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Amount of Boost With a Stock Head Gasket?

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Chrono

20+ Year Contributor
142
7
Dec 12, 2002
Calgary,
Hey there, I have a questiong dealing with the amount of boost that can be ran on the stock head gasket. Question being because I have all the parts ready to go on my car yet and dealing with the issue of how much boost will I run. I mean I see a low 12 secord potential but I dont know if I will need a Cometic Head gasket or if the stocker will be enough. I plan on running 15 lbs on the street and I was thinking about 20-25 on the track, there are so many outloos on this, I figure Id see what you guys also think.
 
I have heard the stock gasket is fine up to like 23-24 psi on a turbo that size. I personally am running the metal gasket because I figured while the block is out I might as well have it decked and put on something stronger... I guess just try it and when it blows then upgrade.
 
The stock oem gasket can take alot with ARP head studs. I have ran 25-28 on stock gasket in the past, I have a friend that runs 25psi and 75shot with stock gasket now. I think it boils down to tuning................ But if you have the block out of the car I would get it surfaced and use a metal headgasket.
 
Yea the stock head gasket with studs is all you need unless you are boosting above 30 PSI!! The only reason why a gasket would fail is from detionaltion.
 
Well only wondering you know I dont plan on going past 25 PSI...I mean 25 is a very large number to me....I mean hell I aint no Shep :thumb:
 
And with that motor work (DAMMM!!) and mods that is a 11.00 second car all day. 27 psi shifting at 8k should get you there . :thumb: :thumb:
 
Chrono said:
Well only wondering you know I dont plan on going past 25 PSI...I mean 25 is a very large number to me....I mean hell I aint no Shep :thumb:

You have the motor/turbo to do it thats what you built it for right :confused:
If I had a set up like that I would sleep in it :laugh:
 
TSIfreek, Man I only want to hit mid 11's thats the goal...Also if I can do it with 20 PSi Id be happy...but hey I got that extra 5 incase....But like I said taken that it is a Daily Driver, and not a race car i want to take all the right precautions
 
Chrono said:
TSIfreek, Man I only want to hit mid 11's thats the goal...Also if I can do it with 20 PSi Id be happy...but hey I got that extra 5 incase....But like I said taken that it is a Daily Driver, and not a race car i want to take all the right precautions


Guys hit mid 11s on a stock bottom end and built head. Thats what I have and my goals but waiting on the 50 trim and mods I need. I understand you want a relable car but just think a stock motor and stock head can rev to 7K. 8K on that motor is no problem You have a nice set up there and those HKS cams like high RPMS. I would give my left hand for what you got dude. :thumb:
 
Thanks TSi, Im just glad the wife let me do it :p Oh well, time to put it all together, still a few peices im missing but hey all comes in time.
 
I say just get a metal headgasket. I mean, looking at your mod list you have done alot to your head/block so why skimp out on the head gasket - its one of the most important gaskets on our cars. Even if the stock one can handle it, it would still be nice to have the extra strength. But some would say, if its not broke don't fix it. I guess its all up to you.
 
I don't mean to take over the post, but I have a related question, how much could you run with the OEM headgasket, without the ARP studs? (I just wanna make sure I don't overboost when I start modding)
 
There's no real answer to this question, some cars run the stock HG and studs no problem, others fail at relatively low power output. And because its a pet peeve of mine, boost is the wrong thing to measure a HGs capacity against. 25 psi on a 14b (30 lbs/min) is a lot different from 25 psi on a well supported 60-1 for example (50 lbs/min). Knock can certainly do it, since high pressure is a big part of it. But it is also possible to get cylinder pressure high enough to blow the HG without knocking, at high airflow/rev.

I have also found that more important than which gasket you choose, is how you install it. If you use ARP studs, which you might as well if you're in there, be absolutely certain to clean threads with the appropriate tap (M12x1.25 for 6 bolt, M11x1.25 for 7 bolt) so crappy threads dont alter the clamping force to fastener torque ratio. Also use the Moly lube from ARP (cheap at summit, couple bucks for a tube if your stud kit didnt come with any), avoid using motor oil and the higher torque figures ARP gives for it. Torque in a few stages, making the last one the biggest. I like to use 20, 40, 90.
 
95GSXracer said:
There's no real answer to this question, some cars run the stock HG and studs no problem, others fail at relatively low power output. And because its a pet peeve of mine, boost is the wrong thing to measure a HGs capacity against. 25 psi on a 14b (30 lbs/min) is a lot different from 25 psi on a well supported 60-1 for example (50 lbs/min). Knock can certainly do it, since high pressure is a big part of it. But it is also possible to get cylinder pressure high enough to blow the HG without knocking, at high airflow/rev.

I have also found that more important than which gasket you choose, is how you install it. If you use ARP studs, which you might as well if you're in there, be absolutely certain to clean threads with the appropriate tap (M12x1.25 for 6 bolt, M11x1.25 for 7 bolt) so crappy threads dont alter the clamping force to fastener torque ratio. Also use the Moly lube from ARP (cheap at summit, couple bucks for a tube if your stud kit didnt come with any), avoid using motor oil and the higher torque figures ARP gives for it. Torque in a few stages, making the last one the biggest. I like to use 20, 40, 90.

I agree with the stages, but how tight do you guys actually torque them down to? I personally did 20,40,60,90, but some members argue that 90 is too much with lube? How will I know if I damaged anything?
 
and also back to the boost question. Is is possible to run 24 psi on pump gas (93) with proper tuning on a bigger turbo? I'm running 20 psi right now on my turbo ( scm61 ) and have a forged internals motor with a 1g head and cams and I'm afraid to try and go higher with the boost. Sorry to steal your thread, but it's kinda related I hope since we have similar setups.
 
1fast97gsx said:
and also back to the boost question. Is is possible to run 24 psi on pump gas (93) with proper tuning on a bigger turbo? I'm running 20 psi right now on my turbo ( scm61 ) and have a forged internals motor with a 1g head and cams and I'm afraid to try and go higher with the boost. Sorry to steal your thread, but it's kinda related I hope since we have similar setups.

You have a turbo of that size and don't know what boost you're capable of running?!
What is with some of you guys? Do you just order sh*t off the internet and take the parts to somebody to have them put on and then guess at tuning? Use a f*cking logger and some gauges and figure out for *yourself* what *your* car is capable of running on *your* setup. Nobody can tell you how much to run for you and unless you can learn and figure that sh*t out on your own you'll never be as fast as the guys that know wtf they're doing with the same setup.

WTF happened to the days when DSMers started with the basic mods and smaller upgrade turbos and learned how to tune before they went all out? All I hear anymore is 50trim this and 50trim that from guys who don't even know how to f*cking change a valve cover gasket.
 
On a TDO6H 20g, TDO6 50 trim, TDO6H 56 trim, and stage3/60-1, I am able to run over 25 psi on pump gas with no knock. Did 430 to the wheels on the blown 56 trim. The big key is intercooling, the rest is tuning.

ARP recomends 86 ft-lbs with the moly lube for the 6 bolt 12mm studs. 11m studs for the 7 bolts need less torque, 71 is suggested.
 
turbowop said:
You have a turbo of that size and don't know what boost you're capable of running?!
What is with some of you guys? Do you just order sh*t off the internet and take the parts to somebody to have them put on and then guess at tuning? Use a f*cking logger and some gauges and figure out for *yourself* what *your* car is capable of running on *your* setup. Nobody can tell you how much to run for you and unless you can learn and figure that sh*t out on your own you'll never be as fast as the guys that know wtf they're doing with the same setup.

WTF happened to the days when DSMers started with the basic mods and smaller upgrade turbos and learned how to tune before they went all out? All I hear anymore is 50trim this and 50trim that from guys who don't even know how to f*cking change a valve cover gasket.

Its not that I dont know what im capable of running I just want to know how much boost a stock head gasket can hold, it's that simple. Also I have a logger, I also have gauges and not to mention I have worked my self up. Back in 2001 I was running, I had a Big 16G with a 2G Maf and 550's bla bla bla. I tuned my car and worked on it and after a year of fun I decided to go bigger, and Ive been workin up to it ever since. Also, I can chagne a valve cover gasket, you know I can even change all my fluids. So please turbowop, before you go off on me please realise im asking a simple question on a stock head gasket regaurding the amount of PSi it can hold. And im only asking because I never went over 17 with my old set-up
 
turbowop said:
You have a turbo of that size and don't know what boost you're capable of running?!
What is with some of you guys? Do you just order sh*t off the internet and take the parts to somebody to have them put on and then guess at tuning? Use a f*cking logger and some gauges and figure out for *yourself* what *your* car is capable of running on *your* setup. Nobody can tell you how much to run for you and unless you can learn and figure that sh*t out on your own you'll never be as fast as the guys that know wtf they're doing with the same setup.

WTF happened to the days when DSMers started with the basic mods and smaller upgrade turbos and learned how to tune before they went all out? All I hear anymore is 50trim this and 50trim that from guys who don't even know how to f*cking change a valve cover gasket.

Eat a dick man .. I had a 16g last year with all supporting mods for that. I rebuilt the motor with forged internals, swapped on a 1g head....why mess with a little 16g then? Oh and I did EVERYTHING myself. Not many people on here have this setup and post the boost they run, and I don't want to keep going higher and higher without having an idea where the max boost is.

Besides ... who on here as my EXACT setup and has posted their boost numbers? Ok so how am I supposed to know? Ignorant people like yourself should not post useless information like this.
 
95GSXracer said:
On a TDO6H 20g, TDO6 50 trim, TDO6H 56 trim, and stage3/60-1, I am able to run over 25 psi on pump gas with no knock. Did 430 to the wheels on the blown 56 trim. The big key is intercooling, the rest is tuning.

ARP recomends 86 ft-lbs with the moly lube for the 6 bolt 12mm studs. 11m studs for the 7 bolts need less torque, 71 is suggested.

Ok yea ... I have the 11mm studs, however used the 12mm torque specs because I wasn't aware there was a difference. :thumbdown
 
1fast97gsx said:
Eat a dick man .. I had a 16g last year with all supporting mods for that. I rebuilt the motor with forged internals, swapped on a 1g head....why mess with a little 16g then? Oh and I did EVERYTHING myself. Not many people on here have this setup and post the boost they run, and I don't want to keep going higher and higher without having an idea where the max boost is.

Besides ... who on here as my EXACT setup and has posted their boost numbers? Ok so how am I supposed to know? Ignorant people like yourself should not post useless information like this.

You're a moron. Plain and simple. If you can do all that sh*t yourself than you should know how much boost you can run by logging the car and watching for detonation. It also depends on the efficiency of said turbo at certain boost levels, which you should know since you did research on the turbo before you bought it, right?

When I put the FP green on my car I didn't get on the forums and ask what "max boost" my car is capable of. I went out and figured it out for myself by TUNING. But I tell you what....I think you could run 35psi with your "forged internals" setup just fine on pump gas. Go out and do some nice long fourth gear pulls. After that go out and eat a dick yourself f*ckstick.
 
turbowop, im not asking the amount of max boost to put in my car. If you read it, im simply asking the amount of boost that the stock head gasket can hold, nothing more. As for my Amount of PSi I know that, I want to run upwards of 25 and a max peek of 27. And yes I did the research on all my parts bla bla bla.......... so please stop using this thread to bash ppl, use it for its correct purpose.
 
Chrono said:
turbowop, im not asking the amount of max boost to put in my car. If you read it, im simply asking the amount of boost that the stock head gasket can hold, nothing more. As for my Amount of PSi I know that, I want to run upwards of 25 and a max peek of 27. And yes I did the research on all my parts bla bla bla.......... so please stop using this thread to bash ppl, use it for its correct purpose.

Fine.

I've seen cars with the stock HG and ARP's hold 30psi before with a 20g on racegas. Last year with stock headbolts and a s16g mine held upwards of 25psi on racegas but that fell to 19psi by redline. I ran it that way for a lot of track days without a problem. Now I run ARP's and a Mitsu MLS headgasket and so far it's held 27psi from the FP green on racegas and I'm sure could hold more. I run around 21 psi on pump without issues. This is just my experience with my car and mods so that may not work for everybody. It all just depends on too many things which is why nobody can really tell you what *your* car will do when you start turning up the boost. That is why I emphasize tuning so heavily. If you're going to start turning up the boost into the upper 20's psi level you better know what the hell you're doing. Not just what some guy on the internet told you it was okay to run.

I'm sorry but I just hate when people with large mod lists come on the forums and ask how much boost they can run. It makes me wonder how the hell they got to the point they're at.
 
BTW, why do you have two different intake manifolds listed in your mod list? Ported fuel rail, wtf? B&M afpr?.....you do realize you can only raise fuel pressure with that right?
 
2G one is the exahaust mani...And yes I know what the B&M does
 
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