Practical Limit for OEM head-bolts / gasket

[belize1334]

I've read through a few threads on this topic and the consensus always comes down to, "why bother finding the limit when ARP head-studs are a cheap fix." But for class rules, I'm thinking about trying to get as much as I can out of an ALL OEM long-block and 14b. Now I know that the tune has alot to do with it and also the intercooler efficiency and all sorts of other jazz but, ballpark, what are we talking about here?

Assuming a great tune and all the support, can I consistently run 20psi (looking for 250+whp) on a 14b and expect the head-bolts to hold? If not, what do you guys think the upper limit is? Since 6-bolt head-bolts aren't stretch-to-yield can they be over-torqued to keep the head from lifting?

 

[Barnes]

I'm like 99.99999% sure that if you don't knock, there is no way in hell you will ever need anything more than stock bolts and HG using only a 14b.

 

[JSchleim18]

I've seen people with 16G's and larger running 25 PSI on the stock 6 bolt setup.

 

[Polish]

I've personally done 25+psi (Whatever it spikes to with the WG tied shut) with my old s16g on a bone stock motor.

Unless you knock to high hell and run 87 octane you'll be fine with 20-22psi from a 14b.

 

[belize1334]

That's what I wanted to hear. I'll assume then, that as long as I'm still in 14b / 16g territory, if I keep the knock under control the long-block won't complain.

The idea here, as some of you may recall from my previous threads, is to run the in D-SP for autocross which is class largely populated by sub-150hp cars (D) and which allows almost anything you can do in street-modified so long as you're stock engine and stock turbo. So, if I do it right I could be making twice the typical hp and clean up. /ubbthreads/images/graemlins/cool.gif

Thanks for the fast replies.

 

^Watch out because I had a 110hp bmw 2002 and cleaned up with guys like you with stock turbos. lol

 

[belize1334]

^^ I'm not saying that there won't be competition out there. But the class has become better for turbos since they lifted the boost-control restriction. Given that, I think I'll do better in D-SP with a stock motor 14b then I would in Street Modified with gobs of power...and it'll be a lot cheaper to stay fast.

 

[donniekak]

I've run a 20g at 35 psi, a hx40 at 38 and a 16g at 30, all on stock headbolts and e-85. I have no doubt at all i would have blown the headgasket if i would have had any detonation. But the e85 kept everything in check.

 

One thing if you are doing parking lot racing, get a GOOOOD intercooler. When I did the low speed stuff (70 mph just getting in to 3rd then slamming on brakes) I was heatsoaking my liquid to air ic on a garrett t3. This was on my 911 and on long pulls it did fine but just didnt have the airflow at those low speeds. I would suggest a LARGE air to air for a 14b at max boost and slow speeds.

 

[belize1334]

Well, I'm sticking with A2W since I can fit it without hacking the bumper. The core is ENORMOUS (over 400 in^3) and I'll be pairing that with an equally huge front heat exchanger. That's the trick, for me, since class rules don't allow cutting of the bumper which is what keeps DSMs and GVR4s out of SP for the most part.

 

[evo8ya]

20psi, should be nothing with no knock and a good tune. (not a stock tune) The stock mapping is trying to run about 23* at peak timing which is waaaaaay too much for anything over stock boost. A intercooler may help alittle, but a retune will keep everything in check.

 

Quoting belize1334:
Well, I'm sticking with A2W since I can fit it without hacking the bumper. The core is ENORMOUS (over 400 in^3) and I'll be pairing that with an equally huge front heat exchanger. That's the trick, for me, since class rules don't allow cutting of the bumper which is what keeps DSMs and GVR4s out of SP for the most part.



I saw your core and that should be good with a big aftercooler and a very efficient pump. Good luck and post vids!

 

[belize1334]

Yeah the trick is gonna be that front aftercooler and a good tune. I'm gonna need to buy an un-hacked bumper since I already butchered mine and then I'll be putting the aftercooler basically where the AC condensor used to be (though not so close that it heat soaks from the radiator). As for the tune it'll probably be speed density ala DSMap or v3-light so that I can get my timing under control and keep knock at bay.