Uprated fuelling questions - answers needed!

[lockwood77]

Hi all, I think I\'m going to upgrade my FD\'s fuelling in some way, as the current 421bhp is arriving courtesy of original injectors via an HKS FPR and an uprated (presumably! it\'s noisy...) fuel pump. I don\'t have a pressure gauge (although will probably fit one during this operation), but you have to guess it\'s running pretty high pressure through the stock injectors...

So, I have some questions about my options and what\'s required:

1. It seems the simple option is to change the secondary fuel rail and add 1680cc injectors. However, you can evidently also change the primary rail and use a variety of injectors, 850cc seeming to be the most common. As these things use enough fuel already, what benefits are gained from larger primaries and am I right in assuming fuel economy would suffer more than just upgrading the secondaries?

2. I have a mix of jubilee and (I presume) AN fittings on my fuel hoses. AN is clearly the way to go from what I\'ve read - am I likely to need any extra adaptors/mods other than the fittings themselves?

3. The KG Parts secondary rail states the necessity of removing the ACV - I\'m assuming that\'s academic on a single turbo car with no cat!?

4. Do I need anything other than the fuel rail and injectors (with suitable spacers by the look of things), as I already have the FPR and fuel pump?


I\'m hoping Pip will actually do the fitting as I\'m booked in for mapping on the 18th July anyway (new exhaust with optional wastegate plumbing should be on by then), but I want to make sure I\'ve selected the right option and got all the bits!

Thanks for your help guys, any tips appreciated!

[clive]

O/K lets see if we can help however i\'m sure Pip will have fitted many of these so he will know whats needed to fit this on for you,

You can fit the KG Parts rail and keep the  primarys stock however I have to think your already on 850 in the primarys and secondarys if you have this horsepower.

You say you have a bunch of fittings are these ones that came with the rail or what you already had ? , I ask because to keep the stock primary set up you really could do with the KG Parts adaptor that lets you keep the banjo fitting on the front of the secondary rail.

[lockwood77]

Hmm, that\'s a good question Clive - all I\'m referring to is what I can see with everything intact, where I can see the fuel hose has some jubilee clips but also an AN fitting for the FPR. I don\'t really know what I\'m looking at when it comes to the fuel rails, presumably I can\'t really see them without removing the plenum?

Interesting re: the 850s - again, presumably it\'s impossible to tell without removing stuff?

[clive]

If the secondary rail has already been changed you will see this looking into the front of the engine under the plenum but as you say without stripping the top plate off the primary\'s you won\'t know what injectors are underneath,

I will say though because this is a high pressure fuel system your dealing with and a leak could be disastrous it may be best if Pip sorted this all for you if your not 100% confident

Hope this helps

[lockwood77]

Thanks Clive. That\'s what I thought re: Pip, this is not something I want to play around with myself! Just need to make sure I\'ve got the right bits for him in time.

On the basis I may have 850 primaries already, sounds like just the secondary rail/injectors is the way forward. I did spot the primiary rail adaptor for the KG rail, which I\'ll make sure I have if that\'s the one I get.