First impressions: Rotary Performance secondary fuel rail
 

Hi Guys -

I've been slowly building up a car for one of the guys here and we're finally at the point where we're getting the motor all happy and ready to go back in the car. One of the things we wanted to do was to add some more fuel, he had stock injectors and a Walbro fuel pump but we wanted some more headroom for a high-300hp setup.

For years many people have gone with 1300cc secondaries - these are simply 850cc injectors that are bored out. I'm running this setup on my car with great results. But, in recent years I've heard more reports of people having problems with this, either with injectors locking open or closed.

So, I was looking for another path for this car. Found this -

https://rotaryperformance.com/collec...ant=1120136240

All said and done you're at about $510 with the rail and injectors.

What I liked about the setup was the ability to use the stock fuel pressure regulator and to use the stock fuel temp sensor. I also liked that you could bolt the banjo bolt from the primary rail straight on.

Got the kit and installed it this weekend. Note the engine is out of the car on an engine stand so that was probably way easier than in the car. I also had the rat's nest off the car at the time. The engine is simplified sequential with all the emissions solenoids removed from the rat's nest. There is also block off plates for the emissions stuff. But, I think this rail would fit with the emissions and air control valve all in place. The black color for the rail is very "stealth" if you're going for that.

The rail itself is steel, comparing the weight of the new rail, injectors, and FPR to the old rail, injectors, and FPR this setup shaves about a half pound off. It feels heavy in the hand but does save weight which is always nice. The kit includes bolts to bolt it to the LIM, new crush washers, and a new O-ring for the FPR which is really nice.

You will need to remove the diffusers for the secondary injectors from the lower intake manifold. Fortunately this motor wasn't too old and I had replaced them at that time so they weren't hard to get out with a little WD-40 and a pick. If you were doing this on the car with old diffusers that could be an issue. The new injectors have very nice "caps" on the end that snug right down into the intake manifold and put the nozzle of the injector deep in there.

The fitting for the FPR to bolt onto hit the lower intake manifold when installing. This engine has a JDM lower intake manifold, I don't know if that could be a reason but I think that portion of the LIM is the same. A little bit of grinding (only 1-2mm of material) and it fit fine.

Bolting the banjo bolt fuel line from the primary showed that the rail seemed to be slightly back towards the back of the motor more than the stock rail. The banjo bolt did bolt up but the hose is pushed a bit. I don't know if this will be a problem long term. Also, the hose from the FPR to the rat's nest had to be trimmed about 3/4 of an inch, again I think the fuel rail is positioning components in a slightly different place.

The fuel temp sensor bolted right up and plugged in no drama. The sensor is touching the outside of the rail, it doesn't directly measure fuel temp like on the stock rail. But, I don't see any reason why this wouldn't do the trick.

Speaking of plugging up, the stock fuel injector plugs connected right up to the new injectors, no pigtails or wiring. Nice! They are high impedance injectors so you don't need resistors or anything like that. They also emailed me the Datalogit settings for these injectors (size, lag time, etc) so I'll be all set when it's time to fire things up.

The competition to this setup would be the Full Function Engineering "step up" kit. I think overall it's a nicer setup, but you will be spending more money. About $850 with 1300cc injectors. For the money you get a lighter rail, an adjustable fuel pressure regulator, and Injector Dynamics injectors. Also, no provision for the stock fuel temp sensor.
FD Fuel Step Up Kit | Full Function Engineering

But, for a lot of people just looking to get the most out of the stock twins that's a lot of money.

So, sum it up -

PROS
- Price
- Keep emissions
- Keep stock FPR (less money and plumbing)
- Keeps stock fuel temp sensor

CONS
- Fit could be better

I would definitely recommend this setup. It's nice to have options in our community for mods, it breeds competition and lets you pick what's right for you and your car.

Dale

Chris Ott over at RP is pretty much The Man when it comes to all things rotary, from FBs to our FDs.

Whenever I have an odd issue with an FD or need to bounce ideas off someone, he's pretty much my Go To Homie. Both he and Ari are big time assets to our community and many of the newer owners would do well to get exposure to these guys. They've split their business in the recent past,

Chris is at www.RotaryPerformance.com and

Ari is at RX7.COM Performance and Repair Parts for RX-7 and RX-8 :icon_tup:

Good info. I thought about this when i was looking to upgrade.

Chris is a go to person to go for any Rotary needs. Awesome guy!
This can be an off topic but I have to ask but have you guys installed an adjustable FPR with stock primary Rail and the RP secondary Rail from above?

I don't think a lot of people have this rail at this point. But, I don't see it being super bad to install an aftermarket FPR on in the car if that's what you're asking.

Dale

Hey Dale, following up to see if you have any more miles/experience on this setup? I like that the FFE step up has the FPR which allows you to run the IDs at the proper pressure, but I've also heard complaints that it didn't fit with the rats next and required more modification than I'd like for something of that price. Seems like this option is a little smoother/easier for those that will still retain sequential turbo control.

Even with the ID2000s delivering less fuel capacity (lower fuel pressure) I'd still think this setup would be good up to around 400hp right?

We're getting closer and closer to starting the car - I still have no information on how it does unfortunately. Was hoping to have a solid weekend of working on the car but I just got a head cold so we'll see :).

Dale

Chris installed this fuel rail in my FD a few years ago when it first came out with RC 550cc primaries for rock solid idle and 2200 cc Bosch EV14 secondary's. The ability to put in the 2200's allows for any future modifications to my HP needs or any need to change the injectors in the future. Future proof. Even at 16 psi, which I don't typically run, the injector duty was only around 65-70%. I am still twin sequential and have the stock fuel pressure system. I have had no problems of any kind and the car is rock solid on street tuning with no major variations in AFR's, no fuel leaks, or any known problems.
Mike

One other thing. Chris does a mod where he gets rid of the turbo solenoid that is by itself above the rats nest and has the different shape and is a different type. He simply reroutes the vacuum hoses and electrical to use one of the unused standard solenoids for the EGR or other emission solenoids. This frees up some of the space near the new fuel rail and is more reliable than the stand alone turbo solenoid, which fails often.
Mike

Thank you for bringing this thread back up, this sounds like a possible option for those of us with emissions and wanting to keep the twins!

That's a cool idea! I'll have to steal that one :).

Dale

Yup, Chris has quite a few cool tricks..... he's literally an Original Rotary Gangster. He's a humble guy, so I don't mind banging the drum for him :nod:

^This. One of the best resources in the rotary community.

Since we are heaping much praise on Chris, one more mod he does may help everyone out. This may be his mod or something he learned from someone else. Lots of people have had problems through the years with ignition breakup at higher rpm's, especially with water-meth injection. I, like many other people, use the HKS Twin Power, which helps but doesn't always solve the problem. Many have switched to AEM coils, some have used the FC coils, etc. Chris, does what Chuck did with the fuel pump mod. He uses a relay and jumps the power directly from the battery terminal positive to the coil harness. This bypasses the standard engine harness power and delivers full voltage directly to the coils. They are then much more efficient in recharging quickly, particularly at high rpm. No or little breakup.
Mike

Interesting! I know Chuck Westbrook did something similar a while back. That makes a lot of sense!

Dale

sorry guys, I don't mean to take this off topic but I'm very interested in the coil bypass mod. Can anyone direct me in the appropriate direction? Seems like a great mod to perform that would compliment the fuel pump rewire perfectly.

-groovin

Thanks for the detailed review. I decided to go with the rotary performance fuel rail. Do I just need to configure the powerfc after installing? What do I need to change? Thanks!

Chris Ott at RP sent me the settings to use. It basically scales the injectors so they are good to go.

Buddy of mine has the same setup (550cc stock primaries, RP 2000cc secondary rail) with a Borg Warner S362 turbo and had the setup tuned this weekend. Made 362hp to the wheels. Injectors did great and didn't miss a beat.

Dale

16psi.

Dale

When installing this. Did you put the injectors in the rail first or put them in the block first? The metal vacuum hose for the turbo actuators are in the way of the banjo bolt . I can't move the fail far enough towards the front of the car to install the rail.

I always put them in the rail first then install. But, I don't have that front vacuum line mess, I typically remove that.

Dale

I have that FR on my FD, installed by Chris @ RP when the car was getting its first R&R in close to a decade. I've got an Apex'i RX6 turbo on my car and put down about 325rwhp. No issues what so ever delivering fuel for that setup.

Put in an order and Chris emailed and said that this is being redone as a billet part... Waiting for one of the first run...