crpndeth

I'm installing a twin 50mm turbo ls6 with prc stage 2.5 heads,bbk intake ,backwards mounted shortys,h-beams and low compression pistons,and i need advice on a cam for it.It is going in a 1987 ford thunderbird turbo coupe car with a th350 trans and a spooled,axled 8.8.The cars weight goal is 2800-3000lbs.I was thinking of running a stock zo6 cam,does anyone do that and how well would that cam work?What about the hot cam for ls1 ? The exhaust a/r is .96 so its a little big i'm going to put the turbos as close as i can to the headers,to keep the velocity up.

Shawn @ VA Speed

iTrader: (3)

I wouldnt go too low on compression,most people go way too low.the ls6 cam works really well with boost,i have made well over 600rwhp with the ls6 cam,but you could pick up a couple more hp with a little bigger cam

crpndeth

Thanks shawn @ va speed,is 9 to 1 ok .The turbos are capable of 500hp ea.I was thinking if it i can get it to make close to 400hp at the tires i should be able to double that at 1.5 bar of pressure.What cam do u recommend shawn?My goal is 800hp to the tires with enough injector.

PREDATOR-Z

IMO that is too much boost unless it is just a fun car. 1.5 bar is 21>22 PSI. To hold that much cylinder pressure, you are going to need serious clamping forces on the head. I would keep the boost level at around 1 bar max for the type of parts you are using. (for reliability purpose)

cam: 230/230 .590/.590 114+2 LSA

Properly supported and tuned this should give you in the neighbourhood of 700 horses at 1 Bar

crpndeth

Sorry i mistated i meant to say 1 bar (my bad).Im sure i've seen twin turbo cars in gm high tech mag that makes 800-900 to the tires at 15lbs.Is it a sealing issue with it being aluminum on aluminum that they (LS6s)don't like 20+ lbs?I have followed the outlaw 10.5 scene for many years and sbf have made huge power with four bolt holes per cyl.and running aluminum blocks.Is it that the chevy loyal are used to 5 bolts per cyl pre ls1 stuff?And what is it that lets go when you really put the power to them?Should i find a iron 5.7 to build to be safe?I don't mean to rile any feathers with the roosters on this forum just asking questions,thanks.

Shawn @ VA Speed

iTrader: (3)

the factory alum heads are your weak link in head gasket sealing,the decks are thin,i have seen ls2's with aftermarket heads handle 27lbs of boost with mls gaskets,if you really want to crank the boost up put on some aftermarket thick deck heads and head studs-the block will handle the power just fine

PREDATOR-Z

Like Shawn says, from my experience to push past 1 Bar reliably aftermarket castings like AFR, TFS or similar are a better choice.
Boosting is adictive and also expensive.
The trick is to know your limitations according to your parts for the combo. For mid to high boost, there are various techniques to hold a better seal and O-ringing heads is one of them, but all of that ads up $$$.

If you cannot afford aftermarket heads, use studs for sure, make double sure your deck surfaces are straight and stay within the reliable parameters.

If $$ not an issue, get the longblock built by a reputable shop that has boost experience like VA Speed.
For research read around like Nelson Racing and such, he is well known for all aluminum turbo combos.

87silverbullet

iTrader: (11)

You will get some better answers in the forced induction section. There are guys there running stock heads with GM gaskets running 15# of boost. As far as cam choice you can look at the Speed Inc turbo grinds and EPP has a turbo cam that runs really well Bob at EPP can help you with some of your questions in the forced induction section.

PREDATOR-Z

Yes,
BTW 14.7 lbs/in" is 1 BAR and as stated this can be done reliably if motor is well prepped on stock casting.

crpndeth

I guess my limitations are my heads as you guys said,what is the max hp that i should limit myself to with those heads.If the car can make 800-900 at 1 bar is that about it reliability wise?Or do i need to stay below that hp goal for reliability ?

Shawn @ VA Speed

iTrader: (3)

800 hp can be attained reliably with a 5.7 if the engine is built properly and the components are matched correctly,you need the cam,compression ratio,cyl head flow,turbos and everything else matched otherwise it will not live.you also need to make sure the heads and deck surfaces are perfectly flat with the correct finish,use head studs and tq them properly,use the correct gaskets-lots of people use the wrong size head gaskets for the bore or combustion chamber they are using-one last thing,it doesnt matter how good the engine is,if the tuner isnt good with fi stuff,it will break anyway

crpndeth

site and i like what i saw,i couldn't look long mama came in my room when she heard the "devil music" playing !!!Just kidding who sings that song on there site and i think that syclone was in gm high tech last month wasn't it?

crpndeth

the only thing i have for the fi is the computer,wiring harness and bbk intake i may go with a victor jr,blow thru setup with a front mount dist.It is pretty popular around here and i have rode in some cobled up home made stuff in my town that flies a 302 with gt40p heads and 2 t-3 off a turbo-coupe that runs 6teens.Another 306 with victor jrs and a 88mm with no intercooler that ran low 6"s with 8-10 lbs it had awful lag though,my previous car a 358w in a 2900lb car ran 6.60 and this 88mm car scared me on the street with its acceleration.So a 346ci with a big single or my twins better run 5's.All my buddies have 5 sec or faster cars .It might be easier to throw the fi tuning out of the equation and go simple my car isn't going to be a dd.I would probably save some $ at the same time.

PREDATOR-Z

Running fast & quick is not all about power. You have to setup your suspension and weight transfer right as well. Meaning with the right power to weight and right application to the ground, you can do those numbers with a bit less Hp than what you anticipate.

crpndeth

Thanks for your advice.