25-10-2014, 02:12 AM
They definitely have to be rolled, the cost of the material, which needs to be 190,000psi strength material minimum, is considerably more than just using silver steel.
There was a bunch of us who went down this road before, and had a big batch made up, but later found that they just wern't comparible to those made by APR. The material they use is just too specialised.
I think stock bolts are 12.9 grade, 176,000psi bolts, ARP's are over 190,000-200,000psi
The stock bolts stretch beyond their yield point, and ARP's have specific torques to challenge extension right upto the point of yield, using specified lube too, which can make a 50% difference on load.
There really is too many factors to make your own, and reliably able to take the load past that achievable of the stock bolts.
It really is just worth it to pay ARP the 200 quid they cost, because of the research and development gone into the bolts themselves.
There was a bunch of us who went down this road before, and had a big batch made up, but later found that they just wern't comparible to those made by APR. The material they use is just too specialised.
I think stock bolts are 12.9 grade, 176,000psi bolts, ARP's are over 190,000-200,000psi
The stock bolts stretch beyond their yield point, and ARP's have specific torques to challenge extension right upto the point of yield, using specified lube too, which can make a 50% difference on load.
There really is too many factors to make your own, and reliably able to take the load past that achievable of the stock bolts.
It really is just worth it to pay ARP the 200 quid they cost, because of the research and development gone into the bolts themselves.
![[Image: 22f2b6b2-758b-4c1c-96fb-6fa9c6059b13_zpsf306b56b.jpg]](http://i585.photobucket.com/albums/ss299/Ha11elujaz0rs/22f2b6b2-758b-4c1c-96fb-6fa9c6059b13_zpsf306b56b.jpg)