sniperperformance

iTrader: (5)

Ok guy i wanted to throw this out there just to see if im in the right ball park. so please understand im not loaded so my turbo brand selection is the best i can do. Im going to be useing 2 T4 on3 70mm turbos im thinking .68 A/R on the hotside.

mods to the motor

katech rod bolts
ARP head studs
LS9 head gaskets
243 heads should put me around 9.1
cam similar to the cam used by hot rod mags twin turbo 5.3l
LS1 intake for now. will upgrade to LS6 when i find one
also obx up and foward turbo headers.
h-beam rods (maybe)

I know im going to get people post up use a quality turbo. use tnetics, use comp, use master power. i dont have that kind of loot this will be a one shot deal for me. i have 5 kids and no real play money. so please be kind...


so what do you think. thanks for any help.

BottleFedZ346

iTrader: (17)

What's your power goals?

geoguy1369

iTrader: (2)

im interested in hearing this also. I have a stock 5.3 for now that i was considering on3 70mm twins which would later be going on a forged lq4 looking for 1000whp but not sure if the will be enough to hit it easily.

Boo"SS"t

iTrader: (2)

Is this an auto or manual? what size turbine wheels? Can you get those turbos with a little bit smaller compressor wheel? you won't really need that 70mm, it'll just be an extra rotating mass for your set-up which equals lag.

sniperperformance

iTrader: (5)

1st off thanks for the replies guys.

i would like to see around 700+ rwhp

this is a auto 4l80E i had sitting around.

turbo specs below:
Turbo Specs

Cold Side:

Compressor Wheel 70mm

.70 a/r

4” Inlet and 2.5” Compressor Outlet

Inducer- 70.15mm

Exducer- 94mm

Exhaust Side:

Exhaust Housing T-4 Flanged Divided

Available in 2 A/R sizes - .68 or 1.0

3.0" Vband outlet

Inducer- 64.5mm

Exducer-

360 degree Thrust Bearing

sniperperformance

iTrader: (5)

they also have a 67mm ball bearing thats alittle rich for my blood. i know this would be almost perfect though. just cant aford it. $687

Compressor:

Inducer: 66.6mm

Exducer: 84mm

Inlet: 75mm

Outlet: 50mm

Exhaust:

Flange: T4

Outlet: 3” Vband

A/R: .81

Inducer: 74.2mm

Exducer: 64.5mm

sniperperformance

iTrader: (5)

anyone?

silver_82

Ive got twin 66mm turbos with .88 ar on my 5.3 but its more of a drag setup. If your building it for drag racing and can deal with a little lag then id go with something similar but if its a street deal then go with a smaller set.

And btw the twin 66s i have are more turbo than a stock/budget 5.3 can handle. I really dont think you will need twin 70s, unless they are a unefficent design and in that case id get something better anyway.

Give us some details on the rest of the combo

sniperperformance

iTrader: (5)

it will be used as a weekend cruiser but mostly ran at the track.

katech rod bolts
ARP head studs
LS9 head gaskets
243 heads should put me around 9.1
cam similar to the cam used by hot rod mags twin turbo 5.3l 228/230 range 114 lsa
LS1 intake for now. will upgrade to LS6 when i find one
also obx up and foward turbo headers.
h-beam rods (maybe)

Boo"SS"t

iTrader: (2)

I would'nt go any bigger than 66mm(inducer) on the cold side and not anymore than 65mm(exducer) on the hot side, you could even go with 62mm turbine wheel, and go with either .68 or .81 a/r. you could get away with .81 since you have an auto but, I personally would go with .68a/r to go with your 5.3 motor for more boost response on the street.

sniperperformance

iTrader: (5)

so let me ask you this. seems how i dont have the money to buy a perfectly spec'd set of turbo's. do you think the 70mm with a .68 hot side will do.

i know there will be some lag. but if it comes on around 3500-4000 it will have to do till i can get past the build stage of my project. and upgrade later.

thanks for the help and the replys

Boo"SS"t

iTrader: (2)

Maybe I should be more clear. I'm not saying that the 70mm itself will be the main cause of a lag, I'm just saying that a twin 70mm for your power goal is a bit overkill and a little more rotating weight that the turbine wheel has to spin considering again...your power goal. I was just thinking of a more suited turbocharger for your set-up. But, in regards to.... "If that turbo would work" I'd say yes. Just go with .68a/. What size turbine wheel (exducer) does it have?

sniperperformance

iTrader: (5)

compressor exducer is 94mm.

going over my power goal wont bother me. heck if this motor blows its no big deal. i dont want to. i'll just keep the boost turned down. as all my main money is going into my ls 421. thats the reason for the money crunch.

i know i have a good while longer on the main engine before it is complete. so this is a teaser motor that if everything gos right i plan to sell. dont get me wrong im on a budget. and by no means am i rolling in money.iv got 2 years into the 421 so far, and that was paying for the machine work and pistons. the 5.3l was given to me and the turbos where also by a good friend to get me going till i can finish the real motor.

98blackbirdta

iTrader: (7)

turbos will do fine

Black98s10

I'm doing twin on3 67mm ballbearing turbos midmounted on my 5.3L s10. 2.5" piping from headers to turbos should spool fine.

Boo"SS"t

iTrader: (2)

I asked for turbine exducer NOT compressor.

silver_82

Ive got 73mm exh wheels on mine, the performance is great, makes good power and is fast but is a lill laggy cruising in 2nd gear on the street and takes a touch more than 4 seconds on the brake to build 11lbs in order to get a good 60ft. When the power comes on its like a frieght train, but if it was strictly a streetcar then Id go with a set of 57mm or 60mm twins for better response. The only reason Im using s366's on mine is I already had bought them for a 390 cu sbc and thought what the hell I try them out

OP, I read your original post about the motor specs, I was wanting more info on the car, weight? converter? expectations? Does the trans have a brake? If you dont have a brake then you will most likely have difficulity building boost and getting a good 60ft.

Also are you trying to buy a set of turbos for your 421 that would "get ya by" on a 5.3 until its done? Thats the only reason I can think of why you are pushing so hard for the large 70mm turbos when there are tons of inexpensive smaller turbos out there.

LSJM1

iTrader: (15)

are there any e-bay 57-60mm with a p trim exhaust .68 a/r
gt35's?

sniperperformance

iTrader: (5)

sorry, just received the e-mail back from on3 there saying the set i have are 64mm exducer

these turbos where givin to me by a good friend. i have a couple of comp oiless 72mm turbos for my ls 421,

car specs are

4l80E w/brake (not installed yet)
car is about 3300 with me in it (1985 camaro w/cage most interiour is gutted)
cheap dayco 2800 converter.
12 bolt rear 3.08 gears right now. will change later.

theres none that i have heard anything good about. on3 isnt by no means the best but i have seen these turbos run for a couple years and they where fine. mine are new never used.

thanks guys for your patiance and your help. i look forward to your responces.

silver_82

I didnt read where you had the turbos already. My bad. If you already have em then hell ya bolt them puppies on. You have a good friend there if hes letting u use his stuff.