Well I think I'm finally gettin most the parts to get my truck back together and I finally have enough money to buy some studs and 60 lb springs (if my VE isn't toast) and so I think I'm ready to put the 3000/5000 twins on. I'm wanting to get them on by the middle of march since we have a dyno day around then. The guy I bought them from ran both of these turbos as singles just like I have to. So some of the cold piping is cut up to run the turbos as singles. I could weld all the pipes back together (gotta figure out where they all go first) and add some more pipe on since these kits have a big silicone elbow instead of pipe on parts of it. The guy i got them from said he didn't have that silicone piece and that he thought it didn't work very good anyway because he thought it would collapse and block off the air under pressure unlike a solid pipe would. So my question is should I weld all this 3" piping back together and add a few pieces or should I just go with all new 4" piping and put it together myself? What are the advantages of 4" piping over 3" piping or is there any? any spool up differences? the inlet of the 3000 turbo is 4" so 4" would make sense but yet the compressor wheel is under 3" so I was debating. What do you guys think? thanks

 

3" for sure, easier to plumb and less space taken up. That wheel will not exceed the flow limits of a 3" pipe, I promise.

 

If you are talking about the discharge of the compressor on your big turbo feeding the inlet of the little turbo, you want to leave the pipe at 3" until right when you tie into the inlet of the little turbo. I have read and heard of many trying 4" to tie both together, and they always loose spoolup.

For reference try looking up some pictures of turbo kits (BD, Industrial, Source, etc).

 

Yeah thats what I mean. Alright I'll probably just stick with 3" piping then since thats what it originally came with. I figured it would spool a little quicker with 3" but wasn't sure. Plus 3" is cheaper to bend and buy.

 

So what's going on with your transmission? Are you running the 47RH now?

 

Not yet, I still have the stock a518 in it. I'm gonna run it til it pukes then put this 47rh in, I got just about everything to swap it in. But I am still lookin around for a shift kit and maybe a tc for it for the right price before I put it in. I've been driving nice lately so this 518 has been holdin fine.