The idea of a larger turbo had entered my mind, but I'd have to restart my entire build. I've pieced together several parts now. If I were to go with a larger turbo, they'd most likely have t3/t4 flanges. This poses a problem, because then I'd have to buy an intake manifold (I planned on using my stock one, but ported), a custom #bolt flange for the o2 sensor housing, and a custom downpipe (or have the one I have re-welded). I already have a downpipe, and the only o2 sensor housing I can use that allows me to have a 38MM Tial WG (which I already have) recirculate uses Mitsubishi stock turbo flanges. I quickly got the idea out of my mind until I was ready to go big (GT35R).
Today, I saw something interesting as I was looking through posts. A member had asked a question about where he could buy an install kit for a 16g (oil lines, washers, gaskets, etc). Another member linked him to the DSM Turbos page on STM's (Street Tuned Motorsports) website. I clicked on it, as I needed an install kit as well, hoping to be able to purchase one. The first thing I saw caught my attention- a 50 trim turbo that uses the stock mounting flanges. Looking deeper into it, it didn't cost that much money. $629 for turbo without the internal wastegate. My jaw dropped- I decided to do some more research. STM had recently started to carry these 50 trim Garrett turbos, but I found out that SBR (Slowboy Racing) had been carrying these for a while. They use Garrett cores, so all parts are interchangeable and the quality is there. For the price, you just can't beat it. A 50 trim would double the size of my stock t25. For the compressor side, at least. I'd be able to go with my original plan of using a ported stock 2G exhaust manifold and a Punishment Racing o2 housing w/ External WG recirculated.
I've been up all night deliberating what I would do. I realized that the price of a new 50 trim falls within the boundaries of my budget. Another thought crossed my mind- will my fuel upgrades be able to keep up? After some more research, I found several instances of others running 50 trims at 20+ PSI with 650cc injectors at below 80% IDC under full boost. This is perfect for me, since my fuel management will be an Apex'i AFC Neo. Since this is a piggyback system, it is said that the AFC Neo cannot control more than 680cc injectors, since instead of actually modifying the fuel curve of the ECU, it is only fooling the ECU's fuel readings and advancing the timing to compensate. My 190lph Walbro fuel pump will do just fine for my horsepower goals, as long as I get the rewire kit, which isn't very expensive. Everything seems to be falling in place for this new turbo, and I really think that's the turbo I'll be running.
