Hi guy,

I'm boosting to 25 psi on stock turbo and I heard that by precaution, I should change the head stud because the head could lift up???

On the stock stud, i shouldn't run more than 22 psi???

Does anybody have already blow his head because boosting at 25psi on stock turbo with tune that doesn't knock??

Thanks!

 

Should be fine on stock studs as long as the tune is good.

 

you'll be fine.. but if you're going to be messing about with the boost you had better have a wideband or you run the risk of going lean

 

What octane is the pumpgas in your area? The IX cylinderhead is more knock resistant than the non-MIVEC heads due to improved combustion chamber heat removal via redesigned water passages.

 

I imagine he'll be running either 91 or 94.

 

That would be me. the evo was running 100 octane unleaded boosting at 23 psi peak tapering to 21. The day it happened we were at a hpde at Thunderhill. The car was a 2 driver that day so it didn't get much of a break to rest between sessions. The other driver was a novice so in actuality he wasn't driving it to hard though, so idk. I kept teasing him because when he would pull in the tires were barely warm,haha.

It was not a fault of the tune or anything other than the way it happened was a total freak occurance, but yes from the reminants of the mess I assume from the headstuds being loose enough to remove by hand, and from coolant getting in the combustion chamber, that my head lifted.

ARP studs are good precaution and they aren't that expensive in the scheme of things. If you have your head off just get a set, whether they are the regular or the fancier 625 custom age plus, its good insurance.

 

I have 94 octane gas and the car is well tune by me(with external wideband, 3port controller...), I'm running this setup since 3 months but I'm doing lapping and a guy at the place we lap said he tune a lot of evo and that at this boost, the head could lift up but I have never heard of that before and I think you confirm that the stud can wait (until I modified other piece to get more of that 4g63,hiiii)

Thanks!

 

I dont do lapping, but I am assuming relatively long, sustained, full boost intervals at WOT, in high temp ambient conditions, huh?

I like knowing my EGT's from the #1, or #2 exhaust runner, under sustained WOT, full-boost running. Also, IAT's sourced at the IC oulet(UICP).

I like precise, repeatable, digital readout on an EGT gauge, with a peak hold function and high temp playback and logging capabilites with adjustable temp alarm. Zeitronix is nice. SPA Technique makes a nice gauge too. With good temp data you can make educated choices otherwise you are just guessing.

 

I think a wideband 02 at the very least would have saved me from destroying my motor.

 

What's old is new again? At what point is it okay to start telling people to search?

This is kinda old news, dude.



It comes down to tune, but I'm running stock studs at 21psi with spikes up to 24psi without issue in my track evo.

 

30-31 psi on the stock studs for the past 4 years

 

Sorry about your blown motor, Tommi.

 

Should be fine, but if you have the time and a little bit of cash, arp headstuds will help you sleep at night. Prior to changing mine, I hated having that little gremlin of a thought in the back of my mind during each pull. ARP headstuds got rid of that worry and they aren't too pricey.

 

generally speaking a bad tune/runaway detonation will cause the head to lift, obviously within reason. 30 psi out of an ef4 and I have no worries, my tune is solid.

 

Did you have straight 100oct or a blend? If it was straight, did you also increase the timing for that octane? That sucks about blowing the headgasket on a track day.