Increasing the fuel pressure on standard 380cc injectors with supporting mods such as: full de-cat, ported headers, front mount intercooler, k&n, parallel fuel mod, walbro pump, FPR, etc. All on an early WRX phase 1.... this is an initial step before new engine with bigger injectors much later in the future. Could this give 300 x 300, obviously with suitable ECU and Map?

Cheers,
Gaz

 

similar to my set up with apexi ecu unit, i have a v1 sti, but changed the inj to 440's

had an avcr installed and mapped and it runs around 310bhp-ive been told. altho i think the torque maybe a touch over optimistic? could be wrong.

waas told at that my inj and maf were maxed out

 

Cheers for the info jef..... i was trying to avoid changing the injectors at this stage is all. I know they will be maxxed out but was wondering if increasing the fuel pressure would give abit more head room. Didnt think of the maf sensor maxing out tho :S

Any mappers out there that can tell me if im being stupid or not whats the max that could be gotten with 380cc injectors in terms of BHP and torque? I know alot of people are probably thinking why not just change the injectors but Im just asking out of curiosity.

Thanks again,
Gaz

 

Not sure of this is 100% accurate or not but try here
Scoobypedia | Trusted knowledge for everything Subaru | Knowledge / Estimated Horse Power from Injectors

 

Thats a pretty good table, cheers for that! Thats the sort of thing I wanted to know, if its possible to give abit more head room using the 380 injectors just by increasing the fuel pressure and re-map.

Anyone know why that table only suggests 3.5bar fuel pressure?

 

Possibly to prevent the fuel pump killing itself. Unless you go for a external pump.

 

makes sense.... cheers for the replies

Gaz

 

Mine made 330/289 at standard fuel pressure on 380's. Injectors were maxed from circa 5K rpm IIRC.

 

micky, you're nuts with how far you take your mods lol

 

just to be on the safer side i would say 440cc would be better you can pick them up cheap as chips 80 for a set

 

Gaz don't spend all that money and scrimp on the most important part ??? fuelling ! Sure way to speed the process to a new engine IMHO.

c.£60 for a set of 440's £30 for an adaptor kit, if you really want to crank it up get these flowtested and increased to 860's IIRC by Lateral for £165. Leave the ported headers, and parallel fuel rails for now if cost is an issue. Don't faff about trying for 300/300 on 380's waste of time on all but the most optimistic of RR'ds

 

Why does the chart say 380s will only do 276bhp @100%? Did subaru really send out v2 STIs at 100%

 

was told you're better of to over-spec slightly, rather than run smaller injector/turbo/fuelling etc at their max..............

 

I'm mapped at 282bhp on 380cc. And if memory serves, max IDC is set at 98%. Boost is 1.3bar dropping to 1.1bar.

So the v.2 STi, being 275PS (271bhp) (@1.0-1.1bar I think), should have been okay.

 

Yeah, I had a v2 STI RA which has a few bits done then mapped on PFC and it felt a lot faster afterward but the mapper commented it was at 100% IDC.. just surprised that if 380s are virtually at max IDC at standard that anyone bothers. I know most figures are bull**** but there must be some gains, or are they all just through 'using' the fuel better i.e. better mapping?

I was just suprised that knowing how safe OEMs like to be they made cars that were that close to the limit.

 

my93 wrx , standard td05 turbo , ported headers ,decat straight through exhaust , free flowing air filter , standard ecu with scoobyecu fitted 1.2 bar boost , standard 380cc injectors , standard fuel pressure , run with a knocklink and air/fuel indicator was fine for the 8 years i had the car .

Mark

 

Yeah, I meant to add that ^^^ to my post too. I'm surprised that Subaru would choose to run injectors that close to their limits!

As you say, manufacturers normally build in more that adequate margins, so as to account for the most arduous of use... and to prevent a flood of warranty claims/complaints for, otherwise, broken engines!

 

Correct me if im wrong but i thought the early STI's had early 440's?? 440's you can fit to early classics with no adaptors?

 

Perhaps they did? Anyone?

I would think that's more likely, based on the reasoning above.

 

Ill let someone in the know confirm. Though im very sure there was V1 V2 yellow 440's, i was looking for a set a few weeks back and got offered both types, the later 440's (need the fitting collars for) are slighty better flowing so i opted for them and got a fitting kit.

 

I didn't realise ph.2 were "better flowing" than ph.1/1.5 ones!

I've got 550cc waiting to go in (with other mods obviously) - they're ph.2s too

 

Its only something iv read on here, so dont take it as gospel lol

Pretty sure im right with the early 440's, like i said i was offered both types after posting in the Wanted section



To the OP defo go with 440s, not really advisable running on 100%. Got mine for £70 delivered plus a fitting kit for £30. Then you could push to 300-320.

 

380's are fine for 300bhp. I've been running 303bhp / 290 ft/lbs for over a year now and the fuelling is fine. All I've got is full de-cat, Polar Performance chip, FMIC and a dawes device set to give me proper 1.1 bar of boost.

Edit: its a MY1995 WRX.

 

yellow 440's can be bought for p1-1.5 only the they go v2 which need the adaptor kit to be fitted for p1-1.5

hope this helps

 

I'm still running 2 pot OEM front brakes.

December 2006 I fitted my front mount, and my car has ran in this state of tune since.

I only fitted my Fuelab FPR in late 2008/early 2009, even then I only fitted it as I won it at SSO 2008; I wouldn't have bought it - have you seen how much they are from Lateral Performance

Phase 1.5 440cc injectors fit in the phase 1 rails. Adaptors are needed to fit phase 2 injectors.

Fairly sure no V1/V2(Phase 1) came with 440cc injectors, they were introduced with the V3(Phase 1.5). Happy to be corrected though.

 

380 Ph1 are single spray IIRC and Ph2 440's are Multi spray of sorts, finer fuel delivery atomisation bla bla bla, but yes I have read that too

Mine runs much better on 440's IDC aside, multi spray is better than single. 380's wouldn't be my choice regardless of what may or may not have been achieved.

 

You crank!


I recently got the 3-port from a US vendor on eBay - £107 without gauge. Gauge cost £20. But import costs/fees of the Fuelab came to £30 - so £157 all in - a saving of £33 over Marks. Marginally worth the hassle?


That's right.


That's what I thought too

 

all version 1/2 pre facelift imprezas ran 380cc injectors weather they were uk/wrx/sti or not.
version 3/4 sti ran 440 yellows and were a direct fitment to phase 1/1.5 fuel rails.
version5/56 imprezas ran 440s irrespective of weather they were uk,wrx,sti and need fuel rail collar adapters as they were were phase 2 engines.

 

That's exactly how I understood things too.

 

if it helps yellow 440s out of a 1998type r went straight into my 93wrx