I am adding a new type of fuel rail on the RX-7 that sits between the upper and lower intake manifold. This methond is quite popular among the high HP Japanese race cars. If your currently fuel system is already maxed out and you don't want the hassle of taking off the stock one, this one is a lot easier to put on.

The fuel rail can hold up to 4 top feed injectors. If you use APEX Power FC, you can splice the wires off the stock injectors harness and use high impendence top feed injectors such as those off the 2nd gen TII RX-7. You can obtain the used TII injectors for around $25 and just send them out to RC Engineering to be cleaned for $25 each. Of course you can use any type of top feed injectors as you choose to.

The target price is $350 for the adapter plate and the fuel rail itself. The injectors shown are not included.





If any one is interested, please let me know. Thanks.

Chuck Huang

 

Wanna see mine

 

If you want to brag about yours, sure. haha

Chuck

 

I assume this is FD only, or at least FD UIM and LIM only? Also did you have to put in longer studs so that the UIM can still bolt up. Are there any clearance problems? Has it been tested as to whether this setup atomizes the fuel well, or to find out if the fuel collects on the walls of the manifold?

- Steiner

 

Yes, FD UIM and LIM only.

You do have to put longer studs and the price include those.

There is no clearance problem. The fuel adapter is only 2 cm (0.79") thick.

Yeah, proven by Scoot Sports and Revolution Motorsports in Japan. They are the ones who start using this type of fuel rail. The owner of Datalogit uses this type of fuel rail as well.

Chuck

 

That doesn't look like the flow of the fuel would be very beneficial. Doesn't it need to be oriented more towards the direction the rest of the air is going? I would think that fuel would end up sticking to the interior of the intake manifold. Which is why Mazda's rails point downstream to the manifold.

 

I was thinking the same thing. You'd better have some high intake velocity through those runners to get it to mix well with the ~60+ psi of fuel coming out of those injectors. It may work out well though as long as you turn them on at the highest boost possible.

 

I was thinking the same thing before I got it. But then there are many race cars in Japan use the same set up. I am going to try it out and see how it works.

Chuck Huang

 

its pretty interesting to calculate how fast the air is moving through the piping...

i haven't done the calculations for a rotary cfm or do I know the cross section in the manifold in that section... but for example a 4g63 that is moving 550 cfm through a 2.25 inch intercooler pipe...the air is moving at about 0.6-7 mach.

fast.

assuming the injectors are only going when you're on boost...the air flow should easily carry the fuel.

edit:
oh yah...i forgot...some of the latest performance fuel injection systems don't have the fuel injectors pointing at the intake valves...they're pointing the opposite direction...upstream...

john