TA0502

Hi, I've been searching around on here for turbo info on my 5.3 build, I've found most everything I'm looking for but I wanted to get some opinions on my turbo choice, here's the specs of what I've already picked up:

Compressor: A/R 0.80 air inlet:4" outlet:2.5" inducer:76.71mm exducer:102.36mm
Turbine: A/R 0.81 inducer:64.5mm exducer:74.5mm Turbine housing flange:T4 Exhaust outlet: V band

I originally planned kind of the standard 5.3 build with ls6 cam and springs, arp head studs, etc. and to run one of these turbos, but I also have a chance to buy a second one and go twin but I'm worried that the turbo may be on the big side to twin, what do you guys think? Is this turbo going to do alright as a single? Would it push the power band into a bad spot with twins?
Thanks.

The BallSS

iTrader: (9)

You need way more info than that bud.
BUDGET:
POWER GOALS:
Engine Specifics:
Intended Use:
Fuel Type:
Transmission Type:
Differential Gear:
Space Constraints:

TA0502

Budget's not a huge issue, I don't really have a power goal, mostly street with some strip use, probably 91 octane with water/meth, LM7 with LS6 cam, ls6 valve springs, ARP hardware, 3 bar map, could go further on it but haven't decided 100% yet, chances are I'll be running a th400 with a stall, haven't picked gears yet. Also the car I'm sticking it in is a pretty big old beast so I have a lot of engine bay space. just looking for feedback on spooling characteristics for the 5.3l and if twins would just be a dog at this size on a 5.3.

slocaddy

I dont know about turbo sizing, although pretty sure those would be very large set up as twins, especially on the street.

Now on to your list of parts: you speak in riddles lol! You say "ls6 cam and springs" followed up with "3bar map arp studs, and water meth"....

Oh, you do have a power goal in mind......allot!
Sounds like you have a nice parts list, there a much better cam/spring /pushrods to compliment those other parts
Let's see this "beast".....

TA0502

Ya, I was worried about the spool time being too slow, I've done a TON of reading as I usually do before a build, I'm not new to forced induction but I am new to the LS, the last turbo car I built was an srt-4, punched to a 2.6l, forged rotating assembly, strapped crank, oversized stainless valves, Brian crower stage 3 cams, gtx3076r, water meth, 125 shot of nitrous, etc, etc, etc. It made loads of power, but the car cost me three times as much in suspension mods to try and keep that power to the ground in a fwd car lol. I missed the sound of a v8 and rwd so I bought a 79 Trans Am and built an n/a small block 400. Then I missed the feel and power of the turbo setup so I sold the car and here I am trying to get the best of both worlds.

That's kind of the main reason my parts list looks strange, some things, like a 3 bar, water meth and head studs, are pre-existing knowledge of turbo systems that I know I'm going to want, but my 5.3 specific parts are pretty much all what I've been reading is the best route to go in tech articles and build threads. I've got the 5.3 and the turbo already, most other things are still bouncing in and out of my shopping cart still but a friend of mine bought 2 of these turbos and only wants one, so I can get a second for trading him a rear end setup that I can't use anyway, that's the main reason I thought about doing twins but if they'll spool like junk because of the engine cubes then I might be shooting myself in the foot.

silvea

iTrader: (1)

Oh hey another SRT4 guy. I built me one of those haha. I kept it at 2.4 with stage 4 crower cams and a 6262 no nitrous. Yes it was hell getting it to hook up. I'd ditch the ls6 cam it really isn't that good for boost. You'd see major improvements having one custom made and they aren't that expensive. Twins or single your choice. Remember it runs off one bank so a 5.3 each bank would be about 2.65 liters liters of displacement. So each turbo should have about the same characteristics as your srt. You could easily get away with twins just can't get massive ones. Some 70mm turbos should be responsive yet make good power.

The BallSS

iTrader: (9)

Well I'll tell you, I'm currently running a T7875 which sounds pretty close to what you described on a SBE LS1 with a manual trans.
It lights off fast and carries power out to 6,500 rpm at least, maybe farther but 6,500 is about where I shift at.
I've got a Gen IV 5.3 that will be going in at some point like you so I can only imagine that my shift points will be extended and higher boost levels achieved.
If you can get that turbo for the right price for a single for street use I think you'd be in good shape.
If hood space and budget is no issue than a billet wheel Borg would be ideal, Jose or Reed can help spec on out for you.
I don't think twins with that turbo would be a good idea for the street, I'd imagine they'd be pretty lazy until they got some steam behind them lol.
Hopefully someone with more turbo application experience will weigh in.

The BallSS

iTrader: (9)

But not the 7575's he's looking at using right?

Bowtie316

iTrader: (1)

The turbo he has looks like a 7665 with a .81 exhaust a/r. The exhaust turbine will be a choke point on a 5.3 as a single especially with the .81 a/r but it could still spool quickly and make good power, maybe 600rwhp I don't know.

Two of them might be laggy on a 5.3 but may be perfect for a 6.0. It depends on what packages easily and what the overall goals are.

I say run the single turbo as is, and when you want more power, go to a 7875 or something.

silvea

iTrader: (1)

Nope those would be quite lazy on the street. Even 70's would be lazy now that I think about it for street use. Remember a lot of guys use single 7675 turbos on 5.3 and make big power like 700rwhp. Having 2 means stuffing twice as much air. So if you aren't looking for numbers over 1k your turbos would be quite over sized.

silvea

iTrader: (1)

The larger the turbos the more lag and they are lazier. Just something to keep in mind. Honestly for what parts you are using it's a very budget friendly build. I'd use a borg s480 make some good power, save a bunch of money and take advantage of that large engine bay. Lots of guys use them on 5.3 with good results. It would be fairly responsive yet have potential towards 900rwhp. You'd be able to grow with it should you decide to build a more serious engine.

silvea

iTrader: (1)

Yeah he has just a standard 7665. He'd have to lean on it pretty hard to get it to choke noticeably. Remember guys used those for years with no issues. Not that it's hard to choke one out but on a 5.3 that's budget built I doubt he plans on pushing it that hard. Here's the next issue. Say he chokes that 7665 and upgrades to a 7875 there a decent increase in power but he would likely take advantage of that in the first retune and the next time he steps up it goes to a turbo that would likely need you to redo your piping to take full advantage. Doing it once is the cheapest way.

TA0502

So it sounds like the twins wouldn't be a good idea, I've seen a few twin builds with them making great 1/4 mile passes or dyno runs but you never see a power curve to go along with it so you can't really pin down at what rpm they really get into boost. Even that twin 76 hot rod magazine 4.8 build didn't give any information besides peak numbers and a half assed parts list. I guess my other question would be, are the 6.0's just as good with boost? I've seen a ton of 5.3 builds but they don't get mentioned at much. It's looking like I'll just be running a single on this 5.3 but I figure I might as well ask.

Black89Z51

iTrader: (2)

Billet 7875 from VS Racing. 2.25" hotside.

Tried and true. It'll give you more power than you'll need on the street, with good manners.

JoeNova

If you have it, run it. Its a standard T4 flange. Upgrading if you're not happy won't take much effort.

silvea

iTrader: (1)

5.3's are a dime a dozen. 6.0 are considerably more expensive. That's why everyone uses the 5.3. That was my intention to go 5.3 but I ended up with a 6.0 block which I've spent tons of money at the machine shop getting forged pistons rods ect... it's a solid engine and very capable of making really big numbers it's just not cheap. If you blow a 5.3 it's just 400 bucks and a few hours in the garage. If I blow my 6.0 it's thousands to repair. That's why guys get 5.3.

slocaddy

What this guy says.
Boost the crap out of it!

The BallSS

iTrader: (9)

Ah okay, I ran a TC7868 before moving up to the T7875.
The TC7868 was like a light switch, instant boost but it was all done by 5,500 rpm on my SBE LS1 w/ 317 heads.
With a street tire manual trans it was tough to modulate the power, in an auto car though with a higher rear gear would've been a different story I think.
Start with the 7565 and when it gets boring throw a 7675 in there since it will bolt right in.
Then when your really strung out spring for a different setup with a billet S480 lol.

TA0502

I've gotten some great advice so far, thanks. Another question, it'll cost a few more dollars but for cam and springs I was looking at this cam

https://m.summitracing.com/parts/cca-sumlsgt105

With a set of the comp beehive springs good for .625 lift, would that cam make a decent difference seeing as it's set up to be a turbo application cam?

Bowtie316

iTrader: (1)

That cam is very similar to the tried and true sloppy stage 2 cam that is cheaper.

http://www.jegs.com/i/JEGS-Performan...00582/10002/-1

I would use this cam with pac 1218 springs if you just want to stab something in and go. It really depends on your goals.

If you already have the ls6 cam, give it a try, lots of guys have used it an made power over the stock cam.