to draw the charge into the cylinder. Choosing a carburetor is a very important step in building a blower motor. Weiand high flow water pump (cast iron or aluminum available - see our complete water pump section for applications). If your engine is larger, your boost will be lower. For 6-71 and 8-71 blowers, Weiand again recommends running a hydraulic cam, as long as you keep the boost level below 10 PSI. This is why it is important to have a blower that is sized in relationship to the engine displacement. Running the blower very slowly in relation to engine speed, such as would occur in our example above of a 6-71 on a 327, would result in inefficiencies at lower engine speeds. This "fuel/air charge" is drawn into the cylinders as a result of the vacuum created when the piston travels down the cylinder. MACHINING: Blocks; bore & hone, deck, sleeves, o'ring, pour Heads; 3 to multi angle valve job, port, flow, grind/ equalize, diamond/ bronze guides, seals, springs, shims, o'ring, deck, bead. It's important to realize that there are no hard and fast rules and the suggestions made here are general in nature. you will typically see the boost readings go up in the higher rpm ranges. A handy device to have is an ignition system with a "boost retard control," such as the Holley Ignition P/N 800-450. BUILDING ENGINES that perform & outlast the competition. On the big block, Weiand offers the Pro-Street 177 for good low to midrange power, the 6-71 for strong mid to high-range power, and the 8-71 through 14-71 for large displacement, high boost/rpm engines. MACHINING: The Progress of our Engine Dyno & Room Build April 2, 2019. Additionally, keep in mind that the larger the blower, the more potential for low speed boost "leakage" to occur because the total clearance path is much longer on a larger blower. The company also offers slightly "bigger" cams for the next performance level up. Supercharger boost, however, is not totally constant. NOTE: It is important to understand that for all practical purposes, an engine does not know what size supercharger is bolted to it. Pistons; off/on, pin fit, angle intake/ exhaust cuts, deck, dome, bead. NOTE: We do not recommend using these devices in marine applications. Sold for $368,500. Remember that rarely are any two modified engines similar in how they react to boost and compression ratio combinations, so don't expect to copy what someone else may have done and achieve a successful installation. Conclusion This design has even more "twist" imparted into the blower rotor and does provide more power. The "mildest" of Weiand's blowers are the Pro-Street superchargers, which are set to produce from 5 to 7 pounds of boost.