Moser Engineering Driveline Insight - CHP Insider

Rob Moser of Moser Engineering Gets Us up to Speed on the Latest Driveline Innovations

Stephen Kim May 1, 2009 0 Comment(s)
0905chp_03_z Moser_warehouse Location_with_a_10_year_warranty_on_all_parts 1/12

10-Year Warranty
Moser knows that many racers need to stretch a buck, and a comprehensive warranty never hurts. If you break an axle, Moser will fix it. "We offer a 10-year warranty on all our race-legal axles that are 33-splines and larger, which is a true testament to the quality of our products and the confidence we have in them," says Moser. "Moser Engineering has such a long and proven track record that we have no problem backing up our U.S.-made alloy axles with this type of replacement policy. Our experienced technicians have seen it all, and many of them are at the track every weekend racing. Having them steer you into the right product from the very beginning is a big part of the battle."

0905chp_04_z Set_of_moser_zxles Formula_on_how_to_find_the_right_axle 2/12

Spline Count
Properly sizing your axles can be tricky. Axles too small are prone to breaking, while ones too big eat up power. Fortunately, Moser has a simple formula to help select the right axles. "First multiply your engine's torque by its First gear ratio, its ring-and-pinion ratio, and 0.90 to account for driveline loss," explains Moser. "This will give you a figure that represents the maximum amount of torque transmitted to both axles if you launched at your engine's torque peak and dead-hooked out of the hole. A 30-spline axle is rated at 6,200 lb-ft, a 31-spline at 7,000, a 33-spline at 8,200, a 35-spline at 9,600, and a 40-spline at 12,000. As long as the figure from the formula is smaller than the torque rating of the axle, you'll be in good shape. Since axles are rated individually and not as pairs, sticking with this plan will make it virtually impossible to break an axle since you'll have a safety factor of 200 percent built in."

FORMULA

Torque at
rear axles
= Torque x First gear
ratio x Rear gear
ratio x 0.90

Axle Manufacturing
"The process of manufacturing an axle starts with the type of alloy used, which ultimately affects every process on down the line. Since we are dealing with an alloy material with steep gradients in carbon content, hardness, tensile strength, and microstructure from the surface to the center of the axle, the primary design consideration is the type of application an axle will be used in. Most project cars fall under the street/strip umbrella, and those particular applications require an axle that has a good hard Rockwell rating for longevity, but too deep of an induction hardening process can make the shaft brittle. This is one area where my dad's experience running a forging company for all those years paid off. He had contacts with multiple forging companies all across the country along with teams of engineers at his disposal, which he used to develop the proprietary material that we use today. There is a big reason why we still work closely with a local forging company and do our own heat treating and rough and final machining. With all of the imported products coming into the market these days, it is critical to have complete control over the entire manufacturing process. Moser Engineering prides itself on only using U.S.-made and designed steel forged in U.S. plants using Moser-designed dies and tooling."

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Differentials
At some point, Bow Tie horsepower will get to a level where a locker or a spool is a must. Not many people are hardcore enough to give up a limited-slip differential in a street car, but fortunately they've come a long way in terms of strength in recent years. "There are a lot of great limited-slip units being made, and probably one of the best is the Detroit TrueTrac," Moser explains. "We have seen some incredible power numbers go through this Posi unit, but any failure with this type of differential is going to be related to launch rpm and torque loads. With some finesse and experienced control, you can see these in a street tire car handle 800 hp reliably."

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