No, really? You think?
I don't know, companies these days, eh? Tschh.



[Edited by nom - 7/2/2003 12:02:18 AM]

 

The latest newsletter from MRT in Australia has this to say about increasing fuel pressure with an adjustable fuel pressure regulator ;-).


"A long known weakness of all WRX models is the standard fuel rail setup, which has long been a cause of melted pistons in Cylinder #2, as a result of running lean on modified cars. Many people and workshops believe that fitting an adjustable fuel pressure regulator will solve this, but it wont. The issue is not just fuel supply but the harmonics of the fuel pulses generated by the fuel pump. Higher pressure regulators simply mask the problem, and why fit one anyway, the Impreza has a rising rate fuel pressure regulator fitted as standard.

On the MY93-00 GC model we developed our own in house modification which solved the problem, although on MY01 GD model onwards, a more versatile solution was required (allowing standard injectors, larger STi units and longer, larger, aftermarket injectors to fit correctly). There were full details on our custom billet aluminium rail kit in last months newsletter (MRT Part no is MUSSE128-kit)."

Any opinions welcome :-))).

 

I think that most people are aware of this that have upped the power of their cars significantly. That's why a lot of people (heavily modified) haven't just fitted an adjustable fuel reg but have done the parallel feed modification to the fuel rails too.

Tony.

 

They also usually fit the pressure regulator along with an uprated fuel pump as the standard regulator has been known to give up the go if the fuel pressure is increased some what.

 

So whats the deal with the OEM rising rate regulator being sufficient? I still do not understand? Take the FSE adjustable fpr, for example, it is also a rising rate regulator but can be adjusted to hold more pressure than the OEM on idle or on boost!! So it will feed more fuel per minute through the same size injectors, right?

 

The OEM FPR cannot flow enough fuel when used with an uprated pump, thus the pump builds back pressure causing irregular/unstable fuel pressures.

Andrew...

 

I dont believe the harmonics ****..

If my fuel pressure stays as I wish then I dont care

David

 

The standard rising-rate regulator isn't very good... after fitting an uprated one, suddenly the ECU seems to be able to hit the same AFR every time - so a less overly-cautious mix can be used, so more safe power. We like.
Although that's 'overall'... I can see that it's quite possible/probably that with the standard serial set-up that some injectors will have a higher pressure than others, hence flow more, and the best FPR in the world can't fix that, whereas a parallel fuel feed could get much closer.
Not too sure what the MRT thingy's talking about though

 

Call me a cynic but I presume they have a larger profit margin with the "Custom billet aluminium rail kit".