BMW makes their cylinder heads from aluminum. While this is beneficial for many reason, they do not react well to overheating. Especially prevalent on older BMW engines, and over-temp situation has been known to cause the head to warp. Turner Motorsport carries Genuine BMW replacement heads and parts to make your next rebuild a success.
ARP uses a premium grade 8740 alloy that is rated far superior to "aircraft" quality. Each stud is heat-treated, ensuring complete heat penetration, to increase the clamping load up to 200,000 psi. ARP studs are threaded after heat-treat, which gives them 1000% (that's ten times!) better fatigue strength than studs threaded prior to heat-treat. Threading the studs after heat-treating is more difficult and costly (as it's harder on tooling) but the results are well worth the effort. These simply are the best head studs we've found and we highly recommend them in both racing and forced induction applications. Due to the additional clamping force between the head and block, these are IDEAL for turbocharged engines.
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Enhance your BMW N55 engine's ability to handle higher levels of boost with 5150's custom-designed Head Stud Kit from ARP, the global leader in fastener technology!