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adjustable fuel pressure regulator

3922 Views 13 Replies 7 Participants Last post by  scarified
Quick question folks. New turbo should be arriving soon then i've decided to hold off getting a Z32, injectors etc and get the car mapped by red dot racing so it'll be running smooth again.
Do I need a adjustable fuel pressure regulator? Somethings i'm reading say yes, others no.
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yeah i've just recently uprated the fuel pump. Ross matey will that work on an Rb20det then? Only states Neo block. If it does i'll take it.
I'm not up on gtsts, but I thought adjustable fprs were just to squeeze more out of incorrectly sized (i.e. too small) injectors?
if your running a high pressure pump you do.
This is wrong!

No, you do not need one, 100% not.

As long as your pump flows enough and your injectors are correct size for your desired setup/power goal you do not need an aftermarket fuel pressure regulator as the standard one will be perfectly fine.

I am running the standard one on my 430bhp R34 GTT too. And even my R33 GTR with 500+bhp is running standard. Ask a tuner and they will confirm.

Yes mate, you´re right somehow. People often use aftermarket adjustable fuel pressure regulators to squeeze more out of their current fuel system. In example the R33 GTST has 380cc injectors (iirc). So theoretically on a six cylinder engine these will max out around the same bhp mark to (give or take 5%). So normally won´t support the 400bhp level. But it can be done by using an adjustable fpr and upping the fuel pressure from 3bar to say 3.5bar. This means you squeeze more fuel through every injector cycle. By adjusting the map accordingly you can reach more power although the injectors are theoretically undersized. At least undersized in terms of the "normal" way you would want to set your fuel system up. Can be done though and has been tested and proven by people like RSP.
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Thanks RXXXIV that's a use full answer. I'm on standard injectors, no idea what they are. I've just put in a brand new Walbro fuel pump so that's all good. I'm aiming for around 300-320bhp with this.

Just been onto Dan at A-Plan and it's gonna cost me another £145 on my insurance when i get the new turbo and a remap as i'll be piling on about 100bhp. So i'm gonna be sitting around 300-320bhp. Sorry ballou i'll give it a miss mate. The injectors are the next step anyway.
fwiw I know the GTR one can handle it; maybe gtsts come with a lame fpr (or his was just knackered!).

Or getting it properly mapped means any fuel pressure rise due to higher flow pump is then 'mapped out'. I'd get a proper remap over an adjustable fpr, every time.
i fitted injectors with loads of spare capacity, but Rod at RB still advised fitting an adjustable regulater for the fine tuning, so i would say if you have chance of one for sensible money get one fitted, it cant do any ham, i ended up having to get RB to fit one and the fpr alone was £110+vat! (they only use tomei)
if your running a high pressure pump you do.
no you dont

keith didnt have one on his old 650bhp gtr engined gtst

if the injectors and pump are speced correctly then no
... but Rod at RB still advised fitting an adjustable regulater for the fine tuning...
Was that fine tuning of the invoice? ;)
Lol at Ru. Right thanks for all the input guys. I'm gonna get this turbo in then scrape some cash togeather for the remap and ask red dot what they'd like when they do the custom remap.
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