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TECHNICAL => ALL MOTOR TALK => Topic started by: Thomas on October 09, 2017, 07:14:01 AM

Title: head studs for 400-450whp
Post by: Thomas on October 09, 2017, 07:14:01 AM
Will APE head studs / nuts do?

I'm going to drop head studs / new head gasket and a spacer for now for low boost, and later (in a year or so) rebuild the engine to get about 400-450whp.
Title: Re: head studs for 400-450whp
Post by: RansomT on October 09, 2017, 07:36:43 AM
That's what I run in my nitrous bike (and my HC all motor bike) and haven't had any issues.  The nitrous bike is in that 400-450 range.
Title: Re: head studs for 400-450whp
Post by: wildphil69 on October 09, 2017, 10:10:06 AM
They will do. If you plan on pushing further you may want to look at the 1/2" studs
Title: Re: head studs for 400-450whp
Post by: Thomas on October 09, 2017, 08:44:02 PM
Any machining needed? I see that ARP's have few first threads cut to keep block and cylinder walls from deforming under load
Title: Re: head studs for 400-450whp
Post by: wildphil69 on October 09, 2017, 09:53:43 PM
The oem size are direct fit the 1/2" require machining
Title: Re: head studs for 400-450whp
Post by: Oz Booster on October 10, 2017, 02:58:39 AM
I am trying an 11mm stud next week, same pitch as the 10mm so i hope to just chase the thread with the new size , and simplify the upgrade and end up with the correct stretch at ~72ft lbs
Title: Re: head studs for 400-450whp
Post by: Thomas on October 10, 2017, 08:20:59 AM
Are you using custom studs or are you using studs for some other engine (maybe with minor mods)?
Title: Re: head studs for 400-450whp
Post by: Thomas on October 10, 2017, 09:02:12 AM
The oem size are direct fit the 1/2" require machining
That's clear. I was wondering if there a point of doing something like you see on the attached picture to keep block from deforming too much (few threads are cut on the right side of the studs).
Title: Re: head studs for 400-450whp
Post by: wildphil69 on October 10, 2017, 11:49:50 AM
That is so the stud can bottom out into the case.
Title: Re: head studs for 400-450whp
Post by: Oz Booster on October 11, 2017, 01:25:00 AM
Are you using custom studs or are you using studs for some other engine (maybe with minor mods)?

Upgrade studs for EJ20 and EJ25 Subaru , right length and pitch
Title: Re: head studs for 400-450whp
Post by: Thomas on October 11, 2017, 10:22:49 AM
Awesome info. Thanks for sharing! Keep us posted.  :thumb:

BTW it's still not 100% clear to me. Should I machine the ends of APE studs? It's basically a 15 min job and I have free access to a lathe.
Title: Re: head studs for 400-450whp
Post by: gsxrdan on October 11, 2017, 03:08:15 PM
I have ape 10mm in one engine and 1/2" bolts in another. 10mm gave no issues with 14-20 lbs . I'm putting 30 lbs to my 1/2" with no issues. I'm going to try 10mm arps this time.