2G Stock injectors enough?

[Dirtbike29]

I believe I have stock injectors (450cc) will that be sufficient enough to run the car with all the mods? I’m not trying to make power just drive normally.

Intake
Intercooler
Radiator
ARP head studs
Kiggy timing adjustment
Adjustable cam angle sensor
272 comp cams
AEM fuel pressure regulator
Boost controller
AEM x gauges AFR and boost
Intake manifold
Catch can
Injectors ?
Adjustable cam gears
Fixed HKS style wastegate
Bypass valve
1g throttle bodywork

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[pauleyman]

No. If you flow more air you need more fuel. It's that simple. If you're talking about just cruising around and no WOT yes that's fine.

 

[Stapl3]

Run it.

 

[Dirtbike29]

Run it.

I am going to I was reading different forms people just bumped the fpr up to 50-55 and got 380 wheel with stock 450cc

 

[CanadianTalonTC]

I am going to I was reading different forms people just bumped the fpr up to 50-55 and got 380 wheel with stock 450cc

Why would you go through all of the work to modify it and not get larger injectors? They are not even that expensive at all.

What are you doing for engine management?

 

[Kryndon]

What boost are you running and what type of 16G is that? You've got an external gate setup so I am assuming you're running at least 20 psi. Stock 450cc injectors on stock ECU with a 16G was boost cutting at 1.2 bar (~18psi) brick wall. I am assuming duty cycles were within the 90% range. My Passport G-Timer at the time with correct car specs inputted estimated 290 BHP not WHP, so you're not getting anywhere NEAR 380 whp with those.

I think your setup is already good enough for flow and to support the 16G that you will be hitting boost cut all the time and it will feel awful unless you purposefully run it at a ridiculously low pressure like 12 psi. But since you don't have an aftermarket ECU, you wont be able to tune bigger injectors so even if you get your WOT okay with some FPR adjustment, your idle and cruise/city driving will SUCK.

For the time being. lower your boost to just below where you get boost cut, and in the meanwhile look for an ECMLink V3. Trust me, this is on of the BEST most long-term mods you can do to a DSM.

 

[Justin DuBois]

Eh - that is so old school, you might as well be running an AFC, which is not on your list, but neither is an ECU mod to deal with all the mods.

I think upping the base fuel pressure to squeak out more HP is a stop gap measure, but if that is your jam - let the data tell you.

You need to know what your injector duty cycle is at your max boost at redline. Can you get that?

 

[Dirtbike29]

Why would you go through all of the work to modify it and not get larger injectors? They are not even that expensive at all.

What are you doing for engine management?

I purchased the car unfinished. Was told 750cc. just bolted in engine and trans I did everything else myself and I just finished it bought Tactrix to find out what I’m running it’s a GST black box ECU,

With ceddymods already half installed the tune is out of whack. I’m getting it tuned next Wednesday so it can idle with all the mods. I can later update the tune for bigger injectors easy

It had every thing in a box basically so I had no idea until yesterday what I had after I booked the tune thinking it was 750cc

What boost are you running and what type of 16G is that? You've got an external gate setup so I am assuming you're running at least 20 psi. Stock 450cc injectors on stock ECU with a 16G was boost cutting at 1.2 bar (~18psi) brick wall. I am assuming duty cycles were within the 90% range. My Passport G-Timer at the time with correct car specs inputted estimated 290 BHP not WHP, so you're not getting anywhere NEAR 380 whp with those.

I think your setup is already good enough for flow and to support the 16G that you will be hitting boost cut all the time and it will feel awful unless you purposefully run it at a ridiculously low pressure like 12 psi. But since you don't have an aftermarket ECU, you wont be able to tune bigger injectors so even if you get your WOT okay with some FPR adjustment, your idle and cruise/city driving will SUCK.

For the time being. lower your boost to just below where you get boost cut, and in the meanwhile look for an ECMLink V3. Trust me, this is on of the BEST most long-term mods you can do to a DSM.

I have Tactrix with GST black box ECU. It already had launch control with ceddymods installed on the ECU. I will be able to change the injector size and update the tune myself after I get a base map for the mods that I’m bringing it to a tuner that does DSM. I was planning to run extremely low boost as I will be daily driving it

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Eh - that is so old school, you might as well be running an AFC, which is not on your list, but neither is an ECU mod to deal with all the mods.

I think upping the base fuel pressure to squeak out more HP is a stop gap measure, but if that is your jam - let the data tell you.

You need to know what your injector duty cycle is at your max boost at redline. Can you get that?

I can do that sir I know it will be min 85% just to support the mods I have a 2018 WRX running 75 % duty it’s fine just keep the boost around stock levels to stop knocking. I have everything to do anything to the car just need some knowledge about what is bad for these cars.

 

[Justin DuBois]

I can do that sir I know it will be min 85% just to support the mods I have a 2018 wrx running 75 % duty it’s fine just keep the boost around stock levels to stop knocking I have everything to do anything to the car just need some knowledge about what is bad for these cars

With a boosted 4G63, octane is king - and E85 is race fuel. Don't skimp at the pump if you can get 94oct for street driving - get it, else 91oct is everywhere.

Run minimum boost until you have a handle on how the injectors are performing - and the Wideband is your friend. Target 10.7 AFR when WOT (safe rich), 14.7 AFR idle and light cruise.

You will eventually want to log some data, and find out what PSI boost you are hitting, What Knock you are detecting, and what injector duty cycle you are reaching.

 

[Dirtbike29]

With a boosted 4G63, octane is king - and E85 is race fuel. Don't skimp at the pump if you can get 94oct for street driving - get it, else 91oct is everywhere.

Run minimum boost until you have a handle on how the injectors are performing - and the Wideband is your friend. Target 10.7 AFR when WOT (safe rich), 14.7 AFR idle and light cruise.

You will eventually want to log some data, and find out what PSI boost you are hitting, What Knock you are detecting, and what injector duty cycle you are reaching.

I’m in Canada we have chevron 94 e0
And shell 93 e10 shell tested better all ways by local Subaru club the guys tuning it are in the local dsm group and have helped me build and wire im not to worried

 

[Justin DuBois]

I’m in Canada we have chevron 94 e0
And shell 93 e10 shell tested better all ways by local Subaru club the guys tuning it are in the local dsm group and have helped me build and wire im not to worried

Good - 94oct will make good power with good timing without knock, and you will be able to use the knock sensor to help you tune your setup. If you are detecting knock, you are running too much of something - Boost, Timing, or your AFR is too high.

 

[Dirtbike29]

Good - 94oct will make good power with good timing without knock, and you will be able to use the knock sensor to help you tune your setup. If you are detecting knock, you are running too much of something - Boost, Timing, or your AFR is too high.

What should I set my open pressure setting at if I’m running 12 psi on the boost gauge or is that figured out when on the dyno

 

[Justin DuBois]

What should I set my open pressure setting at if I’m running 12 psi on the boost gauge or is that figured out when on the dyno

You can setup the boost without a dyno. 12psi is good. I can't achieve less than 17psi at redline with the way my setup flows, so if your waste-gate can flow enough to get to 12 - that would be good.

Stock T25 would naturally fall off at higher RPM, and that is what you are setup for with stock injectors.

 

[import solutions]

Stock injectors are enough to handle a t25

 

[Justin DuBois]

Stock injectors are enough to handle a t25

Right - my point is the turbo on the car is not a T25. If it was, the stock injectors would be fine. The OP needs to keep the boost at minimum, as there is a built in limit with a T25 that does not exist here.

 

[Dirtbike29]

You can setup the boost without a dyno. 12psi is good. I can't achieve less than 17psi at redline with the way my setup flows, so if your waste-gate can flow enough to get to 12 - that would be good.

Stock T25 would naturally fall off at higher RPM, and that is what you are setup for with stock injectors.

My waste gate is currently open dump don’t even have a screamer pipe on it yet

Right - my point is the turbo on the car is not a T25. If it was, the stock injectors would be fine. The OP needs to keep the boost at minimum, as there is a built in limit with a T25 that does not exist here.

What should I gap my spark plugs at and what brand ngk?

 

[curt-s]

For a t25, ngk br6es or bpr6es. At this stage, either will work and are equal performance at that power level.
.028" gap will work fine

 

[Justin DuBois]

I run NGK-BPR7ES. Its a colder plug, and does not warm up as quick. Idle is a little less reliable until it warms up.

 

[Dirtbike29]

I run NGK-BPR7ES. Its a colder plug, and does not warm up as quick. Idle is a little less reliable until it warms up.

Okay so that’s what I have in the car I checked the gap it’s 0.28 and it explains why it runs better warmed