poppopbangbang
Nurburgring
- Joined
- 25 May 2015
- Messages
- 480
I've had a lot of people contact me regarding the studs I did for my 996 C4 exhaust manifolds and the few I have left over aren't even slightly going to cover how many people want them so if it's not treading on any toes I'm going to make some more for people. Just to be clear this is very much beer money fund and not some attempt to become the titanium decade + old Porsche exhaust stud king or similar :wink:
People have requested two different lengths/designs and also washers. We only have a C4 at work so beyond that I'm working on what I've been told by those wanting a set so please feel free to correct stud numbers etc. if required.
They will all be made from Ti6Al4V which is stronger than pure Ti but retains the same stiffness. It will never, ever rust, rot, corrode or do anything other than remain a stud.
All 996 and 997 as far as I can tell use an M8 X 28mm bolt but with different heads depending on application. All manifolds appear to be 10mm thick flanges with a 2-3mm gasket depth which makes 15-16mm installation depth at clamping into the cylinder head. Hence the design of these studs with a 15mm thread on one end which once installed and butted up to the shank is 15.5mm installed depth. I recommend you use an M8 Aerospace K-Nut with them which is a 10mm headed fastener so can be installed easier than a 13mm bolt can when dealing with larger primaries etc. on aftermarket manifolds as you're using a 10mm socket not 13mm. They are also self locking and keep planes in the air so pretty well proven. Depending on the design of your manifolds you may well want to use washers under them if they have oversized holes in the manifold flange.
So stud choices are:
M8 X 45mm. 15mm Thread on one end, 10mm shank and 20mm thread on the other end. I have used these as exhaust manifold studs on my 996 and they provide 10mm additional thread beyond a standard aerospace M8 K-Nut without washer. These will fit C2/C4, Turbo and GT3 as far as we can make out as they are all on the same fastener accordingly to the Porsche parts book. The extra length makes installation of the nut much easier and doesn't hamper installation, on C2/C4 you can wind the rear most stud in once the manifold is bolted up via the others to avoid having to undo the coolant hard lines to make room. These studs weigh a smidge over 8 grams each.
M8 X 40mm. 15mm thread one end, 5mm shank and 20mm thread on the other end. Essentially identical to the above but with a 5mm shank. This was a size requested so it's here. Will provide 5mm thread protrusion if using a standard M8 K-nut without washer. These studs weigh a smidge under 8 grams each.
M8 Ti washer. Erm.... it's an M8 washer, made out of Ti. Not a lot else to say about that one.
For 996 C2 and C4 you'll need 12 studs (6 per side) and probably 12 washers but check what your clerances are like between the end holes and the primary as on some aftermarket manifolds this is very close. If it is you can use a washer if desired on the centre studs.
For 996 GT3 you'll need 12 studs (6 per side) and probably don't need washers as these manifolds appear to have a more sensibly sized hole..... but check!
For 996 Turbo you'll need 18 studs (9 per side) and probably 18 washers but same caveat as above C2/C4 with regards end primaries and mounting hole spacing. It seems you can also use the same studs to bolt up the Turbo to Manifold joint.
Making just a few of these studs is quite expensive but doing a lot brings the price down quite considerably. If in total I can make more than 100 studs of either size then they are £5 per stud, if it's less than 100 but more than 50 it's £6 per stud. Likewise for washers, more than 100 and they're £2.50 each, less than 100 but more than 50 and they're £3 each.
Assuming five C2/C4 owners want some and three turbo owners want some then we are over the 100 mark. So that would make the total cost:
C2/C4/GT3. 12 Studs = £60. 12 Studs with washers = £90
Turbo = 18 Studs = £90. 18 Studs with washers = £135
M8 X 1.25 6 Point K Nuts cost us £1 each so happy to provide those at cost if required or you can source from Tweeks, Merlin etc.
Basically a lot of money to hold some exhaust manifolds on when standard Porsche bolts at £1.54 each will do the trick but these studs will never end up as a rusty blob you can't get a socket on
Also if anyone with a C2/C4 wants a set to replace their rusted standard ones and is worried about them breaking on removal then I'll lend you my Stomski Racing bolt repair kit as long as you promise to send it me back!
Installed pics:
Note in this pic the clerance to the primary, you won't get a washer on if yours are like this.... but with a K-Nut you don't really need a washer unless the manifold mounting holes are oversized.
Any one who is interest post below with what you want and if it's enough people then I'll order some bar stock next week.
People have requested two different lengths/designs and also washers. We only have a C4 at work so beyond that I'm working on what I've been told by those wanting a set so please feel free to correct stud numbers etc. if required.
They will all be made from Ti6Al4V which is stronger than pure Ti but retains the same stiffness. It will never, ever rust, rot, corrode or do anything other than remain a stud.
All 996 and 997 as far as I can tell use an M8 X 28mm bolt but with different heads depending on application. All manifolds appear to be 10mm thick flanges with a 2-3mm gasket depth which makes 15-16mm installation depth at clamping into the cylinder head. Hence the design of these studs with a 15mm thread on one end which once installed and butted up to the shank is 15.5mm installed depth. I recommend you use an M8 Aerospace K-Nut with them which is a 10mm headed fastener so can be installed easier than a 13mm bolt can when dealing with larger primaries etc. on aftermarket manifolds as you're using a 10mm socket not 13mm. They are also self locking and keep planes in the air so pretty well proven. Depending on the design of your manifolds you may well want to use washers under them if they have oversized holes in the manifold flange.
So stud choices are:
M8 X 45mm. 15mm Thread on one end, 10mm shank and 20mm thread on the other end. I have used these as exhaust manifold studs on my 996 and they provide 10mm additional thread beyond a standard aerospace M8 K-Nut without washer. These will fit C2/C4, Turbo and GT3 as far as we can make out as they are all on the same fastener accordingly to the Porsche parts book. The extra length makes installation of the nut much easier and doesn't hamper installation, on C2/C4 you can wind the rear most stud in once the manifold is bolted up via the others to avoid having to undo the coolant hard lines to make room. These studs weigh a smidge over 8 grams each.
M8 X 40mm. 15mm thread one end, 5mm shank and 20mm thread on the other end. Essentially identical to the above but with a 5mm shank. This was a size requested so it's here. Will provide 5mm thread protrusion if using a standard M8 K-nut without washer. These studs weigh a smidge under 8 grams each.
M8 Ti washer. Erm.... it's an M8 washer, made out of Ti. Not a lot else to say about that one.
For 996 C2 and C4 you'll need 12 studs (6 per side) and probably 12 washers but check what your clerances are like between the end holes and the primary as on some aftermarket manifolds this is very close. If it is you can use a washer if desired on the centre studs.
For 996 GT3 you'll need 12 studs (6 per side) and probably don't need washers as these manifolds appear to have a more sensibly sized hole..... but check!
For 996 Turbo you'll need 18 studs (9 per side) and probably 18 washers but same caveat as above C2/C4 with regards end primaries and mounting hole spacing. It seems you can also use the same studs to bolt up the Turbo to Manifold joint.
Making just a few of these studs is quite expensive but doing a lot brings the price down quite considerably. If in total I can make more than 100 studs of either size then they are £5 per stud, if it's less than 100 but more than 50 it's £6 per stud. Likewise for washers, more than 100 and they're £2.50 each, less than 100 but more than 50 and they're £3 each.
Assuming five C2/C4 owners want some and three turbo owners want some then we are over the 100 mark. So that would make the total cost:
C2/C4/GT3. 12 Studs = £60. 12 Studs with washers = £90
Turbo = 18 Studs = £90. 18 Studs with washers = £135
M8 X 1.25 6 Point K Nuts cost us £1 each so happy to provide those at cost if required or you can source from Tweeks, Merlin etc.
Basically a lot of money to hold some exhaust manifolds on when standard Porsche bolts at £1.54 each will do the trick but these studs will never end up as a rusty blob you can't get a socket on
Also if anyone with a C2/C4 wants a set to replace their rusted standard ones and is worried about them breaking on removal then I'll lend you my Stomski Racing bolt repair kit as long as you promise to send it me back!
Installed pics:
Note in this pic the clerance to the primary, you won't get a washer on if yours are like this.... but with a K-Nut you don't really need a washer unless the manifold mounting holes are oversized.
Any one who is interest post below with what you want and if it's enough people then I'll order some bar stock next week.