General concerns when contemplating forced induction

[cowboy bebop]

Hi guys,

I was thinking about HP in the 2JZ-GTE today and the fortification issues we had to address as the boost levels, and cylinder pressures rise. I've been leaning towards the 2uz-fe because of the iron block, like the 2JZ-GTE. My concerns are with the 1uz, and higher HP levels.

Once the boost levels rise with the with the 2jz, and we hover around 1000rwhp, it's generally accepted that headlift becomes an issue. We solved this in my personal motor by installing 1/2 inch head studs. If someone was to run the 1uz-fe, how would the problem of headlift be addressed since it has an aluminum block.

Also, realizing that the 1uz 6 bolt main is effective, how stout will can the mains be when the studs are rooted in the aluminum block?

Thanks for what help I can get.

Eric

 

[Lextreme II]

For the head, we use ARP studs and each head will get 10 studs. As for main, don't worry about it. The side bolts will hold the crank in place. If the side bolt fails, then the whole block will get destroy.

One option you can do would be converting the 10 mm head studs to 11 or 12 mm head studs. Some machining will require. The main can also take 11 mm studs too with some minor machining. However, if you do ARP all over with good internal parts, then u should ok.... I have ARP all over my block and MLS gaskets in my Single Turbo Lexus LS400.

 

[Red Supra]

There is 8 cylinders to bear the cylinder pressure. In case of the 2jz, once the motor is prepped for big boost and enough power is made to break things you will see cylinder liners crack between 3 and 4. With good 1/2" head studs the head won't lift at 60psi.

Top fuel dragsters run aluminum blocks.

 

[cowboy bebop]

Thanks guys, I was thinking of those concerns earlier today. I'm still leaning towards the iron block of the 2uz-fe however because of the displacement, and iron block, but it's good to hear that the 1uz-can take the cylinder pressures even though it's block is aluminum. I've not dealt with an aluminum block before so I'm sure of it's stronger and weaker points.

For instance, my head studs are torqued to 100ft/lbs, I am wondering would the aluminum block of the 1uz be able to handle that kind of tourque without ripping the headstuds right out of the hole? Like I said, I'm not familiar with an aluminum block, and what it can / can't do.

Thanks guys,

Eric

 

[Lextreme II]

If my memory serve me correctly. ARP studs on aluminum is about 60 to 70 ft/lbs but dont quote me for that.

 

[vvega]

over tighting bolts does nothing other than weaken them

v

 

[cribbj]

IIRC, ARP's recommendations for their 2JZ-GTE head studs are lower than the stock torque, and several in the Supra community have had their heads lift at high boost. Most of us torque anywhere from 10% to 25% higher than ARP's recommendation for this reason.

If I was contemplating serious boost with the 1UZ (like Eric probably is) I might be investigating Helicoils or similar for the head studs.

 

[vvega]

its not hard to do
personally i never go bu manufatures specs whe it comes to bolt
it simepl
you need to know
the material
thred type and pitch and shank lenght
from this you can work out the peak strength torque for the bolt
and yes it is normally higer the the manufactura specs

or you could just do a streeeeeeeeeech test
that way you know what your dealing with and when your bolt is at perfect tension

bolts are not a hit and miss item there able to be calculated
fact of the matter is is the bolt is at the right streech and your getting lift you need to go to a larger bolt

helicoils will stop the bolt stripping out ... but that shouldnt happen at the corect tension

the first guy had the right idea with the larger bolts
there is no substaute for proper engineering

v

 

[cowboy bebop]

:bigeyes: The situation with the 2JZ is that if you run a higher boost, and run a stock torque on head studs, you run a higher risk of head lift when approaching 1000rwhp. So the cure for this is to run them down to 100ft/lbs and keep your cylinder pressures somewhat below stratospheric levels. Keep in mind, for most Supra owners, the V8 swap will only be undertaken with the prospect of laying down at least 800rwhp on a daily basis, because in fact, the 2JZ will do that quite readily.

For reference, when the 2JZ is pushed to to over 40psi, with N2O on top of that, the cylinder pressures are so intense that fuels that hover around 125 and 130 octane have to be used. You can understand why torquing the head studs down to 100ft/lbs is the first thing you do.

 

[vvega]

interesting
you can spend the money to poke 40 psi and nos in there as well as the money to run a 800 hp car
but you cant spend the money to re-engineer the studs
in fact your rather use "stock" bolts to do what is completely out of there design spec

i put it to you like this
the reason you get head lif is because the bolts are streching under boost or the head is flexing......
straight off that should tell you that you have well exceeded there limits
and need to be uprated
over streching them to remove there elastisity is what your doing
the enginering term is going past there yeld point ,meaning that you have now damaged the structure of the fastning

i cant see how you justafie this as a good thing to do ??

v

 

[cowboy bebop]

vvega, owning a high HP Supra myself, I will leave it at this:

A 10mm ARP head stud at stock torque at 4 digit levels gambles with headlift. History has shown this. However, what we do to correct this is switch to 1/2 inch ARP headstuds torqued to 100ft/lbs.

When the switch to 1/2 inch headstuds torqued to 100ft/lbs is made the headlift stops.

If I decide to install a 2uz-fe into my Supra, and given my experience with the
2JZ-GTE, I will do my best install 1/2 inch headstuds.

Eric

 

[Lextreme II]

1/2" head studs will be awesome. I wonder how much would it cost to convert them.

 

[cowboy bebop]

As I remember with the 2JZ, it was only a few hundred dollars to have the holes run though in the block and head. Plus running the holes through the gasket, and cost of the studs. To be safe, I'd earmark $500.00 dollars for it, and if you have cash left over afterwards, then it's Miller time.

Eric

 

[vvega]

been a enginner i will leave you with some facts to ponder

for the 1/2 inch headbolts......
yeap i completely agree
1/2 inch headstuds are well within there stretch range @100ft/lbs
this i have no issue with as its a good example of how proper engineering can be used to overcome a problem

a 10mm bolt at 100ft/lbs would have gone into plastic defamation @ 90ft/lbs
so anything after 87ft/lb will only extrude and deform the stank and whilst your wrench is reading 100ft/lbs what you will be reading will be the MOA(moment of inerta) rather than the true clamp pressure

thats from a engineering standpoint
i know what metals do and have studied it in depth in a labratory over tighting a bolt to past its yeld is one of the tests you do at uni
im sorry but if you think you know more that 100's of years of delevopment and testing then you really need to stand back and take another look

so keep with teh 1/2 ich studs

 

[cowboy bebop]

been a enginner i will leave you with some facts to ponder

for the 1/2 inch headbolts......
yeap i completely agree
1/2 inch headstuds are well within there stretch range @100ft/lbs
this i have no issue with as its a good example of how proper engineering can be used to overcome a problem

a 10mm bolt at 100ft/lbs would have gone into plastic defamation @ 90ft/lbs
so anything after 87ft/lb will only extrude and deform the stank and whilst your wrench is reading 100ft/lbs what you will be reading will be the MOA(moment of inerta) rather than the true clamp pressure

thats from a engineering standpoint
i know what metals do and have studied it in depth in a labratory over tighting a bolt to past its yeld is one of the tests you do at uni
im sorry but if you think you know more that 100's of years of delevopment and testing then you really need to stand back and take another look

so keep with teh 1/2 ich studs

How'd I know that you were an engineer.... Look, I'm new here so I don't want to get in a match because it doesn't solve anything. I will say that at high boost levels, headlift becomes an issue especially is you are winding down into an aluminum block. Headlift becomes an issue with 2Js and I am certain that at certain levels, it would become an issue with the 'uz family of motors. It's inexpensive to convert, and you know what they say about an ounce of prevention...

My recomendation for those who want to boost high, especially Supra owners who are accustomed to 600-900 rwhp daily, is to go with 1/2 inch head studs and forget about it. This is assuming everything is in place for the 1/2/3uz-fe to accept them. Do it once, do it right, and never have to do it again.

 

[vvega]

now thats some great advice my man

v

 

[Tex]

been a enginner i will leave you with some facts to ponder

for the 1/2 inch headbolts......
yeap i completely agree
1/2 inch headstuds are well within there stretch range @100ft/lbs
this i have no issue with as its a good example of how proper engineering can be used to overcome a problem

a 10mm bolt at 100ft/lbs would have gone into plastic defamation @ 90ft/lbs
so anything after 87ft/lb will only extrude and deform the stank and whilst your wrench is reading 100ft/lbs what you will be reading will be the MOA(moment of inerta) rather than the true clamp pressure

thats from a engineering standpoint
i know what metals do and have studied it in depth in a labratory over tighting a bolt to past its yeld is one of the tests you do at uni
im sorry but if you think you know more that 100's of years of delevopment and testing then you really need to stand back and take another look

so keep with teh 1/2 ich studs

your statement about 1/2 headstuds WOULD be true if all metals were created equal. if you get a chance look at a rockwell hardness test sheet.All the measurements are for the metals hardness and are measured in psi. from that you can calculate a metals tensile strength which is a metals resistance to being pulled apart. so before you can say a 1/2 inch headstud is better than a 10mm you have to look at the materials used in the studs if the 10mm's material has a higher tensile strength you can torque it higher than the 1/2 stud despite it's heavier cross-section. not trying to be an *** just backing up the old statement bout bigger being better.

 

[vvega]

your statement about 1/2 headstuds WOULD be true if all metals were created equal. if you get a chance look at a rockwell hardness test sheet.All the measurements are for the metals hardness and are measured in psi. from that you can calculate a metals tensile strength which is a metals resistance to being pulled apart. so before you can say a 1/2 inch headstud is better than a 10mm you have to look at the materials used in the studs if the 10mm's material has a higher tensile strength you can torque it higher than the 1/2 stud despite it's heavier cross-section. not trying to be an *** just backing up the old statement bout bigger being better.

did you not read his post the camparson was between the stock head bolts the 10mm arp's amd the 1/2 " arp's
we not talking about grabbing a rusty bolt off the ground
i know what a rockwell tester is
i used to use one to check tensile strength of solution treated and precepted alloy..... back when i was working in aircraft manufacture

we had a bit of info to work with
read back a bit and you will se that the bolt material has been covered

there is a lot of info in this threed you just need to start at the beginning and read though to see how we came to the final conclusions

cheers for checking though

v

 

[Lextreme II]

Please keep in mind that 1uzfe and 3uzfe blocks are aluminum and 2uzfe is iron. I believe the aluminum block have much lower torque tolerance.

 

[Tex]

didn't mean to sound like an ass, i read the post from the beginning, then re-read it. I was just throwing out some food for thought. I deal with issues along these lines every day, i'm currently involved in aircraft maitenance in the USAF as a machinist and welder.