Turbo Selection

[VinnyV81]

Hello,

My name is Vincent and I am kinda new to these forums. I have been working hard on my FC for a while now and I'm in my 5th year of owning and modding the car. I've made a lot of changes but power has always been something I've wanted more of (naturally).

So, I'm looking into turbocharging my N/A S4 motor. I have an spare S5 NA engine that I could use too, but I like the fact that the S4 motor has a little less compression. Here is my setup now:

1987 RX7 S4 with S5 5 lug swap
Full ISC Racing coil over suspension
N/A Clutch type LSD with 4.10 gear
Megasquirt MS3X with stock NA injectors running full sequential
Walbro 255 lph pump
Aeromotive 1:1 FPR with stock fuel lines
OMP and all emissions removed-premix only
ISC Dual pass aluminum radiator (massive)
Electric fan
ISC Dual pass oil cooler (massive)
Stock port motor with S5 upper and lower intake swap
Pinneapple racing 5th and 6th port sleeves wired open
Racing Beat wrapped header with ISC mid pipe and 3" all the way out

For the most part that's what the car has now. I have some S4 upper and lower turbo intake manifold's coming and I'm going to convert the lower to work with the 6 port motor using Aaron Cake's write up. But, I have a few questions since I'm new to turboing a rotary engine.

Turbo selection

I know that this is probably a loaded question, but I would like a turbo that has great boost response from the bottom all the way up. I know that a lot of that comes with tuning work from what I've read, but I wanted to get everyone's opinion on turbo sizing options.

Keep in mind that I don't want to spend big bucks either (again, another shocker...lol). I know a lot of people run diesel turbo's and whatnot, and that may be an option. The megasquirt works very well now that I've got it somewhat decently tuned.

My power goals are probably around the 300 to 350 whp range, but again peak power isn't really what I'm after. I wouldn't mind running more in the future if it warranted it though. Smooth, linear power delivery is what I'm after. I know that this might be difficult to obtain with the rotary engine's exhaust characteristics, but I'd like some opinions. T3? T4? Divided flange? A/R options? What type of exhaust manifold is best? I have looked at some stock ones but most of them have cracks so I don't think that would be a great option. Fuel injector size advice would be helpful as well.

And if there is a "guide" for this kind of stuff and I just haven't found it yet, please feel free to provide me a link! I don't mind reading what's out there at all.

Thanks in advance for the help!

-Vincent