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So what do you guys think would be better, placing the venturi siphon on my return line or on my lift pump.
im planing on using my series 2 oem pump for lift and the Walbro 450 for the feed line.
may guess would be the lift pump as it’s not regulated?
The lift pump will have to be back-pressured for a siphon to work. Which lift pumps generally are low pressure. I don’t believe that to be a suitable option.
Even though Radium shows it both ways, imo it’s better to power the siphon off of the high pressure fuel supply line than the bypass return. Even if that means teeing off the high pressure discharge line back through the top of the fuel pump module. That is one of the drawbacks of an external surge tank.
I’d suggest taking an S1 pump module, fitting it with a lift pump, and using it on the RH saddle to pump over into the LH saddle instead. A low pressure lift pump is more tolerant of running dry than a high pressure pump. There are any number of control strategies you can use to turn it on/off if you want to go that far with it.
but I suppose the siphon on the bypass return is easier. I don’t like the idea of it having variable flow and pressure, which is then also variable back pressure on the bypass as well.
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What exactly would you do to a lift pump to back pressure it?
Also, I want to make sure I'm understanding you correctly, you recommend connecting the siphon off of a T connected to the main fuel line feed before the rails and regulator as the first listed option? If so I could easily due this off the feed pump in the fuel tank, as I have a internal surge tank setup.
It sounds like the there will be a variable pressure after the fuel pressure regulator upon return to the tank, is that correct?
just teeing it off between the fuel pump discharge and the fitting in the top plate and keeping it all inside the tank is your best option. Think I was confused that you had an external surge tank, but went back and reviewed the thread to see that you have an in-tank setup.
So the instructions for the Radium siphon pump lay it out for you. The amount of fuel flow capacity being bled off does need to be accounted for as explained:
FWIW I have mine set up like the top diagram in the Radium instructions (jet pump on return line) and it seems to be working just fine...BUT I rarely if ever let the car get below a 1/4 tank just strictly by habit.
to be fair my thoughts on it were theoretical only, and perhaps the FPR compensates for backpressure automatically, but just the same the pump discharge pressure and flow are unlikely to be equalled by the bypass pressure and flow **under continuous WOT conditions** as compared to street operation.
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I’ve been working on the fuel pump hanger/surge tank for awhile now. Here are some pictures.
I had to buy the doorman special tool to fix my fuel line connectors, man did that make a difference. It’s practically impossible to insert them by hand. you can see the finished product in the first picture.
So my main problem with this whole thing is that I can’t use the fuel pump filter sock, either on the feed pump or the lift pump, because the top hat and surge tank won’t compress enough to seal correctly. So do I have to use them? I installed an in-line filter before the rail.
I’m thinking I can trim the central support to give myself about 1/4 an inch and possible be able to use a filter sock on the lift pump.
Or maybe there is a low profile filter sock that will work? What do you guys think?
Also, as you may be able to see in my pictures I have the siphon connected to the lift pump so not to the feed line or the return line. So hopefully won’t have to deal with the drawbacks that come with either one of those lines.
My order from sakebomb garage arrived. Thinking about mounting here in front of the engine. They will be under the air/water cooler intake tubing.
what do you guys think about mounting in this location vs on the engine.
those have a lot of juice and you need to be concerned about electronic interference; closest and shortest lead wires away from other critical wiring such as the ESS is best imo. Stroker did something similar putting them at the front of the engine with long lead wires. He had some EMI/RFI issues, though some of it seems to be resolved with resistor spark plugs. It’s on my future rework list though.
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They fit nice down where the drivers side motor mount was in the stock car... depending on what you use for a mount setup. Makes for short wires that are away from everything important
those have a lot of juice and you need to be concerned about electronic interference; closest and shortest lead wires away from other critical wiring such as the ESS is best imo. Stroker did something similar putting them at the front of the engine with long lead wires. He had some EMI/RFI issues, though some of it seems to be resolved with resistor spark plugs. It’s on my future rework list though.
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Thanks. I was wondering about interference of some kind. My mechanic used to always have me check my spark plug wires on the renesis to make sure the plastic separator was installed. Maybe, I should get the sake bomb mount and install in the stock rx8 location. Benefits of the Rx8 front cover 😁. Well as long as the turbo oil feed in not in the way.
They fit nice down where the drivers side motor mount was in the stock car... depending on what you use for a mount setup. Makes for short wires that are away from everything important
I’ve considered that location but my oil filter relocation kit is down there taking up some of the room.
I’ve been working on the fuel pump hanger/surge tank for awhile now. Here are some pictures.
I had to buy the doorman special tool to fix my fuel line connectors, man did that make a difference. It’s practically impossible to insert them by hand. you can see the finished product in the first picture.
So my main problem with this whole thing is that I can’t use the fuel pump filter sock, either on the feed pump or the lift pump, because the top hat and surge tank won’t compress enough to seal correctly. So do I have to use them? I installed an in-line filter before the rail.
I’m thinking I can trim the central support to give myself about 1/4 an inch and possible be able to use a filter sock on the lift pump.
Or maybe there is a low profile filter sock that will work? What do you guys think?
Also, as you may be able to see in my pictures I have the siphon connected to the lift pump so not to the feed line or the return line. So hopefully won’t have to deal with the drawbacks that come with either one of those lines.
So I am considering either buying this kit or just 3D printing my own basket, but am curious do you retain the fuel level sensor with this? Or how is fuel level monitored?
Edit: shows how dumb I am, level sensor is on the passenger side. Got it.
There is a level sensor on both sides that add together to give correct readings.
Interesting. I did notice the JDL also has "Sensor" terminals so it likely does then.
I ended up just ordering it now actually. The website still has the black friday sale prices active (you have to add them to the cart first) and it brought it down to like $467.
Yes the JDL retains the fuel level sensor. You can’t tell from my picture but there are 3 plug connectors. One for the sensor, another for the feed pump and another for the lift pump that all fit into the fuel basket/surge tank.
I think you will like it Flickert.
I’m patiently waiting for the rx8 coolant thermostat adapter for our swap from JDL.
Yes the JDL retains the fuel level sensor. You can’t tell from my picture but there are 3 plug connectors. One for the sensor, another for the feed pump and another for the lift pump that all fit into the fuel basket/surge tank.
I think you will like it Flickert.
I’m patiently waiting for the rx8 coolant thermostat adapter for our swap from JDL.
I assume you mean this? Very nice if so. Do some show and tell when it arrives please.
Also on your surge tank install, did you end up cutting down the rod and fitting the filter on the lift pump? I Think this is a viable solution if you can get it all to fit. Probably copy you honestly
It may be that but I was under the impression he was going to redirect all coolant lines forward away from the turbo area as well as retain the thermostat.
I assume you mean this? Very nice if so. Do some show and tell when it arrives please.
Also on your surge tank install, did you end up cutting down the rod and fitting the filter on the lift pump? I Think this is a viable solution if you can get it all to fit. Probably copy you honestly
That one is for the REW engine. He is supposed to be making something for renesis front cover that is not electric pump and redirects all the coolant lines forward away from turbo area or so I thought.
I did not have the courage to shorten the support post as my filter sock was not fitting very securely and everything is a really tight fit. There may not be enough room due to corrugated lines and connectors. I thought I would just run it without the sock for now until I can figure out what filter sock I need. It’s really not that difficult to remove the fuel canister the way I wired it.
Last edited by Warrior777; 12-01-2022 at 09:54 PM.
06-11-2022, 11:20 PM
