BNR stage 3 twins with stock injectors; yes or no?
 

Hey all,

First off, I searched. :nod:

I haven't quite found a definitive answer as to whether or not I can safely run the BNRs using the stock fuel system. I'm keeping all emissions and installing the Rob Bailey solenoids as well. I don't imagine that I'll be boosting past 11 psi until I install new secondaries and my PFC.

I figured that once the turbos were installed I'd hook up a wideband just to make sure that everything is smooth regarding the AFRs.

Any advice or things to watch out for?

Mods are as follows:

M2 stage 3 ECU
M2 large IC
M2 carbon airbox
M2 downpipe
RB catback

I have a buddy that went this route with his FD. He has a similar setup to my current FD and has a great tune. His car runs like a top and he beats on it. The most important thing would be the tune.

Yeah.

I have a PFC that's currently mapped for 550/1680s that isn't installed.

The motivating factor here is making sure the car will be safe running the BNR/stock fuel schema until I install the PFC and tune. Once that time comes around, I'll have put together a new fuel system for the car.

I'm really just trying to be safe with the mods rather than do something stupid and blow an engine.

You should def be fine running the stock fueling. The biggest thing to worry about with the stock fuel is overboosting. The turbos themselves won't cause you to overboost and since the WG is ported on all BNRs you've actually got less chance of creep.

That's what I thought. I figured that since the WG is ported and I'm still running the stock cat I should be fine. I never see any more than 11psi on the stock twins anyway.

Keep in mind that pressure isn't the only important variable, mass flow is what gets you. You could still only be running 11 psi but moving a much larger volume of air. If you're going to the trouble of swapping the twins, and have the PFC and injectors why not do it all at the same time?

That was the original plan. I'm trying to scale back a little bit as to not overwhelm my bank account since I have a wedding to pay for in a few months. I have the PFC and the injectors. I need a pump, sec. rail, fittings and FPR. Gonna have to wait on some of those for a month or so.

I just want to make sure that it is safe to run the turbos with the stock setup. It seems as if it is safe to a point.

I ran my BNR's with the completely stock fuel system with an open exhaust, DP, Midpipe (non resonated), and a catback, CAI, large PFS intercooler, on an UNTUNED PFC base map on the track (NJMP) with AI and the motor is fine and AfR's were fine. This was at 12-13psi boost.

I went single now though. AFIK, the BNR's I had were the Upgraded versions with the higher flowing compressor wheels too.

I hit 95% duty cycle on stock injectors with a Supra fuel pump... 12psi stock turbos.

Id keep it at 10psi.

I'm currently running BNR's with the stock fuel system (albeit I have a walbro 255 pump), full DP/Bonez Cat/Catback, I have a fuel system waiting to go in, but my pulley kit is backordered (need to delete the air pump).

I've had no problems with overboost (I am running an AVC-R as well though) set at 12psi and I haven't overtaxed the injector duty cycle yet.

Do keep in mind I rarely beat on my car, I only ever really max boost pulling onto the highway.

-Geoff

Personally, I would wait and do it all at once. Every car and environment is different. Some may have had no problems, where you will have a blown engine.

You would be right there at the limit, and with a rotary, its not worth the risk.

http://rx7.com/cgi-local/3rdgencalc.cgi

As mentioned, if you do it, I would not exceed 10psi.

Thanks for the input everyone.

You might be fine but I wouldn't trust it. Besides running a bigger fuel pump I'd get a extra set of 850's and run them in the primary rail just to be safe.