I would like to know a general opinion about the use of the arp over size head studs for a e36 m3. Are they really necesarry? I already have race ware head studs and they have done there job. But at the moment I have the engine block at the machine shop and already purchase the arp oversize studs. I am planing on increasing the boost up to at least 20 psi, the pistons are j.e. low and pauter rods with also main bearing arp studs. If you think I am missing something please let me know. THANKS :eyecrazy

I would like to know a general opinion about the use of the arp over size head studs for a e36 m3. Are they really necesarry? I already have race ware head studs and they have done there job. But at the moment I have the engine block at the machine shop and already purchase the arp oversize studs. I am planing on increasing the boost up to at least 20 psi, the pistons are j.e. low and pauter rods with also main bearing arp studs. If you think I am missing something please let me know. THANKS :eyecrazy

What do you exactly mean by oversize? The actually diameter of the stud itself is larger than before? If so you will have to have the block and head machined to accept the larger stud. Seen this done on very high boost applications to keep from lifting the head or blowing a gasket, but that is in the neighborhood of 45psi +.

I didnt go with oversized studs, but many people opt to...

I didnt do it because the metal is allready then enough, and i didnt want to run the risk of pulling a thread. If i pull a thread now, then i can go bigger, but if you go bigger from the start, you are stuck with keencerts or something like that.

I run 20psi without a problem. There is only a 5lb difference in load between the 10mm and the 11mm studs. Just use a lot of moly-lube...

-Keith

PS if you allready have them and your engine is at the machinist, ready to be tapped, you might as well go for it i dunno...

I went ahead and had my block taped out for the s54 studs. I don't really see why it would hurt to use larger studs if you are already at that point:dunno

The standar size is 10mm and the over size are 11mm. The over size can be torque a little bit more like 75 ft# so it should prevent trhe head from lifting.

Iceman633 I agree in your line of thinking. If I pull a thread now I have the option of going oversize at that moment without the use of kentcert. Are you sure is only 5lb of diference in torque?. By the way I have followed your project and is very similar to mine. Can you give an up date of your awesome car? Thanks for your interest

What is pulling a thread and kentcert?






Juker008

Iceman633 I agree in your line of thinking. If I pull a thread now I have the option of going oversize at that moment without the use of kentcert. Are you sure is only 5lb of diference in torque?. By the way I have followed your project and is very similar to mine. Can you give an up date of your awesome car? Thanks for your interest

The apr 10mm stud is rated at 65ft/lbs i believe, the 11mm i rated at 70ft/lbs...

If u pull a thread with the 11mm head studs you have to buy a new head, if u pull them with a 10mm u can re tap the head...

its your choice...

-Keith

ARP headstuds are of high quality. I'm using 11mm studs for ~31psi of boost. Others in the subaru community have done the same without leaks. Years ago ARP had some QC issues so bigger studs(13mm) were necessary--but they fixed their design. I highly doubt you will rip out an 11mm stud. We have not had any head stud failures in the subaru community except with one guy who suffers leaking head gaskets doing top speed pulls >150mph.

B

The apr 10mm stud is rated at 65ft/lbs i believe, the 11mm i rated at 70ft/lbs...

If u pull a thread with the 11mm head studs you have to buy a new head, if u pull them with a 10mm u can re tap the head...

its your choice...

-Keith I think you mean block not head. ///J.T.///

I think you mean block not head. ///J.T.///
Yes you are right...