12valve

ok, im planning on makin the famous twins setup, hx35-ht3b,
with an 40 mm wastegate, for the small charger,

everything has been worked out except for this 1 question:

can i keep the boost low enough (<50psi)?
meaning that i cant do the headwork here in mexico....

or what is needed? o-ring? headstuds?
Now we only have a 215 pump and 4k gsk, later putting in maybe 435 injectors.

PS: I want the performance of a friends truck, who as an HTB2/12 -62
which makes 45 psi boost. im planning on a very lil bit more power.

gunracer1

i'm running 55#s on my set up and it is all stock, right down to the headbolts. they have never been messed with in 235k or so miles. but i do not build boost down low and i have a loose converter. some trucks can take it and others can't. it is a luck of the draw thing.

high country

timing and your addiction to meth/water will be a big factor too, get greedy with either.....new headgasket. studs would be easy insurance, they are not o rings but you can put em in w/o a tear down and you get a chance to retorque everthing.

12valve

Im not guna use water/meth.

si, is it possible to only do head studs? and NOT o-ring?
how much boost would only head studs support?

ratsun

Timming is key
If you keep it with-in reason say 16 or less you can probbably get away with 50-55 and studs (my 24v went out after a year at 50-55 no studs) keep in mind all engines are not built the same so theres no magic formula. I have heard of people running 60-65 for long periods with just studs but did they get lucky? I also know of stock engines that lost HGs so..... With my prior experiences and twins on my 24v I am not putting them on this 12v untill I can pull the head and O-ring it as I just cant stop myself from using the power (lackofselfcontrolpaul ) You wont believe how much power you were missing out on once you put twins on a over-fueled engine.

12valve

thanx man.

so my kinda original question was: can i stay under 50 boost with a set of twins? or is it necerary to make about 60 or 70 pis to make power and keep egts down?

or am i guna blow a headgasket on the first trip, if i give it full throttle?

TxDiesel007

Precisely why my next thing is headwork

I want to get keepers, retainers, and the 60lb valve springs.... I dont know tho, i wanna run the same twin setup, i have a brand new 3B in the box at home, all i need is the piping, just how nessesery are the o rings and fire rings for a twins application? I do understand that i will need the ARP studs..

was i misunderstanding that these things are only needed for super high HP applications? I would estimate a good properly setup 35/3B twin set will put about 60-70 lbs of boost,

also what is the purpose of the fire and O rings? and finally out of curiosity, HOW MUCH will a decked out head with o rings keepers and retainers and so forth probably cost?

Rick

Willy91

Rick, I would think that 12mm studs and ) o-rings would be good for you.
These prices are from Hasley
Valve springs=$120
Titanium Keepers and Retainers=$285
Head studs $445
You can get the head o-ringed for $200-$300
Here's haisleys website http://www.haisleymachine.com/

high country

you could run just studs for now and ring the head someday if you need to, some guys never need to......plent do though

Willy91

It be eaiser just to do the rings while you had the head off to do studs. Just my 2 cents worth.

ratsun

_____________________

TX
My PDR kit has 2 blow offs in the cold line to the IC that you set at what you want. When I first put them on I set them at 50 and enjoyed my new found power(using most of my fuel efficently) however knowing I still had exess fuel (high temps and black smoke) caused me to crank up the pressure and pop the HG. The amount of boost your setup makes will depend on your fueling ability but I ran (after the o-rings) 65psi nicely and think 75-80s not out of the question. FYI I ran the truck bone stock (no box/injectors) with my twins and you couldnt tell they were on, no noticable spool-up difference after I removed them so you dont have to have high power/lots fuel for twins. As for the o-rings they machine a grove in the head around the combustion chamber and insert a thin SS wire that seats into the HG and from what I understand the firerings actually cut into the head and block to replace the fire ring in the HG.

12valve

do the blow off's keep the boost below 50? if i adjust them to it?

and what and how do they look-work?

i found some at the hardware store, they had about an 1/4 orifice, it seemed to be very small to me, and tehy where adjustable from 25 psi to 125.

so if a twins setup would make 60 psi, then afer installing 2 blow off valves, would it be around 50?

ridofpwrstroke

My BD's spooled to 64psi with just studs. I still run same setup at 54psi and have not had a problem. It is on a 24valve, but maybe help u out. I would put on studs and run it to 60. If you do blow the HG, then ring it.

12valve

ok thanks. that helps! hey, where and how much are the studs?

what do i need to look for?

my brother asked me if it didnt work, to let an advanced shop harden the studs, so they wouldnt stretch out....
or maybe fabricate new studs, with hard material, or let them harden it...

just a thougt... what do they have to support?

wannadiesel

You can get the studs from many of the vendors on this site, also Summit and Jeg's can get them. Not sure who's easiest to deal with in getting stuff to Mexico. The studs should be installed as is. The head does not have to come off, but the holes should be bottom-tapped so the studs don't stick up too much and cause interference with your valve covers.