The weak link in a connecting rod has always been the bolt, and racers know that nobody builds a better bolt than ARP. However, it is critically important to monitor the stretch of each bolt and replace it when it has permanently elongated by .0005¹. Below you will find an extensive listing of aftermarket connecting rods and replacement bolt specifications.
In some instances, you may want to go to an ARP rod bolt made from a better grade of material. This will provide you with improved reliability. However, please understand that when you want bolts made from exotic, super high strength materials, the cost will increase significantly. If youre on a budget, its best to go with the most cost-effective solution. This is typically defined by the loads that are carried by the bolts in terms of piston/rod weight and the rotational speed of the engine. The most cost effective design is the one in which the bolt strength is just great enough to handle its anticipated load plus a safety margin for the occasional overloads. Using a material which has far more strength than required is not as cost effective but will definitely give you an extra margin of safety and longer service life.
You should also know that ARP rod bolts are superior to those from other manufacturers. Especially in the area of fatigue strength. Testing has shown ARP rod bolts to have ten times the fatigue strength of other bolts. In the chart below, youll find a bar chart that graphically shows the difference between ARP Pro Series rod bolts and the fastener made by a leading competitor. Its easy to see why ARP bolts are superior. As such, it makes good sense to rely on ARP for optimum connecting rod service and reliability. Make the most of your racing budget and rely on ARP rod bolts. Youll find the ARP name proudly stamped on each bolt as your assurance of quality.
*Features* * Forged in-house at ARP using only the finest quality materials * Heat-treated using special vertical racks to assure complete 360° penetration * Threads rolled after heat-treat to provide up to 10-times longer fatigue strength * Precision CNC-machined to exacting specifications * Specially designed for optimum reliability in each application.
*Wave-Loc Features* * Wave-Loc surface contacts the rod and cap for optimum alignment and reduction of fluctuating stress which strengthens the rod itself! * Provides snug fit for all OEM connecting rods (interference range of .001¹ to .005¹), despite wide range of factory rod bolt hole tolerances. * Available for most applications. * Superior material grain flow because of patented Wave-Loc surface design as compared to knurled bolts that have sharp edges and built-in stress risers. * Galling and scoring of the rod is virtually eliminated because thereis only smooth contact and absolutely no digging.
*Materials Used In ARP Connecting Rod Bolts**8740 CHROME MOLY:* Until the development of todays modern alloys, chrome moly was popularly considered a high strength material. Now viewed as only moderate strength, 8740 chrome moly is seen as a good tough steel, with adequate fatigue properties for most racing applications, but only if the threads are rolled after heat-treatment, as is the standard ARP production practice. Typically, chrome moly is classified as a quench and temper steel, that can be heat-treated to deliver tensile strengths between 180,000 and 210,000 psi.
ARP Part # --- 260-6302
This kit fits the 2004+ STI and the 2006+ 2.5 Liter WRX only.
These will not work with the 2.0 Liter WRX rods, but there is another kit available. Please e-mail us to check price and availability.