Many, many problems lol. Aftermarket regulators for turbo applications are generally rising rate regulators. ie they increase pressure under boost at set rates depending on the regulator chosen.
Most regs are 1:1, but there are a few that have different ratios. I'm still a bit confused as to exactly what you are trying to achieve. Better fuel economy? More power? Individual injector trim is not often a big concern for most, and those it does concern have generally already stumped up the cash for a proper aftermarket ECU. The Emanage Ultimate does individual trim, if that is a major consideration for someone on a budget. Can be had for around the same price as nistune.
Tackling the principle for starters. A simple Power/Economy switch would do. Generally speaking I prefer to make my own power electronics from heavier duty components with higher power ratings. Especially when it comes to machinery. this is opposed to a lot of the junk on the market in terms of the components and PCB manufacturers are tending towards using. Ie solid machined PCB as opposed to tin foil rubbish, or say a 5A diodes as opposed to some of the surface mount junk. I've been meaning to get an EFI controller for a while now. But I would limit it to one and we have other cars. In terms of the 300ZX I have had for over 10 years now. I have just had to replace the whole interior bar the seats and carpet, box is out waiting for clutch, bushes need replacing, clear coat has gone pretty rude so paint. To be honest I've already pissed that much money up the wall on it. I nearly gave up on it and got sick of friggen looking at it sitting there. But she's practically straight as a die and I ask myself, if I sell it, what the frig would I buy if I want another sports car. So I decided to keep it cause she's been worth every friggen penny. But right now my priority other than the repairs. Is a custom engine coolant and inline oil cooling system, maybe trans. Lowered springs, struts, tension rods etc. To be honest I would prefer something with either electronic or hydraulic actuation.
On vacuum they are 1:1, on boost they vary depending on the reg purchased. ie: some are 1.5:1, some are 2:1. ie: it increases fuel pressure as boost increases.
I've had quite a few regs pass through my hot little hands and have only had one that was a different ratio than 1:1 (a Malpassi). IMO, a ratio other than 1:1 is a stupid idea for our applications. Just makes tuning too damn hard with no benefits. A backyard hack from back in the day when big injectors were too expensive/hard to find.
My understanding of rising rate is that the fuel rail pressure follows boost on a 1:1 basis. At idle, Fuel rail pressure/fuel reg outlet pressure is approx 43 PSI. Plus 10psi of boost, actual fuel rail pressure is 43PSI + 10 PSI = fuel reg/rail pressure = 53 psi... IE: fuel pressure rises at a constant rate referenced to boost pressure. Thus the actual rail pressure remains 43psi referenced to plenum internal pressure. Thats what the little black hose going to the plenum is. Early days FPR's didnt do that and where referenced to ambient air pressure. I think these where used mostly on carby cars which weren't Hi Po or turbo charged. A fuel reg which rises non linearly with boost pressure? WHY ??? Thats what a tune is for. At least with ECU controlled engines. I spose on carby cars fuel pressure rate rising above 1:1 could be used to keep a reasonable jet size for idle and an artificially LARGER jet due to RISING rate above 1:1 for larger throttle openings. I dont really know much about carbies. Just generally how they work. The little hose for rising rate is the little one you can see going from the reg body to the plenum. BTW that a NISMO adjustable reg
Actually based on further research, I had it right in the first place. Non rising rate is 1:1, essentially fuel pressure will increase relative to boost. Rising rate reg ratios vary, for example 1.7:1 as in the Malpassi. I'm sure there are other ratios with different brands/models but can't be frigged searching lol. So a 1.7:1 rising rate reg will essentially increase fuel pressure by 1.7psi for every 1psi of boost. But yes the actual 'mechanics' are not as simple as that but that is essentially the outcome as far as I understand it, on a very basic level.
Just found this interesting tid bit. Also as far as I know (may pay to check) injector flow increases with the square root of fuel pressure. So a 21% increase in pressure will only increase injector flow by 10% since 1.10 = sqrt(1.21). Seems these sort of NON linear style fuel reg are used for artificially getting more fuel in the engine while using stock injectors. IE: when you are too cheap to buy injectors sized for the job.... IMO that there could be issues with fuel pumps doing this, seeing they are generally unreliable for fuel delivery over 65-70 PSI
Yep, saw that too tekky. Very handy info Still rising rate regs are useful if all you need is a small increase in fuel to maintain safe afr's with a mildly modified system, without having to go to bigger injectors and an aftermarket ecu to suit. It seems zed owners have it good with Nistune, being able to handle increased injector size at such a low cost. The cheapest option otherwise afaik is eManage Ultimate, which is about double Nistune once you get all the bits to install it, and although it does have an injector resize feature, it doesn't work very well. I went back to manual adjustment in mine. From there you step up to full aftermarket ecu, which can get expensive quick. So for a little more boost, or a more efficient intake (ie bigger smics) requiring a little more fuel, a rising rate reg may be a good fit.
I see all vacuum referenced FPR's as "rising rate", the rate at which they rise is generally 1:1 but some are available at a higher ratio. Interestingly at idle our fuel pressure is approx. 36.3 PSI and the 43.4 PSI with vacuum reference removed, so is the engine is creating approx. 7 PSI vacuum at idle all being good ?, this seems to be reflected by the OEM boost gauge, a vacuum leak might reduce this, one way of spotting an issue.
Just re read through this thread (except drifters posts lol), must admit it has become quite confusing, including some of my own posts lol. But I blame it all on ZX_DORIFTER lol sorry drifter Still, had another good laugh at this post :rofl:
From my understanding "rising rate" must be other than 1:1. But I have a limited knowledge of regulators. Irrespective of vacuum:fuel pressure ratio. Rate of flow is always rising is it not? I was looking at nismo regulator when I posted original comment. They specify a slope which looks to be linear to me. Nothing about a rising vacuum:fuel ratio. http://www.nismo.co.jp/en/products/competition/engine/regulator.html
