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Old 12-12-2018, 12:14 PM   #116
John V
No more BMWs
 
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Join Date: Apr 2005
Carmudgeonly Ride: Ram, MS3, CX-5, RX-8
Location: Glenwood, MD
Posts: 14,753
I don't think anyone is reading this thread anymore, but what the heck

I have made progress on a bunch of little things over the past month. I pulled the engine so I could finish building the oil and fuel systems, install cams, swap the crank pulley over, and re-time the engine. No pictures of any of that, because my hands were covered in cam lube and I didn't feel like getting my phone dirty.

I finished the important part of the wiring as well. The MR-Spyder power steering pump is wired in with a dedicated 4AWG wire from the battery, which will be behind the driver's seat.

Most of the interesting stuff was finishing up the fuel system, which was something I'd never done before. I ran E85 on my last car, but I never changed the fuel system (other than the pump and injectors) to accommodate it. The RX-8's stock fuel lines are about 5/16, which is probably sufficient for the power levels I'll be running but I wanted to create a return-style fuel system that never existed on an NC or an RX-8, so it necessitated some plumbing changes. I ended up deciding on a new 3/8" (-6AN) PTFE feed line from a new fitting at the fuel pump, to a 10 micron filter, to a flow-through fuel rail with an external rising-rate (1psi fuel pressure increase for each 1psi of boost pressure) fuel pressure regulator. I also wanted an ethanol sensor in the return line so I picked up a standard GM (Continental) sensor.

The PTFE fittings are a little bit weird to work with until you're used to them. Lots of band-aids were needed.

Flow-through fuel rail with 6AN fittings on each end.



Feed line is 6AN through a 10 micron filter mounted in the trans tunnel, and 6AN all the way back to the pump. The stock feed line is used for the return. I put the E85 sensor in the return line.





I turned a simple plug to defeat the pressure relief valve in the RX-8 fuel pump assembly. This is normally where the fuel pressure is set in a stock vehicle.



Bulkhead fitting with a 3/8 barb inside the pump assembly and 6AN on the outlet. The barb connects right to the barb fitting on the pressure side of the pump. The stock siphon mechanism is preserved.


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