swap headbolts with ARPs = safe Evo3 16G @ 24PSI DD?

[Korndogg]

hey guys
searched around but couldn't really find an aswer specific to my evo3... weird, thought that would be easy..

anywho, if i swap my stock headbolts with ARP studs would it be safe to run 24PSI on daily with my evo3 16G? or is that pushing it?

my next 2 planned mods are ARP headstuds and 264/272 cam setup.. i would say 50hp is reasonable from that.. is this also safe? or am i starting to push the stock block too far?

it's a daily driver, so reliability is my larger concern. it has been very reliable so far, just wondering if 24PSI is safe.. esp with stock HG. i am currently running 20PSI with stock headbolts




oh, also, has anyone ever had problems with a headbolt not coming out? i would think not since there's no reason for them to rust..... but i wouldn't want to break one, heh.


thanks a lot

 

[1SloColt]

You don't need ARPs to run 24psi daily driven. EVo III 16g on 24psi is not gonna make enough power to have to build the motor. People run 28-30psi on 1g headbolts on stock HG without problems, so wouldn't see daily driving it to be too much of a problem.

 

[4gsx63]

ARP headstuds and stock composite headgasket can handle 24psi on most bolt-on turbos. They are not the limiting factor on whether you could run 24psi however. Tuning is the key. If you're planning to run 24psi DD on pump gas, becareful even with ARPs.

Make sure to replace with new stock composite headgasket and spray it with copper headgasket sprayer. If you decide to go with aftermarket metal gasket, make sure your head/block surface are flat. Follow the proper procedures when putting everything back together. Good luck!

 

[Korndogg]

30psi on stock bolts? i dunno about that.. and the 7bolt motors have smaller headbolts which stretch more anyway.. as is my understanding...

 

[Korndogg]

ARP headstuds and stock composite headgasket can handle 24psi on most bolt-on turbos. They are not the limiting factor on whether you could run 24psi however. Tuning is the key. If you're planning to run 24psi DD on pump gas, don't even bother.

Make sure to replace with new stock composite headgasket and spray it with copper headgasket sprayer. If you decide to go with aftermarket metal gasket, make sure your head/block surface are flat. Follow the proper procedures when putting everything back together. Good luck!

yes, that was my plan.. 24psi on 93 pump.. what's wrong with that?
and i was intending on leaving the hg for now, just swapping the bolts for the ARPs. i can replace it when it starts to go, but for now i'll leave my timing belt (i just changed it a couple of weeks ago, not real into doing that again right now)

 

[CanadianTSi]

I run 24psi daily on my 50 trim with the stock gasket and studs...It's all in the Tuning

 

[Korndogg]

oo, on a 50 trim 'eh?

now what makes your tune so safe as you're suggesting.. mostly the fact that you've got no knock? or are you running esp rich or something along those lines?

thanks for the help

 

[CanadianTSi]

No knock is the key, knock raises the cylinder pressure tremendously and pops the gasket.

I wouldn't say I'm rich, it's at -38 up top with 650's...

 

[Korndogg]

No knock is the key, knock raises the cylinder pressure tremendously and pops the gasket.

I wouldn't say I'm rich, it's at -38 up top with 650's...

huh, crazy. i'm at like -22 up top with 580s. my car seems to like to run rich though... timing starts getting pulled if i yank out any more fuel *shrug* (new OEM o2's)

 

[GVR4592]

I usually run between 24-25 psi daily, most current turbo was a PTE 60 trim on 92 octane. Stock gasket and bolts (80,000 miles). Like CanadianTSi said it's all in the tuning

 

[Korndogg]

so with the assumption that it's safe with proper tuning, how do you guys go about making sure you don't knock during the process of tuning? how do you know when you're about to be too lean without actually going there? or is it okay as long as it's not too bad... for example, how would you progress from 20psi to 24 safely?

it would theoretically be unsafe you just turned it up to 24psi, and then tune to add fuel until you don't knock..

would you turn the boost up to 21, tune, 22, tune, 23, and so on?
or would you richen the hell out of your AFC and then turn up the boost.. then you could lean out the lower rpms until it knocks, back off, then move up on the rpms?

thanks for all the help guys.
much appreciated

 

[1SloColt]

30psi on stock bolts? i dunno about that.. and the 7bolt motors have smaller headbolts which stretch more anyway.. as is my understanding...

Thats why I said 1g headbolts. 1g headbolts are grade 8, which means they have a tensil strength of at least 176,000psi, in which case they could be more durable than that rating, but not any less, whereas ARPs are rated at 190,000psi. Thing about ARPs is that you can torque them more than OEM headbolts, I torque them to 100ft/lbs. There are numerous people running 28-30psi on stock stuff and have yet to have problems.

 

[GVR4592]

I always start rich, then slowly and carefully lean it out. A little bit of knock during tuning shouldn't hurt anything. Intercooler size can have a big affect, so if you are running a stock sidemount then you should be very careful, hot intake temps can lead to knock.

 

[Korndogg]

I always start rich, then slowly and carefully lean it out. A little bit of knock during tuning shouldn't hurt anything. Intercooler size can have a big affect, so if you are running a stock sidemount then you should be very careful, hot intake temps can lead to knock.

24 seems pretty high for a stock smic.. hehe

i've got a fmic (johnny racecar. seems to work pretty damn well. always hot on one side but cool to the touch on the other

 

[daren_p]

The ic will make a huge difference. Even at 18 psi I would see knock by the time I was mid way through 3rd or 4th with my upgraded HRC smic. Once I upgraded to a Victory Performance fmic, I never see knock. Thats good to know that with proper tunning 24 psi shouldn't be a problem on a DD. I will be running arp headstuds next spring when the car comes out of storage and I was going to run 20 psi on 94.

 

[eclipsegsx97979]

im running 20 psi with an fp green and dsmlink and no probs so far with stock bolts and hg. im not going to have the hg and studs replaced until i start working on the head and what not or it blows... but if the head is gonna be off might as well do some work in there and not just change the hg and studs...


kevin

 

[eclipsegsx97979]

i just put down 375 to all 4 wheels so we will see how long it holds up... its also not my daily driver...

kevin

 

[dsm-onster]

so with the assumption that it's safe with proper tuning, how do you guys go about making sure you don't knock during the process of tuning? how do you know when you're about to be too lean without actually going there? or is it okay as long as it's not too bad... for example, how would you progress from 20psi to 24 safely?

it would theoretically be unsafe you just turned it up to 24psi, and then tune to add fuel until you don't knock..

would you turn the boost up to 21, tune, 22, tune, 23, and so on?
or would you richen the hell out of your AFC and then turn up the boost.. then you could lean out the lower rpms until it knocks, back off, then move up on the rpms?

thanks for all the help guys.
much appreciated

You will still knock if you run rich and run too much boost for a particular setup. Believe me. I know. I lifted my 1G head (supposed to be harder and thicker head bolts) doing this. Here's what i did. You get more power from timing than from a leaner AFR. So i dial in my base settings and turn my boost up 1-2 psi at a time until i get to my target boost based on my horsepower goals on my compressor map. If i'm geting no knock i proceed to advance the timing up to 3 degrees (seams to be a good number for me and other engines i've tuned). If i'm getting no knock i lean her out until i get knock.

Of course, now i have a WBO2. I recomend it as a neccesity to tune with not a luxury. I just dial her in at 10.5:1 or so (don't be silly and run 9:1 AFR so you can run 27* timing)then i raise the boost to where i want it based on my compressor map calculations. If i have no knock, I have my way with the timing until she's running on the ragged edge.

If you run ARPs even on the stock hg, you will probably never pop the gasket (if she's torqued to 100+ ft-lbs). That meas you'll have no "safety fuse". If you detonate at the right time often enough you will melt a hole in your piston or break your rings or even drop a piston completely. I always say get ARPs if you plan on running over 20psi. Unless you're sure about your tuning skills. It is easier and less expensive to replace your HG than your block. I am not trying to scare you though the 4g63 block is tough as he!! and the long block is not prone to detonation like other engines i've worked with.

Bottem line look at your logger and don't get greedy. Shoot for your boost goal, more timing, and a decent AF ratif course, I suggest water injection and a decent flowing FMIC.