B16fun

iTrader: (2)

Morning,
Could anyone advise if an adjustable static or an adjustable rising rate FPR is preferred?
Thanks,
Andy.

bludgod

iTrader: (3)

An adjustable FPR will allow your tuner to run your injectors a little more - but without tuning all it will do is rob you of power as the ECU is sending in too much fuel.

Ask your mapper which brands they find work best and get shopping

B16fun

iTrader: (2)

Hi mate,
Thanks for your reply. The car I am currently building is a track day toy and so I am adding all my mods before taking it to be mapped to suit everything, as such, I don't currently have a mapper.
I was wondering more if a static or rising rate fpr is better as I've spotted a competitively priced rising rate one from a well known manufacturer but before I buy it I wanted to see what the general thinking was in terms of if a rising rate is preferred or not.
Can anyone suggest a respected mapper in the greater Manchester area with me not currently having one?
Thanks,
Andy.

bludgod

iTrader: (3)

1:1 rising rate is what you're looking for then :

http://www.scoobyworld.co.uk/catalog...oducts_id=1854


http://www.rallysportdirect.com/Aero...sure-Regulator

or

http://www.advancedautomotives.com/f...uge-2004-p.asp

Try and get one with a gauge so you can set it up and adjust it properly - to little and the car will buck and shudder like driving on an empty tank, far too much and you'll be out of fuel by the time you get to the dyno

bludgod

iTrader: (3)

what's the full spec of the car anyway?

boosted

Static.
To understand this you must first understand the job of the fpr.
Static will keep the fuel pressure accross the injector constant.
To understand this you must understand boost and engjne vacuum in the manifold.
High vacuum the fpr will reduce fuel pressure by exactly the same amount of vacuum your running. Vice versa with boost.
If you set it at 3bar atmospheric (either with vac pipe off reg or the pump running with engine off) when your car makes 1 bar boost the fuel pressure will rise to 4 bar, exactly 3 bar above boot pressure, maintaining 3 bar accross the nozzle. Vice versa of you pull .8 bar vacuum the fpr will drop fuel pressure by same amount, so 2.2 bar rail or 3 bar accross the nozzle.
Rising rate will increase fuel pressure accross the nozzle by it's ratio. 1.5:1 for example. So if you set you atmospheric fuel pressure at 3 bar, when running 1 bar boost your rail pressure will be 4,5 bar, therefore the pressure accross the nozzle will be 3.5 bar, and rising at a rate of 1.5 the boost pressure. Not an easy thing to tune with, usually used as a cheap bodge on NA cars converted to turbo as a fuel enrichment aid.

bludgod

iTrader: (3)

yup - or if you need to poke a little more out of yours to smooth things up top. Don't forget as well the extra strain the higher pressure puts on your fuel rails and the fuel pump too.

I'd say it's OK if you had say 550's and you need 600's but not if you have 440's and need 1000's!

B16fun

iTrader: (2)

Some good replies there, thanks guys. I'll look for an adjustable static in that case.
The car isn't overly specced but it is a 2.0, currently standard turbo although I would like to go to a td05 18g, equal length tubular headers, decat up pipe 3" decat down pipe and system, 440cc injectors, fmic, 3 port bcs, 255lph pump and a panel filter.
I intend on getting it mapped to suit.
Cheers,
Andy.

bludgod

iTrader: (3)

with an 18g i'd say at least pickup the 550's as even with the FPR you'll be limited when on boost. remember 18psi on an 18g is way more air than 18g on your TD04 and all that air needs fuel.

B16fun

iTrader: (2)

Yeah, I know what you're saying. I'm keeping an eye out for some 550's at a reasonable price.

2pot

iTrader: (3)

Use 1:1 rising rate

Just to explain why: a static fpr can't maintain a constant pressure differential across the injector.

HTH