vettewreck

iTrader: (1)

So im trying to get a list hammered down and I think ive got it all figured out but the turbo size. I know someone who is selling a pair of Bullseye s256 turbos (56mm) but im curious to know if they can make 850+rwhp. I was thinking of going with a pair of T66's but these s256 are a good deal. But I need to make sure they can support 15-20lbs of boost and make the power im looking for before I buy them. Any thoughts guys?

Or maybe something like T66? Twin 66mm? I have no clue guys. Help me out please.

Also, it will be a forged bottom end, AI ported 317 heads, good size cam (no clue on specs yet), matching springs, hardened push rods, LS6 intake and im guessing 80lbs injectors. (maybe bigger?)

Twin turbo c5

I'm not sure if they'll make 850 but my corvette had twin 62mm turbonetics on it and made 670hp 623tq on 14psi and meth. That might give you an idea of what is possiable . This was on a completly bone stock ls1 stock cam and everything top to bottom.

crazyelf

iTrader: (21)

We just did twin t3 s261 on a stock cube ls3 and it did 1100+ at 19.5 psi. Those will make 850 easy on a 5.3.

vettewreck

iTrader: (1)

But an LS3 is much more displacement than a 5.3 so... Tell me why you think they will make 850. Im not questioning you... I simply don't know. And I assume a s261 is a 61mm? Ive had some other people tell me they MAY make 700-750... so its a big deal to me bc im not doing this twice haha

hellbents10

iTrader: (10)

I think they would make 950 at the flywheel for sure on a 5.3l.

vettewreck

iTrader: (1)

Ok cool. Just hoping to get some more opinions. Need to be 100% they can manage my goal of 850 to the tires. Its going through a T56 so not a lot of drivetrain loss.

Possibly even thinking about trying some chinese T76s. Those will probably make the power just won't last long. (but at $200/300 each no biggie)

Forcefed86

iTrader: (4)

How good of a deal are we talking on the S256’s?

Depends what the motor is making NA IMO. If its bone stock (depending on what model 5.3) I don’t think you’ll make it by 20psi. If your making 400hp before you add boost that’s a different story.

This is twin 57mm (cheap china 57’s) on bone stock 5.3 (with valve springs) for a good comparison. The BW turbos will perform better, but it’s still pretty far from 850whp. It is an auto, but at 23 lbs dropping to 20 it only made 650whp.

https://ls1tech.com/forums/forced-in...st-outing.html

I’d jump straight to a 60mm range of compressor if I were trying to make those numbers with a stockish 5.3. I would look into a t4 .9x AR with a 65mm(ish) exh wheel too or you mayhave back pressure issues.


IMO 76’s would be lazy and not much fun on a manual 5.3. To me the whole point of twins is to size them small enough to have better response than a large single. A single 76 could make 850 at the wheels on a 5.3.

vettewreck

iTrader: (1)

2- S256 less than 5k miles $600 for the pair.

Not a stock 5.3. Fully reworked CNC ported 317 heads from AI, good cam, matching springs (I think AI said 630 or whatever that means for springs), ported LS6 intake, matched ported throttle body (can't go bigger bc it won't fit under my hood) and forged pistons and rods.

Forcefed86

iTrader: (4)

Well with the "good" cam you can't go wrong! Should be over 400hp as it sits then. In a perfect world 14.7 lbs should double that. (at crank) So I'm sure you'd meet your goal with enough boost. Go for it... Don't want to over turbo it, it would be lazy with a manual.

vettewreck

iTrader: (1)

^^ what about my deal? lol I edited it after you quoted me haha

Forcefed86

iTrader: (4)

seems like a great deal if the Exh housings are Large enough to not choke the motor.

vettewreck

iTrader: (1)

The guy doesn't know the exhaust housing. This is all I have to go on…. Where do I want to be on exhaust housing size?

Torqueshaft

Check on the exh. housing for a A/R number if it has one...

Just looked at Bullseye web page and it looks like the only s256 turbo with a v band exh. outlet is a 74/64 Turbine Wheel 0.70 A/R.

Full specs they have posted...

S256 V-Band Outlet 74/64 Turbine Wheel 0.70 A/R
Turbocharger Name - S256
Compressor Wheel Inducer - 56mm
Compressor Wheel Exducer - 80mm
Compressor Wheel Trim - 49
Turbine Wheel Inducer - 74mm
Turbine Wheel Exducer - 64mm
Turbine Wheel Trim - 75
Turbine Option - Outlet - 4 bolt
Turbine Option - Inlet - T3
Turbine Option - A/R - 0.70
Horsepower Rating - 300-550

I would think a pair of those might get you close...Depending on the specs of your "good" cam.

Forcefed86

iTrader: (4)

Looks like they are all t3 and range from a .55-.85AR. Unless they are the .85 I'd think they would be too small.

The fact that they don't have the 4" inlet compressors seems odd too. May not even be the extended tip units? I think I'd keep looking.

http://www.extremepsi.com/store/prod...roductid=19267

Better off with a pair of holset hx35's or HX40's.

vettewreck

iTrader: (1)

Good thing I kept asking. Thank you guys very much. Sucks I have to pass on such a good deal but if they aren't right for what I'm looking for, then I have to move on. Not looking to spend $1200 PER turbo right now either. Gotta get the motor done first!

Might just settle for some ebay T66's and see what they can do for a bit. Looking for the right turbos is exhausting and too complicated lol

LS1NOVA

iTrader: (12)

You dont have to spend $1200 per turbo. Call Forced Inductions or look on their site. Many options in the $719-850 range. Dont go too crazy with small cubes and a manual trans though.

vettewreck

iTrader: (1)

Forcefed86 I believe Im gonna go with what you recommended! Check you PMs... opinions? Thank you sir!

fireburr

iTrader: (3)

You seem to be in about the same boat I am with a few different mods like worked heads and throttle body so I am curious to what you find too. I've been looking for quite a while for the right twins for my setup low compression 383 and have come across these turbos from cx racing. I've had a really good experience with the company and the quality of the product is suprisingly good for the money. I would like to support the local companies, but $700-800 per turbo is just out of the question until I can find a better job. If you try these turbos, I'm very curious on how they will perform. They do have different exhaust housing options, I just posted one I had watched on my ebay.

http://www.ebay.com/itm/270939306819...#ht_5205wt_784

Forcefed86

iTrader: (4)

Those exh. housings are really small for a 383...

I like this one for a 5.3...

http://www.ebay.com/itm/Turbo-Charger-T4-T70-0-70-A-R-0-96-A-R-Turbine-500-HP-Civic-B18-240SX-SR20DET-/180809263166?pt=Motors_Car_Truck_Parts_Accessories&hash=item2a1912683e&vxp=mtr
This one would be better for a 383 imo.

http://www.ebay.com/itm/T4-Twin-Scroll-T78-Turbo-Charger-0-70-1-05-A-R-4-Anti-Surge-1000-HP-Supra-RX7-/161071948547?pt=Motors_Car_Truck_Parts_Accessories&hash=item2580a2e303&vxp=mtr

vettewreck

iTrader: (1)

Why does the first link say .70 AR .96 AR then when you scroll down it says you are bidding on a 0.70 A/R Compressor, 0.81 A/R Turbine??

Which one do I need??