What's up everyone,

It doesn't seem like there's been much discussion on this, so I'm curious what your thoughts are. I currently have a popcharger, z-tube and MD 5/16 spacer. I'd like to get a set of headers and an ECU reflash in the next couple months (and possible high-flow cats). Do you think increasing the WOT fuel pressure by roughly 5% with an adjustable FPR will complement this setup?

I had a similar setup in my old Pontiac, and it worked wonders. The ECU piggyback I had didn't give me the gains I expected, so I got an adjustable FPR and bumped up the WOT pressure by 5%. By force-feeding a little more fuel into the mixture, it brought all of my mods to life.

I'm by no means an expert on the VQ35 though, so I don't know if this is a bad idea. Any thoughts are appreciated.

 

are you talking about a manual adustment valve, that would be bad on this engine, just get a utec and do it correctly

 

Yeah, I was thinking of a manually adjusted regulator. I had a feeling it wasn't a good idea, since no one appears to have one.

 

The problem is this. Your old car had a fuel return system. Your G does not. So I'm not sure there is fuel pressure regulator made for the newer returnless systems. I think you have to convert to a return style. Even then, blindly putting more fuel into the engine, isn't the greatestest way to gain power.

 

The product I was thinking of is the aeromotive adjustable FPR. Z1 and AAM both sell them for the coupe. You brought up an interesting point though. On my old car, I didn't blindly increase the fuel pressure. My particular model year had an OEM FPR that was 4 psi below the optimal setting at WOT. Pontiac fixed the problem on subsequent models. I got an aftermarket FPR, increased WOT pressure by 4 psi to fix the problem, then increased by another 2 psi to account for the additional airflow from my mods. This was a calculated risk, and it worked out fine. I had the car 6 years. Everything else in it was a piece of garbage, but the engine held up fine. Just had to perform basic maintenance.

 

Cool, can you post a link to the product?

 

Here's the link from AAM:

http://www.alteredatmosphere.com/mm5...y_Code=350Z_FS

It's a tricky call, I know there's a fine line between benefits and risks.

 

Dude they made that for people running FI and with a return fuel system

 

Okay, I see, so you need to upgrade the entire fuel system. Oh well, hopefully the reflash will be good enough.

P.S. An adjustable FPR can be just as useful in NA applications if the stock regulator is restrictive (as was the case on my old car). I wasn't going to increase fuel pressure to 70 psi or anything. Was thinking of upping it 2 psi, maybe. I just have a gut feeling that a remap alone won't bring out the full potential of the intake/exhaust mods. Software can only do so much.

 

Just a different way to achieve the same end I suppose... Though without a fuel return you have no way to shunt excess fuel (i.e. without a low pressure side) but I'm not sure that all adjustable regulators require that (I think some are just inline).

 

yeah, sounds like it may be playing with fire without a fuel return. I'm still learning about the G. Seems like it's a lot harder to do (what used to be) simple mods now. Most of my experience is with domestics though.

 

An Apexi SAFC is probably a better way to add fuel. If you need more fuel that is.

 

Thanks, I'll look into that.

 

The only way that this mod would make sense if you NEEDED mor fuel, i.e. you are reaching 100% injector duty cycle. Then you can conceivably get an FPR and raise it to 0 psi from the stock 51, to allow more fuel flow. There is no way that any NA bolt on mods increase volumetric efficiency enough to max out stock injectors. Even then, btw, I'd probably not connect hte vacuum line and have a static FP setup, just like stock.

 

Thanks, I think you got to the root of my question. It sounds like the stock fuel system is good enough to handle most NA mods. I'm probably just used to cars that have crap for stock parts, still getting used to the fact that the G was actually engineered properly! 51 psi is pretty good for a 3.5L V6. I've read up a little more on the forums and I think I'm leaning toward a UTEC (if I go forward with the headers and high-flow cats).