bigbreak_2000

I started having issues with a fuel leak at the hose connections to the FPR. Currently the engine (1981 280zx modified 3.2 FI NA) has 320cc injectors, 190lph fuel pump and the stock fuel rail from a '77 280z. Motor puts out 220-230RWHP. The 280z FI fuel rail uses a FPR that has 2 inlets. I am considering switching back the stock 280zx FI fuel rail which fits the stock design FPR that has only 1 inlet. IMO this later design eliminates one of the rubber hoses. The question I have is there a difference in the fuel pressure provided by the 280z setup vs the 280zx setup?

I was told the regulator with the 2 inlets maintains a higher pressure (42psi) vs the stock NA 280zx setup which maintains 37psi? Not sure if these quotations are at idle with vacuum or WOT..Is there any validity in this statement that the FPR with the 2 inlets maintain a higher pressure than the later 280zx one's with the one inlet?
Further, I don't want to spend money on a custom rail unless there is a good reason to go with a custom rail. I already have the stock fuel rails and stock FPRs.

I was also told there is a difference between the FPRs of the 280zx NA and 280zx Turbo. Is this true? Searching online for 280ZX FPRs, seems they are all the same.

NismoPick

I'm not sure if the 2port FPR is set to a higher pressure, but you could find out by checking your fuel pressure, or by checking the FSM (www.xenons30.com/reference).

The benefit of an aftermarket fuel rail is the ease of install / removal, and heat reduction.

The 280zx n/a and turbo both use the same FPR (specs are the same).

If you want a good aftermarket adjustable FPR, use a real AEM FPR, or similar name brand one. The cheap ebay ones do allow for adjustability, but leak down making for hard starts.

hoov100

All those mods and no tune?

bigbreak_2000

Thanks for the replies.
I found out that the stock FPR was actually modified to increase the pressure. There is a way to tap in the top cap a little bit, this forces the diagram down and raises the static pressure, and through research I also came across a method described by Porsche folks where the internal spring is replaced (remove the top with a pipe cutter and then tig weld it all together again).

I think the cause of the problem I ran into with the leakage, is that the FPR was not perfectly aligned with the 2 ends of the rail, causing a slight kink in both inlet hoses, and over time these hoses must have developed an internal abrasion. Further, when cold, these hoses are really stiff, which even though clamped at both ends, does not seal perfectly. The reason why I did not experience this leak when the engine is hot, is that the hoses soften and expands a little bit and may be sealing a little better. The hoses are the correct size Nissan FI high pressure type.

The spark and fuel is managed with MSD and Adaptronics ECU. The motor was tuned on the engine dyno at 42psi. We've dyno's the mtor up to 7k rpm and it is not running short of fuel.

I looked at the AEM FPR but need to figure out how to align the fittings and attach it back to the rail. Jim Wolf technologies makes an adjustable one where the housing looks almost stock, but again the bracket seems made for an aftermarket fuel rail.

FricFrac

A 3.2L stroker is a ragged edge build - don't cheap out with a mickey moused FPR. There are a lot of quality FPR that you can buy and mate it up with a proper fuel rail like a Pallnet or JSK.

slownrusty

Agreed..listen to this man!