Miata Turbo Forum - Boost cars, acquire cats. - Attn Euro bros: WTB Non-US NB fuel rail & regulator

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Attn Euro bros: WTB Non-US NB fuel rail & regulator

Like the title says, I'm looking for a fuel rail and regulator from a 1.8 (1.9?) ltr BPxx engine. Regulator is rail mounted and has a vacuum nipple. These should be found on UKDM EUDM & JDM BP-Z3 engines, any NB1/MK2/NBFL/etc. I would consider any attached fuel line or plumbing to be a bonus. I would expect some of you bros in Europe and England may have stumbled over these while harvesting squaretops for US buyers, so here is an opportunity to make a couple extra bucks. :party:

Would also be interested in the J/EU/UKDM NB regulator alone if you upgraded to an aftermarket adjustable unit.

Before everyone starts dumping "OMG its the same thing this is not ClubRoadster JDM means nothing!" bullshit hate on me, yes there is a difference. As far as I can tell, everywhere else on the planet got NBs with legit return fuel systems with vacuum referenced regulators, and I'm trying to replicate that system in the most OEM way possible, so that means stock parts.

So, if you have a goofy rail and regulator sitting in your garage left over from you JDM engine swap, LMK what you got.

The UK/European BP-Z3 used a returnless type fuel system, the same as in the USA. Looking at the one sitting on my bench, the fuel rail and snubber are the same as supplied to the USA. You're looking for a BP-4W return type fuel rail and regulator. There is one on eBay UK for about 50 quid.

MAZDA MX 5 MK11 1.8 PETROL FUEL INJECTORS SET OF 4 INC LOOM AND RAIL/PIPES. | eBay

I'm pretty sure the only difference is the regulator. The BP-4W rail itself is the same as the USA version.

Excuse my ignorance, but what's better about a return fuel system? Thanks

skou: TY for the kickass data and clarification. I'll add that to my list of insanity, and thank you for the links. You are right, its exactly what I'm looking for. Pitty the eBay UK seller doesn't list international shipping.

scenturion: The NB has a super goofy fuel system as far as I'm concerned. It runs 60psi constant regardless of boost or vacuum. It just kinda... moves fuel. The 260cc factory injectors are actually 305cc @ 60psi fuel pressure. Good, right? Well under vacuum they effectively get bigger as the fuel pump is not pushing against 100kpa (atmo) and under boost, they get smaller as every +1 PSI in the manifold is like -1 PSI in the rail. At 168kpa MAP (14psi atmo + 10psi boost) my 260cc (305) injectors become 225cc (275) injectors. That's 275cc is enough fuel for like 140hp @ 80%DC according to RC's calculator.

TL;DR: Shit's no bueno.

A vacuum referenced regulator eliminates this swing. It drops pressure at idle and raises it under boost in what should be a 1:1 ratio to compensate for MAP. I'm hoping this will make the car easier to tune and more fueling more consistent.

From what I understand, the 99/00 returnless system is pretty easily overwhelmed with an aftermarket pump (IE Wally 255, etc). By adding a return and changing out the regulator, I'm hoping to avoid that situation.
I'm trying to eliminate the radical dynamic swing in injector size when I put my FIC 650cc EV14's and MS3 in the car.
The factory ECU is programmed to deal with the swing, and I will need to be able to convert back to OEM non referenced pressure when I put the stock ECU and injectors back in. I'll be able to do this by simply disconnecting a vacuum line rather than gutting or reconfiguring my fuel system underhood.
I need to keep it looking OEM. I figure the easiest way to do this is with OEM parts, thus I'm looking for the non US variants of the parts that do what I want them to do.

Just so you know, I know I'm overcomplicating the system, but this is generally how I operate. I actually have a 1:1 vacuum referenced 3 bar regulator from an earlier Miata that fits my rail that I plan to run with my FICs, but I want an easy swap option without ripping my fuel system apart every time I need the stock ECU and injectors.

:party:

Quote:

Originally Posted by EO2K (Post 1058280)

...I want an easy swap option without ripping my fuel system apart every time I need the stock ECU and injectors.

Wouldn't a USDM NA 1.8 regulator on a USDM NB1 fuel rail work? Same set-up when swapping a '99-'00 head onto an NA. Easier and less expensive than buying EUDM/JDM parts.

I have an NB regulator from a 99 fuel rail. If my current 1.8 NA regulator will 100% work/fit with my VVT head/squaretop and 99 rail, you can have mine for shipping cost. I need to know it'll work/fit 10303% though first.

I'm meeting my engine guy tomorrow, could pick it up then and send it out.

Quote:

Originally Posted by skou (Post 1058689)

Wouldn't a USDM NA 1.8 regulator on a USDM NB1 fuel rail work? Same set-up when swapping a '99-'00 head onto an NA. Easier and less expensive than buying EUDM/JDM parts.

True, except its gold and has that stupid 90° outlet on it that makes it impractical to plumb in anywhere.

http://parts.arlingtonmazda.com/prod..._38728_std.jpg

Quote:

Originally Posted by Oscar (Post 1058694)

Winning! LMK and we can work something out.

If it doesn't pan out with Oscar, this is the one off of a 1.8 NA. Black with a straight return outlet. Mazda part number KJ01-13-280.

http://parts.arlingtonmazda.com/prod...%252d280).html

http://parts.arlingtonmazda.com/prod...46526_zoom.jpg

Yep, that will probably physically fit, but it will be 3 bar, NB runs non vacuum referenced 4 bar. I think I even have one in my garage.

Does the EUDM Mk 2 return type fuel system run at 4 bar?

Everything I'm reading says it does, but god help me if it does not.

Edit: Actually, it would pretty much have to or the guys playing with the BP5A ECUs on their otherwise stock 99/00 BP4W engines would be totally screwed. Injectors are the same red top 260cc 195500-3310 so the pressure pretty much has to be 4 bar.

But yeah, the OEM rail mounted 4 bar regulator is what I'm after

I'm not sure how you concluded that the stock nb fpr gets easily overwhelmed by a wally 255, but in my experience that was never the case

Quote:

Originally Posted by EO2K (Post 1058797)

Uhh, how would we be screwed? Would it be running super lean/rich because the injector duty cycle would be different or something?

I have a BP5A ECU but havent tried it out yet.

Sorry for all of the questions, this is all new to me :party:

I'm starting to think I should have posted this in the DIY section or something :rofl:

Quote:

Originally Posted by skou (Post 1058807)

A bit of conflicting information here....

Mk2 1.8L - Std Fuel Rail Pressure - Forced Induction & N/A Power Mods - MX5Nutz Forum

Blergh

Quote:

Originally Posted by 18psi (Post 1058808)

I'm not sure how you concluded that the stock nb fpr gets easily overwhelmed by a wally 255, but in my experience that was never the case

Then I wish people would stop saying it. Maybe I misread something? :vash:

Quote:

Originally Posted by scenturion (Post 1058838)

No worries! It's not so much duty cycle that changes, its the effective size of the injectors. Raise the pressure and you get more fuel for the same size pulse. I stole this from a Ford Modular forum, it may halp:

Quote:

Open Loop and Closed Loop are two terms used to describe the fueling mode the computer is in.

In closed loop fueling, the computer takes readings from the oxygen sensors which read +/- of 14.64 AFR (Stoich) and makes corrections for it. If your car is idling @ 13.5 AFR, the 02s can see this, and will know to pull out enough fuel to get back to stoich.

In open loop, the fueling is purely based off the MAF transfer function and the open loop fuel table. This table has to be calibrated any time you make MAF changes, and changes that affect the airflow of the MAF.

When a car is started, the computer is in open loop until certain criteria is met. The o2 sensors need to be heated to work properly, so this is the main reason there is a delay.

After the sensors are heated up, the car goes into closed loop and the O2 sensors make their corrections.

The computer will go back into open loop under a variety of conditions. Throttle Position (TP) is one way.

There are parameters in the computer that determine what the TP is for Open Loop, and other things.

When that TP is reached, and the car goes open loop, and richens up.

Read more at: http://www.modularfords.com/threads/...p-vs-Open-Loop

In open loop, the ECU is running on minimal inputs and a static fuel table that is only so big. It's making a lot of assumptions based on what is supposed to be constant (in this example, available fuel) and its not really using a lot of feedback from the system. I don't know how big that table is or how much correction the factory ECU can make, but I would imagine if you yanked 15% of the available fuel by reducing pressure in the system, things would be on the edge a bit when it went open loop. I'd tread lightly and run a wideband.

Quote:

Originally Posted by EO2K (Post 1058797)

Everything I'm reading says it does, but god help me if it does not.

Edit: Actually, it would pretty much have to.... Injectors are the same red top 260cc 195500-3310 so the pressure pretty much has to be 4 bar.

You're probably right, makes sense. Out of curiosity, I did a little searching last night.

Off of Frank's Westfield MX5 website:

Quote:

The 99-00 FPR is set to 4 bar or 58 psi.
The 94-97 FPR is set to 3 bar or 43.5 psi.

Unfortunately he's checked out and isn't receiving calls anymore, so a bit difficult to confirm his source.

The USDM 2000 Mazda MX5 Miata Workshop Manual states for fuel line pressure:

Quote:

370-420 kPa (3.7-4.3 kgf/cm2, 53-61 psi)

That's confirmed by a Mazda tech here for a EUDM 2000 MX5 Mk2 1.8:

http://www.justanswer.com/mazda/4zab...odel-year.html

Hope it works out for you.

Actually, that "Just Answer" link is even better. What's pictured there is the regulator attached to where my NB all the gobledegook bullshit loops and connectors that make no sense. On my car there is a "Pulsation Damper" in that location, but that could easily be replaced with a regulator attached to a return.

IIRC, the FAQs say that the Walbro 255 overwhelms the stock fpr on the NA RETURNED systems. Which is why a lot of those guys used to (still?) run the 190 HP. I have ran the 255 on stock 99/00 returnless system for quite some time and it works well.

Also, you can get a used NA fpr for ~15 bucks from partsgroup or something, just like the one in that rosenthal link.

I also am looking into doing a returned fuel system conversion as well, good luck!