Quote:
Originally Posted by whis9
how much of an improvement is adding a return to returnless car, this is only a track car. the car is completely torn down, so I figure if it nets a good return I would add it now. maybe a stage 0 or 1
Thanks
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A return system will have no contribution towards resolving fuel starvation. The only basic thing that can help at all, is an upgraded fuel pump. By upgrading the fuel pump, even if the engine doesn't need it, will increase return volume (the stock system does have return fuel, its just happening inside the sending unit), which will increase pressure to the OEM transfer siphon, increasing it's ability to recover fuel from the driver side. This is more of a "in theory" sort of thing. In practice, I doubt it would be very noticeable if at all.
A return system is something I would recommend for any VHR car over 10psi of boost, or over 500-550rwhp. It doesn't seem to be needed below that from my own testing, although there are some cars at lower power than mine that I have heard reports of fuel pressure dropping. While my car is currently on the stock rails and return-less setup, there are a few feet of the fuel plumbing that is upgraded much larger... not because I thought I would need it, but because I wanted to reroute my fuel lines away from the turbos and manifolds. Larger aftermarket plumbing was built for this. This is the only reason that I can come up with right now why my car seems to be able to run a little more power than others without a return. Our soon to be released kits will include upgraded plumbing. Our basic Stage 0 (been available a couple years now) is just a return conversion and leaves the plumbing otherwise stock, and wont do anything to help flow, but will resolve the first signs of pressure drop from the stock fuel system.
But again, just to be clear, return systems alone will not help resolve fuel starvation in the 370z.