fireburr

iTrader: (3)

Ok here's what I'm starting out with. Car is a 97 Trans am convertible with ls swap 383. It's 9:1 compression, eagle rotating assembly, 243 heads, ls6 intake, head studs, 228/234 115 cam, twin 255s in tank, #60 injectors, and a4. The current setup is a rear mount cx racing t76 ceramic ball bearing with .96 exhaust housing and I plan on doing a front mount this winter.

My plans are to be in the 800-1000hp mark. The car is a cruiser with the occasional track day so don't want too much lag like I'm having now. I'm really starting to head towards the twin cx racing ceramic ball bearing gt35's with t4 .68 housings. I've heard lag and no lag from different threads so I don't know what is right. I'm thinking because of my low compression it could be more laggy. My question is should I put my current turbo up front, twin gt35's, or something else bigger or smaller?

DEFYANT

First off. Bigger injectors.

Second, I would really go with a better brand of Turbo, Precision has "Entry-Level" Turbochargers that are just as cheap, and more reliable than those CX Racing Units.

fireburr

iTrader: (3)

Ya I forgot to mention 80# injectors would be on the way. I haven't seen a precision ball bearing turbo for $400 shipped unless I just haven't looked. The cx racing turbo I have now is pretty nice quality and the company has great customer service. If I could get a precision that cheap I would be all over it.

DEFYANT

If they are sized properly, and your cam is right you should have no issue spooling journal bearing turbochargers.

fireburr

iTrader: (3)

Well if they can match the eBay turbo price I will go with them but I'm still in the question of size that I need for my setup. I am in a tight budget as everyone usually is so the cheaper the better without going too cheap. I've found out I'll never go as cheap as on3 again but cx racing does have a fairly quality product for the money from what I've had experience with and they do back their product.

HexenLord

For now, front mount the same turbo. You'll spool a lot sooner with more power potential. From there you can upgrade to the CX 80mm if you want over 800 or ab S475 or even 480 for 700 bucks and get the power you want without having to redo everything.

fireburr

iTrader: (3)

The thing is I don't want to change my setup again if I'm not satisfied. Has anyone used a set of gt35's? Right now they have a sale on ball bearing t4 housing gt35s for $404 free shipping or $279 free shipping for journal bearings with ported housings. I'd like to not be maxing turbos out to squeeze hp so I'm thinking two will take less effort to make more power than one. I do car shows too and I like the look of twins but my main concern is finding the right size since I'm using a lower compression ratio.

HexenLord

Compression doesn't effect spool as much as you would think. While it does have an effect, most people would have trouble really noticing it. A one point bump might net you a couple hundred rpm sooner on similar tunes. Most people wouldn't notice 150-200 rpm in spool.

Your cam and torque converter will have a much greater effect on spool.

Forcefed86

iTrader: (4)

9:1 is low compression these days huh? What size is the exhaust piping leading to your turbo now? Is that a 65mm exh. wheel on your current turbo?

Your power goals seem a bit lofty. 800-1000hp for a cruiser? With 29x12" slicks and 3.10 gearing anything over 17lbs on my setup (well under 800hp) is totally useless on the street. Even rolling into the gas at 50mph I'd blow the slicks off. I'd guess thats around 600whp and I'm geared much taller than most.

With traction control and a few other tricks people do manage huge power on the street , but its a constant struggle and most of the power isn't applied to the wheels until the cars already going well over 100mph.

I'd bet it would make a night and day difference with a much smaller cam, properly sized hotside, and larger turbo on your curent setup.

fireburr

iTrader: (3)

I wouldn't think that power would affect street driving because of the power coming on later in boost. My current setup makes 513 but not till around 5800. I'm sure different variables would make it run much better but I'd mainly like to get my ground clearance back and not deal with the extra oil in the charge piping plus rely on the pump. I like the thought of having big numbers for when I make it to the track I don't have to launch really hard to make a decent time and also for show and tell at car shows. It won't spin the 315 nt05r's I have now when they are cold from a dead stop. I could probably deal with 700-800 if it is a handful but I just don't have an idea. The exhaust piping is 2.5 forward and back. My gearing is 3.42 and I would say my car probably weighs right in at 4000 lbs so I might not have that big of a traction problem. Here are the turbo specifics:

Compressor Inlet 4"
Compressor Outlet 2.5"
Bearing Ceramic Ball Bearing on Compressor Side Compressor
Cooling Oil +Water
Oil Cooling Fitting 1/8" NPT Feeding. M8 x1.25 Return Flange Mounting Screws
Water Cooling Fitting M16 Threaded
Flange Standard T4
HP Rating 500-700 HP
Internal Wastegate None
Compressor 76mm Wheel Compressor
Turbine P Trim .96 A/R Turbine
Compressor Wheel 102.4mm/76.7mm
Turbine Wheel 74.1mm/64.6mm
Hot Side 3" V-band