Hi all,

I'm not really clear on when an adjustable fuel pressure regulator is needed :

My planned mods on an 01 WRX :

TD04 Hybrid
STi TMIC
Decat apart from Ninja sportscat downpipe
Walbro 255L fuel pump
(Plus other stuff to make it stop and go round corners !)

Hopefully will achieve 320bhp +.

So, I believe the car has 380 injectors :

Do I need BOTH the adj pressure regulator and 440 injectors, only one of these, or neither ?

Cheers for any thoughts - even if you don't know but can tell me what you are running yourself !

Andy Mc

 

If you keep your standard 380cc injectors I think you will need a pressure regulator. I have one on my bugeye with identical spec list.

If you choose to upgrade injectors then most people go for STI pink injectors which are 500cc IIRC. The standard regulator will be OK if you go this way.

I would say you have more chance of making 320bhp if you upgrade your injectors. I'll be upgrading mine within the next month, so I can let you know!

 

i would change the injectors, you will want 440's at least to get 320bhp and they will still be good for a little buit more as well in the future, if your going to buy new though then get 550's.
An adjustable FPR isn't needed at this level of tune although the walbro is, spend the money elsewhere

 

Many thanks folks (plus Jason and Mark ).

 

Do 550s max out looking for a powerlevel of 450bhp?

 

Looking at 650cc or 740cc.

STI pink 505cc at regular pressure/550cc at increased fuel pressure injectors max out at about 370bhp at regular fuel pressure, with adjustable reg you will be on the limit about 400bhp-420bhp.

 

Allright I even thought that, but my injectors are 550s Phase 2 injectors, I think they are "real" 550s aren´t they?

 

Aren´t the phase2 550s "real" 550cc injectors?!

 

I always thought the newage injectors are 505cc and the classic phase 2 550cc, is that wrong?

 

Yes, Classic Phase 2 are 440 cc, they are yellow in colour, so are some after market 550 cc so i could understand your confusion.

 

Incidentally, I went for a Walbro and STi pink injectors - then found out that the injectors weren't needed for my Hybrid TD04 !

 

No , but you have made the right choice ...
Out of interest how much power are you making on your TD04 hybrid , I have seen 309 on a standard Td04 and this would have been approx 10% beyond what the 380's would flow...Sti pinks are always the easiest way to go and allow headroom for more power later...