Twin Turbos
Race Director
Joined: Jun 2009
Posts: 10,428
Likes: 9
From: Southside of Western Norte Americano State of Confusion, ColoFornia
St. Jude '13
Im no Turbo expert.. but ummm 2 questions.. if you are looking at 4-5 pounds of boost.. why use 2 turbos? and is there actually room for all that? I would think that a small single twin scroll turbo would be sufficient to generate 5 pounds of boost, and depending on where you live.. 2-3 pounds of boost will get you to sea level equivalent which the stock system should certainly handle.. Good luck with it.. if nothing else, polish hell out of it, it will at least look cool..
(Im thinking I would scrounge salvage yards for a turbo (the new Mini Coopers have a very nice responsive unit) before I would buy the Chinese version.. if something comes apart those pieces are going down the engine..)
(Im thinking I would scrounge salvage yards for a turbo (the new Mini Coopers have a very nice responsive unit) before I would buy the Chinese version.. if something comes apart those pieces are going down the engine..)
Drifting
Joined: Oct 2006
Posts: 1,554
Likes: 13
From: Romeoville IL
Im no Turbo expert.. but ummm 2 questions.. if you are looking at 4-5 pounds of boost.. why use 2 turbos? and is there actually room for all that? I would think that a small single twin scroll turbo would be sufficient to generate 5 pounds of boost, and depending on where you live.. 2-3 pounds of boost will get you to sea level equivalent which the stock system should certainly handle.. Good luck with it.. if nothing else, polish hell out of it, it will at least look cool..
(Im thinking I would scrounge salvage yards for a turbo (the new Mini Coopers have a very nice responsive unit) before I would buy the Chinese version.. if something comes apart those pieces are going down the engine..)
(Im thinking I would scrounge salvage yards for a turbo (the new Mini Coopers have a very nice responsive unit) before I would buy the Chinese version.. if something comes apart those pieces are going down the engine..)
I looked at mine and the lay out, single looks like an easier option to me for keeping AC. But it's up to the person doing the fab. work.
Burning Brakes
Joined: Jul 2006
Posts: 1,080
Likes: 2
From: Pittsburgh PA
Twins should spool faster, but you are right at 5 psi, it's not a big deal. But if this is just an early stage and plans for more boost and you want twins, then do your fabrication as twins to start, so you are not reinventing the wheel to switch between twins and single.
i'd shop around for some used turbos for sure for this buildup. Key is finding a good wastegate and having a spring in there that can control down to 4-5lbs. If not, you will see more than 5lbs and seriously risk blowing that motor.
As far as cheap ecm control, convert to 91-92 730 ecm speed density setup with 2 or 3 bar map and run either code $58 or the newer improved code $59 files from GM turbo trucks syclone/typhoon.
I'm running a 730 ecm with code $59 on my twin turbo 401with 10psi with no real problems so far. Had difficulties along the way but its close to being all figured out now. My wastegates are not in great location however and my 6-7psi spring acts like 10psi spring. The design of the system needs to be optimal to accurately control boost to those low levels.
