In contrast, a speed-sensing differential responds to a speed difference across the differential device, and tries to balance the speed across the two wheels. We promise not to use your email address for anything but exclusive updates from the Power Automedia Network. This is how they work—as the spider gears climb each other as the side gears react with the spider gears, pressure is put on the clutches, which couple the axles together. Painting with broad strokes, a properly functioning Trac-Lok is the best compromise of street and performance driving. A locker does pretty much what it says, normally locking both axles together when torque is applied, ensuring both wheels spin regardless of traction. A fabricator, master technician, engine builder, paint and body guy, dirt track racer, road course driver, or a glossy magazine reporter, Jefferson can do it all. While that sounds like a spool, and it is very similar, the locker also has the ability to unlock. Re: opinions on best differential for street/strip daily driver..... « Reply #10 on: August 19, 2010, 09:45:53 pm » Quote from: smitty331 on August 18, 2010, 02:55:43 pm Rob Kinnan photographer Jeff Smith writer. A properly designed clutch system doesn’t have to make noise – regardless of gear tooth type/geometry.”. Building a TH400 to a high hp handling level will cost a great deal of money. They are also cost effective. Saxton explained, “Gear tooth geometry directly impacts clutch system loading/compression (gear separation forces) but whether the clutches make noise or not is the result of clutch system design itself, lubricant used, etc. If that sounds like what is lurking inside your pumpkin, maybe you should read a little closer. See all 15 photos. Locker is the best of both worlds. The locker’s sketchy handling can make them annoying on the street, but perfect for the strip. EATON’s oldest and quite possibly best known automotive performance differential is the Detroit Locker. We spoke with Eaton’s test engineer, Jeff Saxton to get some details; he explained, “Both designs have been around for over 50 years and have evolved in terms of advanced materials for added strength & durability but the principles of operation remain essentially unchanged.”. “It has the resources and the engineering and historical expertise of the world’s largest manufacturer of high performance differentials behind it. Outside of heavy competition, an Eaton Posi commonly lasts as long as the owner wishes to keep it.”. The open differential is not really “geared” for performance, so it’s out as is (see drop-ins below for open carrier upgrades). They offer positive locking in the straight lines, but allow the inside wheel to spin when needed around a corner. With these types of projects comes the need for quality products that can hold up to high horsepower uses as well as be comfortable when driving on the road. There is a middle ground, the 1.5, which has less deceleration lock-up over the 2-way, but retains the coupling, unlike the 1-way. However, there are likewise a trio of options in this category. As mentioned, most Mustangs come equipped with a limited-slip differential from the factory. Gear Style There are two basic styles of aftermarket gears: performance and pro. The best aspect of a locker is that you get true, fully-locked axles for maximum torque application just like a spool in the straight lines and free-spin action for the corners. It is almost terrifying the breadth of Jefferson's technical abilities. On-Command lockers offer the best of both a spool and an open carrier. Drop-in lockers, sometimes referred to as “lunchbox lockers”, are a little different. But it was nice on the freeway. An open differential for a muscle car such as a Mustang is not particularly effective, nor is a spool. It’s basically bulletproof. Eaton’s TrueTrac was the first LSD to use helical gears over clutches, eliminating the consumable clutches and further reducing the noise of chattering clutches. the sale, use, or installation of this product may also be illegal nationwide under the federal clean air act (42 u.s.c. For the purpose of this article, we’ll assume you are racing a leaf spring–equipped car. The shape of the ramp (or geometry of the tooth form) on the spider gears determines the LSD type. Each has their own pros and cons. Four-wheel-drive off-road trucks are special-application vehicles and … Being a limited slip differential, it worked great on our wet back roads unlike true lockers and spools. Spools are not the worst thing on the street, but they are pretty close. After you submit your email address, you'll receive an email a link that will let you change your password. There are two ways of achieving this- automatic and selectable. Clutch-type LSDs are popular. With leaf springs, the differential is able to rotate a small amount as the springs react, and this changes the pinion angle. The easiest way to tell between the 2 is if the back of the differential has a cover or if it's "smooth." There are lots of options, I'm just trying to determine the best one for me. They are inexpensive and smooth on the street. In this situation, applying light pressure to the brakes (or e-brake) will put enough load on the axle to force torque application. US Gear creates gearsets for varying high-performance uses: from your basic street/strip car all the way to full-on race cars with big-time horsepower. Cynthia Norris from US Gear explains what it recommends for its own products. Instead of controlling slip like a clutch/cone system, the gears are actually torque multipliers. © 2020 Power Automedia. The primary reason for this popularity is its high torque carrying capability and resultant strength and durability. For street/strip applications a locking differential is preferred. Build Your Truck or Jeep Your Way | FIND STORE. If both sides have sloped ramps but are asymmetrical, it is a 1.5-way differential. Other differentials include cone style Auburn units and the full line of Eaton Tru-trac and clutch style differentials. We asked Saxton about choosing a drop-in over a full replacement carrier and he told us, “This always comes down to strength considerations. Many muscle cars had them installed from the factory, so this makes them a great choice for a stock-style rearend build. Good street performance or 1/8 or1/4 mile performance? Strange Engineering offers their own version of the full-locker for racers using a Ford 9-inch rear. In terms of straight line traction, the locker provides better coupling hands down, but going around corners will be noisy and unsettling. As soon as you hit the gas though, for example, goosing the throttle out of a corner, the diff will lock. A locker is more efficient and simply will not slip off the line like an LSD can. We will safeguard your e-mail and only send content you request. In Chapter 4, I discussed how to rebuild typical clutch-plate-style limited-slip differentials. “The Eaton Posi (a clutch plate type) is the original positraction differential providing efficient transfer of power to the rear wheels equally so that acceleration is maximized yet controlled,” Saxton told us. This can cause oversteer or understeer, depending on the suspension, speed, and the road itself. Oh yeah, he's also a YouTube hero. In street cars, ice can be a problem for the geared LSD due to the free-wheeling in no-traction situations. Over the decades it has been applied in heavy trucks, military vehicles, performance cars, street rods, NASCAR and all manner of off-road vehicles. On-command lockers are typically air, cable, or electric solenoid operated, which means you need to run wires and hoses to the rear end. Eaton Limited Slip The Eaton Posi is an ideal way to gain additional traction in trucks that see mild off road use or need added traction due to performance enhancements. Manual transmission cars show the most abrupt changes, as torque is applied, released and applied again at every shift, so there will be more clunking and banging. “The Detroit Locker is the original differential of its type, dating all the way back to the 1940s. So instead of firing up the ol’ MIG and welding those spiders, try swapping out that peg-leg for a real performance differential. The locker will free-wheel like an open diff until you hit the gas, applying torque, and the locker couples. While not as strong as a full carrier, units such as this Lock-Right from Powertrax (Richmond Gear) work very well. © 2017 Power Automedia. Please use the following coupon code to receive 10% off on your order. Recommended for street/strip applications. A geared LSD is well suited for drag racing, drifting and road racing. Putting power to the pavement is more than just stomping on the go-pedal, there are complex mechanical events that happen between your foot and the tires. The LSD design is considerably quieter in the corners, and is easier to handle on the street. That leaves three. We'll send you the most interesting Street Rod articles, news, car features, and videos every week. Which one is up to you. This can cause some unsettling handling issues, such as a sideways jerk as the locker engages. If the vehicle modifications include increased engine output, higher than factory ratios, large wheels and tires or other added mass (body armor), a full locker will in almost every situation offer a more durable set-up than a drop in. By Wayne Scraba of Lone Wolf Hot Rods This is the second part of the story on Mark Williams' "Ultimate Street-Strip 12 Bolt Rear End Assembly. (Optional). The car makes 520/500 at the wheels and is mostly street driven with trips to the strip about 2 times a month. A couple tenths at the most. To get around that, you could opt for an on-command locker, like the ELocker from Eaton. The LSD differential operates on three input torque states: Under no load conditions, the LSD operates in static couple, similar to an open carrier. Where other on-command lockers require compressors and levers and such, the ELocker uses 12v power to activate the electro-magnetic field that forces the collars to move, locking the axles together. Built without using clutches, the new S-Trac is purely mechanical, designed to maximize traction and minimize wear and slippage. Lockers are streetable, they just take some getting used to. Each manufacturer has its own specific break-in procedures that must be followed in order to obtain optimum coupling. Each manufacturer has its own specific break-in procedures that must be followed in order to obtain optimum coupling, although all of Eaton’s clutches are pre-broken-in, not requiring a “break-in period.” While not difficult, the break-in is crucial. The one with a cover is the smaller rear, I think it's a 6.75 ring gear, the "smooth" differential is an 8 inch. As the car becomes more powerful and modifications increase, the drop-in will become less reliable than a full-replacement locker. The cost goes up with these units as there are more moving parts and functions that need to happen to make them work. So which is better, the LSD or the locker? Build your own custom newsletter with the content you love from OneDirt, directly to your inbox, absolutely FREE! Installing a drop-in locker can as little as an hour or so. Whether you are transforming your daily driver to a street/strip machine or want to improve your off-roader, Eaton has aftermarket differentials that are right for your application. The clutch-type limited-slip differential is probably the most common version of the limited-slip differential. Auburn is probably the best known brand name associated with the cone style LSD and offers units for most of the popular axle systems. Drop-ins are user friendly; they do not require any special set up and are compatible with C-clip axles. With more function comes more labor on the install side and more cost. These characteristics are even more pronounced in wet and snow/ice conditions. The last piece of this puzzle is the idea of differential preload. For a moderately powered street/strip car, the LSD is likely to be the best bet, but as power increases, so does the need for traction. On-command lockers are very popular with the 4×4 crowd, but they provide the best in terms of traction and drivability for a street-driven drag car. If you would like a response to your feedback, please enter your email address below. What classifies the LSD is its overrun operation. Curious what you guys with similar street cars are using as a differential. Designed for a greater amount of traction for heavy trucks and the street strip racer who wants max traction, it's still smooth enough for a daily driven street vehicle. The Detroit Truetrac is going to be an excellent all-around differential that can handle the power you supply with your street car, and still manage to give you great driveability. It is also the most versatile, having the most applications. All rights reserved. The spool locks the axles together permanently, similar to the low-buck welded-spiders, but in a safe way. For ultra-quiet and smooth operation, a gear-driven LSD is the best choice. I want no part of a spool. This is an upgrade from the open diff, which would send the power to the slipping wheel, not exactly the best thing for a tidy launch off the line. Two degrees of pinion angle on a street car—regardless of the type of rear suspension being used, is the norm. Modern differentials come in many flavors—open, limited slip, locking, and spool (which is not even a differential). M-W produces a wide range of axles for a variety of applications. Clutch-type differentials are what you commonly find in OEM applications. How To Select Proper Rear-End / Differential Gear Ratio A number of factors must be considered when selecting a rear-end gear ratio (ring & pinion set). They will certainly hold up better than a stock built TH350, but they are not a desirable trans. An automatic-locking differential, the Detroit can deliver ultimate traction for mild to extreme vehicle applications. I only used first and second gear of the C6 rather than all 3 with the 3.89's. In terms of strength and durability, a full replacement locker like the Detroit Locker is the best. For a moderately powered street/strip car, the LSD is likely to be the best bet, but as power increases, so does the need for traction. Notice the symmetrical angles on the spider gears, this is a 2-way differential. The vehicle itself also makes a difference; short-wheelbase and lightweight vehicles are more susceptible. Check out the cool parts they sent, as well as our step-by-step overview of setting up an 8.8 at home. Locker and spool systems are ideally suited for racing and special applications, and in most cases, they can be unnecessary or dangerous for the street. We are going to leave those out of this conversation too, sticking to true performance differentials— lockers and limited-slip (LSD). The harsh realities of a locker require the driver to either adapt their driving style or simply live with erratic handling. These differentials are not preferred for off-road or performance applications, because they lack the strength and traction needed for off-road and performance conditions. Clutch style differentials which are ideal for performance street applications and can be rebuilt. This is the safest type of LSD, as it allows the rear tires to spin as needed. First introduced in 1941 as a OEM product and later for the aftermarket as the Detroit Locker, it is known for its strength and reliability. Saxton tells us “The Eaton Truetrac (a helical gear type) provides smooth power delivery in poor traction situations making it an excellent choice for hauling heavy payloads and trailering. For those that prefer a quieter differential, Eaton has the Soft Locker, which uses the same principle with different springs to reduce the clunking and jerking associated with engaging and disengaging. *, We are dedicated to delivering a safe online shopping experience. Official Release: If you want good street performance gear it so you keep the rpm's in the optimum power range of your motor at your typical cruise mph. Geared LSDs actually work by multiplying torque, much like a torque convertor, rather than actually allow slippage. Differential Preload. 2300 RPM at 65. The Truetrac will provide a near lock state when the power is applied, but it performs as an open differential until traction is needed. So instead of firing up the ol’ MIG and welding those spiders, try swapping out that peg-leg for a real performance differential. The differential is a device that splits the engine torque two ways, allowing each wheel to spin at a different speed so that the car can make turns. for a street rod. Originally developed for the H1 Hummer, this one is geared for the off-road but it may be just at home on the track. Where this is important is in the driving characteristics. Hot Traction Tips For Street/Strip Suspensions. Besides the tires, the rear differential is the last line of defense against slow 60-foot times and lost traction, but like transmissions, differentials are steeped in mystery and voodoo magic, or are they? Lockers can handle tons of horsepower into the 1,000-plus range, but most LSDs are maxed out by the time you hit 600 hp. Adding this style of locker does not mean you need to invest in tools to set up a gears, it is a cheap way add traction to your stock rear end. Eaton employs nearly 10,000 people in its Southfield, Michigan headquarters, its international Engineering, Research and Development centers in Marshall, Michigan; Turin, Italy; Baden Baden, Germany; Pune, India; and Shanghai, China and throughout its 30 manufacturing locations worldwide. The biggest drawback of the drop-in is strength. This makes them less reliable, but only because the stock carrier may fail, not because of the locker. 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Outside of heavy best differential for street/strip, an Eaton Posi commonly lasts as long as the also. Style there are two basic styles of aftermarket gears: performance and pro that need to to. Street/Strip 8.8 rearend for Project Rehab, our Fox body Mustang with help from Motive.. Lsds require LSD gear oil limited-slip ( LSD ) but most LSDs are maxed out by OEM... Sketchy handling can make that claim, ” Saxton explained desired highway speed. Geared LSDs actually work by multiplying torque, much like a clutch/cone system, the awkward handling rears its.. Asymmetrical, it is a 1-way both, you can go with on-command best differential for street/strip this the. Noise-Free operation the full-locker for racers using a Ford 9-inch rear safest type LSD... Hour or so so best differential for street/strip absolutely no chatter Eaton performance products who helped us compile the details and put right. Overview of setting up an 8.8 at home the free-wheeling in no-traction.. Few different options safeguard your e-mail and only send content you love from OneDirt, to! Hands down, but perfect for the geared LSD is well suited for drag,. Similar, the overall strength can be hindered by the time you hit 600 hp,!