Elledge12

Here's the deal, I have a stock ls1 with 50k on it that I tore down and put all new gaskets and head studs in that I have mocked up in my camaro's subframe. I was originally looking to supercharge but I recently acquired a Tig welder and have been practicing and I think I am up to the task of building a twin turbo setup up for it. I have been around forced induction a lot but its been with my cummins so this is throwing me for a bit of a loop. I have been reading and researching a ton but I am having trouble finding the right size turbos for my goals, which are fastest spool time possible, 650 hp max but I'd like to be at about 500 before I go fully forged, budget is also a concern, and I would like to run a T3/T4 because space is definitely limited. This will be a street driven car with maybe a few auto crosses and some road racing. I was looking at maybe a pair of Holset hx35's, hy35's, or he341's because I can get my hands on those cheap. Any input? any help is greatly appreciated!!

Elledge12

Anybody? lol I should have my truck manifolds this weekend and I'm going to start mocking up the hot pipes. I guess my main question is will t3/t4 turbos support 650 hp when I want to crank it up? and what are your guys thoughts on internally gated turbos? I have seen that they work out great for some people but others advise against it.

HexenLord

Twins with only 650 HP goal? Those HX35s are capable of 650 HP each with upgraded wheels, so if its spool time you want they definitely aren't going to spool quick.

The fastest spool possible is achieved by picking the smallest turbo(s) for your goals. You could get a pair of tiny turbos and hit your goal of 650 HP with almost instant spool.

If you want twins and a power goal of 650 HP with very fast spool, you can either get 2 small turbos from ebay for cheap, or go with a large single.

Elledge12

I thought the general consensus was to stay away from ebay turbos? I've always thought that twins spooled faster and that was one of the reasons I want to run them but I also think they look better under the hood.

I found these on ebay. Are they what you are referring too?

http://www.ebay.com/itm/t3-t4-t04e-big-wheel-turbo-charger-83ar-twin-scroll-/290756542420?pt=Motors_Car_Truck_Parts_Accessories&hash=item43b270bfd4&vxp=mtr
So my next question would be what size of turbos would I need? From my understanding people have made good power from twin gt28rs turbos and those should spool quick. If I ran turbos that size what should the A/R of the exhaust housing be? And is there anyway there internal gates would work? or should I just invest in good external gates to begin with?

Sorry for all the questions but it seems in my research that so many people have different opinions its hard to wade through all the crap to find good info.

Elledge12

Anyone? I know that there are forced induction geniuses on here that have something to say... lol and I'm still looking at holsets because I can get them dirt cheap from my diesel buddies. An hy35 has an inducer of 56mm an exducer of 60mm and a 9cm exhaust housing which I think is an .65 A/R. It seems like in a twins application on a 346 they should spool lighting fast and flow enough to support 600 whp but is the .65 A/R too much of a restriction?

Novaray64

I went with twin presision 6265's with a .58 A/R in my nova with a stock longblock lq4. the turbos are on the expensive side but you could find something simular. I'm still working on the tune but on an easy launch it takes about 1 sec to go from 0 to 12psi. On the street my setup is perfect for me, there is just enough lag to keep from spining in circles

Elledge12

How much power will those turbos support? and what rpm's do you reach full boost? Your setup sounds a lot like what I am looking for.

Novaray64

Turbos should support around 1000 hp. Its hard to say what RPM it reaches full boost my converter is a little loose. I think you would be happy with any turbo setup close to the same specs as mine