I am just about to make a purchase for my build and am debating between the two.

We know that the L19's are much more capable then the standard ARP's but at which point should one consider the beefy 1/2 studs?

I tried to find a debate or discussion between the two and wasn't able to come up with anything.

Has anyone expierenced headlift with L19's?

What power levels are the L19's being used to?

Thanks Guys.

JP

 

No headlift with L19's up to 652whp on the Dyno Dynamics...700whp+ DynoJet.

That said, I would probably opt for larger studs if the goal is a race car...or mostly racecar...rather than the 550whp fast street cars most people are building. Either way, you can't go wrong...I would go with whatever your engine builder/tuner suggests.

 

WHich ones are better, just wondering??? arp or the l19's????

 

If you are building your block I would just go with the 1/2s. I mean its getting machined anyway WTH. l19s are great for people who have already built the block and had headlift with the standard arps since no new machining is needed.

 

I'm probably going to go with L19's just for the fact that I don't trust any local shops to try to install the 1/2" and I can install the L19's myself.

 

To the OP, you are so close to SVRT (Overzealous1) that it should be a no brainer...go with the 1/2" studs. Send him a PM, I'm sure he will be more than happy to offer you personal advise.

 

The only drawback we saw on the 1/2" headstuds is the fact it is a pain to modify the headgasket to fit.You need to be VERY carefull enlarging the holes.
The metal compound of the L19's is different than the standard ARP's and more suited for a race car applications and is more prone to corrosion over time. Now someone is going to be swift to debate this, however I suggest you call Sam@GTM and ask him, he will tell you the truth straight up, as he has no vested interest in which head studs he sells.
Or you can call ARP themselves and they will give you the lowdown. Just keep in mind ARP does not make a part number for the 1/2" studs for the VQ, they are from a Domestic application
All the big boys will be running the 1/2" this year, bigger is better.

 

OP, if you want to check out the 1/2" studs in action, I have some pretty good pics in my build post which is going on as we speak...

https://my350z.com/forum/forced-induction/261608-svrt-engine-build-aps-tt-pics-inside.html

 

My bad, I just now realized you were already privvy to my advise after re-reading my original build thread...

 

Hi

 

Hello?

 

1/2:
more costly to install.
Cheaper material ($$$)
More surface area
possible failure due to improper install
have been used on high horsepower applications (800rwhp+ 350zs and 1400rwhp Supra)

L19
more costly material
cheaper to install
have been tested on 600+rwhp 350zs and 1400rwhp Supras (12mm L19)

The L19s have not been tested to the extreme high horsepower numbers yet on the Z. The 1/2" have done well so far. It is just a matter of time till someone can find out what the limit is, if any on the L19s

We stock the L19s, 12mm, and 1/2" stud upgrades. I believe for the average build, the L19s are the best choice.

 

Just curious: can you (do you need to) use anti-seize on the L19s to prevent corrosion?

 

There is a lot of misinformation out there about L19 and corrosion/contamination. L19 cannot be heat treated in the same fashion as the standard ARP's and coated. They must be kept in wax paper, and carefully handled. Once they are installed and sealed in the engine, there is no issue with contamination or corrosion. Threads are coated with moly lube, prior to installation.

 

I believe just comparing the tensile yield strength of L19 and 1/2 studs will tell you which can provide the most clamping force if everything else is equal. As long as you can develop the desired clamping force w/o pulling threads with the L19's it sure makes a lot of sense to me.

 

When Todd did the pull out test for us with the standard sized studs, they pulled at 110-115ft/lbs. Larger studs have a much higher pull out trq.

But even with larger studs, most people are trqing in the 90-95 ft/lb range. There is a danger in overtrqing as well, even if the threads can physically take it.

 

Your correct. Over torquing is as bad as under torquing. Assuming that the base threads can handle it you want the torque about 10% under the tensile yield strength to avoid damaging the fastener by stretching in into its plastic zone. Idea clamping force is not the most you can create as things will begin to distort and can create as many problem as it solves. Ideally you want enough clamping force to provide a good gasket seal but more importantly fasteners that will not stretch under high boost and allow head lift. This is why fastener tensile yield strength is critical.

 

I can confirm Sam/GTM, has also informed me of the same thing.

 

And i also confirm that Sam told me the same thing too! We can agree to disagree on things, and Sam and I are still good friends.

 

but I would trust Sam's opinion based on 20 years in the industry over yours and mine put together.. Samand I are also good friends too..