Roadcourse issue, I get starve once I get below about 12 gallons in the tank when taking right hand corners.

 

Well that sucks. It is one of the reasons I chose the 350z over the 370z. I plan on doing a few track days a year with the 350z basically stock. The majority will be done in my track only 240sx.

 

On street tires or slicks? I think Terra is running slicks and getting much higher sustained lateral G's than I am. On my semi slicks I only had starvation issues when below a 1/2 tank of gas.

 

I'll be on Bridgestone RE71Rs. They are about equal to an NT01 as far as grip goes (actually faster for a couple laps but then fall off a little) according to a friend that did some datalogging and testing on his time attack evo.

 

For me no aero and I'm pretty much bone stock so that should keep things a little slower through the corners. I'll let you guys know what I experience.

 

RS3 or NT01, and I have aero work. In was between 1/4 and 1/2 tank depending on the turn before the aero.

 

How many track days have you put on your system? Street driven also?

There is a flaw in the circuit you constructed that should eventually show its face.

You have defeated your factory in-tank fuel pump module's ability to recover fuel from the left side of the fuel tank. It accomplishes this by re-purposing the factory regulator's bypass fuel volume and sending it to a pair of venturi jet-pumps. One of the jet-pumps is what created the vacuum for the in-tank transfer hose that pulls fuel from the left side of the tank. With your proposed circuit, the factory regulator would never open, therefore the jet-pumps would be dormant.

Of course, fuel slosh will be moving fuel back and forth all over the tank anyway, and the slow pumping siphon probably becomes of little value on the road course. However, should the vehicle be driven on level ground street conditions for a considerable time where the fuel will not slosh much, the factory fuel pump will fail to fill the surge tank when the fuel level on the right side of the tank is depleted, leaving the vehicle inoperable despite the fuel level gauge indicating significant fuel remaining.

 

Its been track and street driven in this configuration for around 8 months, for a total of around 5000 miles (. The stock siphon still functions as required due to the DW300 sitting in the factory basket and the venturi is drill modded with the factory regulator in place. I've run it all the way to "E" without issue on the highway. All the tracks I drive with 1 exception are at least 3 hours away.

My fuel level gauge only uses resistance from the left side sender.

As for level ground conditions, I challenge you to find a US highway that matches the straight flatness of the German autobahn.

 

Some detail is missing.

As your system has been described, your siphon would not function. With a factory fuel system, the regulator opens because the fuel system is closed and pressure builds until the regulator opens, to regulate pressure to 52psi.

As described, Your system is sending fuel to an open circuit, and the regulator would never open and send fuel to the venturis, which not only need fuel, need fuel pressure to function.

America has flat lands that the entire country of Germany would likely fit into

 

Since I have yet to install mine, will I run into this problem. Stock pump, nothing modded , just a return off the surge tank running back into the stock basket ?

 

True, but also with enough potholes to slosh your fuel. I went out and pulled the bucket. When I did the original build for the fuel system I had run the return hose into the bucket with a threaded barb fitting to get the venturi system fitting. I forgot about that one, good catch.

 

To clarify, you replaced the factory regulator with a replacement fitting (such as found in the CJM return correction kit, or otherwise custom made), and the surge canisters overflow plumbed through this fitting to power the jet-pumps?

This would be a system that I know would work, with one catch. The surge canister itself will be pressurized at low engine load due to the jet-pumps restriction in the overflow circuit. This would have me prefer a very stout surge canister construction, and possibly wish to make sure it is mounted to the exterior of the vehicle.

 

Yes but it is correctable following the additional step he recalls just after your post.

 

Very interesting about the stock syphon. Thank you for pointing that out.

 

Read something about someone modifying the stock siphon and adding an extra hose to it to pull more fuel from the other side. I guess they will have a kit together shortly, I'm very interested.

 

You mean a better performing setup than the CJM fitting? Do tell.

 

The CJM fitting just allows you to continue use of the factory siphon when you convert to a return and delete the factory regulator. Its not intended to do anything else.

You could add any number of additional jet-pumps to the system if you wanted, several are available from OEMs or there is a billet one from Radium you could add.

No matter what you do with the siphon, that is not a cure for fuel starvation, it will just speed up fuel recovery to the right side of the tank after it has sloshed. No siphon system can save you from the slosh that occurs during the turn... it can only recover that fuel that has sloshed more quickly... which would be useful in such environments as a right hand NASCAR track perhaps.

 

Picked up an extra fuel pump basket today. Thinking about one on each side feeding the surge. Then I don't have to worry about the jet pumps

 

It will perform well it just wont be reliable.

 

What do you mean reliable and why?