Hi, all. I am currently trying to peice together my own custom turbo kit. I am new to all this stuff and I have a few questions.

What would a good size be for T3 Turbocharger if I want to run around 6-10 lbs (intercooled) boost. What else should I take into acoount when trying to find the right size turbo. I am reading up on the A/r ratio's and whatnot. But I wanted to get some personal opinions especially if you already have experience with Eco's and T3 turbochargers.

I have also found this website to be very helpful...

www.homemadeturbo.com

Thanks alot.



2004 Cavalier
13.2@105........
Mods...
BFG Drag Radials
Saab Turbo kit
2.5 exhaust, w/cutout
Spec Stage 2+ Clutch

T3 super 60 or 60 trim will be more than enough to have very healthy spool while having enough room to grow. It will provide enough airflow to make more than enough hp to max out the stock rods, so if you plan on sticking with the stock internals, that should suit you fine.




Arrival Blue 04 LS Sport
Eco
Turbo
Megasquirt
'Nuff said

scarab: what exactly would be those limits of the stock rods? i certainly havent found them to be anywhere near the 283HP everyone seems to think is the limit. i wish people would stop quoting that damn build book and use some logic and home made and home tested results. especially since everyone is trying to compare GMs nitrous testing, and a dry shot at that, to boosted use and strain. totally unrelated stress levels. i should know my current power level this weekend and ill prove that 283HP number is bogus.



I used to race cars, now I race myself.
5K PB: 24:50
10K PB: 54:26

Jay never said that the stock internals were only good to 283 HP... He never gave a hp figure at all. All he said was that a 60 trim t3 (super 60 or not) is good till about the same point that the stock internals are good for. Your 110% right that the eco CAN handle more than 283. According to HAHN's testing a safe max point is about 300... not that you can't go past 300, but that's the point where your on the ragged edge.

Now looking at my recent dyno sheet I'm making 225 WHP which is around the 260 mark for crank HP. This is at 9.28 PSI When you do a compressor map you'll find that the t3 60trim is fine at this level. I have doen the map all the way up to a presure ratio of 2.0 (14.5 psi) and even at this level the turbo still is fine, sure you wouldn't want to go much farther, but it's ok at that point.

Now i don't have exact numbers here, but in general lets say I'm going to get another 10HP per psi 260 at 9psi now 300 at 13-14psi. Again not that 300 is where the eco will break, but it's getting to the point where any errror in tuning will result in bad things.

The point I'm trying to make is that I have seen alot of people on here get "size happy" over turbos. I have been told by several that my t3 is to small for the eco. The fact is that it seems to match my motor pretty nicely as i am noticing from my experiances.

I do agree with you, the eco can DEFINATELY handle more than 283 under boost.. DEFIANTELY, But jay never said it can't
All love man


<img src=http://home.comcast.net/~richnj221/smiley.gif>

i was also look to get a turbo. what is the 60 tirm. i heard it but i don't understand what it means

60 trim is the "size" of the compressor....

When you look at turbos theres ALOT of information you can find. The most common numbets you will see are the a/r ratios of both the compressor and turbine housings. Basicly what someone means when they say "a 60 trim t3 turbo" is a t3 turbo(t3 is simply the style of the turbo), with a 60 trim compressor, as opposed to a t3 with a 42 trim compressor.

Theres alot more to it than the following statment, but in general the larger the number of the compressor (and turbine) the more air it will flow.


<img src=http://home.comcast.net/~richnj221/smiley.gif>

Exterminator wrote:Jay never said that the stock internals were only good to 283 HP... He never gave a hp figure at all. All he said was that a 60 trim t3 (super 60 or not) is good till about the same point that the stock internals are good for. Your 110% right that the eco CAN handle more than 283. According to HAHN's testing a safe max point is about 300... not that you can't go past 300, but that's the point where your on the ragged edge.

Now looking at my recent dyno sheet I'm making 225 WHP which is around the 260 mark for crank HP. This is at 9.28 PSI When you do a compressor map you'll find that the t3 60trim is fine at this level. I have doen the map all the way up to a presure ratio of 2.0 (14.5 psi) and even at this level the turbo still is fine, sure you wouldn't want to go much farther, but it's ok at that point.

Now i don't have exact numbers here, but in general lets say I'm going to get another 10HP per psi 260 at 9psi now 300 at 13-14psi. Again not that 300 is where the eco will break, but it's getting to the point where any errror in tuning will result in bad things.

The point I'm trying to make is that I have seen alot of people on here get "size happy" over turbos. I have been told by several that my t3 is to small for the eco. The fact is that it seems to match my motor pretty nicely as i am noticing from my experiances.

I do agree with you, the eco can DEFINATELY handle more than 283 under boost.. DEFIANTELY, But jay never said it can't
All love man

I'd just like to concur with Exterminator...it's easy to choose too large of a turbo.

Are there disadvantages to doing so? You bet! An overly large turbo will not only reduce street enjoyment with its reductions in low-end torque (as compared to a more conservatively sized unit), but it can also negatively affect 1/4 mile performance.

Horsepower @ peak is fun to brag on, but if the available powerband is too narrow and peaky due to an oversized turbo, the 'area under the curve' will be less than optimal, and the car simply will not accelerate as hard in low-to-mid RPM, whether on the street, or at the track.

Should one choose a turbo based upon their future plans for more HP...in other words, buy an oversized unit now, so as not to have to buy another later? I see this as a matter of personal preference, but today's turbos are very adaptable. In many cases, an exhaust housing A/R ratio change and/or compressor upgrade is all it takes to move a given turbo to 'the next level'. Even if you do end up purchasing a completely new unit, the one you take off is typically easy to sell to recoup some of the cost.

Look at it this way...what does one invest in a car like this...typically well into five figures. A few hundred bucks spent later isn't all that much to be optimally sized now. And optimally sized WILL make the car more enjoyable, and undoubtedly quicker, in its first iteration. Why hobble it with too big of a unit?



Bill Hahn Jr.
Hahn RaceCraft

World's Quickest and Fastest Street J-Bodies
Turbocharging GM FWD's since 1988
www.turbosystem.com