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Project FD RX7 Restomod: Part 33 – Fuel System (Engine)
To support the power goals of our engine, we turned to Radium Engineering to upgrade the fuel rails, fuel pressure regulator, fuel pulsation damper, and install three pairs of Deatschwerks 1,500cc injectors.
I am suprised you used Earls Super Stock hose for fuel lines. They don't recommend those for gasoline use, let alone any kind of alcohol. Typically its used for ATF lines and coolant lines. Why not use a product line intended for the use? Overall great install, nice and clean.
Project FD RX7 Restomod: Part 33 – Fuel System (Engine)
To support the power goals of our engine, we turned to Radium Engineering to upgrade the fuel rails, fuel pressure regulator, fuel pulsation damper, and install three pairs of Deatschwerks 1,500cc injectors.
That was my issue with the radium rails. not that it is radium's fault but you want to utilize the -8AN (1/2" hose). you need to do something similar to that.
I have used a different approach and so far i havent seen anyone else do it with the -8AN
I used a 150 degree fitting and a 30 degree fitting. the hose length was only around 2.5" if I recall (its been a few years) this is what I came up with.
I had to use a local speedshop , Bruce's speed shop in NJ (RIP Bruce) but this was the solution . Picture is not very clear but you get the idea
I am suprised you used Earls Super Stock hose for fuel lines. They don't recommend those for gasoline use, let alone any kind of alcohol. Typically its used for ATF lines and coolant lines. Why not use a product line intended for the use? Overall great install, nice and clean.
From the article:
"This push-on fitting hose is rated for fuel, race gas, E85, Diesel, coolant, and transmission fluid with a max working pressure of 250psi and 250*F, which is well above the fuel pressure that the system will see."
Originally Posted by R-R-Rx7
That was my issue with the radium rails. not that it is radium's fault but you want to utilize the -8AN (1/2" hose). you need to do something similar to that.
I have used a different approach and so far i havent seen anyone else do it with the -8AN
I used a 150 degree fitting and a 30 degree fitting. the hose length was only around 2.5" if I recall (its been a few years) this is what I came up with.
I had to use a local speedshop , Bruce's speed shop in NJ (RIP Bruce) but this was the solution . Picture is not very clear but you get the idea
Your installation is very clean. I will need to see if my -12AN crank vent line will be able to clear the way you routed the fuel line. If so, I might copy your design
"This push-on fitting hose is rated for fuel, race gas, E85, Diesel, coolant, and transmission fluid with a max working pressure of 250psi and 250*F, which is well above the fuel pressure that the system will see."
Your installation is very clean. I will need to see if my -12AN crank vent line will be able to clear the way you routed the fuel line. If so, I might copy your design
By all means my friend. i couldnt use a hose end, the hose is too short for that. i had to use those fittings that require a hydraulic crimp that i don't have.
"This push-on fitting hose is rated for fuel, race gas, E85, Diesel, coolant, and transmission fluid
Ehh... While Super Stock technically is SAE J30R9 rated, even the manufacturer only states that it is "tolerant" (not "resistant") of pump gases being an unlined rubber hose and Holley instead recommends using a PTFE-lined option of theirs for ethanol applications in particular.
It is probably not a problematic solution given this doesn't have to last 250,000 miles of consumer use, but definitely not the best one for this application.
I pulled these attachments from Earl's website. This hose is not recommended for fuel use. Just thought you might want to be aware since hose product selection is such a small dollar item. I have been using Speed Flex with E85 with no issues.
That was my issue with the radium rails. not that it is radium's fault but you want to utilize the -8AN (1/2" hose). you need to do something similar to that.
I have used a different approach and so far i havent seen anyone else do it with the -8AN
I used a 150 degree fitting and a 30 degree fitting. the hose length was only around 2.5" if I recall (its been a few years) this is what I came up with.
I had to use a local speedshop , Bruce's speed shop in NJ (RIP Bruce) but this was the solution . Picture is not very clear but you get the idea
Instead of looping the secondary into the primary(like stock), I am going to split from the firewall into a Y, then into the back of each rail. Have the FPR sit on the front side of the secondary, with the primary feeding into the 2nd IN, then the -8AN out for return line. My hope is that it will be a little easier and potentially keep pressures to both rails more consistent.
Project FD RX7 Restomod: Part 32 – Deatschwerks DW400 Fuel Pump and Fixing Fuel Starvation
We upgrade the fuel pump to a Deatschwerks DW400 and fix the FD RX-7’s notorious fuel starvation issue by making a surge tank and using a DW100 lift pump paired to a Holley HydraMat mounted in the tank.
FD RX-7s are notorious for fuel starvation issues on road courses when the fuel level drops below ¾ of a tank, and especially when the fuel is below ½ a tank. To solve this problem, we created a surge tank out of the stock plastic fuel pump baffle by using the GarageAlpha Hyper Fuel Baffle/Surge Tank Cover, a Holley HydraMat, Deatschwerks DW100 lift pump, and a few CV100 fuel cell surge tank check valves.
In the article:
-Holley HydraMat
-Deatschwerks DW400 Fuel Pump (with flow a chart vs Walbro 525 "Hellcat" pump)
-Deatschwerks DW100 Lift Pump
-Surge Tank Check Valves
-GarageAlpha Hyper Fuel Baffle/Surge Tank Cover
-Radium Engineering Electrical Bulkhead Stud Kit
-Holley 4-Wire Horse Shoe Bulkhead Kit
-Stock Fuel Hat Disassembly and Modification
-Stock Fuel Tank Analysis
I've been through that article several times now. Great idea! I never considered using the hydramat to fill a surge tank instead of running them straight to the pumps. Although I have some reservations about using hydramat, mostly just the idea of the lifespan being 5-10 years. That's a good amount of time, but I'd like to do something with an even longer span if possible, especially if I have to dig it out of the corners of the tank. So I was wondering about running two hoses to each corner of the tank with a filter sock on each instead of a hydramat, then to a T which feeds into a lift pump. I was concerned about one of the hoses only pulling air at any given time, but the other hose would theoretically be pulling fuel so it's not like the pump would actually be cavitating, and since it's just going into a collector box anyway, it shouldn't matter if there are a few air bubbles going into it.
I'll also be having my fuel level going to the ECU now, so I'm considering seeing if the Elite can activate that pump only after it reaches a certain fuel level instead of having it run all the time. No need to use that pump to fill the collector box when you have a full tank, right?
Thoughts?
Also, I assume you've tested this setup quite a bit since you did this mod a year ago. How did it go?
Originally Posted by Valkyrie
This gives me some ideas. I wonder if HydraMat and a lift pump to keep my FEED baffle box full would allow me to run with less fuel at a significantly lower cost than the Radium surge tank kit.
On another note, I would love to see the car in action. For the longest time I had assumed it wasn't being driven.
I was thinking the same, I have the FEED box and I can only get down to 3 gallons left in the tank before I have to fill up. Better than 5 gallons like it was with just the factory box, but still. Although I'm considering making a taller box and seeing if I can get it a little wider too, and still incorporate the check valves.
I've been through that article several times now. Great idea! I never considered using the hydramat to fill a surge tank instead of running them straight to the pumps. Although I have some reservations about using hydramat, mostly just the idea of the lifespan being 5-10 years. That's a good amount of time, but I'd like to do something with an even longer span if possible, especially if I have to dig it out of the corners of the tank.
Removing the fuel pump & hanger is very quick and easy. The location that I mounted the hydramat is very accessible and easy to reach, while being effective at picking up fuel from the far right corners of the tank, to solve the scavenging issue.
Originally Posted by speedjunkie
So I was wondering about running two hoses to each corner of the tank with a filter sock on each instead of a hydramat, then to a T which feeds into a lift pump. I was concerned about one of the hoses only pulling air at any given time, but the other hose would theoretically be pulling fuel so it's not like the pump would actually be cavitating, and since it's just going into a collector box anyway, it shouldn't matter if there are a few air bubbles going into it.
I would mock this setup up with some buckets of fuel to verify, but I think that if you use standard fuel filter socks on 2 pumps connected with a "T"-fitting and one sucks air, the cavitation would prevent the system and other pump from continuing to work. The biggest benefit of the Hydramat is that if fuel is touching any part of the hydramat, it effectively sucks up the fuel.
Originally Posted by speedjunkie
I'll also be having my fuel level going to the ECU now, so I'm considering seeing if the Elite can activate that pump only after it reaches a certain fuel level instead of having it run all the time. No need to use that pump to fill the collector box when you have a full tank, right?
Thoughts?
That's a good idea.
Originally Posted by speedjunkie
Also, I assume you've tested this setup quite a bit since you did this mod a year ago. How did it go?
I was thinking the same, I have the FEED box and I can only get down to 3 gallons left in the tank before I have to fill up. Better than 5 gallons like it was with just the factory box, but still. Although I'm considering making a taller box and seeing if I can get it a little wider too, and still incorporate the check valves.
The track testing has been delayed because I am switching ECUs again. I hope to do the track testing, benchmarking, and fuel surge tank testing here in the next month or two. From what i've heard, fuel starvation tends to happen more in the 7-10 gallon range (with the tank 1/2-3/4 full). If you haven't had issues until you're down to 5 gallons and now 3 gallons with the FEED box, then you're doing a lot better than most. Do you track or autocross your car? What tires do you use?
The FEED inner tank is extremely effective for something so simple.
In my experience, you can run the fuel pretty low on tracks that don't have steep uphill (or downhill, probably) left-hand corners.
I've had it as low as the 1/4 mark at Sportsland Sugo without issue (not on purpose, though...).
The third corner on Ebisu Circuit West is the reason I bought the FEED tank to begin with. You need much fuel to be safe here.
