[Lotus]

I use the non-adjustable 3.5 bar version.
It is referenced to the manifold. My fuel pump is beefy enough to support this.

why should I adjust fuel pressure? I have a mappable ECU for tuning.

 

[mattkosem]

I use the non-adjustable 3.5 bar version.
It is referenced to the manifold. My fuel pump is beefy enough to support this.

why should I adjust fuel pressure? I have a mappable ECU for tuning.

Yep, I noticed the same and rephrased my post shortly after I sent it. My substantially more basic setup has even less need for such a thing.

The vacuum reference on the k-tuned one I've got now is capped/unused, which (I hope) their design must tolerate in the event of a diaphragm leak given that they provide them that way. It isn't a big deal to send a vacuum reference from a Bosch-style regulator to the manifold, but it also seems common to just leave it connected to nothing in applications like this 😟.

--Matt

 

[Lotus]

Honda is using a fixed fuel pressure for the K20a2, hence many do not use as it changes the mapping.
If you map it anyhow, you can also run it referenced, especially with bigger injectors it is helpful as fuel pressure is lower at low MAP extending injector duty cycle.

 

[mattkosem]

OH! Yes, that makes sense. I'd have to retune if I hooked mine up because the moving vac levels would cause fuel pressure to move as well. It looks like by ~5psi or so.

Radium's instructions make connecting the hose seem optional, so perhaps that is acceptable with that setup as well.

Quite a few adapters to fit Bosch "mini" regulators into flexible installations are available, so that's a nice way to guarantee a quality component is keeping the fuel in check.

--Matt

 

[AWD]

I got a hybrid racing fuel pressure damper a while back and it really helped smooth things out.

 

[mattkosem]

Neat, thank you!

My K-Tuned rail looks to have a port down there. The last couple days the problem has gotten worse, maybe because it has been cooler.

If I still have problems after replacing the reg, I can add something like that too. I ordered the Radium adapter and an e36 regulator (those cars also use 3.5 bar). It should fit right where my current stuff is, and hopefully help 🤞.

The noise persisted on my way home from a meet last night, and the car felt like it was losing fuel. I could see from the Hondata app that I was leaning out, so something is definitely wrong. Thank goodness I was able to drive gently and get home without major issues. 🤦 It was nighttime, and the pressure gauge is under the hold, so I couldn't see what was actually happening or how bad.

I thought I was getting the good stuff buying into the K-Tuned brand, but I don't have many of their parts left on my car at this point. My header still eats a spring every couple weeks, and it'll just be the fuel rail and fuel/clutch hoses once that is replaced. Sigh...

 

[AWD]

My bad, my fuel damper was actually radium engineering 20-0776, not hybrid racing. It attaches to the vacuum line. Before that upgrade, my fuel pressure gauge would falter, now it holds steady.

 

[mattkosem]

No sweat. I know the feeling! 😅 A bunch of companies make dampers. I can find one I like if I need it.

 

[mattkosem]

@AWD I saw your thread over here: Fuel pressure pulse damper?

I can't see how badly my current setup bounces like crazy as well when blipping the throttle, because the k-tuned gauge seems "numb" and wont move unless there's a huge amount of change...but I can see that it still moves in spite of that so it was enough to convince me to grab one.

I'm gonna give the damper deatschwerks sells a shot. It seems to be the most fitment friendly, and it seems like I could tuck it in a couple different spots. My K-Tuned rail has an 8AN port underneath like yours, so I'll try there first.

With any luck I'll have all this stuff sometime this week. 🤞

--Matt

 

[mattkosem]

I've been unfair about K-Tuned here. I've spent about $3500 with them, largely on parts they're reselling to comprise a turnkey kit, and have only had problems with a few things.

Of the pieces I bought...

• The Hasport mounts have been great
• The "budget" axles, bought from a reseller, weren't up to my needs
• 4-1 Header leaks when cold and sheds springs regularly
• Chassis harness works great
• Alternator relocation kit didn't want to keep the alternator on the car (not just me, and I don't believe the belt was too tight)
• Front upper control arms have been problem free
• Upper coolant housing had an exhaust leak, but is sealed now with HondaBond
• Fuel system, apart from the regulator, has been fine.
• Various little other adapters/hoses/plugs (coolant temp, throttle, clutch, etc.) Have been fine.

In any event, my Radium stuff should be here by Thursday. Hopefully things will normalize.

 

[LotusElise]

I've spent about $3500 with them, largely on parts they're reselling to comprise a turnkey kit, and have only had problems with a few things.

What do you expect when you buy something? Maybe my thinking is not relaxed enough for that aftermarket stuff. There is a difference in application, e.g. if something get into a race car or in a daily driver. Would a FPR noise care the driver if the FPR does its job? KTuned doesn't think much about application or fitting for my experience:

• KTuned water plate delete kit - spend another 150 Euro to get a right sized bore and O-Ring plus hose adapter DIY done - did neither fit the hillclimb nor the DD application
• KTuned alternator relocation kit - the stiff version, alternator wheel didn't match up the belt line properly, had to modify it for a few efforts and Euro's - did neither fit the hillclimb nor the DD application

If I had knew this before I would have designed my demanded functionalities myself instead of paying tax, shipping, custom fees and DIY adaption of the product. BTW, I've bought the FPR from Aeromotive Pro-Series, which full fills its function as specified. Noise? I have so much noise from exhaust and intake, I can't claim about other noise sources .

 

[mattkosem]

@LotusElise I love your perspective, as always. ❤ You hit the nail on the head.

The downside of buying a "turnkey kit" is that they all include a bunch of aftermarket "racecar parts" (very loose term) whether you need it or not. In some cases, this is great and helpful. In other case, not so much. I chose convenience over reliability and am paying for it, nothing more nothing less. It isn't the first time, and probably won't be the last.

OEMs tend to do a really good job at things like mounting belt-driven accessories and regulating fuel pressure, so I'm happy to grab suitable stuff from OEM parts bins when there's no compelling reason not to do so. For the upper coolant housing, it had to go because I'm using AN stuff and there isn't an OEM part that does that, so I compromise and deal with it.

My alternator is now where Honda intended, using a tensioner from Honda, and hasn't been a problem since. Here's hoping a FPR from 90s BMWs that happen to run the same fuel pressure as K20s in a little adapter is equally drama free. 😎

--Matt

 

[mattkosem]

The DeatschWerks pulse damper came today, and I can see right away that it isn't gonna work. It has full AN connections on it, which won't clear the center port on my fuel rail.

I guess I'll re evaluate the need once I've got the FPR and a properly working gauge. I have a proper flow-through return style fuel system so maybe the pulses won't be too bad with a working reg.

--Matt

 

[LotusElise]

OEMs tend to do a really good job

Yeah, they do. I've work now since 9 years for OE's and OE supplier. To get products into the market is a challenging road through quite a few steps to take: internal specification, customer specification, norms and regulation of the market itself and all need to be proven and certain conditions. Sometimes that part take the lead in cost and time, e.g. if you go on rail or marine applications. Automotive is quite driven by Safety regulations and norms and has it's own standards, differently from industry regulations/norms. Honda and especially Toyota were leading companies regarding quality in mass production. Soichiro Honda and Takeo Fujisawa, the founders of Honda had quality in focus since the founding of the company. A lot of quality methods, which are used world wide and got standard, coming from that little island.

 

[mattkosem]

Well, off to a bad start. I got everything installed and the regulator I got from ECS Tuning seems to hold 10psi at most. 🤦‍♂️ It must be stuck open. If I pinch the return line more pressure builds.

Guess I'll have to wait for a new top.

--Matt

 

[mattkosem]

I disassembled the K-Tuned reg to take a peek while I wait. It honestly doesn't look too bad inside, but there is a scar right on the ridge where the ball bearing that relieves the pressure seats. I assume it must have been like this at assembly time.

Not sure why, but there was RTV sealing the diaphragm to the top and base. The diaphragm itself looks fine, and I don't see any obvious problems with the ball.

The tension spring has some crazy rough grind marks on it, but otherwise seems fine.

Might just be that busted seat making it operate inconsistently.

--Matt

 

[mattkosem]

Ah geez, still isn't holding pressure...

It'll start and run, but 10psi is all it'll get so barely idles is what I see (for a brief moment to test). If I pinch the return line, I can easily see 30+ psi. Maybe this bimmer FPR has a funky o-ring size or something, making it incompatible with this adapter.

 

[mattkosem]

I'm getting the impression that the FPRs are both fine, but that there are 2 sizes of Bosch FPR "reflow adapter" nipples. Mine is definitely 7mm, but the VW style ones (and probably others) are 9mm.

I bet I'm getting no pressure because the o-ring isn't seating because the hole is too big.

--Matt

 

[mattkosem]

Yeah, that was it. The quickest suitable model I could get is a "Eurospec" branded unit, meant to be a retrofit for VAG vehicles.

The pressure makes me wonder if it's a rebranded Porsche 3.8 bar unit with 3.5 stamped on it but it holds pressure, runs smoothly, and doesn't make any weird noises.

Bosch makes a 0280160562 unit that is a perfect fit and an OEM part for a bunch of vehicles, but they're all Euro cars so nobody over here stocks it. I'll grab one most likely, but I can tune around this one either way.

I'm not seeing any apparent need for a pulse damper. Pressure is steady.

--Matt

 

[AWD]

Radium Engineering makes good parts. My fuel pressure gauge would never hold steady until I got the RE damper installed.