Hey everyone,


I’m nearing completion of the exterior and interior work on my FD RX-7 rebuild, and now I’m shifting focus to the engine support systems as I start assembling my single turbo setup.

The goal is around 400 hp, running pump fuel most of the time, but with the ability to switch to E85 occasionally. I want the setup to be clean, reliable, and responsive — mainly for street use with some spirited driving.

1. Fuel System — Rail Kit & Injectors

I’m planning to keep a standard-style in-tank pump setup, possibly an upgraded drop-in unit.

Looking for recommendations on fuel rails and injector sizing that’ll support around 400 hp with occasional E85 use.

• Best fuel rail kits for proper fitment and flow on the 13B-REW single turbo setup?
• Ideal injector size for ~400 hp on pump gas, with enough margin for E85?
• Any preferred brands (ID, FIC, Radium, etc.) you’ve had success with?

2. Throttle Body — Electric Conversion vs. Mechanical

I’m considering either:

• Going with an electronic pedal adapter & sensor, or
• Staying with a mechanical throttle body (possibly larger diameter).

For those who’ve done ETC conversions on the FD, how’s the response, idle control, and ECU integration compared to a standard cable setup?

Would you say it’s worth it for drivability at this power level, or better to stay mechanical for simplicity?



3. Brake Booster Delete & Clutch Feed Setup

I’m also looking at the Chase Bays Single Piston Brake Booster Delete and their clutch feed adapter.

If anyone has first-hand experience with that setup (or similar systems), I’d love to know:

• Pedal feedback/modulation vs. stock
• Any bleeding issues or long-term reliability concerns
• Better alternatives for a street-driven single turbo FD

My goal is to keep the car balanced — responsive, easy to drive, and reliable, not just about peak numbers.

Any advice, part suggestions, or feedback from those with similar builds would be hugely appreciated.


Thanks in advance!

 

" car balanced — responsive, easy to drive, and reliable"

really great objectives. and possible.

this could be book length, but no..

400 rw rotary hp requires 3500 CC of gross injector deliverability on gas.

ethanol has 76,330 BTUs per gallon and gas has 116,090... so for E85 you will need approx 40% more capacity.

a better way to determine what you need as far as fuel capacity is to use the turbo's max air output.

there are around 85 decisions that need to be considered when going single turbo. they should be thought of as constructing a chain. one weak link and...

not only do you need to make the right decision but in the real world, correctly prioritizing each is important. my FD is pretty close to built. no electric TB. i love the OE TB with the 3 butterflies. i have no problem making 677 rwhp at 23 psi w my setup w the stock TB. i like linearity in everything... as you said balance.

there are so many things up the chain that you could spend your $s and time on.

one item that should be further up the chain is a Radium fuel surge tank. i bought mine immediately after sucking air with 12 gallons in my tank. it may be one of the best engineered items available for our cars.

i really like Full Function Engineering Light Rails. having the pedestal remain on the motor, as opposed to all the other rails, makes install easier. i also use their idler pulley and Hall ignition trigger kit.

your brake booster elimination, going to non assisted brakes, is an unusual mod. not for me. i have run, and continue to run, a very similar setup. manual brakes, manual steering. linear. i have an engine customer running the Chase Bays setup. it works fine. no problem bleeding and of course brake bias adjustability is so easy..

my site might be helpful:

http://www.colemanprecisionrotaries.com/

good luck w the other 80+ decisions

.

 

Hey man, really appreciate you taking the time to write all that out — lots of solid info in there.
I like how you put it about the “chain” of decisions; that’s exactly how it feels when you’re piecing everything together.



Good call on the Radium surge tank too. I’ve heard similar stories about fuel pickup issues, so that’s definitely moving up my list.
The FFE rails sound great as well — I didn’t realize how much easier that pedestal setup makes installs.



On the throttle side, my car actually had an engine bay fire from the previous owner, so I’m basically rebuilding everything from scratch.
That’s why I’m torn between getting the stock triple-butterfly or going to an electronic setup since everything’s already apart.


Appreciate the notes on the brake and steering setup too. Sounds like the Chase Bays system works well once dialed in.

Thanks again for the insight, really helps hearing it from someone who’s been through it.