ARP head studs

[daniel sanat]

i dont think that mopac returns your money back just credit . as this has happened to my friend might aswell sell them on here

[Matt Fredrikson]

Wow was that back from the dead!

[Ryan Coft]

I picked up A1 headstuds from magnus, it's what they put in their drag cars and they last forever apparently.

Might try those.. They are more though, think they were about $250

[andrew volcz]

i called around to a few places today (magnus didnt pick up) and was told by one vendor out in Ontario that the A1's are no longer available (as in they stopped making them) and only whats out there is left. not sure how true that is but from the looks of stock levels anywhere in NA, its believable.  the L19's are still available and actually use the same stud... its just the nut that differs.  ive found them for $265+ US in the states, and $280-300 within Canada.

[lyle chavez]

I have A1's on mine and I like 'em. Got it from Magnus a while back

[Kristopher]

Don't think I saw this thread back then. But I prefer bolts on composite gaskets and studs on MLS for a few reasons.

A couple of them are here
http://www.thomasnet.com/articles/hardware/head-stud-bolts

[Ivan Skare]

ARP'S are good for anybody. If you're installing and torquing everything properly then you shouldn't have a problem.

[Richard Clark]

ARP'S are good for anybody. If you're installing and torquing everything properly then you shouldn't have a problem.

And using the proper lube.

[John Hartman]

and rechecking the torque later on.

[Phil Maki]

cylinder pressures...

you want really high boost with all sorts of additional knock retardants added to your fuel and air mix?  Well how much can you really compress this homologous mixture (lets hope that's the right word) before you reach some sort of hydrolock situation?  Static comp ratios in the 9's can be kinda dicey when you're trying to make large HP numbers, and all of this fuel/air mixture will need some room (read; lower comp ratios)

I would wager a guess that one's cylinder intake charge approaches a supercritical fluid at these higher comp ratio's, lifting the head.

This could also be just ramblings.  But what else causes high cylinder pressures?  Ding!  or more like Ping.  Get your detonation under control and lifting heads will be a thing of the past.

i digress

phil

[John Hartman]

huh.  Lowell runs 9:1 with 30+ psi.

My Mazda runs 9.5:1 and 16psi STOCK.

Gotta keep the knock in check is the biggest thing I would think.

[Kimyee Lai]

I would wager a guess that one's cylinder intake charge approaches a supercritical fluid at these higher comp ratio's, lifting the head.
phil

Just a quick analysis...air has a density of approx. 1.1kg/m3.  Air as a liquid, 870kg/m3, at STP.  That's almost 800 times difference.  If we assume 28 psi gauge turbo pressure (3x atmosphere), roughly 3*1.1 = 3.3 kg/m3 will get you to the input air density.  To get to liquid form means increasing the density by 263 times.  "Aha" you say, what about fuel?  Okay, so let's say you're running pig rich at 10:1 AF ratio, it's easy to see that most of the volume is occupied by air, not fuel. "Aha" you say, what about temperature?  Well, density actually decreases with temperature so I'm neglecting it for the sake of laziness and conservatism.  So unless if you have a 263:1 compression ratio, you will NOT see "hydrolock" lifting the cylinder head.  I'd stick with the Ping theory if I were you .

[Zach Holt]

L19s! today my aprs failed at 18psi.

[KevinBuckham]

For best sealing I think you will want a 7-bolt 2G head and L19s or A1s.  Perhaps the 7-bolt 1G head is stiffer as well.  Not that I followed that advice. (6-bolt 1G head w/ ARPs here.)

I also wouldn't be surprised if ARPs are the same material as stock head bolts.   (Both are good.)

[daniel Dee]

My L19 studs have held firmly multiple dyno runs in the 30 to 41 PSI range.
Torque @ 100 ft/lbs (be carefully)