anybody here running stock headstuds over 28+psi?
IMO, the only reason head stud were recommended in the early US EVO days was because of horrible tuning back then, before EVOScan came out and we could check knock.
Head gaskets blow because of cylinder pressure, NOT boost pressure. Knock makes cylinder pressures go though the roof.
Head gaskets blow because of cylinder pressure, NOT boost pressure. Knock makes cylinder pressures go though the roof.
$95ish for basically nothing beneficial and some extra work. As you can see, nobody is complaining about the stock studs. Plus, the 1x1 headstud method is questionable. You can do cams without re-doing the timing if you ziptie the gears to the belt. Pulling the head makes it even harder.
You really only need upgraded headstuds at big power, 400-500+ hp
You really only need upgraded headstuds at big power, 400-500+ hp
Just curious, looks like a lot of you guys have cams...why not do headstuds while you were in there? Seems like it's cheap insurance especially if you guys were planning to go big power.
Just seems like it would be one of those variables you wouldn't want to have to worry about with high boost.
Just seems like it would be one of those variables you wouldn't want to have to worry about with high boost.
IMO, the only reason head stud were recommended in the early US EVO days was because of horrible tuning back then, before EVOScan came out and we could check knock.
Head gaskets blow because of cylinder pressure, NOT boost pressure. Knock makes cylinder pressures go though the roof.
Head gaskets blow because of cylinder pressure, NOT boost pressure. Knock makes cylinder pressures go though the roof.
Questionable? What are you talking about?
Its a FACT that head gaskets blow from cylinder pressure and not boost. If you dont know, cylinder pressure is in the 100s or 1,000s PSI. You think 30psi of boost is gonna matter. Its all about detonation. Detonation causes cylinder pressure to go too high.
Extreme cylinder pressures from detonation blows the head gaskets, NOT boost. If you dont believe me, go pick up a EFI book.
Its a FACT that head gaskets blow from cylinder pressure and not boost. If you dont know, cylinder pressure is in the 100s or 1,000s PSI. You think 30psi of boost is gonna matter. Its all about detonation. Detonation causes cylinder pressure to go too high.
Extreme cylinder pressures from detonation blows the head gaskets, NOT boost. If you dont believe me, go pick up a EFI book.
Last edited by Evo_Jay; Mar 30, 2010 at 10:23 AM.
Questionable? What are you talking about?
Its a FACT that head gaskets blow from cylinder pressure and not boost. If you dont know, cylinder pressure is in the 100s or 1,000s PSI. You think 30psi of boost is gonna matter. Its all about detonation. Detonation causes cylinder pressure to go too high.
Extreme cylinder pressures from detonation blows the head gaskets, NOT boost. If you dont believe me, go pick up a EFI book.
Its a FACT that head gaskets blow from cylinder pressure and not boost. If you dont know, cylinder pressure is in the 100s or 1,000s PSI. You think 30psi of boost is gonna matter. Its all about detonation. Detonation causes cylinder pressure to go too high.
Extreme cylinder pressures from detonation blows the head gaskets, NOT boost. If you dont believe me, go pick up a EFI book.
Last edited by chu; Mar 30, 2010 at 12:02 PM.
Wow, you get pretty fired up over the interwebz. And Evoscan helped, how? Dont take this as a smart comment, I'm just trying to learn! From what I've read, it wasn't the gaskets that blow, but rather the headstud were weak, and stretched under high boost, leading to a bad sealing head. Am I wrong?
Wow, you get pretty fired up over the interwebz. And Evoscan helped, how? Dont take this as a smart comment, I'm just trying to learn! From what I've read, it wasn't the gaskets that blow, but rather the headstud were weak, and stretched under high boost, leading to a bad sealing head. Am I wrong?
Ill explain nicely.
When we got EVOscan and the ability to check our tunes, we found that some "tooners" used WAY too much timing, and let the knock sensor do the work. This lead to mild power cars (300-400whp) blowing head gaskets. These "tuners" then said that APR studs were needed for those power levels. They were wrong, the tune were detonating too much.
It dont think I have ever seen a documented case of the OEM head bolts stretching, especially in a car with 300-400whp.
before I built my bottom end i ran 30 psi on my stock motor with stock head bolts on methanol and got on it almost everyday, raced my car every weekend and put about 50,000 miles on it and nothing bad ever happened.
As long as you dont have any consistent knock you should be fine.
As long as you dont have any consistent knock you should be fine.
Last edited by 06mr775; Mar 30, 2010 at 02:53 PM.
