Is there any higher performing injectors for the WRX besides the STi?

Diversion · 08-22-2002, 05:18 AM

Is there a reason people use the STi injectors? Are there no other injectors out in the aftermarket that exceed the performance of 565cc of flow? How much WHP can be made from the STi injectors? When is it necessary to need higher than 565cc injectors?

Jay

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Pavlo · 08-22-2002, 08:23 AM

565cc per minute should be okay for about 400 crank (break) HP, on standard fuel pressure, which is 3 bar above manifold pressure. However the duty cycles will probably be higher than 85%, which is a nice number to stay below.

You can up the fuel pressure using an adjustable regulator to 4 bar above manifold, provided your fuel pump can keep up, which I doubt an sti one can. The 4 bar will give you another 15% flow, so they will flow like 650cc injectors, which should be enough for any power you are likely to get from 2litre with a VF series turbo.

If you find you want bigger injectors, you can use 740cc secondaries out of the twin turbo Mazda RX-7, which should fit straight into your current fuel rails. You can also fit injectors compatible with the later Nissan Skylines, you can get Nismo uprated ones in sizes up to about 1000cc per minute.

If you want wheel HP, take .75 of the crank hp for a reasoble estimate.

Paul

STi_Pete · 08-22-2002, 08:40 AM

lil easier than the last suggestion.....

Power Enterprises 650 drop in injectors...

morphgabbin · 08-22-2002, 09:04 AM

denzo makes 800cc for the WRX, but I think you need a stand alone to run them.

Pavlo · 08-22-2002, 09:10 AM

Well, I don't know what's hard about fitting skyline or rx-7 injectors, they drop straight in.

Might be harder to find some in the US. Here a set of injectors costs upwards of about £400 ($600 ish) new, whereas i can get RX-7 injectors for about £40 each from a Japanese car breakers yard.

I think the easiest thing would be a an adjustable fuel pressure regulator, and raise the fuel pressure to 4 bar above manifold pressure. Probably set you back about $120 US.

But as said above, you will need a different ECU. A S-AFC or something will sort of do it, but if you fool the ECU into think the airflow is different you will also advance the ignition. As the ECU uses airflow as a load measurement for the fuel and ignition maps, and as you would have to lean it out, it would think there was less load, so put on more advance. If you have already raised the boost you might be screwed.

Paul

alfriedesq · 08-22-2002, 09:28 AM

I'm working with PS right now to come up with some of the 650 injectors that have the spray turned 90 degrees so that you can use the stock WRX injector plug placement - critical for GDB's - but not so critical on GDA's

Anyway - in a few days I will have pricing and will post info on a gruop buy

TypeC · 08-22-2002, 12:54 PM

Quote:

Originally posted by Pavlo
565cc per minute should be okay for about 400 crank (break) HP

Several people have made 400+whp on the stock STi injectors. Cobb said they were finished at 420awhp (GDA too).

alfriedesq · 08-22-2002, 01:55 PM

Quote:

Originally posted by TypeC

Several people have made 400+whp on the stock STi injectors. Cobb said they were finished at 420awhp (GDA too).

Well - looking at some of my approx 360 - 380 wheel hp data logs I can see 130 % and 140 % duty cycles on the sti injectors at higher fuel pressure with Perrin rails

While this may actually work of c16 race fuel - - I'd say its less that ideal

My estimate is that the max safe hp for stock injectors si about 265 - 270 wheel hp

and 330 - 340 with sti injectors

Don't forget that on street fuel the WRX likes fairly rich a.f ratios which are hard to maintain at higher boost points without serious fuel supply

Tuning Factory Inc. · 08-22-2002, 02:18 PM

Power Enterprise has 650 and 800cc injectors depending on your needs.

Diversion · 08-22-2002, 07:45 PM

If you had a 500 horsepower turbo, what injectors would you want? I just want some injectors that will be good with any huge turbo and allow room for tons of power.. I'd hate to spend $400+ on STi injectors and not be able to use the full potential of any of the massive turbos.

Jay

rayder · 08-22-2002, 09:53 PM

Blitz will be releasing adapters that will fit their injectors to the WRX very shortly.

08-22-2002, 05:18 AM	#1
Diversion Scooby Specialist Member#: 18651 Join Date: May 2002 Chapter/Region: South East Location: Jacksonville, Florida Vehicle: 2009 370Z 6MT Brilliant Silver	Is there any higher performing injectors for the WRX besides the STi? Is there a reason people use the STi injectors? Are there no other injectors out in the aftermarket that exceed the performance of 565cc of flow? How much WHP can be made from the STi injectors? When is it necessary to need higher than 565cc injectors? Jay * Registered users of the site do not see these ads.

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08-22-2002, 08:23 AM	#2
Pavlo Scooby Specialist Member#: 23015 Join Date: Aug 2002 Location: Wellingborough, UK Vehicle: 95-> GC8 Black, blue and blue	565cc per minute should be okay for about 400 crank (break) HP, on standard fuel pressure, which is 3 bar above manifold pressure. However the duty cycles will probably be higher than 85%, which is a nice number to stay below. You can up the fuel pressure using an adjustable regulator to 4 bar above manifold, provided your fuel pump can keep up, which I doubt an sti one can. The 4 bar will give you another 15% flow, so they will flow like 650cc injectors, which should be enough for any power you are likely to get from 2litre with a VF series turbo. If you find you want bigger injectors, you can use 740cc secondaries out of the twin turbo Mazda RX-7, which should fit straight into your current fuel rails. You can also fit injectors compatible with the later Nissan Skylines, you can get Nismo uprated ones in sizes up to about 1000cc per minute. If you want wheel HP, take .75 of the crank hp for a reasoble estimate. Paul

08-22-2002, 08:40 AM	#3
STi_Pete Scooby Newbie Member#: 14576 Join Date: Jan 2002 Location: Long Island N.Y. Vehicle: 2002 WRX Sedan Silver	lil easier than the last suggestion..... Power Enterprises 650 drop in injectors...

08-22-2002, 09:04 AM	#4
morphgabbin Scooby Newbie Member#: 15466 Join Date: Feb 2002 Location: oh Vehicle: 2002 wrx silver	denzo makes 800cc for the WRX, but I think you need a stand alone to run them.

08-22-2002, 09:10 AM	#5
Pavlo Scooby Specialist Member#: 23015 Join Date: Aug 2002 Location: Wellingborough, UK Vehicle: 95-> GC8 Black, blue and blue	Well, I don't know what's hard about fitting skyline or rx-7 injectors, they drop straight in. Might be harder to find some in the US. Here a set of injectors costs upwards of about £400 ($600 ish) new, whereas i can get RX-7 injectors for about £40 each from a Japanese car breakers yard. I think the easiest thing would be a an adjustable fuel pressure regulator, and raise the fuel pressure to 4 bar above manifold pressure. Probably set you back about $120 US. But as said above, you will need a different ECU. A S-AFC or something will sort of do it, but if you fool the ECU into think the airflow is different you will also advance the ignition. As the ECU uses airflow as a load measurement for the fuel and ignition maps, and as you would have to lean it out, it would think there was less load, so put on more advance. If you have already raised the boost you might be screwed. Paul

08-22-2002, 09:28 AM	#6
alfriedesq Scooby Guru Member#: 6788 Join Date: May 2001 Location: Stamford, CT 06902 Vehicle: 2005 STI 10.9 @ 130	I'm working with PS right now to come up with some of the 650 injectors that have the spray turned 90 degrees so that you can use the stock WRX injector plug placement - critical for GDB's - but not so critical on GDA's Anyway - in a few days I will have pricing and will post info on a gruop buy

08-22-2002, 02:18 PM	#9
Tuning Factory Inc. Vendor Member#: 3600 Join Date: Jan 2001 Location: Detroit, Michigan, USA	Power Enterprise has 650 and 800cc injectors depending on your needs.

08-22-2002, 07:45 PM	#10
Diversion Scooby Specialist Member#: 18651 Join Date: May 2002 Chapter/Region: South East Location: Jacksonville, Florida Vehicle: 2009 370Z 6MT Brilliant Silver	If you had a 500 horsepower turbo, what injectors would you want? I just want some injectors that will be good with any huge turbo and allow room for tons of power.. I'd hate to spend $400+ on STi injectors and not be able to use the full potential of any of the massive turbos. Jay

08-22-2002, 09:53 PM	#11
rayder Scooby Specialist Member#: 14535 Join Date: Jan 2002 Location: SoCal Vehicle: 02 Impreza WRX Silver	Blitz will be releasing adapters that will fit their injectors to the WRX very shortly.