BNR + fuel
 

I'm thinking about upgrading to a BNR turbo.

My car currently: S5, stock intercooler, PowerFC, full exhaust, upgraded fuel pump, stock injectors.

What size injectors are recommended for each stage?

Will I need a Fuel Pressure Regulator?

Always need a fuel press regulator. I recommend aeromotive.
Secondary injectors need to be atleast 1680's in my opinion.
What fuel pump are you using. I would also.recommend reading up on known issues with bnr turbos. Boost control.issuez ect

1680 seems a little large for stage 1&2 don't you think?

I am hoping to go as far as possible while still using the stock IC. That's why I am leaning towards the stage 1 or 2.

BNR seems like the best option for the money.

Yes, 1680 is overkill for a stage 1 or 2 BNR. On my old setup I ran 720cc primaries and secondaries and that worked well with a BNR 2. It all depends on how much boost you plan on running.

I think in the 8-12psi range. I want to be able to really beat in the car for track days.

You could get away with 720cc secondaries then, that's not much more than stock boost. If you wanted, 720cc primaries would afford a good safety barrier.

I would go for 1000cc injectors just for that extra headroom, incase in the future you get a better a intercooler and start running 14-17 psi on the BNR.

720 primary and secondaries will be safe up to about 350hp, with 1000cc secondaries, its safe up to about 420hp

2 questions:


What boost and HP is the stock injector setup safe for?

What boost and HP would 550primary & 720secondary be safe for?

stock i/c? yikes

You hadnt mentioned it was for bnr 1 or 2. Yes, 1680's are a bit overkill. But you have a Power FC. I would still.recommend 1680's. Or close to.

I've read even running more than 10 psi on stock Turbo and tmic for extended periods can cause major heat soak.

Im sure its fine if you're not constantly wot at 12 but if you are then its a bad idea.

Stock. Some would say a pound or two over, but on an old, worn out system I wouldn't risk it myself.

I ran 11psi on the stock turbo with this setup and a front mount, not sure what HP I made though as I never dyno'd it. By the seat of the pants I'd say 240, but just a guess.

I am guessing for this car and its use stage 1 or 2 would be fine. Just a little better than stock and more consistent is what matters to me.

I will be upgrading the radiator and oil collet and building some ducting for them.

So I guess I will keep the boost at the 10# region and go for reliability.

What's the most power youve seen on the stock Turbo with a tmic using an rtek 1.7?

That's what ill be doing once I upgrade my ecu and fuel pump.

Right now all I have is 720cc secondaries and a fcd.

2nd Generation Fuel Calculator <- Fuel calculator that tells you what injectors sizes are good for. It assumes stock fuel pressure and doesn't account for any other factors like intercooling or fuel pump. It just assumes everything else is overbuilt. So use it as a general guideline rather than a rule.

I'm pretty sure that the stock ecu etc can do more than 183.9 -199 HP Max

I'd think the stoxk ecu can do up to 80% duty cycle, but I really don't know. Does anyone here know?

How does stock ecu calibrate what the injector duty cycles are?

Well, that's the thing... considering that it isn't tuning itself and doesn't adapt to larger injectors, without a piggyback system like an S-AFC the stock ECU isn't going to reliably make any more power than stock. Just throwing bigger injectors on there and upping the boost, then guessing if it's tuned well enough to not blow the motor isn't reliable.

I'm running a hybrid turbo, stock intercooler, rtek 2.1, and full stock fuel system right now. It's good for about 8 lbs of boost but that's it. Just a bit more than stock. I'm still running the stock 550/550 map that rtek gives you too. I want to play around with the fuel correction and just see how far I can go with the stock system. It stays in the 11's on my wideband until you hit about 4500rpm and the turbo really spools up. I have 720 secondaries, walbro pump, and an aeromotive fpr to install yet and then I plan on pushing the system further.

I'm putting the gsl se secondaries in and they're said to be 680cc but from the research ive made they're 720cc on our fc's fuel pressure.

I could use 550cc secondaries but I'd have to get them cleaned, figured there is no reason to use them since I have a full exhaust and they're insurance that I won't run lean.

I still have to port my wastegate and put everything together, hoping to have it start next month sometime.

Ill see their true flow when I look at the papers from injector rehab after receiving them. Should be back in a few days. Will upload pics.

I think I will shop for 4x720cc injectors. Just to add a little more range throughout the power and for 10psi tune.

At what point would I need to upgrade the fuel rail?

At this level, the rail isn't a restriction. At least another 150ish hp before it's going to become an issue. However the stock FPR is an issue with the larger pumps, i.e. Walbro 255 and larger. They overwhelm the stock unit and run higher than stock fuel pressure all the time.

If you're using an external FPR, I'd suggest removing the stock unit from the fuel rail. S5's are more of a pain because it's built into the rail itself requiring you to cut it off.

A lot of people do run the stock FPR with an upgraded pump, but it's a rather messy way to deal with the need for more fuel. Since it's a track car, I'd try to eliminate weak points in the system as much as possible.

Holy Hell! I've been searching for this answer for a week! You can't imagine the search word combinations I've been through.

Thanks for the detailed reply.

What size AN fitting should I look into for the FPR... -6, -8, -10?

I purposely left it a bit open-ended because I haven't done it before. Swapping to S4 rails or getting aftermarket rails (Rising RPM has a nice set) seems more popular than modding the stock S5 ones.

Here's a diagram from the fuel setup suggested by reTed from FC3spro.com. Unfortunately the website doesn't seem to work any more. Too bad since there was a lot of good info on there.
https://www.rx7club.com/forum/attach...postid=2051433

Here's my setup info for reference.

Rtek 2.1 - Arghx boost-based "conservative" timing map
T04b V-trim hybrid (BNR stg. 2-like)
720cc primaries/880cc secondaries
FD fuel pump
stock rails
stock FPR
stock TMIC
Aux. Injection (400cc, 100% water)

Boost hits 15 psi peak and tapers off to around 10 psi by redline. Injector duty cycle peaks at about 70% and mixtures are in the 11.0 to 11.5 range under full boost. Without AI the air temps skyrocket within seconds at full throttle. It's much faster than w/ the stock turbo due to increased pressure and air volume. With AI, temps don't move: https://www.rx7club.com/2nd-generati...ction-1005319/