stoddardlly

Hey guys i have researched a bit and am planning on building a twin turbo 5.3. I have done some research on here and other sites and find mostly single turbo builds going for large turbos with room for more. I am only wanting a maximum of 600 rwhp. I want to use a smaller matched pair of turbos to acheive very quick response (hardly any lag time).

I was thinking for the base engine i have a early 2000's 5.3 iron block in good shape just needs the crank polished...put some chevy bearings back in and upgrade to the newer ls rods with floating pins and possibly entry level forged pistons with rings gapped properly and upgrade to mls gm head gaskets for the 5.3 with arp head studs. i need to replace the timing chain as its loose enough. i was thinking a decent cam. how does the ls6 cam work on these 5.3 turbo builds? im keeping the stock truck intake and thinking of building truck shorty headers turned upside down and have an air to air intercooler.

Im building this as a street warrior truck used to show off and also have as a back up daily driver. i also plan to pull cars (around 5k average) now and then so i want it to hold up.

my question is what you recomend for cam choices i dont want anything too exotic. also what would be a decent size and set of turbos for this kind of build. thanks

Twin turbo c5

I'd personaly get a custom cam if I was going to take the time to do a cam swap. I just got a isky triple 12 for my 6.0. As for turbo selection lots of different options I'm sure someone will chime in with a little more detail than me but I'd say talk to Jose at forced inductions and your guessing on what will work is done when you call him. I'd say something like twin 62's would work good if you had a custom and converter to go with it.

HexenLord

You could hit 600 whp on a stock cam, stock pistons/rods, stock intake/throttle body, stock exhaust manifolds.

Anything you upgrade from there is only going to make hitting that number easier, but they won't be necessary.

Twin turbo c5

Hexanlord is right I made 670 on a bone stock motor, cam and everything with twin 62's on a 5.7 . Shouldn't be hard with a 5.3.

stoddardlly

Ok thanks guys. I should explain a bit more this is gunna go in a mid 90's 4x4 truck with a manual so I want ultimate spooling off the bottom I suppose single or twin....just needs to come in strong I'd say 1500-2k max and flow enuf for about 500 rwhp

HexenLord

1500-2k max, as in RPM?

Built the system around torque numbers and get a turbo thats only capable of 500-600 and push it to the max.

You gotta realize, a turbo capable of 500 whp is going to be making insane torque if its at full tilt at 1500 RPM. You won't get any traction, and if you do, your drivetrain is probably going to go boom.

Twin turbo c5

I'm thinking he's meaning start coming in on boost . I'm sure he wants it to to be fast spooling. Am I right?

stoddardlly

Yeah that's where I want it to come in at its a 4x4 truck so I could run it in 4x4 if I have a lack of traction....this isn't gonna be a drag racer just a fun street/ snow and some mud truck.

I Tore down my 5.3 yesterday and its an early one with the non floating rods....I'd kind of like the better floating ones and everyone says late model rod bolts are better than early ones.

Would something like a used ls6 cam be better than the 5.3 stocker? N/a output is compounded by boost so I wouldn't have to run as much? Or would I be better off getting a turbo specific cam?

Also new rods and pistons, what should I run for rings? New gm ones and just give them extra gap?

How is the 03-05 TAC drive by wire throttle body I have gunna hold up?

How do you guys run the pcv system with boost and would I need 60 or 80 lb/hr injectors with what kind of rail and pressure regulator.

What is a good oil pump to run more volume for the turbos?

Sorry for so many questions this is just a little more involved than a carbed SBC. Haha. Thanks for everyone's replies!

HexenLord

If your goal is only 500 whp, you can forget half of what you just typed.

Like I said before:

You can upgrade rods/pistons if you want, but 500 whp is well within the limits of the gen 3 internals.

Stock cam will get you there. LS6 cam will make it easier, stock turbo cam will make it even easier yet.

Run stock GM rings. You'll likely have to gap them to begin with, so it won't hurt to gap them a little larger for boost.

How will the DBW setup hold up? Well, since theres no cable, I guess there are less parts to get stuck/break. You also get free cruise control with the DBW.

There are 500 PCV threads on here. Those three letters alone in the search bar up above should get you everything you need to know and then some.

60-80 lb injectors are fine, especially since they are right in that bang for the buck range. Stock rails, stock fuel pressure if you feel like it.

Most of us don't care about running a bigger oil pump. Now you're just overcomplicating things.




Get a stock motor. Put 60-80 lb injectors in it. Put the turbo on it. Enjoy.

If you don't hit 500 whp, turn the boost up a little. Still don't hit it? Throw in a cam. You really shouldn't have to go much further than that.

stoddardlly

yeah im sure im overcomplicating this, its just hard to beleive you can pull so much out of these things on stock everything haha. I think im gunna upgrade to the floating rods and pistons though as it will make me feel better. cylinders look great but gunna have them deglazed for the new rings also. so if you gap the rings to say .019'' stock, say id go to .024''? and ive read some on here say to gap the 2nd ring on these roughly .003" to .005" larger than the 1st ring to eliminate flutter under boost?

on a turbo related note i found garrett's turbo finder app, anyone have any real luck with this? it recomends anywhere from a gt2860r to a gt3271 but the calculator says my boost ratio will be 2:1 which seems pretty high?

So my plans are:
late model 5.3 floating rods and pistons with new gm rings properly gapped for boost,
new gm bearings,
gm mls 5.3 head gasket,
arp head bolts,
truck manifolds or shorty headers for turbos,
ls6 cam and valve springs pending more research
new oil pump.

HexenLord

Truck manifolds work great. Ls6 cam is good for 50 or so HP on a very mild boosted 5.3. PAC 1218 springs are kinda the go to springs for low lift boosted setups since they are cheap and reliable.

stoddardlly

I was just thinking headers are easier to weld different flanges to for turbos instead of making adapters from the manolifolds but I may try the manifolds first as they'd probably be more rugged. I'd like to do a little cam to help not need as much boost.

I'd still like to update the rods and pistons as its a little extra insurance for me against reliability and not so expensive.

Thanks for everyone's input its much appreciated.

HeavyMetl

iTrader: (2)

I understand wanting a tough engine, but any 5.3 in nearly any working condition at all can handle 500rwhp easily. Of course a bad tune will kill anything, but the factory rods/pistons are incredibly tough....especially when compared to any old small or big block factory parts. Upgrading for such modest boost and hp goals just doesn't make much economic sense, that's th beauty of the junkyard LS, you get one heck of an engine for minimal cash outlay.

Spend your money on the turbo, fuel system, tune, and transmission/tq convertor.

Pyro6000

This has been dead a few days, so I'd like to give it a bump. I'm seriously thinking about building an almost identical truck, with the exception being that I'd like to be able to select a high/low boost setting. Something like 600hp for a normal driving setting, and 900hp when I'm feeling frisky. Possibly running two fuel tanks, a smaller one filled with 110 for the 900hp setting. (I don't yet know how to do this. This is the planning stage.)

I too was considering forged dished pistons. Still am, really... I think a fresh bore is always a good idea for any kind of performance engine. I'm sure by now we've all read Hot Rod Magazine's Big Bang Theory article, and I'm not going to lie, that is a big part of why I even want to try this. I'll have Comp recommend a cam, run a Schuman oil pump, LS7 valve springs if they're enough, (I have a set at the shop) etc. In one of the sticky FAQ pages, they mention 6.0 heads. I can get those for $100 each locally, so that might be a better way to get more flow/lower compression. I have an engine dyno I can use, and I know a guy with the tuning software who would do the tuning for me.

I've been wanting to learn more about turbos before I choose the actual pair, but have been having trouble finding a website that explains the options in detail without being written in Greek. Some of the links in the FAQ here are broken for me. I'm leaning towards a pair of T70 size, .70a/r, but admittedly am not sure.