Hey guys, first time posting on this board.

Guys, if I wanted to rebuild a '98 LS1 A4 and wanted to put a turbo set-up like Rob's then:

1)How many cubes does everyone suggest? Forged 3xx ci? I have seen a number of 9'sec 4 bangers, so larger in my eyes is not always faster.

2)This might be the wrong question, but how does one calculate the trim needed for this setup?

3)Does having a stall (vig 3200) affect the engine/turbo dynamics?

I will probably have more questions, but these should give me a good starting direction.
Thanks!

 

for Cubic inches you could go many ways if you use the stock block stock stroke you'll be limited to 348 cu in. now if you whanted a bigger strock you could bumpp up to a 4" stroke (382) or could switch to a 6.0 iron block and have 385 (stock stroke) or 404ish 4" bore 4" stroke.
The most important thing is you get your CR right, depending on your needs 9.0 for a street set up and 8.5 for a track set up.
Ive seen 700rwhp out of a 348 aluminum block and 707rwhp out of a iron block, so anythings possible.

picking the right turbo is also important, you need to find one with your power requirements, but not much past that to help with spool time, making sure the right power curve is there.
I chose the T-76 cause it should support the 700rwhp i crave (less then 200 to go)

 

So lets say I went with a forged 346 with 8.5 cr and H/C.
1) How would you calculate the turbo's trim needed for this application?

2) Would a 3200 stall be large enough for the turbo?

Thanks!

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Wolverine-02:
<strong> So lets say I went with a forged 346 with 8.5 cr and H/C.
1) How would you calculate the turbo's trim needed for this application?

2) Would a 3200 stall be large enough for the turbo?

Thanks! </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">1)You would need to call knowledgible people , or shops and tell them what hp you want, the Rpm that you want your power , the engine size (which you already stated) etc... Also you should tell the transmission type , and the weight of the car, as well as the intended usage (drag, street/strip, daily driver, road race ....)
Learning how to read compressor maps will help also.


2) As far as the torque converter, "Would a 3200 stall be large enough for the turbo?" ............ For what turbo?
You need to know what turbo you will use before you can answer that. But most likely, even with a nice size turbo, that should be enough with a nice size V8 motor. Again you need to know what turbo though. It may actually be too much if the turbo is a smaller one. Which would just cause excessive tire spin.
Turbos also like lower stalls than normal aspiration. It's a fine balance. The place where you get the turbo, or kit can make a torque converter recomendation when you give them info about the car, like stated above. If you go to the precision turbo site, I think www.precisionte.com they even have a chart of the turbos with the price, hp rating, and recomended stall converter. (Some of the stalls are quoted for 3.8 liter turbo buicks, so it will probably spool quicker on a bigger motor , even with the same or lower stall).

 

Anyone understand turbo trims?