fuel pressure regulator

[chris frizzell]

Hello everyone has anybody fitted a billet fuel rail to a 280z and if so can you recommend a adjustable FPR . looking at a sytec but not 100% many thanks chris

 

[Wally]

I would look into aeromotive for a fpr. Not something you want to cheap out on.

 

[jonbills]

i would recommend Aeromotive regulators too, I have an adjustable 5-50psi one on my car - worked with my carbs until a few months ago and is now working with my efi and ITBs.

I don't have a 280z or a billet fuel rail though.

 

[Alphabettispaghetti]

I have love for this one.

https://aeromotiveinc.com/ultralow/

however for some reason I like glass.

https://www.glencoeltd.co.uk/malpassi-85mm-filter-king-with-glass-bowl-8mm-unions/

 

[jonbills]

they look nice, but I think the Malpassi ones aren't a patch on a proper bypass regulator.

 

[Alphabettispaghetti]

they look nice, but I think the Malpassi ones aren't a patch on a proper bypass regulator.

for carbs though, I thought it'd do?

so you you limit pressure before or after the carbs?

 

[jonbills]

for carbs though, I thought it'd do?

so you you limit pressure before or after the carbs?

yes, I'm sure they'll do a job, up to a point. but they limit pressure by restricting flow so I always worried that there wouldn't be enough flow at sustained high load. I think thats why you put them after the carbs.
with the bypass regulator, you can put it anywhere you like in the flow and it just bleeds off excess pressure though the bypass.

 

[Makesy]

I use a Sytec and it does the job just fine.

Old pic, but it's the purple thing in the bottom right.

Don't buy the super cheap unbranded ones, they'll leak and probably fail.

Stick with a brand name (Aeromotive, Sytec, AEM maybe?) And you won't go far wrong.

I currently have a gauge attached but I'm removing it now it's at the pressure I want and will plug it instead.

 

[Mark N]

I used a Sard FPR mounted directly on the rail and fitted a Fuelab gauge.
I found a -6AN female to 1/4"NPT fitting to minimise the amount of fittings between the rail and FPR.

 

[chris frizzell]

Thanks like the look of it fitted to the end of the rail . did you keep the cold start ? Chris

 

[Mark N]

Thanks like the look of it fitted to the end of the rail . did you keep the cold start ? Chris

No, I fitted the FAST EZ EFI and got rid of ageing injection system.

 

[Alphabettispaghetti]

I ordered a malpassi as it’ll be fine with my retro spec and lower power

 

[chris frizzell]

Had a gander and i think i will go for the aeromotive .ordered the AN6 fittings as you dont get them all with the kit due to different fuel line (rubber or braided ) . only 2needed though so £11 . but need some thread seal any good one on the market ? stupid but not fitted a rail before and it save gettting some crap . good that some folk have do this before thanks chris

 

[Pondo]

I have a Malpassi, (without the glass). This is also before the carbs, are you saying I should either have this after the carbs Jon or that I might notice increased performance with a better bypass regulator.

I realise I am starting out from the very beginning in terms of understanding so apologies if these questions seem daft, I have a facet fuel pump one end with triple Weber’s on an l28. Slowly learning though, interested to see my fuel pump orientation now after reading Frankys other thread, I’m not sure without checking if my car still has the pump mount.

Also please correct me if I’m wrong but the fuel pump is pressuring too high for the carbs so my malpassi is limiting the flow? What’s different about the aeromotive unit compared the the Malpassi for instance.

 

[jonbills]

View attachment 39534 I have a Malpassi, (without the glass). This is also before the carbs, are you saying I should either have this after the carbs Jon or that I might notice increased performance with a better bypass regulator.

I realise I am starting out from the very beginning in terms of understanding so apologies if these questions seem daft, I have a facet fuel pump one end with triple Weber’s on an l28. Slowly learning though, interested to see my fuel pump orientation now after reading Frankys other thread, I’m not sure without checking if my car still has the pump mount.

Also please correct me if I’m wrong but the fuel pump is pressuring too high for the carbs so my malpassi is limiting the flow? What’s different about the aeromotive unit compared the the Malpassi for instance.

Actually, I'm not sure now I think about it! if you put it after the carbs, maybe the carbs see the full pressure and that would be no good.
but I am sure bypass FPRs are better!
The difference between the two types: the Malpassi one has an in and an out, and the pressure in the out is controlled by restricting the flow between the two.
With the bypass regulator, there's an in, an out and a bypass. The bypass is connected to the return line. The bypass is held closed by a sprung door, that opens progressively at the target pressure. The more pressure, the more open the door is and the more pressure is bled off through the bypass. It makes it so that the pressure in the entire hose run from the tank to the end of the output is all at the same pressure - the target pressure.
On mine, I have it before the carbs/efi, and it just dead-heads at the last carb/TB. so the pressure from the tank to the last carb/TB is always the target pressure.
does that make some sense?

 

[Alphabettispaghetti]

another way, is some regulators limit flow when limiting pressure.

Posh ones limit pressure without limiting flow.

 

[Pondo]

Cheers both of you, makes sense.